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1
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Acquah C, Seth SK, Feng C, Jockusch S, Levi L, Falcón-Cruz NV, Li L, Crespo-Hernández CE. dTAT1: An Unnatural Nucleoside Exhibiting Low Photocytotoxicity for Genetic Code Expansion. J Phys Chem Lett 2025:5390-5397. [PMID: 40401918 DOI: 10.1021/acs.jpclett.5c00763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2025]
Abstract
Synthetic biology aims to expand the genetic code by increasing cellular information storage and retrieval. A recent advance is the dTAT1-dNaM unnatural base pair, which is more photo- and thermostable than dTPT3-dNaM while maintaining high efficiency and fidelity in vitro and in vivo. However, the photophysics and cytotoxicity behavior of dTAT1 under UV light have not been investigated. We demonstrate that dTAT1 populates the triplet state upon 390 nm excitation but exhibits minimal cytotoxicity in cells. Analysis of reactive oxygen species indicates that dTAT1 produces a low singlet oxygen quantum yield of 17% while it generates superoxide, a less harmful reactive oxygen species. Its triplet lifetime is 2.7 times shorter than that of dTPT3, contributing to its lower photocytotoxicity. These findings highlight the potential of dTAT1 for safe genetic code expansion and therapeutic applications, providing valuable insights for designing next-generation unnatural nucleosides with minimal impact on cellular health.
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Affiliation(s)
- Chris Acquah
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Sourav Kanti Seth
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Chuang Feng
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Steffen Jockusch
- Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Liraz Levi
- Celloram Inc., Cleveland, Ohio 44106, United States
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, United States
| | - Nitza V Falcón-Cruz
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Lingjun Li
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
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2
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Lever F, Picconi D, Mayer D, Ališauskas S, Calegari F, Düsterer S, Feifel R, Kuhlmann M, Mazza T, Metje J, Robinson MS, Squibb RJ, Trabattoni A, Ware M, Saalfrank P, Wolf TJA, Gühr M. Direct Observation of the ππ* to nπ* Transition in 2-Thiouracil via Time-Resolved NEXAFS Spectroscopy. J Phys Chem Lett 2025; 16:4038-4046. [PMID: 40232202 PMCID: PMC12035857 DOI: 10.1021/acs.jpclett.5c00544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2025] [Revised: 04/07/2025] [Accepted: 04/07/2025] [Indexed: 04/16/2025]
Abstract
The photophysics of nucleobases has been the subject of both theoretical and experimental studies over the past decades due to the challenges posed by resolving the steps of their radiationless relaxation dynamics, which cannot be described in the framework of the Born-Oppenheimer approximation (BOA). In this context, the ultrafast dynamics of 2-thiouracil has been investigated with a time-resolved NEXAFS study at the Free Electron Laser FLASH. Near Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS) can be used to observe electronic transitions in ultrafast molecular relaxation. We performed time-resolved UV-pump/X-ray probe absorption measurements at the sulfur 2s (L1) and 2p (L2/3) edges. We are able to identify absorption features corresponding to the S2 (ππ*) and S1 (nπ*) electronic states. We observe a delay of 102 ± 11 fs in the population of the nπ* state with respect to the initial optical excitation and interpret the delay as the time scale for the S2 → S1 internal conversion. We furthermore identify oscillations in the absorption signal that match a similar observation in our previous X-ray photoelectron spectroscopy study on the same molecule.
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Affiliation(s)
- Fabiano Lever
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
| | - David Picconi
- Heinrich-Heine
University, Düsseldorf, 40225, Germany
| | - Dennis Mayer
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
| | | | - Francesca Calegari
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
- The
Hamburg Centre for Ultrafast Imaging, Hamburg, 20148, Germany
| | - Stefan Düsterer
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
| | | | - Marion Kuhlmann
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
| | | | - Jan Metje
- University
of Potsdam, Potsdam, 14469, Germany
| | - Matthew S. Robinson
- The
Hamburg Centre for Ultrafast Imaging, Hamburg, 20148, Germany
- European
XFEL, Schenefeld, 22869, Germany
| | | | - Andrea Trabattoni
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
- Leibniz
University Hannover, Hannover, 30060, Germany
| | - Matthew Ware
- Stanford
PULSE Institute, SLAC National Accelerator Laboratory, Stanford, California 94305, United States
| | | | - Thomas J. A. Wolf
- Stanford
PULSE Institute, SLAC National Accelerator Laboratory, Stanford, California 94305, United States
| | - Markus Gühr
- Deutsches
Elektronen-Synchrotron DESY, Hamburg, 22607, Germany
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3
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Jahnke T, Mai S, Bhattacharyya S, Chen K, Boll R, Castellani ME, Dold S, Frühling U, Green AE, Ilchen M, Ingle R, Kastirke G, Lam HVS, Lever F, Mayer D, Mazza T, Mullins T, Ovcharenko Y, Senfftleben B, Trinter F, Atia-Tul-Noor, Usenko S, Venkatachalam AS, Rudenko A, Rolles D, Meyer M, Ibrahim H, Gühr M. Direct observation of ultrafast symmetry reduction during internal conversion of 2-thiouracil using Coulomb explosion imaging. Nat Commun 2025; 16:2074. [PMID: 40021641 PMCID: PMC11871051 DOI: 10.1038/s41467-025-57083-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2024] [Accepted: 02/06/2025] [Indexed: 03/03/2025] Open
Abstract
The photochemistry of heterocyclic molecules plays a decisive role for processes and applications like DNA photo-protection from UV damage and organic photocatalysis. The photochemical reactivity of heterocycles is determined by the redistribution of photoenergy into electronic and nuclear degrees of freedom, initially involving ultrafast internal conversion. Most heterocycles are planar in their ground state and internal conversion requires symmetry breaking. To lower the symmetry, the molecule must undergo an out-of-plane motion, which has not yet been observed directly. Here we show using the example of 2-thiouracil, how Coulomb explosion imaging can be utilized to extract comprehensive information on this molecular deformation, linking the extracted deplanarization of the molecular geometry to the previously studied temporal evolution of its electronic properties. Particularly, the protons of the exploded molecule are well-suited messengers carrying rich information on its geometry at distinct times after electronic excitation. We expect that our new analysis approach centered on these peripheral protons can be adapted as a general concept for future time-resolved studies of complex molecules in the gas phase.
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Affiliation(s)
- Till Jahnke
- Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
- European XFEL, Schenefeld, Germany.
| | - Sebastian Mai
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | | | - Keyu Chen
- James R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas, USA
| | | | - Maria Elena Castellani
- Clinical Pharmacology Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | | | | | - Alice E Green
- European XFEL, Schenefeld, Germany
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California, USA
| | - Markus Ilchen
- European XFEL, Schenefeld, Germany
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Rebecca Ingle
- Department of Chemistry, University College London, London, UK
| | | | - Huynh Van Sa Lam
- James R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas, USA
| | - Fabiano Lever
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Dennis Mayer
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | | | | | | | | | - Florian Trinter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - Atia-Tul-Noor
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | | | | | - Artem Rudenko
- James R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas, USA
| | - Daniel Rolles
- James R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas, USA
| | | | - Heide Ibrahim
- Advanced Laser Light Source @ INRS, Centre Énergie, Matériaux et Télécommunications, Québec, Canada
- Department of Physics, University of Ottawa, Ottawa, ON, Canada
| | - Markus Gühr
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Institute of Physical Chemistry, Universität Hamburg, Hamburg, Germany.
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4
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Park JW. Analytical nuclear gradient and derivative coupling theories for multireference perturbation methods. Phys Chem Chem Phys 2025; 27:3531-3551. [PMID: 39895376 DOI: 10.1039/d4cp03671a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2025]
Abstract
Electron correlations should be appropriately included in quantum chemistry calculations to accurately describe the energy and wave functions. In multiconfigurational methods, the reference functions are written as linear combinations of multiple electronic configurations to describe static correlations. Using the multiconfigurational reference functions, it is also possible to correct for dynamical correlations using various methods. Geometry optimizations and dynamics simulations are among the most prominent applications of quantum chemistry methods. Such applications become much more straightforward when analytical nuclear gradients are available. Many efficient algorithms for computing analytical nuclear gradients and derivative coupling using multireference perturbation theories (MRPTs) have recently been developed. This work aims to provide a comprehensive and easy-to-follow review of analytical gradient theories and the properties of methods for obtaining analytical gradients and derivative coupling methods using MRPTs. We also briefly review the practical applications of these methods in performing nonadiabatic dynamics simulations.
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Affiliation(s)
- Jae Woo Park
- Department of Chemistry, Chungbuk National University (CBNU), Cheongju 28644, Korea.
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5
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Chen Z, Qin C, Wang X, Pan H, Chen J. Ultrafast Intersystem Crossing in Naturally Occurring Plant Pigments 5-Hydroxyflavones under Direct UV Excitation. J Phys Chem Lett 2025; 16:1184-1190. [PMID: 39848923 DOI: 10.1021/acs.jpclett.5c00052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2025]
Abstract
Flavonoids, a group of natural pigments, have attracted notable attention for their intrinsic fluorescent bioactive properties and potential therapeutic implications. Recent studies have suggested that the photoexcitation of specific flavonoids can also lead to the formation of triplet states, thereby potentially enhancing their applications in photoactivated antioxidant mechanisms. However, the crucial mechanism details about triplet state formation are still poorly understood. In this Letter, the ultrafast excited state relaxation mechanism for a series of 5-hydroxyflavone derivatives was studied by femtosecond time-resolved spectroscopy combined with quantum chemical calculations. Our results reveal the ultrafast ISC (kISC ≈ 1011 s-1) channel, which is sensitive to molecular structure and solvent environment, in 5-hydroxyflavones for the first time. Notably, the triplet excited state quantum yield of 4',7-dimethoxy-5-hydroxyflavone can reach up to 8% in acetonitrile solution. These results are essential for understanding the triplet state generation mechanism in 5-hydroxyflavone derivatives and could help the further development of 5-hydroxyflavone scaffold antioxidant agents.
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Affiliation(s)
- Ziwei Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Chen Qin
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- Key Laboratory of Mineral Luminescent Material and Microstructure of Xinjiang, School of Physics and Electronic Engineering, Xinjiang Normal University, Urumqi 830054, China
| | - Xueli Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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6
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Sun Q, Brédas JL, Coropceanu V. Light-Induced Ring-to-Chain Transformations of Elemental Sulfur: Nonadiabatic Dynamics Simulations. J Phys Chem Lett 2024; 15:9920-9925. [PMID: 39303217 DOI: 10.1021/acs.jpclett.4c02475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
The emergence of high-sulfur content polymeric materials and their diverse applications underscore the need for a comprehensive understanding of the ring-to-chain transformation of elemental sulfur. In this study, we delve into the ultrafast transformation of the elemental sulfur S8 ring upon photoexcitation employing advanced nonadiabatic dynamics simulations. Our findings reveal that the bond breaking of the S8 ring occurs within tens of femtoseconds. At the time of bond breaking, most molecules are in the lowest singlet excited state S1. S1 survives for 40-450 fs before relaxing to the quasi-degenerate manifolds formed by the T1 and S0 states of the S8 chain. This suggests that upon photoexcitation the polymerization of the S8 chains might proceed before the chains relax to their lowest energy states. The derived temporal resolution provides a detailed perspective on the dynamics of S8 rings upon photoexcitation, shedding light on the intricate processes involved in its excited-state transformations.
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Affiliation(s)
- Qi Sun
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, United States
| | - Jean-Luc Brédas
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, United States
| | - Veaceslav Coropceanu
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, Arizona 85721-0041, United States
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7
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Mausenberger S, Müller C, Tkatchenko A, Marquetand P, González L, Westermayr J. SpaiNN: equivariant message passing for excited-state nonadiabatic molecular dynamics. Chem Sci 2024:d4sc04164j. [PMID: 39282652 PMCID: PMC11391904 DOI: 10.1039/d4sc04164j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Accepted: 09/01/2024] [Indexed: 09/19/2024] Open
Abstract
Excited-state molecular dynamics simulations are crucial for understanding processes like photosynthesis, vision, and radiation damage. However, the computational complexity of quantum chemical calculations restricts their scope. Machine learning offers a solution by delivering high-accuracy properties at lower computational costs. We present SpaiNN, an open-source Python software for ML-driven surface hopping nonadiabatic molecular dynamics simulations. SpaiNN combines the invariant and equivariant neural network architectures of SchNetPack with SHARC for surface hopping dynamics. Its modular design allows users to implement and adapt modules easily. We compare rotationally-invariant and equivariant representations in fitting potential energy surfaces of multiple electronic states and properties arising from the interaction of two electronic states. Simulations of the methyleneimmonium cation and various alkenes demonstrate the superior performance of equivariant SpaiNN models, improving accuracy, generalization, and efficiency in both training and inference.
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Affiliation(s)
- Sascha Mausenberger
- Faculty of Chemistry, Institute of Theoretical Chemistry, University of Vienna Währinger Str. 17 1090 Vienna Austria
- Vienna Doctoral School in Chemistry (DosChem), University of Vienna Währinger Straße 42 1090 Vienna Austria
| | - Carolin Müller
- Department Chemistry and Pharmacy, Computer-Chemistry-Center, Friedrich-Alexander-Universität Erlangen-Nürnberg Nägelsbachstraße 25 91052 Erlangen Germany
- Department of Physics and Materials Science, University of Luxembourg 162 A, Avenue de la Faïencerie L-1511 Luxembourg Luxembourg
| | - Alexandre Tkatchenko
- Department of Physics and Materials Science, University of Luxembourg 162 A, Avenue de la Faïencerie L-1511 Luxembourg Luxembourg
| | - Philipp Marquetand
- Faculty of Chemistry, Institute of Theoretical Chemistry, University of Vienna Währinger Str. 17 1090 Vienna Austria
| | - Leticia González
- Faculty of Chemistry, Institute of Theoretical Chemistry, University of Vienna Währinger Str. 17 1090 Vienna Austria
| | - Julia Westermayr
- Wilhelm Ostwald Institute for Physical and Theoretical Chemistry, Leipzig University Linnéstraße 2 04103 Leipzig Germany
- Center for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI) Dresden/Leipzig Germany
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8
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Loreti A, Freixas VM, Avagliano D, Segatta F, Song H, Tretiak S, Mukamel S, Garavelli M, Govind N, Nenov A. WFOT: A Wave Function Overlap Tool between Single- and Multi-Reference Electronic Structure Methods for Spectroscopy Simulation. J Chem Theory Comput 2024; 20:4804-4819. [PMID: 38828948 DOI: 10.1021/acs.jctc.4c00310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
We report the development of a novel diagnostic tool, named wave function overlap tool (WFOT), designed to evaluate the overlap between wave functions computed at single-reference [i.e., time-dependent density functional theory or configuration interaction singles (CIS)] and multireference (i.e., CASSCF/CASPT2) electronic structure levels of theory. It relies on truncating the single- and multireference WFs to CIS-like expansions spanning the same configurational space and maximizing the molecular orbital overlap by means of a unitary transformation. To demonstrate the functionality of the tool, we calculate the transient spectrum of acetylacetone by evaluating excited state absorption signals with multireference quality on top of single-reference on-the-fly dynamics simulations. Semiautomatic spectra generation is facilitated by interfacing the tool with the COBRAMM package, which also allows one to use WFOT with several quantum chemistry codes such as Gaussian, NWChem, and OpenMolcas. Other exciting possibilities for the utilization of the code beyond the simulation of transient absorption spectroscopy are eventually discussed.
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Affiliation(s)
- Alessandro Loreti
- Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
| | - Victor Manuel Freixas
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Davide Avagliano
- Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
| | - Francesco Segatta
- Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
| | - Huajing Song
- Physics and Chemistry of Materials, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Physics and Chemistry of Materials, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
| | - Niranjan Govind
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Artur Nenov
- Dipartimento di Chimica Industriale "Toso Montanari", University of Bologna, Via Piero Gobetti 85, Bologna 40129, Italy
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9
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Liu S, Lee Y, Chen L, Deng J, Ma T, Barbatti M, Bai S. Unexpected longer T 1 lifetime of 6-sulfur guanine than 6-selenium guanine: the solvent effect of hydrogen bonds to brake the triplet decay. Phys Chem Chem Phys 2024; 26:13965-13972. [PMID: 38669188 PMCID: PMC11078201 DOI: 10.1039/d4cp00875h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/14/2024] [Indexed: 04/28/2024]
Abstract
The decay of the T1 state to the ground state is an essential property of photosensitizers because it decides the lifetime of excited states and, thus, the time window for sensitization. The sulfur/selenium substitution of carbonyl groups can red-shift absorption spectra and enhance the triplet yield because of the large spin-orbit coupling, modifying nucleobases to potential photosensitizers for various applications. However, replacing sulfur with selenium will also cause a much shorter T1 lifetime. Experimental studies found that the triplet decay rate of 6-seleno guanine (6SeGua) is 835 times faster than that of 6-thio guanine (6tGua) in aqueous solution. In this work, we reveal the mechanism of the T1 decay difference between 6SeGua and 6tGua by computing the activation energy and spin-orbit coupling for rate calculation. The solvent effect of water is treated with explicit microsolvation and implicit solvent models. We find that the hydrogen bond between the sulfur atom of 6tGua and the water molecule can brake the triplet decay, which is weaker in 6SeGua. This difference is crucial to explain the relatively long T1 lifetime of 6tGua in an aqueous solution. This insight emphasizes the role of solvents in modulating the excited state dynamics and the efficiency of photosensitizers, particularly in aqueous environments.
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Affiliation(s)
- Shaoting Liu
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Yuhsuan Lee
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingfang Chen
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingheng Deng
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Tongmei Ma
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, China.
| | - Mario Barbatti
- Aix Marseille University, CNRS, ICR, 13397 Marseille, France.
- Institut Universitaire de France, Paris 75231, France
| | - Shuming Bai
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
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10
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Jaiswal VK, Montorsi F, Aleotti F, Segatta F, Keefer D, Mukamel S, Nenov A, Conti I, Garavelli M. Ultrafast photochemistry and electron-diffraction spectra in n → (3s) Rydberg excited cyclobutanone resolved at the multireference perturbative level. J Chem Phys 2024; 160:164316. [PMID: 38686819 DOI: 10.1063/5.0203624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/10/2024] [Indexed: 05/02/2024] Open
Abstract
We study the ultrafast time evolution of cyclobutanone excited to the singlet n → Rydberg state through non-adiabatic surface-hopping simulationsperformed at extended multi-state complete active space second-order perturbation (XMS-CASPT2) level of theory. These dynamics predict relaxation to the ground-state with a timescale of 822 ± 45 fs with minimal involvement of the triplets. The major relaxation path to the ground-state involves a three-state degeneracy region and leads to a variety of fragmented photoproducts. We simulate the resulting time-resolved electron-diffraction spectra, which track the relaxation of the excited state and the formation of various photoproducts in the ground state.
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Affiliation(s)
- V K Jaiswal
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - F Montorsi
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - F Aleotti
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - F Segatta
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Daniel Keefer
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Mainz 55128, Germany
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics and Astronomy, University of California Irvine, Irvine, California 92697, USA
| | - A Nenov
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - I Conti
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - M Garavelli
- Dipartimento di Chimica industriale "Toso Montanari," Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
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11
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Navarrete-Miguel M, Giussani A, Rubio M, Boggio-Pasqua M, Borin AC, Roca-Sanjuán D. Quantum-Chemistry Study of the Photophysical Properties of 4-Thiouracil and Comparisons with 2-Thiouracil. J Phys Chem A 2024; 128:2273-2285. [PMID: 38504122 PMCID: PMC10982997 DOI: 10.1021/acs.jpca.3c06310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/16/2024] [Accepted: 03/03/2024] [Indexed: 03/21/2024]
Abstract
DNA in living beings is constantly damaged by exogenous and endogenous agents. However, in some cases, DNA photodamage can have interesting applications, as it happens in photodynamic therapy. In this work, the current knowledge on the photophysics of 4-thiouracil has been extended by further quantum-chemistry studies to improve the agreement between theory and experiments, to better understand the differences with 2-thiouracil, and, last but not least, to verify its usefulness as a photosensitizer for photodynamic therapy. This study has been carried out by determining the most favorable deactivation paths of UV-vis photoexcited 4-thiouracil by means of the photochemical reaction path approach and an efficient combination of the complete-active-space second-order perturbation theory//complete-active-space self-consistent field (CASPT2//CASSCF), (CASPT2//CASPT2), time-dependent density functional theory (TDDFT), and spin-flip TDDFT (SF-TDDFT) methodologies. By comparing the data computed herein for both 4-thiouracil and 2-thiouracil, a rationale is provided on the relatively higher yields of intersystem crossing, triplet lifetime and singlet oxygen production of 4-thiouracil, and the relatively higher yield of phosphorescence of 2-thiouracil.
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Affiliation(s)
- Miriam Navarrete-Miguel
- Instituto
de Ciencia Molecular, Universitat de València, P.O. Box 22085, ES-46071 Valencia, Spain
| | - Angelo Giussani
- Instituto
de Ciencia Molecular, Universitat de València, P.O. Box 22085, ES-46071 Valencia, Spain
| | - Mercedes Rubio
- Departament
de Química Física, Universitat
de València, 46100 Burjassot, Spain
| | - Martial Boggio-Pasqua
- Laboratoire
de Chimie et Physique Quantiques, IRSAMC,
CNRS et Université Toulouse 3, 118 route de Narbonne, 31062 Toulouse, France
| | - Antonio Carlos Borin
- Department
of Fundamental Chemistry, Institute of Chemistry,
University of São Paulo, Av. Prof. Lineu Prestes, 748, São Paulo CEP 05508-000, Brazil
| | - Daniel Roca-Sanjuán
- Instituto
de Ciencia Molecular, Universitat de València, P.O. Box 22085, ES-46071 Valencia, Spain
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12
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Chang XP, Wang JL, Peng LY, Cen XJ, Yin BW, Xie BB. Mechanistic photophysics of tellurium-substituted cytosine: Electronic structure calculations and nonadiabatic dynamics simulations. Photochem Photobiol 2024; 100:339-354. [PMID: 37435854 DOI: 10.1111/php.13835] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/24/2023] [Accepted: 06/26/2023] [Indexed: 07/13/2023]
Abstract
Previously, the MS-CASPT2 method was performed to study the static and qualitative photophysics of tellurium-substituted cytosine (TeC). To get quantitative information, we used our recently developed QTMF-FSSH dynamics method to simulate the excited-state decay of TeC. The CASSCF method was adopted to reduce the calculation costs, which was confirmed to provide reliable structures and energies as those of MS-CASPT2. A detailed structural analysis showed that only 5% trajectories will hop to the lower triplet or singlet state via the twisted (S2 /S1 /T2 )T intersection, while 67% trajectories will choose the planar intersections of (S2 /S1 /T3 /T2 /T1 )P and (S2 /S1 /T2 /T1 )P but subsequently become twisted in other electronic states. By contrast, ~28% trajectories will maintain in a plane throughout dynamics. Electronic population revealed that the S2 population will ultrafast transfer to the lower triplet or singlet state. Later, the TeC system will populate in the spin-mixed electronic states composed of S1 , T1 and T2 . At the end of 300 fs, most trajectories (~74%) will decay to the ground state and only 17.4% will survive in the triplet states. Our dynamics simulation verified that tellurium substitution will enhance the intersystem crossings, but the very short triplet lifetime (ca. 125 fs) will make TeC a less effective photosensitizer.
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Affiliation(s)
- Xue-Ping Chang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, China
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang, China
| | - Jie-Lei Wang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, China
| | - Ling-Ya Peng
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Xu-Jiang Cen
- Ningbo Zhongtian Engineering Co., Ltd., Ningbo, China
| | - Bo-Wen Yin
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, China
| | - Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, China
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13
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Mayer D, Lever F, Gühr M. Time-resolved x-ray spectroscopy of nucleobases and their thionated analogs. Photochem Photobiol 2024; 100:275-290. [PMID: 38174615 DOI: 10.1111/php.13903] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/05/2024]
Abstract
The photoinduced relaxation dynamics of nucleobases and their thionated analogs have been investigated extensively over the past decades motivated by their crucial role in organisms and their application in medical and biochemical research and treatment. Most of these studies focused on the spectroscopy of valence electrons and fragmentation. The advent of ultrashort x-ray laser sources such as free-electron lasers, however, opens new opportunities for studying the ultrafast molecular relaxation dynamics utilizing the site- and element-selectivity of x-rays. In this review, we want to summarize ultrafast experiments on thymine and 2-thiouracil performed at free-electron lasers. We performed time-resolved x-ray absorption spectroscopy at the oxygen K-edge after UV excitation of thymine. In addition, we investigated the excited state dynamics of 2-tUra via x-ray photoelectron spectroscopy at sulfur. For these methods, we show a strong sensitivity to the electronic state or charge distribution, respectively. We also performed time-resolved Auger-Meitner spectroscopy, which shows spectral shifts associated with internuclear distances close to the probed site. We discuss the complementary aspects of time-resolved x-ray spectroscopy techniques compared to optical and UV spectroscopy for the investigation of ultrafast relaxation processes.
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Affiliation(s)
- Dennis Mayer
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Fabiano Lever
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Markus Gühr
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Institute of Physical Chemistry, University of Hamburg, Hamburg, Germany
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14
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Asplund M, Koga M, Wu YJ, Neumark DM. Time-resolved photoelectron spectroscopy of iodide-4-thiouracil cluster: The ππ* state as a doorway for electron attachment. J Chem Phys 2024; 160:054301. [PMID: 38299627 DOI: 10.1063/5.0187557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
The photophysics of thiobases-nucleobases in which one or more oxygen atoms are replaced with sulfur atoms- vary greatly depending on the location of sulfonation. Not only are direct dynamics of a neutral thiobase impacted, but also the dynamics of excess electron accommodation. In this work, time-resolved photoelectron spectroscopy is used to measure binary anionic clusters of iodide and 4-thiouracil, I- · 4TU. We investigate charge transfer dynamics driven by excitation at 3.88 eV, corresponding to the lowest ππ* transition of the thiouracil, and at 4.16 eV, near the cluster vertical detachment energy. The photoexcited state dynamics are probed by photodetachment with 1.55 and 3.14 eV pulses. Excitation at 3.88 eV leads to a signal from a valence-bound ion only, indicating a charge accommodation mechanism that does not involve a dipole-bound anion as an intermediate. Excitation at 4.16 eV rapidly gives rise to dipole-bound and valence-bound ion signals, with a second rise in the valence-bound signal corresponding to the decay of the dipole-bound signal. The dynamics associated with the low energy ππ* excitation of 4-thiouracil provide a clear experimental proof for the importance of localized excitation and electron backfilling in halide-nucleobase clusters.
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Affiliation(s)
- Megan Asplund
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Masafumi Koga
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Ying Jung Wu
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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15
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Jing WQ, Sun ZP, Zhao SF, Shu CC. Unveiling Coherent Control of Halomethane Dissociation Induced by a Single Strong Ultraviolet Pulse. J Phys Chem Lett 2023; 14:11305-11312. [PMID: 38064196 DOI: 10.1021/acs.jpclett.3c03143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
We present a theoretical investigation into the coherent control of photodissociation reactions in halomethanes, specifically focusing on CH2BrCl by manipulating the spectral phase of a single femtosecond laser pulse. We examine the photodissociation of CH2BrCl under an ultrashort pulse with a quadratic spectral phase and reveal the sensitivity of both the total dissociation probability and the resulting radical products (Br+CH2Cl and Cl+CH2Br) to chirp rates. To gain insights into the underlying mechanism, we calculate the population distributions of excited vibrational states in the ground electronic state, demonstrating the occurrence of resonance Raman scattering (RRS) in the strong-field limit regime. By utilizing chirped pulses, we show that this RRS phenomenon can be suppressed and even eliminated through quantum destructive interference. This highlights the high sensitivity of photodissociation into Cl+CH2Br to the spectral phase, showcasing a phenomenon that goes beyond the traditional one-photon photodissociation of isolated molecules in the weak-field limit regime. These findings emphasize the importance of coherent control in the exploration and utilization of photodissociation in polyatomic molecules, paving the way for new advancements in chemical physics and femtochemistry.
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Affiliation(s)
- Wen-Quan Jing
- College of Physics and Electronic Engineering, Northwest Normal University, Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, Lanzhou 730070, China
- Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics, Central South University, Changsha 410083, China
| | - Zhao-Peng Sun
- Institute of Theoretical Physics, School of Physics and Optoelectric Engineering, Ludong University, Yantai 264025, China
| | - Song-Feng Zhao
- College of Physics and Electronic Engineering, Northwest Normal University, Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, Lanzhou 730070, China
| | - Chuan-Cun Shu
- Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics, Central South University, Changsha 410083, China
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16
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Xie M, Ren SX, Hu D, Zhong JM, Luo J, Tan Y, Li YP, Si LP, Cao J. The impact of the chalcogen-substitution element and initial spectroscopic state on excited-state relaxation pathways in nucleobase photosensitizers: a combination of static and dynamic studies. Phys Chem Chem Phys 2023; 25:27756-27765. [PMID: 37814579 DOI: 10.1039/d3cp03730d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
The substitution of oxygen with chalcogen in carbonyl group(s) of canonical nucleobases gives an impressive triplet generation, enabling their promising applications in medicine and other emerging techniques. The excited-state relaxation S2(ππ*) → S1(nπ*) → T1(ππ*) has been considered the preferred path for triplet generation in these nucleobase derivatives. Here, we demonstrate enhanced quantum efficiency of direct intersystem crossing from S2 to triplet manifold upon substitution with heavier chalcogen elements. The excited-state relaxation dynamics of sulfur/selenium substituted guanines in a vacuum is investigated using a combination of static quantum chemical calculations and on-the-fly excited-state molecular dynamics simulations. We find that in sulfur-substitution the S2 state predominantly decays to the S1 state, while upon selenium-substitution the S2 state deactivation leads to simultaneous population of the S1 and T2,3 states in the same time scale and multi-state quasi-degeneracy region S2/S1/T2,3. Interestingly, the ultrafast deactivation of the spectroscopic S3 state of both studied molecules to the S1 state occurs through a successive S3 → S2 → S1 path involving a multi-state quasi-degeneracy S3/S2/S1. The populated S1 and T2 states will cross the lowest triplet state, and the S1 → T intersystem crossing happens in a multi-state quasi-degeneracy region S1/T2,3/T1 and is accelerated by selenium-substitution. The present study reveals the influence of both the chalcogen substitution element and initial spectroscopic state on the excited-state relaxation mechanism of nucleobase photosensitizers and also highlights the important role of multi-state quasi-degeneracy in mediating the complex relaxation process. These theoretical results provide additional insights into the intrinsic photophysics of nucleobase-based photosensitizers and are helpful for designing novel photo-sensitizers for real applications.
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Affiliation(s)
- Min Xie
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Shuang-Xiao Ren
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Die Hu
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Ji-Meng Zhong
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Jie Luo
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Yin Tan
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Yan-Ping Li
- School of Medicine, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Li-Ping Si
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
| | - Jun Cao
- School of Materials Science and Hydrogen Energy & Guangdong Key Laboratory for Hydrogen Energy Technologies, Foshan University, Foshan, Guangdong, 528000, P. R. China
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang, Guizhou, 550018, P. R. China.
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17
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Shu Y, Zhang L, Wu D, Chen X, Sun S, Truhlar DG. New Gradient Correction Scheme for Electronically Nonadiabatic Dynamics Involving Multiple Spin States. J Chem Theory Comput 2023; 19:2419-2429. [PMID: 37079755 DOI: 10.1021/acs.jctc.2c01173] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
It has been recommended that the best representation to use for trajectory surface hopping (TSH) calculations is the fully adiabatic basis in which the Hamiltonian is diagonal. Simulations of intersystem crossing processes with conventional TSH methods require an explicit computation of nonadiabatic coupling vectors (NACs) in the molecular-Coulomb-Hamiltonian (MCH) basis, also called the spin-orbit-free basis, in order to compute the gradient in the fully adiabatic basis (also called the diagonal representation). This explicit requirement destroys some of the advantages of the overlap-based algorithms and curvature-driven algorithms that can be used for the most efficient TSH calculations. Therefore, although these algorithms allow one to perform NAC-free simulations for internal conversion processes, one still requires NACs for intersystem crossing. Here, we show that how the NAC requirement is circumvented by a new computation scheme called the time-derivative-matrix scheme.
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Affiliation(s)
- Yinan Shu
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Linyao Zhang
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Dihua Wu
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Xiye Chen
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Shaozeng Sun
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Donald G Truhlar
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
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18
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Ultrafast Photo-Ion Probing of the Relaxation Dynamics in 2-Thiouracil. Molecules 2023; 28:molecules28052354. [PMID: 36903604 PMCID: PMC10005304 DOI: 10.3390/molecules28052354] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/19/2023] [Accepted: 02/20/2023] [Indexed: 03/08/2023] Open
Abstract
In this work, we investigate the relaxation processes of 2-thiouracil after UV photoexcitation to the S2 state through the use of ultrafast, single-colour, pump-probe UV/UV spectroscopy. We place focus on investigating the appearance and subsequent decay signals of ionized fragments. We complement this with VUV-induced dissociative photoionisation studies collected at a synchrotron, allowing us to better understand and assign the ionisation channels involved in the appearance of the fragments. We find that all fragments appear when single photons with energy > 11 eV are used in the VUV experiments and hence appear through 3+ photon-order processes when 266 nm light is used. We also observe three major decays for the fragment ions: a sub-autocorrelation decay (i.e., sub-370 fs), a secondary ultrafast decay on the order of 300-400 fs, and a long decay on the order of 220 to 400 ps (all fragment dependent). These decays agree well with the previously established S2 → S1 → Triplet → Ground decay process. Results from the VUV study also suggest that some of the fragments may be created by dynamics occurring in the excited cationic state.
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19
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Ullrich S, Qu Y, Mohamadzade A, Shrestha S. The Effect of Methylation on the Triplet-State Dynamics of 2-Thiouracil: Time-Resolved Photoelectron Spectroscopy of 2-Thiothymine. J Phys Chem A 2022; 126:8211-8217. [DOI: 10.1021/acs.jpca.2c06051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Susanne Ullrich
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, United States
| | - Yingqi Qu
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, United States
| | - Abed Mohamadzade
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, United States
| | - Sarita Shrestha
- Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, United States
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20
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Bertram L, Roberts SJ, Powner MW, Szabla R. Photochemistry of 2-thiooxazole: a plausible prebiotic precursor to RNA nucleotides. Phys Chem Chem Phys 2022; 24:21406-21416. [PMID: 36047336 PMCID: PMC7613695 DOI: 10.1039/d2cp03167a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Potentially prebiotic chemical reactions leading to RNA nucleotides involve periods of UV irradiation, which are necessary to promote selectivity and destroy biologially irrelevant side products. Nevertheless, UV light has only been applied to promote specific stages of prebiotic reactions and its effect on complete prebiotic reaction sequences has not been extensively studied. Here, we report on an experimental and computational investigation of the photostability of 2-thiooxazole (2-TO), a potential precursor of pyrimidine and 8-oxopurine nucleotides on early Earth. Our UV-irradiation experiments resulted in rapid decomposition of 2-TO into unidentified small molecule photoproducts. We further clarify the underlying photochemistry by means of accurate ab initio calculations and surface hopping molecular dynamics simulations. Overall, the computational results show efficient rupture of the aromatic ring upon the photoexcitation of 2-TO via breaking of the C-O bond. Consequently, the initial stage of the divergent prebiotic synthesis of pyrimidine and 8-oxopurine nucleotides would require periodic shielding from UV light either with sun screening chromophores or through a planetary scenario that would protect 2-TO until it is transformed into a more stable intermediate compound, e.g. oxazolidinone thione.
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Affiliation(s)
- Lauren Bertram
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Samuel J Roberts
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Matthew W Powner
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Rafał Szabla
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
- Department of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, 50-370 Wrocław, Poland.
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21
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Valverde D, Mai S, Canuto S, Borin AC, González L. Ultrafast Intersystem Crossing Dynamics of 6-Selenoguanine in Water. JACS AU 2022; 2:1699-1711. [PMID: 35911449 PMCID: PMC9327080 DOI: 10.1021/jacsau.2c00250] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Rationalizing the photochemistry of nucleobases where an oxygen is replaced by a heavier atom is essential for applications that exploit near-unity triplet quantum yields. Herein, we report on the ultrafast excited-state deactivation mechanism of 6-selenoguanine (6SeGua) in water by combining nonadiabatic trajectory surface-hopping dynamics with an electrostatic embedding quantum mechanics/molecular mechanics (QM/MM) scheme. We find that the predominant relaxation mechanism after irradiation starts on the bright singlet S2 state that converts internally to the dark S1 state, from which the population is transferred to the triplet T2 state via intersystem crossing and finally to the lowest T1 state. This S2 → S1 → T2 → T1 deactivation pathway is similar to that observed for the lighter 6-thioguanine (6tGua) analogue, but counterintuitively, the T1 lifetime of the heavier 6SeGua is shorter than that of 6tGua. This fact is explained by the smaller activation barrier to reach the T1/S0 crossing point and the larger spin-orbit couplings of 6SeGua compared to 6tGua. From the dynamical simulations, we also calculate transient absorption spectra (TAS), which provide two time constants (τ1 = 131 fs and τ2 = 191 fs) that are in excellent agreement with the experimentally reported value (τexp = 130 ± 50 fs) (Farrel et al. J. Am. Chem. Soc. 2018, 140, 11214). Intersystem crossing itself is calculated to occur with a time scale of 452 ± 38 fs, highlighting that the TAS is the result of a complex average of signals coming from different nonradiative processes and not intersystem crossing alone.
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Affiliation(s)
- Danillo Valverde
- Department
of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes, 748, São Paulo, São Paulo CEP 05508-000, Brazil
- Institute
of Physics, University of São Paulo, Rua do Matão 1371, São Paulo, São Paulo CEP 05508-090, Brazil
| | - Sebastian Mai
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, Vienna 1090, Austria
| | - Sylvio Canuto
- Institute
of Physics, University of São Paulo, Rua do Matão 1371, São Paulo, São Paulo CEP 05508-090, Brazil
| | - Antonio Carlos Borin
- Department
of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes, 748, São Paulo, São Paulo CEP 05508-000, Brazil
| | - Leticia González
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, Vienna 1090, Austria
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22
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Lea MR, Stavros VG, Maurer RJ. Effect of electron donating/withdrawing groups on molecular photoswitching of functionalized hemithioindigo derivatives: a computational multireference study. CHEMPHOTOCHEM 2022. [DOI: 10.1002/cptc.202100290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin R. Lea
- University of Warwick Department of Chemistry Gibbet Hill Road CV4 7AL Coventry UNITED KINGDOM
| | - Vasilios G. Stavros
- University of Warwick Department of Chemistry Gibbet Hill Road CV4 7AL Coventry UNITED KINGDOM
| | - Reinhard J Maurer
- University of Warwick Department of Chemistry Department of Chemistry Gibbet Hill Road CV4 7AL Coventry UNITED KINGDOM
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23
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Teles-Ferreira DC, Manzoni C, Martínez-Fernández L, Cerullo G, de Paula AM, Borrego-Varillas R. Ultrafast Excited-State Decay Mechanisms of 6-Thioguanine Followed by Sub-20 fs UV Transient Absorption Spectroscopy. Molecules 2022; 27:molecules27041200. [PMID: 35208987 PMCID: PMC8878119 DOI: 10.3390/molecules27041200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 11/23/2022] Open
Abstract
Understanding the primary steps following UV photoexcitation in sulphur-substituted DNA bases (thiobases) is fundamental for developing new phototherapeutic drugs. However, the investigation of the excited-state dynamics in sub-100 fs time scales has been elusive until now due to technical challenges. Here, we track the ultrafast decay mechanisms that lead to the electron trapping in the triplet manifold for 6-thioguanine in an aqueous solution, using broadband transient absorption spectroscopy with a sub-20 fs temporal resolution. We obtain experimental evidence of the fast internal conversion from the S2(ππ*) to the S1(nπ*) states, which takes place in about 80 fs and demonstrates that the S1(nπ*) state acts as a doorway to the triplet population in 522 fs. Our results are supported by MS-CASPT2 calculations, predicting a planar S2(ππ*) pseudo-minimum in agreement with the stimulated emission signal observed in the experiment.
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Affiliation(s)
| | - Cristian Manzoni
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, I-20133 Milano, Italy; (C.M.); (G.C.)
| | - Lara Martínez-Fernández
- Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry (IADCHEM), Campus de Excelencia UAM-CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain;
| | - Giulio Cerullo
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, I-20133 Milano, Italy; (C.M.); (G.C.)
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Ana Maria de Paula
- Departamento de Física, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, MG, Brazil;
| | - Rocío Borrego-Varillas
- Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), Piazza Leonardo da Vinci 32, I-20133 Milano, Italy; (C.M.); (G.C.)
- Correspondence:
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24
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Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy. Nat Commun 2022; 13:198. [PMID: 35017539 PMCID: PMC8752854 DOI: 10.1038/s41467-021-27908-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/20/2021] [Indexed: 01/08/2023] Open
Abstract
The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states. Imaging the charge flow in photoexcited molecules would provide key information on photophysical and photochemical processes. Here the authors demonstrate tracking in real time after photoexcitation the change in charge density at a specific site of 2-thiouracil using time-resolved X-ray photoelectron spectroscopy.
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25
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Jin P, Wang X, Pan H, Chen J. One order of magnitude increase of triplet state lifetime observed in deprotonated form selenium substituted uracil. Phys Chem Chem Phys 2022; 24:875-882. [PMID: 34908064 DOI: 10.1039/d1cp04811b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Selenium nucleic acids possess unique properties and have been demonstrated to have a wide range of applications such as in DNA X-ray crystallography and novel medical therapies. However, as a heavy atom, selenium substitution may easily alter the photophysical properties of a nucleic acid by red-shifting the absorption spectra and introducing effective intersystem crossing to triplet excited states. In present work, the excited state dynamics of a naturally occurring selenium substituted uracil (2-selenuracil, 2SeU) is studied by using femtosecond transient absorption spectroscopy as well as quantum chemistry calculations. Ultrafast intersystem crossing to the lowest triplet state (T1) and effective non-radiative decay of this state to the ground state (S0) are demonstrated in the neutral form 2SeU. However, the triplet lifetime of the deprotonated form 2SeU is found to be almost one order of magnitude longer than that in the neutral one. Quantum chemistry calculations indicate that the short triplet lifetime in 2SeU is due to excited state population decay through a crossing point between T1 and S0. In the deprotonated form, shortening the N1-C2 bond length makes the structural distortion more difficult and brings a larger energy barrier on the pathway to the T1/S0 crossing point, resulting in one order of magnitude increase of the triplet state lifetime. Our study reveals one key factor to regulate the triplet lifetime of 2SeU and sets the stage to further investigate the photophysical and photochemical properties of 2SeU-containing DNA/RNA duplexes.
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Affiliation(s)
- Peipei Jin
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.
| | - Xueli Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China. .,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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26
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Teles-Ferreira DC, van Stokkum IH, Conti I, Ganzer L, Manzoni C, Garavelli M, Cerullo G, Nenov A, Borrego Varillas R, de Paula AM. Coherent vibrational modes promote the ultrafast internal conversion and intersystem crossing in thiobases. Phys Chem Chem Phys 2022; 24:21750-21758. [DOI: 10.1039/d2cp02073d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thionated nucleobases are obtained by replacing oxygen with sulphur atoms in the canonical nucleobases. They absorb light efficiently in the near-ultraviolet, populating singlet states which undergo intersystem crossing to the...
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27
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Xie BB, Tang XF, Liu XY, Chang XP, Cui G. Mechanistic photophysics and photochemistry of unnatural bases and sunscreen molecules: insights from electronic structure calculations. Phys Chem Chem Phys 2021; 23:27124-27149. [PMID: 34849517 DOI: 10.1039/d1cp03994f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photophysics and photochemistry are basic subjects in the study of light-matter interactions and are ubiquitous in diverse fields such as biology, energy, materials, and environment. A full understanding of mechanistic photophysics and photochemistry underpins many recent advances and applications. This contribution first provides a short discussion on the theoretical calculation methods we have used in relevant studies, then we introduce our latest progress on the mechanistic photophysics and photochemistry of two classes of molecular systems, namely unnatural bases and sunscreens. For unnatural bases, we disclose the intrinsic driving forces for the ultrafast population to reactive triplet states, impacts of the position and degree of chalcogen substitutions, and the effects of complex environments. For sunscreen molecules, we reveal the photoprotection mechanisms that dissipate excess photon energy to the surroundings by ultrafast internal conversion to the ground state. Finally, relevant theoretical challenges and outlooks are discussed.
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Affiliation(s)
- Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiu-Fang Tang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu, Sichuan, 610068, China
| | - Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
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28
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Zhu YH, Tang XF, Chang XP, Zhang TS, Xie BB, Cui G. Mechanistic Photophysics of Tellurium-Substituted Uracils: Insights from Multistate Complete-Active-Space Second-Order Perturbation Calculations. J Phys Chem A 2021; 125:8816-8826. [PMID: 34606278 DOI: 10.1021/acs.jpca.1c06169] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The photophysical mechanisms of tellurium-substituted uracils were studied at the multistate complete-active-space second-order perturbation level with a particular focus on how the position and number of tellurium substitutions affect their nonadiabatic relaxation processes. Electronic structure analysis reveals that the lowest several excited states are closely concerned with the n and π orbitals at the Te7-C2 [Te8-C4] moiety of 2-tellurouracil (2TeU) [4TeU and 24TeU]. Both planar and twisted minima were optimized for 2TeU, whereas only planar ones were obtained for 4TeU and 24TeU, except for a twisted T1 minimum of 4TeU. Based on intersection structures and linearly interpolated internal coordinate paths, we proposed several feasible excited-state deactivation paths. It is found that the relaxation channels for 2TeU are more complicated than those of 4TeU and 24TeU. The electronic population transfer to the T1 state for 2TeU is easier than that for 4TeU and 24TeU in consideration of the barrier heights from the S2 Franck-Condon point to the S2/S1 or S2/T2 intersections. In addition, the recovery of the ground state from the T1 state for 2TeU will be more efficient than that for the other two systems as well.
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Affiliation(s)
- Yun-Hua Zhu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xiu-Fang Tang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Xue-Ping Chang
- College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000, P. R. China
| | - Teng-Shuo Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, P R. China
| | - Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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29
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Westermayr J, Marquetand P. Machine Learning for Electronically Excited States of Molecules. Chem Rev 2021; 121:9873-9926. [PMID: 33211478 PMCID: PMC8391943 DOI: 10.1021/acs.chemrev.0c00749] [Citation(s) in RCA: 198] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Indexed: 12/11/2022]
Abstract
Electronically excited states of molecules are at the heart of photochemistry, photophysics, as well as photobiology and also play a role in material science. Their theoretical description requires highly accurate quantum chemical calculations, which are computationally expensive. In this review, we focus on not only how machine learning is employed to speed up such excited-state simulations but also how this branch of artificial intelligence can be used to advance this exciting research field in all its aspects. Discussed applications of machine learning for excited states include excited-state dynamics simulations, static calculations of absorption spectra, as well as many others. In order to put these studies into context, we discuss the promises and pitfalls of the involved machine learning techniques. Since the latter are mostly based on quantum chemistry calculations, we also provide a short introduction into excited-state electronic structure methods and approaches for nonadiabatic dynamics simulations and describe tricks and problems when using them in machine learning for excited states of molecules.
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Affiliation(s)
- Julia Westermayr
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
| | - Philipp Marquetand
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
- Vienna
Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
- Data
Science @ Uni Vienna, University of Vienna, Währinger Strasse 29, 1090 Vienna, Austria
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30
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Abstract
Electronically excited states of molecules are at the heart of photochemistry, photophysics, as well as photobiology and also play a role in material science. Their theoretical description requires highly accurate quantum chemical calculations, which are computationally expensive. In this review, we focus on not only how machine learning is employed to speed up such excited-state simulations but also how this branch of artificial intelligence can be used to advance this exciting research field in all its aspects. Discussed applications of machine learning for excited states include excited-state dynamics simulations, static calculations of absorption spectra, as well as many others. In order to put these studies into context, we discuss the promises and pitfalls of the involved machine learning techniques. Since the latter are mostly based on quantum chemistry calculations, we also provide a short introduction into excited-state electronic structure methods and approaches for nonadiabatic dynamics simulations and describe tricks and problems when using them in machine learning for excited states of molecules.
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Affiliation(s)
- Julia Westermayr
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
- Vienna Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währinger Strasse 17, 1090 Vienna, Austria
- Data Science @ Uni Vienna, University of Vienna, Währinger Strasse 29, 1090 Vienna, Austria
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31
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Zobel JP, González L. The Quest to Simulate Excited-State Dynamics of Transition Metal Complexes. JACS AU 2021; 1:1116-1140. [PMID: 34467353 PMCID: PMC8397362 DOI: 10.1021/jacsau.1c00252] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Indexed: 05/15/2023]
Abstract
This Perspective describes current computational efforts in the field of simulating photodynamics of transition metal complexes. We present the typical workflows and feature the strengths and limitations of the different contemporary approaches. From electronic structure methods suitable to describe transition metal complexes to approaches able to simulate their nuclear dynamics under the effect of light, we give particular attention to build a bridge between theory and experiment by critically discussing the different models commonly adopted in the interpretation of spectroscopic experiments and the simulation of particular observables. Thereby, we review all the studies of excited-state dynamics on transition metal complexes, both in gas phase and in solution from reduced to full dimensionality.
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Affiliation(s)
- J. Patrick Zobel
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 19, 1090 Vienna Austria
| | - Leticia González
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 19, 1090 Vienna Austria
- Vienna
Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währingerstr. 19, 1090 Vienna Austria
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32
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Janicki M, Kufner CL, Todd ZR, Kim SC, O’Flaherty DK, Szostak JW, Šponer J, Góra RW, Sasselov DD, Szabla R. Ribose Alters the Photochemical Properties of the Nucleobase in Thionated Nucleosides. J Phys Chem Lett 2021; 12:6707-6713. [PMID: 34260253 PMCID: PMC9634911 DOI: 10.1021/acs.jpclett.1c01384] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Substitution of exocyclic oxygen with sulfur was shown to substantially influence the properties of RNA/DNA bases, which are crucial for prebiotic chemistry and photodynamic therapies. Upon UV irradiation, thionucleobases were shown to efficiently populate triplet excited states and can be involved in characteristic photochemistry or generation of singlet oxygen. Here, we show that the photochemistry of a thionucleobase can be considerably modified in a nucleoside, that is, by the presence of ribose. Our transient absorption spectroscopy experiments demonstrate that thiocytosine exhibits 5 times longer excited-state lifetime and different excited-state absorption features than thiocytidine. On the basis of accurate quantum chemical simulations, we assign these differences to the dominant population of a shorter-lived triplet nπ* state in the nucleoside and longer-lived triplet ππ* states in the nucleobase. This explains the distinctive photoanomerziation of thiocytidine and indicates that the nucleoside will be a less efficient phototherapeutic agent with regard to singlet oxygen generation.
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Affiliation(s)
- Mikołaj
J. Janicki
- Department
of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego
27, 50-370 Wrocław, Poland
| | - Corinna L. Kufner
- Department
of Astronomy, Harvard-Smithsonian Center
for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - Zoe R. Todd
- Department
of Astronomy, Harvard-Smithsonian Center
for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - Seohyun C. Kim
- Howard
Hughes Medical Institute, Department of Molecular Biology and Center
for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Derek K. O’Flaherty
- Howard
Hughes Medical Institute, Department of Molecular Biology and Center
for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Jack W. Szostak
- Howard
Hughes Medical Institute, Department of Molecular Biology and Center
for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Jiří Šponer
- Institute
of Biophysics, Czech Academy of Sciences, Královopolská 135, 61265 Brno, Czech
Republic
- Regional
Centre of Advanced Technologies and Materials, Czech Advanced Technology
and Research Institute (CATRIN), Palacky
University Olomouc, Slechtitelu
241/27, 783 71 Olomouc-Holice, Czech Republic
| | - Robert W. Góra
- Department
of Physical and Quantum Chemistry, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego
27, 50-370 Wrocław, Poland
| | - Dimitar D. Sasselov
- Department
of Astronomy, Harvard-Smithsonian Center
for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, United States
| | - Rafał Szabla
- EaStCHEM,
School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, U.K.
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33
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Guan Y, Xie C, Guo H, Yarkony DR. Enabling a Unified Description of Both Internal Conversion and Intersystem Crossing in Formaldehyde: A Global Coupled Quasi-Diabatic Hamiltonian for Its S 0, S 1, and T 1 States. J Chem Theory Comput 2021; 17:4157-4168. [PMID: 34132545 DOI: 10.1021/acs.jctc.1c00370] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In our recent work, a diabatic Hamiltonian that couples the S0 and S1 states of formaldehyde was constructed using a robust fitting-and-diabatizing procedure with artificial neural networks, which is capable of representing adiabatic energies, energy gradients, and derivative couplings over a wide range of geometries including seams of conical intersection. In this work, based on the diabatization of S0 and S1, the spin-orbit couplings between singlet states (S0, S1) and triplet state T1 are also determined in the same diabatic representation. The diabatized spin-orbit couplings are then fit with a symmetrized neural-network functional form. The ab initio spin-orbit couplings are well reproduced in large configuration space. Together with the neural-network-based potential energy surface for T1, the full quasi-diabatic Hamiltonian for the S0, S1, and T1 states is completed, enabling a unified description of both internal conversion and intersystem crossing in formaldehyde. The vibrational levels on the three adiabatic states are found to be in good agreement with known experimental band origins.
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Affiliation(s)
- Yafu Guan
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Changjian Xie
- Institute of Modern Physics, Northwest University, Xi'an, Shaanxi 710069, People's Republic of China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - David R Yarkony
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Zhu YH, Zhang TS, Tang XF, Xie BB, Cui G. MS-CASPT2 studies on the mechanistic photophysics of tellurium-substituted guanine and cytosine. Phys Chem Chem Phys 2021; 23:12421-12430. [PMID: 34028476 DOI: 10.1039/d1cp01142a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfur-substituted nucleobases are highly promising photosensitizers that are widely used in photodynamic therapy, and there are numerous studies exploring their unique photophysical behaviors. However, relevant photophysical investigations on selenium and tellurium substitutions are still rare. Herein, the high-level multistate complete-active-space second-order perturbation (MS-CASPT2) method was performed for the first time to explore the excited-state relaxation processes of tellurium-substituted guanine (TeG) and cytosine (TeC). Based on the electronic state properties in the Franck-Condon (FC) region, we found that the lowest five (S0, S1, S2, T1, and T2) and six (S0, S1, S2, T1, T2 and T3) states will participate in the nonadiabatic transition processes of TeG and TeC systems, respectively. In these electronic states, two kinds of minimum and intersection structures (i.e., planar and twisted structures) were obtained for both TeG and TeC systems. The linearly interpolated internal coordinate (LIIC) paths and spin-orbit coupling (SOC) constants revealed several possible planar and twisted excited-state decay channels, which could lead the systems to the lowest reactive triplet state of T1. Small energy barriers in the T1 state will trap the TeG and TeC systems for a while before they finally populate to the ground state. Although tellurium substitution would further redshift the absorption wavelength and enhance the intersystem crossing (ISC) rate to the T1 state compared with sulfur and selenium substitutions, the rapid ISC process of T1 → S0 may make it a less effective photosensitizer to sensitize the molecular oxygen. We believe our present work will provide important mechanistic insights into the photophysics of tellurium-substituted nucleobases.
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Affiliation(s)
- Yun-Hua Zhu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
| | - Teng-Shuo Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, P. R. China
| | - Xiu-Fang Tang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China.
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China.
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Zhang K, Wang F, Jiang Y, Wang X, Pan H, Sun Z, Sun H, Xu J, Chen J. New Insights about the Photostability of DNA/RNA Bases: Triplet nπ* State Leads to Effective Intersystem Crossing in Pyrimidinones. J Phys Chem B 2021; 125:2042-2049. [PMID: 33600186 DOI: 10.1021/acs.jpcb.0c10611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The high photostability of DNA/RNA nucleobases is attributed to the effective internal conversions of their bright 1ππ* states to the ground state through conical intersections. Intersystem crossing (ISC) from singlet to triplet excited states is a minor decay pathway in nucleobases and it is observed with ∼1-2% quantum yields (QYs) in pyrimidine bases. Presumably, ISC in pyrimidines takes place from the dark singlet 1nπ* state to the lowest triplet 3ππ* state. However, recent studies showed that ISC from the initial populated bright 1ππ* state to higher energy triplet 3nπ* states indeed occurs in the subpicosecond timescale. Such a mechanism is still poorly understood since direct observation of this pathway is challenging. Herein, excited state dynamics of three pyrimidinones, which share the same skeleton with pyrimidine bases, is investigated in different solvents. Compared to canonical pyrimidine bases, removing the oxygen atom at the C4 position revokes the low-lying dark 1nπ* state in pyrimidinones, resulting in direct ISC from the S1 (1ππ*) state to triplet T3 (3nπ*) state with much higher QYs. Meanwhile, hydrogen bonding between the carbonyl group in pyrimidinones and protic solvents can accelerate vibrational cooling of the hot S1 (1ππ*) state, leading to higher fluorescence QYs and smaller ISC rate constants. These results not only evidence the hypothesis of the direct 1ππ* → 3nπ* ISC mechanism, but also contribute to a better understanding of triplet formation in pyrimidines.
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Affiliation(s)
- Kun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Fufang Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Yanrong Jiang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Xueli Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Haifeng Pan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Zhenrong Sun
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Haitao Sun
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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36
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Fang YG, Valverde D, Mai S, Canuto S, Borin AC, Cui G, González L. Excited-State Properties and Relaxation Pathways of Selenium-Substituted Guanine Nucleobase in Aqueous Solution and DNA Duplex. J Phys Chem B 2021; 125:1778-1789. [PMID: 33570942 PMCID: PMC8023715 DOI: 10.1021/acs.jpcb.0c10855] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The excited-state properties and relaxation mechanisms after light irradiation of 6-selenoguanine (6SeG) in water and in DNA have been investigated using a quantum mechanics/molecular mechanics (QM/MM) approach with the multistate complete active space second-order perturbation theory (MS-CASPT2) method. In both environments, the S1 1(nSeπ5*) and S2 1(πSeπ5*) states are predicted to be the spectroscopically dark and bright states, respectively. Two triplet states, T1 3(πSeπ5*) and T2 3(nSeπ5*), are found energetically below the S2 state. Extending the QM region to include the 6SeG-Cyt base pair slightly stabilizes the S2 state and destabilizes the S1, due to hydrogen-bonding interactions, but it does not affect the order of the states. The optimized minima, conical intersections, and singlet-triplet crossings are very similar in water and in DNA, so that the same general mechanism is found. Additionally, for each excited state geometry optimization in DNA, three kind of structures ("up", "down", and "central") are optimized which differ from each other by the orientation of the C═Se group with respect to the surrounding guanine and thymine nucleobases. After irradiation to the S2 state, 6SeG evolves to the S2 minimum, near to a S2/S1 conical intersection that allows for internal conversion to the S1 state. Linear interpolation in internal coordinates indicate that the "central" orientation is less favorable since extra energy is needed to surmount the high barrier in order to reach the S2/S1 conical intersection. From the S1 state, 6SeG can further decay to the T1 3(πSeπ5*) state via intersystem crossing, where it will be trapped due to the existence of a sizable energy barrier between the T1 minimum and the T1/S0 crossing point. Although this general S2 → T1 mechanism takes place in both media, the presence of DNA induces a steeper S2 potential energy surface, that it is expected to accelerate the S2 → S1 internal conversion.
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Affiliation(s)
- Ye-Guang Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Danillo Valverde
- Institute of Physics, University of São Paulo, Rua do Matão 1371, São Paulo, SP 05508-090, Brazil
| | - Sebastian Mai
- Photonics Institute, Vienna University of Technology, Gußhausstraße 27-29, 1040 Vienna, Austria.,Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
| | - Sylvio Canuto
- Institute of Physics, University of São Paulo, Rua do Matão 1371, São Paulo, SP 05508-090, Brazil
| | - Antonio Carlos Borin
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000. São Paulo, SP Brazil
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
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Rankine CD. Ultrafast excited-state dynamics of promising nucleobase ancestor 2,4,6-triaminopyrimidine. Phys Chem Chem Phys 2021; 23:4007-4017. [PMID: 33554987 DOI: 10.1039/d0cp05609j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ultrafast excited-state dynamics of 2,4,6-triaminopyrimidine - thought to be a promising candidate for a proto-RNA nucleobase - have been investigated via static multireference quantum-chemical calculations and mixed-quantum-classical/trajectory surface-hopping dynamics with a focus on the lowest-lying electronic states of the singlet manifold and with a view towards understanding the UV(C)/UV(B) photostability of the molecule. Ultrafast internal conversion channels have been identified that connect the lowest-lying ππ* electronically-excited state of 2,4,6-triaminopyrimidine with the ground electronic state, and non-radiative decay has been observed to take place on the picosecond timescale via a ππ* out-of-plane NH2 ("oop-NH2") minimum-energy crossing point. The short excited-state lifetime is competitive with the excited-state lifetimes of the canonical pyrimidine nucleobases, affirming the promise of 2,4,6-triaminopyrimidine as an ancestor. Evidence for energy-dependent excited-state dynamics is presented, and the open question of intersystem crossing is discussed speculatively.
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Affiliation(s)
- Conor D Rankine
- School of Natural and Environmental Sciences, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK.
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Uleanya KO, Dessent CEH. Investigating the mapping of chromophore excitations onto the electron detachment spectrum: photodissociation spectroscopy of iodide ion-thiouracil clusters. Phys Chem Chem Phys 2021; 23:1021-1030. [PMID: 33428696 DOI: 10.1039/d0cp05920j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Laser photodissociation spectroscopy (3.1-5.7 eV) has been applied to iodide complexes of the non-native nucleobases, 2-thiouracil (2-TU), 4-thiouracil (4-TU) and 2,4-thiouracil (2,4-TU), to probe the excited states and intracluster electron transfer as a function of sulphur atom substitution. Photodepletion is strong for all clusters (I-·2-TU, I-·4-TU and I-·2,4-TU) and is dominated by electron detachment processes. For I-·4-TU and I-·2,4-TU, photodecay is accompanied by formation of the respective molecular anions, 4-TU- and 2,4-TU-, behaviour that is not found for other nucleobases. Notably, the I-·2TU complex does not fragment with formation of its molecular anion. We attribute the novel formation of 4-TU- and 2,4-TU- to the fact that these valence anions are significantly more stable than 2-TU-. We observe further similar behaviour for I-·4-TU and I-·2,4-TU relating to the general profile of their photodepletion spectra, since both strongly resemble the intrinsic absorption spectra of the respective uncomplexed thiouracil molecule. This indicates that the nucleobase chromophore excitations are determining the clusters' spectral profile. In contrast, the I-·2-TU photodepletion spectrum is dominated by the electron detachment profile, with the near-threshold dipole-bound excited state being the only distinct spectral feature. We discuss these observations in the context of differences in the dipole moments of the thionucleobases, and their impact on the coupling of nucleobase-centred transitions onto the electron detachment spectrum.
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Affiliation(s)
- Kelechi O Uleanya
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.
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Nonoshita D, Kashihara W, Tanabe K, Isozaki T, Xu YZ, Suzuki T. Excited States of Thio-2'-deoxyuridine Bearing an Extended π-Conjugated System: 3',5'-Di- O-acetyl-5-phenylethynyl-4-thio-2'-deoxyuridine. J Phys Chem A 2021; 125:597-606. [PMID: 33307688 DOI: 10.1021/acs.jpca.0c09343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A new thio-2'-deoxyuridine with an extended π-conjugated group was successfully synthesized: 3',5'-di-O-acetyl-5-phenylethynyl-4-thio-2'-deoxyuridine. The thio-2'-deoxyuridine derivative has a large red-shifted absorption band in the UVA region and also shows fluorescence, a rare photo-property among thionucleobases/thionucleosides. The triplet-triplet absorption spectrum and the rate constants (the intrinsic decay rate constant of the triplet state, the self-quenching rate constant, and the quenching rate constant of the triplet state by an oxygen molecule) of the thio-2'-deoxyuridine were obtained by transient absorption spectroscopy. The quantum yield of intersystem crossing and the quantum yield of singlet molecular oxygen formation (ϕΔ) under an oxygen atmosphere were also determined. The ϕΔ value of the new thio-2'-deoxyuridine was found to be substantially higher than all reported values of other thio-2'-deoxyribonucleosides in low oxygen concentrations similar to cancer cell environments. The fluorescence quantum yield depended on the excitation wavelength, revealing certain photochemical reactions in the higher excited singlet states. However, when excited into the higher excited state with non-resonant two-photon absorption, the ϕΔ of the thio-2'-deoxyuridine derivative was found to remain sufficiently large. These findings should be very useful for the development of thio-2'-deoxyribonucleoside-based pharmaceuticals as DNA-specific photosensitizers for photochemotherapy.
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Affiliation(s)
- Daiki Nonoshita
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Wataru Kashihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Kazuhito Tanabe
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
| | - Tasuku Isozaki
- Division of Natural Sciences, College of Arts and Sciences, J. F. Oberlin University, Tokiwa-machi, Machida 194-0294, Tokyo, Japan
| | - Yao Zhong Xu
- School of Life, Health and Chemical Sciences, The Open University, Keynes MK7 6AA, U.K
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
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Moitra T, Karak P, Chakraborty S, Ruud K, Chakrabarti S. Behind the scenes of spin-forbidden decay pathways in transition metal complexes. Phys Chem Chem Phys 2021; 23:59-81. [PMID: 33319894 DOI: 10.1039/d0cp05108j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The interpretation of the ultrafast photophysics of transition metal complexes following photo-absorption is quite involved as the heavy metal center leads to a complicated and entangled singlet-triplet manifold. This opens up multiple pathways for deactivation, often with competitive rates. As a result, intersystem crossing (ISC) and phosphorescence are commonly observed in transition metal complexes. A detailed understanding of such an excited-state structure and dynamics calls for state-of-the-art experimental and theoretical methodologies. In this review, we delve into the inability of non-relativistic quantum theory to describe spin-forbidden transitions, which can be overcome by taking into account spin-orbit coupling, whose importance grows with increasing atomic number. We present the quantum chemical theory of phosphorescence and ISC together with illustrative examples. Finally, a few applications are highlighted, bridging the gap between theoretical studies and experimental applications, such as photofunctional materials.
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Affiliation(s)
- Torsha Moitra
- DTU Chemistry, Technical University of Denmark, Kemitorvet Bldg 207, DK-2800 Kongens Lyngby, Denmark
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41
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Shen L, Xie B, Li Z, Liu L, Cui G, Fang WH. Role of Multistate Intersections in Photochemistry. J Phys Chem Lett 2020; 11:8490-8501. [PMID: 32787313 DOI: 10.1021/acs.jpclett.0c01637] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
It has been generally accepted that the intersection of potential energy surfaces can facilitate nonadiabatic transitions and plays a crucial role in photochemistry. Although most previous studies have focused on the conical intersection of two electronic states, multistate intersections are common in polyatomic molecules, and their key roles in photochemistry have been uncovered by electronic structure calculations and nonadiabatic dynamics simulations. In this Perspective, the algorithms for searching two- or three-state intersections are first examined with an emphasis on the latest development in a general algorithm for location of multistate intersections. Then, we focus on intersystem crossing (ISC) that occurs in the region of multistate intersection, paying more attention to how the state-specific spin-orbit coupling interaction influences nonadiabatic ISC processes. Finally, the interweaving of nonadiabatic dynamics simulation and electronic structure calculation has been recognized as a correct way to ascertain the vital roles of multistate intersections in photochemical reactions.
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Affiliation(s)
- Lin Shen
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Binbin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P.R. China
| | - Ziwen Li
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Lihong Liu
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P.R. China
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Mai S, González L. Molecular Photochemistry: Recent Developments in Theory. Angew Chem Int Ed Engl 2020; 59:16832-16846. [PMID: 32052547 PMCID: PMC7540682 DOI: 10.1002/anie.201916381] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/12/2020] [Indexed: 12/16/2022]
Abstract
Photochemistry is a fascinating branch of chemistry that is concerned with molecules and light. However, the importance of simulating light-induced processes is reflected also in fields as diverse as biology, material science, and medicine. This Minireview highlights recent progress achieved in theoretical chemistry to calculate electronically excited states of molecules and simulate their photoinduced dynamics, with the aim of reaching experimental accuracy. We focus on emergent methods and give selected examples that illustrate the progress in recent years towards predicting complex electronic structures with strong correlation, calculations on large molecules, describing multichromophoric systems, and simulating non-adiabatic molecular dynamics over long time scales, for molecules in the gas phase or in complex biological environments.
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Affiliation(s)
- Sebastian Mai
- Photonics InstituteVienna University of TechnologyGusshausstrasse 27–291040ViennaAustria
| | - Leticia González
- Institute of Theoretical ChemistryFaculty of ChemistryUniversity of ViennaWähringer Strasse 171090ViennaAustria
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43
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Westermayr J, Marquetand P. Machine learning and excited-state molecular dynamics. MACHINE LEARNING-SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1088/2632-2153/ab9c3e] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Conti I, Cerullo G, Nenov A, Garavelli M. Ultrafast Spectroscopy of Photoactive Molecular Systems from First Principles: Where We Stand Today and Where We Are Going. J Am Chem Soc 2020; 142:16117-16139. [PMID: 32841559 PMCID: PMC7901644 DOI: 10.1021/jacs.0c04952] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
![]()
Computational spectroscopy is becoming a mandatory tool for the interpretation of the
complex, and often congested, spectral maps delivered by modern non-linear multi-pulse
techniques. The fields of Electronic Structure Methods,
Non-Adiabatic Molecular Dynamics, and Theoretical
Spectroscopy represent the three pillars of the virtual ultrafast
optical spectrometer, able to deliver transient spectra in
silico from first principles. A successful simulation strategy requires a
synergistic approach that balances between the three fields, each one having its very
own challenges and bottlenecks. The aim of this Perspective is to demonstrate that,
despite these challenges, an impressive agreement between theory and experiment is
achievable now regarding the modeling of ultrafast photoinduced processes in complex
molecular architectures. Beyond that, some key recent developments in the three fields
are presented that we believe will have major impacts on spectroscopic simulations in
the very near future. Potential directions of development, pending challenges, and
rising opportunities are illustrated.
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Affiliation(s)
- Irene Conti
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Artur Nenov
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
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Wu Y, Miao G, Subotnik JE. Chemical Reaction Rates for Systems with Spin-Orbit Coupling and an Odd Number of Electrons: Does Berry's Phase Lead to Meaningful Spin-Dependent Nuclear Dynamics for a Two State Crossing? J Phys Chem A 2020; 124:7355-7372. [PMID: 32869999 DOI: 10.1021/acs.jpca.0c04562] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Within the context of a simple avoided crossing, we investigate the effect of a complex-valued diabatic coupling in determining spin-dependent rate constants and scattering states. We find that, if the molecular geometry is not linear and the Berry force is not zero, one can find significant spin polarization of the products. This study emphasizes that, when analyzing nonadiabatic reactions with spin orbit coupling (and a complex-valued Hamiltonian), one must consider how Berry force affects nuclear motion-at least in the context of gas phase reactions. Work is currently ongoing as far as extrapolating these conclusions to the condensed phase, where interesting spin selection has been observed in recent years.
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Affiliation(s)
- Yanze Wu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Gaohan Miao
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joseph E Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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46
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Mohamadzade A, Ullrich S. Internal conversion and intersystem crossing dynamics of uracil upon double thionation: a time-resolved photoelectron spectroscopy study in the gas phase. Phys Chem Chem Phys 2020; 22:15608-15615. [PMID: 32613978 DOI: 10.1039/d0cp02145h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The photophysical properties of 2,4-dithiouracil (2,4-DTU) in the gas phase are studied by time-resolved photoelectron spectroscopy (TRPES) with three different excitation wavelengths in direct extension of previous work on uracil (U), 2-thiouracil (2-TU) and 4-thiouracil (4-TU). Non-radiative deactivation in the canonical nucleobases like uracil mainly occurs via internal conversion (IC) along singlet excited states, although intersystem crossing (ISC) to a long-lived triplet state was confirmed to play a minor role. In thionated uracils, ISC to the triplet state becomes ultrafast and highly efficient with a quantum yield near unity; however, the lifetime of the triplet state is strongly dependent on the position of the sulfur atom. In 2-TU, ISC back to the ground state occurs within a few hundred picoseconds, whereas the population remains trapped in the lowest triplet state in the case of 4-TU. Upon doubling the degree of thionation, ISC remains highly efficient and dominates the photophysics of 2,4-DTU. However, several low-lying excited states contribute to competing IC and ISC pathways and a complex deactivation mechanism, which is evaluated here based on TRPES measurements and discussed in the context of the singly thionated uracils.
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Affiliation(s)
- Abed Mohamadzade
- Department of Physics and Astronomy, University of Georgia, Athens, GA 30602, USA.
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Observation of Enhanced Dissociative Photochemistry in the Non-Native Nucleobase 2-Thiouracil. Molecules 2020; 25:molecules25143157. [PMID: 32664261 PMCID: PMC7397253 DOI: 10.3390/molecules25143157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 12/12/2022] Open
Abstract
We present the first study to measure the dissociative photochemistry of 2-thiouracil (2-TU), an important nucleobase analogue with applications in molecular biology and pharmacology. Laser photodissociation spectroscopy is applied to the deprotonated and protonated forms of 2-TU, which are produced in the gas-phase using electrospray ionization mass spectrometry. Our results show that the deprotonated form of 2-thiouracil ([2-TU-H]−) decays predominantly by electron ejection and hence concomitant production of the [2-TU-H]· free-radical species, following photoexcitation across the UVA-UVC region. Thiocyanate (SCN−) and a m/z 93 fragment ion are also observed as photodecay products of [2-TU-H]− but at very low intensities. Photoexcitation of protonated 2-thiouracil ([2-TU·H]+) across the same UVA-UVC spectral region produces the m/z 96 cationic fragment as the major photofragment. This ion corresponds to ejection of an HS· radical from the precursor ion and is determined to be a product of direct excited state decay. Fragment ions associated with decay of the hot ground state (i.e., the ions we would expect to observe if 2-thiouracil was behaving like UV-dissipating uracil) are observed as much more minor products. This behaviour is consistent with enhanced intersystem crossing to triplet excited states compared to internal conversion back to the ground state. These are the first experiments to probe the effect of protonation/deprotonation on thionucleobase photochemistry, and hence explore the effect of pH at a molecular level on their photophysical properties.
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Mai S, González L. Molekulare Photochemie: Moderne Entwicklungen in der theoretischen Chemie. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sebastian Mai
- Institut für Photonik Technische Universität Wien Gußhausstraße 27–29 1040 Wien Österreich
| | - Leticia González
- Institut für theoretische Chemie Fakultät für Chemie Universität Wien Währinger Straße 17 1090 Wien Österreich
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49
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Peng Q, Zhu YH, Zhang TS, Liu XY, Fang WH, Cui G. Selenium substitution effects on excited-state properties and photophysics of uracil: a MS-CASPT2 study. Phys Chem Chem Phys 2020; 22:12120-12128. [PMID: 32440669 DOI: 10.1039/d0cp01369b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The photophysics of selenium-substituted nucleobases has attracted recent experimental attention because they could serve as potential photosensitizers in photodynamic therapy. Herein, we present a comprehensive MS-CASPT2 study on the spectroscopic and excited-state properties, and photophysics of 2-selenouracil (2SeU), 4-selenouracil (4SeU), and 2,4-selenouracil (24SeU). Relevant minima, conical intersections, crossing points, and excited-state relaxation paths in the lowest five electronic states (i.e., S0, S1, S2, T2, and T1) are explored. On the basis of these results, their photophysical mechanisms are proposed. Upon photoirradiation to the bright S2 state, 2SeU quickly relaxes to its S2 minimum and then moves in an essentially barrierless way to a nearby S2/S1 conical intersection near which the S1 state is populated. Next, the S1 system arrives at an S1/T2/T1 intersection where a large S1/T1 spin-orbit coupling of 430.8 cm-1 makes the T1 state populated. In this state, a barrier of 6.8 kcal mol-1 will trap 2SeU for a while. In parallel, for 4SeU or 24SeU, the system first relaxes to the S2 minimum and then overcomes a small barrier to approach an S2/S1 conical intersection. Once hopping to the S1 state, there exists an extended region with very close S1, T2, and T1 energies. Similarly, a large S1/T1 spin-orbit coupling of 426.8 cm-1 drives the S1→ T1 intersystem crossing process thereby making the T1 state populated. Similarly, an energy barrier heavily suppresses electronic transition to the S0 state. The present work manifests that different selenium substitutions on uracil can lead to a certain extent of different vertical and adiabatic excitation energies, excited-state properties, and relaxation pathways. These insights could help understand the photophysics of selenium-substituted nucleobases.
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Affiliation(s)
- Qin Peng
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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50
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Cao J, Chen DC. The excited-state relaxation mechanism of potential UVA-activated phototherapeutic molecules: trajectory surface hopping simulations of both 4-thiothymine and 2,4-dithiothymine. Phys Chem Chem Phys 2020; 22:10924-10933. [PMID: 32373808 DOI: 10.1039/d0cp01450h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent experimental investigations of the photochemical properties of a series of sulfur-substituted pyrimidine derivatives provide insights into the phototherapeutic potential of these nucleobase variants. Herein we elucidate the triplet formation mechanism of two prospective UVA-activated phototherapeutic molecules, 4-thiothymine and 2,4-dithiothymine, upon photo-excitation by applying the trajectory surface hopping dynamics at the LR-TDDFT level. Our simulations reasonably reproduce the experimental time constants and demonstrate the preferred triplet formation pathway which starts from the S1(nSπ*) state for both molecules. It is found that deactivation of the first bright state to the S1(nSπ*) state proceeds through a mechanism involving elongation of the C5-C6 and C4-S8 bond-lengths and C2-pyramidalization in 4-thiothymine and involving elongation of the C5-C6 and C2-S7 bond-lengths in 2,4-dithiothymine. The intersystem crossing of 2,4-dithiothymine occurs either at geometries characterized by elongated C5-C6 and C2-S7 bond-lengths or at geometries showing elongated C5-C6 and C4-S8 bond-lengths as seen in 4-thiothymine. The solvents are found to affect the S2 state decay of 4-thiothymine, leading to a competing pathway between S2→ S1 and S2→ T3. This study provides a molecular-level understanding of the underlying excited-state relaxation of the two UVA-activated thiopyrimidines, which may be linked to their potential applications in pharmacological science and also prove helpful for designing more effective phototherapeutic agents.
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Affiliation(s)
- Jun Cao
- School of Materials Science and Energy Engineering, Foshan University, Foshan, Guangdong 528000, P. R. China.
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