1
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Baweja S, Kalal B, Maity S. Spectroscopic Characterization of Hydrogen-Bonded 2,7-Diazaindole Water Complex Isolated in the Gas Phase. J Phys Chem A 2024; 128:3329-3338. [PMID: 38652167 DOI: 10.1021/acs.jpca.4c01113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
We present a systematic experimental analysis of the 1:1 complex of 2,7-diazaindole (27DAI) with water in the gas phase. The complex was characterized by using two-color-resonant two-photon ionization (R2PI), laser-induced fluorescence (LIF), single vibronic level fluorescence (SVLF), and photoionization efficiency (PIE) spectroscopic methods. The 000 band of the S1←S0 electronic transition of the 27DAI-H2O complex was observed at 33,074 cm-1, largely red-shifted by 836 cm-1 compared to that of the bare 27DAI. From the R2PI spectrum, the detected modes at 141 (ν'Tx), 169 (ν'Ty), and 194 (ν'Ry) cm-1 were identified as the internal motions of the H2O molecule in the complex. However, these modes were detected at 115 (ν″Tx), 152 (ν″Ty), and 190 (ν″Ry) cm-1 in the ground state, which suggested a stronger hydrogen bonding interaction in the photo-excited state. The structural determination was aided by the detection of νNH and νOH values in the ground and excited state complexes using the FDIR and IDIR spectroscopies. The detection of νNH at 3414 and νOH at 3447 cm-1 in 27DAI-H2O has shown an excellent correlation with the most stable structure consisting of N(1)-H···O and OH···N(7) hydrogen-bonded bridging water molecule in the ground state. The structure of the complex in the electronic excited state (S1) was confirmed by the corresponding bands at 3210 (νNH) and 3265 cm-1 (νOH). The IR-UV hole-burning spectroscopy confirmed the presence of only one isomer in the molecular beam. The ionization energy (IE) of the 27DAI-H2O complex was obtained as 8.789 ± 0.002 eV, which was significantly higher than the 7AI-H2O complex. The higher IE values of N-rich molecules suggest a higher resistivity of such molecules against photodamage. The obtained structure of the 27DAI-H2O complex has explicitly shown the formation of a cyclic one-solvent bridge incorporating N(1)-H···O and O-H···N(7) hydrogen bonds upon microsolvation. The lower excitation and higher ionization energies of the 27DAI-H2O complex compared to 7AI-H2O established higher stabilization of N-rich molecules. The solvent clusters forming a linear bridge between the hydrogen/proton acceptor and donor sites in the complex can be considered as a stepping stone to investigate the photoinduced deactivation mechanisms in nitrogen containing biologically relevant molecules.
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Affiliation(s)
- Simran Baweja
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Bhavika Kalal
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502284, India
| | - Surajit Maity
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502284, India
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2
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Feng B, Wu W, He Z, Yang D, Wu G, Yang X. Ultrafast Decay Dynamics of the 2 1ππ* Electronic State of N-Methyl-2-pyridone. J Phys Chem A 2024. [PMID: 38690846 DOI: 10.1021/acs.jpca.4c01418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
The ultrafast decay dynamics of N-methyl-2-pyridone upon excitation in the near-ultraviolet range of 261.5-227.9 nm is investigated using the femtosecond time-resolved photoelectron spectroscopy method. Irradiation at 261.5 nm prepares N-methyl-2-pyridone molecules with high vibrational levels in the 11ππ* state. The radiation-less decay to the ground state via internal conversion is suggested to be the dominant channel for the 11ππ* state with large vibrational excess energy, which is revealed by a lifetime of 1.6 ± 0.2 ps. As the pump wavelength decreases, we found that irradiation at 238.5 and 227.9 nm results in the population of the 21ππ* state. This is in agreement with the assignment of the vapor-phase UV absorption bands of N-methyl-2-pyridone. On the basis of the detailed analysis of our measured time-resolved photoelectron spectra at all pump wavelengths, we conclude that the 21ππ* state has an ultrashort lifetime of 50 ± 10 fs. In addition, the S1(11ππ*) state is subsequently populated via internal conversion and decays over a lifetime of 680-620 fs. The most probable whole deactivation pathway of the 21ππ* state is discussed. This experimental study provides new insights into the excitation energy-dependent decay dynamics of electronically excited N-methyl-2-pyridone.
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Affiliation(s)
- Baihui Feng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenping Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhigang He
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Dongyuan Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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3
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Feng B, Wu W, Yang S, He Z, Fang B, Yang D, Wu G, Yang X. Insights into ultrafast decay dynamics of electronically excited pyridine- N-oxide. Phys Chem Chem Phys 2024; 26:8308-8317. [PMID: 38389467 DOI: 10.1039/d3cp06187f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The ultrafast decay dynamics of pyridine-N-oxide upon excitation in the near-ultraviolet range of 340.2-217.6 nm is investigated using the femtosecond time-resolved photoelectron imaging technique. The time-resolved photoelectron spectra and photoelectron angular distributions at all pump wavelengths are carefully analyzed and the following view is derived: at the longest pump wavelengths (340.2 and 325.6 nm), pyridine-N-oxide is excited to the S1(1ππ*) state with different vibrational levels. The depopulation rate of the S1 state shows a marked dependence on vibrational energy and mode, and the lifetime is in the range of 1.4-160 ps. At 289.8 and 280.5 nm, both the second 1ππ* state and the S1 state are initially prepared. The former has an extremely short lifetime of ∼60 fs, which indicates that the ultrafast deactivation pathway such as a rapid internal conversion to one close-lying state is its dominant decay channel, while the latter is at high levels of vibrational excitation and decays within the range of 380-520 fs. At the shortest pump wavelengths (227.3 and 217.6 nm), another excited state of Rydberg character is mostly excited. We assign this state to the 3s Rydberg state which has a lifetime of 0.55-2.2 ps. This study provides a comprehensive picture of the ultrafast excited-state decay dynamics of the photoexcited pyridine-N-oxide molecule.
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Affiliation(s)
- Baihui Feng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
- Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenping Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuaikang Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhigang He
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
| | - Benjie Fang
- Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Dongyuan Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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4
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Lamas I, Montero R, Martínez-Martínez V, Longarte A. Photodynamics of azaindoles in polar media: the influence of the environment. Phys Chem Chem Phys 2024; 26:3240-3252. [PMID: 38193884 DOI: 10.1039/d3cp03412g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
We have studied the relaxation dynamics of a family of azaindole (AI) structural isomers, 4-, 5-, 6- and 7-AI, by steady-state and time-resolved methods (fs-transient absorption and fluorescence up-conversion), in solvents of different polarity. The measurements in aprotic solvents show distinctive fluorescence yields and excited state lifetimes among the isomers, which are tuned by the polarity of the medium. Guided by simple TD-DFT calculations and based on the behavior observed in the isolated species, it has been possible to address the influence of the environment polarity on the relaxation route. According to the obtained picture, the energy of the nπ* state, which is strongly dependent on the position of the pyridinic nitrogen, controls the rate of the internal conversion channel that accounts for the distinctive photophysical behavior of the isomers. On the other hand, preliminary measurements in protic media (methanol) show a very different photodynamical behavior, in which the anomalous measured fluorescent patterns are very likely the result of reactive channels (proton transfer) triggered by the electronic excitation.
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Affiliation(s)
- Iker Lamas
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
| | - Raúl Montero
- SGIKER Laser Facility Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) 48940, Leioa, Spain.
| | - Virginia Martínez-Martínez
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
| | - Asier Longarte
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
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5
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Feng B, Yang D, He Z, Fang B, Wu G, Yang X. Excitation Energy-Dependent Decay Dynamics of the S 1 State of N-Methyl-2-pyridone. J Phys Chem A 2023; 127:10139-10146. [PMID: 38058157 DOI: 10.1021/acs.jpca.3c05745] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
The UV-induced decay dynamics of N-methyl-2-pyridone is investigated using a femtosecond time-resolved photoelectron spectroscopy method. Irradiation in the wavelength range of 339.3-258.9 nm prepares N-methyl-2-pyridone molecules with very different vibrational levels of the S1(11ππ*) state. For v' = 0 (origin) and a few low-energy vibrational levels slightly above the S1 state origin, the radiative decay channel is in operation for some specific vibrations. This is revealed by the excited-state lifetime of ≫1 ns. In addition, some other nearby S1 vibronic states have a much shorter lifetime in the range of several picoseconds to a few tens of picoseconds, indicating that the radiation-less decay to the ground state (S0) via internal conversion is the dominant channel for them. As the pump wavelength slightly decreases, the radiative decay is suddenly not important at all, and the deactivation rate of the S1 state becomes faster. At shorter pump wavelengths, the lifetime of highly excited vibrational states of the S1 state further decreases with the increase in the vibrational excess energy. This study provides quantitative information about the excitation energy-dependent decay dynamics of the S1 state of N-methyl-2-pyridone. Methyl substitution effects on the excited-state dynamics of 2-pyridone are also discussed.
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Affiliation(s)
- Baihui Feng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongyuan Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Zhigang He
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Benjie Fang
- Key Laboratory of Chemical Lasers, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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6
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Hennefarth MR, Hermes MR, Truhlar DG, Gagliardi L. Linearized Pair-Density Functional Theory. J Chem Theory Comput 2023. [PMID: 37207365 DOI: 10.1021/acs.jctc.3c00207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Multiconfiguration pair-density functional theory (MC-PDFT) is a post-SCF multireference method that has been successful at computing ground- and excited-state energies. However, MC-PDFT is a single-state method in which the final MC-PDFT energies do not come from diagonalization of a model-space Hamiltonian matrix, and this can lead to inaccurate topologies of potential energy surfaces near locally avoided crossings and conical intersections. Therefore, in order to perform physically correct ab initio molecular dynamics with electronically excited states or to treat Jahn-Teller instabilities, it is necessary to develop a PDFT method that recovers the correct topology throughout the entire nuclear configuration space. Here we construct an effective Hamiltonian operator, called the linearized PDFT (L-PDFT) Hamiltonian, by expanding the MC-PDFT energy expression to first order in a Taylor series of the wave function density. Diagonalization of the L-PDFT Hamiltonian gives the correct potential energy surface topology near conical intersections and locally avoided crossings for a variety of challenging cases including phenol, methylamine, and the spiro cation. Furthermore, L-PDFT outperforms MC-PDFT and previous multistate PDFT methods for predicting vertical excitations from a variety of representative organic chromophores.
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Affiliation(s)
- Matthew R Hennefarth
- Department of Chemistry, Pritzker School of Molecular Engineering, The James Franck Institute, and Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Matthew R Hermes
- Department of Chemistry, Pritzker School of Molecular Engineering, The James Franck Institute, and Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
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7
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Jaekel S, Durant E, Schied M, Persson M, Ostapko J, Kijak M, Waluk J, Grill L. Tautomerization of single asymmetric oxahemiporphycene molecules on Cu(111). Phys Chem Chem Phys 2023; 25:1096-1104. [PMID: 36530140 DOI: 10.1039/d2cp04746b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have studied 22-oxahemiporphycene molecules by a combination of scanning tunneling microscopy at low temperatures and density functional theory calculations. In contrast to other molecular switches with typically two switching states, these molecules can in principle exist in three different tautomers, due to their asymmetry and three inequivalent binding positions of a hydrogen atom in their macrocycle. Different tautomers are identified from the typical appearance on the surface and tunneling electrons can be used to tautomerize single molecules in a controllable way with the highest rates if the STM tip is placed close to the hydrogen binding positions in the cavity. Characteristic switching processes are explained by the different energy pathways upon adsorption on the surface. Upon applying higher bias voltages, deprotonation occurs instead of tautomerization, which becomes evident in the molecular appearance.
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Affiliation(s)
- Simon Jaekel
- Department of Physical Chemistry, University of Graz, Heinrichstraße 28, Graz, Austria.
| | - Emile Durant
- Surface Science Research Centre, Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK
| | - Monika Schied
- Department of Physical Chemistry, University of Graz, Heinrichstraße 28, Graz, Austria.
| | - Mats Persson
- Surface Science Research Centre, Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK
| | - Jakub Ostapko
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Michał Kijak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jacek Waluk
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.,Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland
| | - Leonhard Grill
- Department of Physical Chemistry, University of Graz, Heinrichstraße 28, Graz, Austria.
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8
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Roy Chowdhury P, Khodia S, Maity S. Solvent assisted excited-state deactivation pathways in isolated 2,7-diazaindole-S 1-3 (S = Water and Ammonia) complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 278:121285. [PMID: 35533603 DOI: 10.1016/j.saa.2022.121285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 06/14/2023]
Abstract
The role of solvent molecules in the deactivation of photo-excited 2,7-diazaindole (DAI) - (H2O)1-3 and DAI - (NH3)1-3 complexes were computationally investigated. An excited-state proton transfer (ESPT) path from the solvent to the DAI molecule was followed using the TD-DFT-D4 (B3LYP) level of theory. The computed potential energy profile of ESPT process has shown intersection between ππ* and nπ* states facilitated via relative stabilization of the nπ* state with decreasing N(7)-Hb bond length. The ESPT process, starting from the DAI-Sn (ππ*) state, crosses through a barrier ranging from 27 to 36 kJmol-1 for water complexes and 26-30 kJmol-1 for ammonia complexes. The energy of the excited state was rapidly decreased with a shorter N(7)-Hb bond length. Subsequently, a significant trend of finding a second intersection between the ground and the excited state was observed for all the complexes. The results firmly suggested a significant deactivation channel of excited azaindole derivatives. In the present system, two competing channels, ESPT and ESHT, were found to be energetically accessible. The energy barriers associated with the ESPT barriers for DAI-(H2O)1-3 complexes are similar to the ESHT barrier, depicting equal dominance of both processes. The increased basicity of the N(7) atom in the excited state resulted a facile ESPT process from the water to N(7) of the DAI molecule. However, DAI-(NH3)1-3 complexes show clear preference for ESHT over ESPT process owing to its higher gas-phase pKa value making it a poor proton donor. The above systems can be used as a model to computationally and experimentally investigate the competing radiative and deactivation pathways of photo-excited solvated complexes of N-H-bearing bio-relevant molecules via proton and hydrogen transfer reactions.
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Affiliation(s)
| | - Saurabh Khodia
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502285, India
| | - Surajit Maity
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana 502285, India.
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9
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Yang D, Min Y, Feng B, Yang X, Wu G. Vibrational-state dependent decay dynamics of 2-pyridone excited to the S 1 electronic state. Phys Chem Chem Phys 2022; 24:22710-22715. [PMID: 36106839 DOI: 10.1039/d2cp03279a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The S1(1ππ*) state decay dynamics of 2-pyridone excited around the 000 band origin is investigated using femtosecond time-resolved photoelectron imaging technique. At a pump wavelength of 334.0 nm, the vibrational ground state and a few low energy vibrational states covered by the bandwidth of the pump laser pulses are excited. The lifetimes of the vibrational states show strong dependence on the vibrational energy and mode. A quantum beat between two lowest energy vibrational states is also observed. This study provides quantitative information about the vibrational-state dependent lifetime of the S1 state of 2-pyridone.
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Affiliation(s)
- Dongyuan Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
| | - Yanjun Min
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baihui Feng
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China. .,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China. .,Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, China.
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10
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Milovanović B, Novak J, Etinski M, Domcke W, Došlić N. On the propensity of formation of cyclobutane dimers in face-to-face and face-to-back uracil stacks in solution. Phys Chem Chem Phys 2022; 24:14836-14845. [PMID: 35697028 DOI: 10.1039/d2cp00495j] [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
UV irradiation of RNA leads to the formation of intra- and inter-strand crosslinks of cyclobutane type. Despite the importance of this reaction, relatively little is known about how the mutual orientation of the two bases affects the outcome of the reaction. Here we report a comparative nonadiabatic molecular dynamics study of face-to-back (F2B) and face-to-face (F2F) stacked uracil-water clusters. The computations were performed using the second-order algebraic-diagrammatic-construction (ADC(2)) method. We found that F2B stacked uracil-water clusters either relax non-reactively to the ground state by an ethylenic twist around the CC bond or remain in the lowest nπ* state in which the two bases gradually move away from each other. This finding is consistent with the low propensity for the formation of intra-strand cyclobutane dimers between adjacent RNA bases. On the contrary, in F2F stacked uracil-water clusters, in addition to non-reactive deactivation, we found a pro-reactive deactivation pathway, which may lead to the formation of cyclobutane uracil dimers in the electronic ground state. On a qualitative level, the observed photodynamics of F2F stacked uracil-water clusters explains the greater propensity of RNA to form inter-strand cyclobutane-type crosslinks.
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Affiliation(s)
| | - Jurica Novak
- Department of Biotechnology, University of Rijeka, HR-51000 Rijeka, Croatia.,Scientific and Educational Center "Biomedical Technologies" School of Medical Biology, South Ural State University, RU-454080, Chelyabinsk, Russia.,Center for Artificial Intelligence and Cybersecurity, University of Rijeka, 51000 Rijeka, Croatia
| | - Mihajlo Etinski
- University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia
| | - Wolfgang Domcke
- Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Nađa Došlić
- Department of Physical Chemistry, Ruđer Bošković Institute, Zagreb, Croatia.
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11
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Ashfold MNR, Kim SK. Non-Born-Oppenheimer effects in molecular photochemistry: an experimental perspective. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20200376. [PMID: 35341307 DOI: 10.1098/rsta.2020.0376] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 06/28/2021] [Indexed: 06/14/2023]
Abstract
Non-adiabatic couplings between Born-Oppenheimer (BO)-derived potential energy surfaces are now recognized as pivotal in describing the non-radiative decay of electronically excited molecules following photon absorption. This opinion piece illustrates how non-BO effects provide photostability to many biomolecules when exposed to ultraviolet radiation, yet in many other cases are key to facilitating 'reactive' outcomes like isomerization and bond fission. The examples are presented in order of decreasing molecular complexity, spanning studies of organic sunscreen molecules in solution, through two families of heteroatom containing aromatic molecules and culminating with studies of isolated gas phase H2O molecules that afford some of the most detailed insights yet available into the cascade of non-adiabatic couplings that enable the evolution from photoexcited molecule to eventual products. This article is part of the theme issue 'Chemistry without the Born-Oppenheimer approximation'.
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Affiliation(s)
| | - Sang Kyu Kim
- Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea
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12
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Khodia S, Maity S. A combined experimental and computational study on the deactivation of a photo-excited 2,2'-pyridylbenzimidazole-water complex via excited-state proton transfer. Phys Chem Chem Phys 2022; 24:12043-12051. [PMID: 35537136 DOI: 10.1039/d2cp01121b] [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
In this report, we present solvent assisted excited-state proton transfer coupled to the deactivation of a photo-excited 2,2'-pyridylbenzimidazole bound to a single water molecule. Experimentally, the mass-selected 1 : 1 complex was probed using two-colour resonant two-photon ionization (2C-R2PI) and UV-UV hole-burning (HB) spectroscopy in a supersonically jet-cooled molecular beam. Computationally, three structural isomers were identified as the normal, the tautomer and the proton transfer product of the PBI-H2O complex in the excited S1 state using B3LYP-D4/def2-TZVPP and ADC(2) (MP2)/cc-pVDZ levels of theory. The most stable form in the ground state, i.e., the normal form, was identified using the excitation spectrum in the 30 544 to 30 936 cm-1 region. The 2C-R2PI spectrum showed a sudden break-off above the 000 + 392 cm-1 region, even though the Frack-Condon activity of the S1 ← S0 transition was measured beyond 000 + 1000 cm-1 in the HB spectrum. The intensity of the bands associated with the excited state intermolecular vibrational modes near the break-off region was found to be drastically decreased, which indicates efficient quantum mechanical tunnelling along the hydrogen transfer coordinate. The sudden disappearance of the intermolecular vibrational modes in the spectrum revealed the existence of a deactivation channel in the PBI-H2O complex near 392-450 cm-1 above the 000 transition. The computational investigation predicted that the deactivation of the excited-state occurred via the intersection between the S1 and S0 states, which was associated with the proton transfer from the H2O to the PBI molecule along the O(3)-H(4)→N(5) coordinate. The highest energy structure was identified as the point of intersection between the nπ* (S2) and ππ* (S1) states. The associated barrier height was experimentally determined to be 392-450 cm-1, which showed a reasonable agreement with the calculated excited-state proton transfer barrier. Competing reaction channels such as dissociation and tautomerization were found to be highly energetically inaccessible.
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Affiliation(s)
- Saurabh Khodia
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana, India.
| | - Surajit Maity
- Department of Chemistry, IIT Hyderabad, Kandi, Sangareddy, Telangana, India.
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13
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Lapinski L, Rostkowska H, Nowak MJ. Distinct class of photoinduced hydrogen-atom-transfer processes: phototautomerizations in molecules with no intramolecular hydrogen bond in the structure. INT REV PHYS CHEM 2022. [DOI: 10.1080/0144235x.2022.2030613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Leszek Lapinski
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Rostkowska
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Maciej J. Nowak
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
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14
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15
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Wang G, Liu T, Caracciolo A, Vansco MF, Trongsiriwat N, Walsh PJ, Marchetti B, Karsili TNV, Lester MI. Photodissociation dynamics of methyl vinyl ketone oxide: A four-carbon unsaturated Criegee intermediate from isoprene ozonolysis. J Chem Phys 2021; 155:174305. [PMID: 34742186 DOI: 10.1063/5.0068664] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The electronic spectrum of methyl vinyl ketone oxide (MVK-oxide), a four-carbon Criegee intermediate derived from isoprene ozonolysis, is examined on its second π* ← π transition, involving primarily the vinyl group, at UV wavelengths (λ) below 300 nm. A broad and unstructured spectrum is obtained by a UV-induced ground state depletion method with photoionization detection on the parent mass (m/z 86). Electronic excitation of MVK-oxide results in dissociation to O (1D) products that are characterized using velocity map imaging. Electronic excitation of MVK-oxide on the first π* ← π transition associated primarily with the carbonyl oxide group at λ > 300 nm results in a prompt dissociation and yields broad total kinetic energy release (TKER) and anisotropic angular distributions for the O (1D) + methyl vinyl ketone products. By contrast, electronic excitation at λ ≤ 300 nm results in bimodal TKER and angular distributions, indicating two distinct dissociation pathways to O (1D) products. One pathway is analogous to that at λ > 300 nm, while the second pathway results in very low TKER and isotropic angular distributions indicative of internal conversion to the ground electronic state and statistical unimolecular dissociation.
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Affiliation(s)
- Guanghan Wang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Tianlin Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Adriana Caracciolo
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Michael F Vansco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Nisalak Trongsiriwat
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Barbara Marchetti
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, USA
| | - Tolga N V Karsili
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, USA
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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16
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Jouybari M, Green JA, Improta R, Santoro F. The Ultrafast Quantum Dynamics of Photoexcited Adenine-Thymine Basepair Investigated with a Fragment-based Diabatization and a Linear Vibronic Coupling Model. J Phys Chem A 2021; 125:8912-8924. [PMID: 34609880 PMCID: PMC9281421 DOI: 10.1021/acs.jpca.1c08132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this contribution we present a quantum dynamical study of the photoexcited hydrogen bonded base pair adenine-thymine (AT) in a Watson-Crick arrangement. To that end, we parametrize Linear Vibronic Coupling (LVC) models with Time-Dependent Density Functional Theory (TD-DFT) calculations, exploiting a fragment diabatization scheme (FrD) we have developed to define diabatic states on the basis of individual chromophores in a multichromophoric system. Wavepacket propagations were run with the multilayer extension of the Multiconfiguration Time-Dependent Hartree method. We considered excitations to the three lowest bright states, a ππ* state of thymine and two ππ* states (La and Lb) of adenine, and we found that on the 100 fs time scale the main decay pathways involve intramonomer population transfers toward nπ* states of the same nucleobase. In AT this transfer is less effective than in the isolated nucleobases, because hydrogen bonding destabilizes the nπ* states. The population transfer to the A → T charge transfer state is negligible, making the ultrafast (femtosecond) decay through the proton coupled electron transfer mechanism unlikely, in line with experimental results in apolar solvents. The excitation energy transfer is also very small. We carefully compare the predictions of LVC Hamiltonians obtained with different sets of diabatic states, defined so to match either local states of the two separated monomers or the base pair adiabatic states in the Franck-Condon region. To that end we also extend the flexibility of the FrD-LVC approach, introducing a new strategy to define fragments diabatic states that account for the effect of the rest of the multichromohoric system through a Molecular Mechanics potential.
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Affiliation(s)
- Martha
Yaghoubi Jouybari
- Consiglio
Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo
Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
| | - James A. Green
- Consiglio
Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), via Mezzocannone 16, I-80136 Napoli, Italy
| | - Roberto Improta
- Consiglio
Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), via Mezzocannone 16, I-80136 Napoli, Italy
| | - Fabrizio Santoro
- Consiglio
Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo
Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy
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17
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Wang J, Blancafort L. Stability and Optical Absorption of a Comprehensive Virtual Library of Minimal Eumelanin Oligomer Models**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202106289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Wang
- Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials Jiangsu Engineering Laboratory for Environment Functional Materials School of Chemistry and Chemical Engineering Huaiyin Normal University No.111 West Changjiang Road Huaian 223300 Jiangsu Province P. R. China
- Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona, Facultat de Ciències C/M. A. Capmany 69 17003 Girona Spain
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona, Facultat de Ciències C/M. A. Capmany 69 17003 Girona Spain
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18
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Wang X, Martínez-Fernández L, Zhang Y, Zhang K, Improta R, Kohler B, Xu J, Chen J. Solvent-Dependent Stabilization of a Charge Transfer State is the Key to Ultrafast Triplet State Formation in an Epigenetic DNA Nucleoside. Chemistry 2021; 27:10932-10940. [PMID: 33860588 DOI: 10.1002/chem.202100787] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/10/2022]
Abstract
2'-Deoxy-5-formylcytidine (5fdCyd), a naturally occurring nucleoside found in mammalian DNA and mitochondrial RNA, exhibits important epigenetic functionality in biological processes. Because it efficiently generates triplet excited states, it is an endogenous photosensitizer capable of damaging DNA, but the intersystem crossing (ISC) mechanism responsible for ultrafast triplet state generation is poorly understood. In this study, time-resolved mid-IR spectroscopy and quantum mechanical calculations reveal the distinct ultrafast ISC mechanisms of 5fdCyd in water versus acetonitrile. Our experiment indicates that in water, ISC to triplet states occurs within 1 ps after 285 nm excitation. PCM-TD-DFT computations suggest that this ultrafast ISC is mediated by a singlet state with significant cytosine-to-formyl charge-transfer (CT) character. In contrast, ISC in acetonitrile proceeds via a dark 1 nπ* state with a lifetime of ∼3 ps. CT-induced ISC is not favored in acetonitrile because reaching the minimum of the gateway CT state is hampered by intramolecular hydrogen bonding, which enforces planarity between the aldehyde group and the aromatic group. Our study provides a comprehensive picture of the non-radiative decay of 5fdCyd in solution and new insights into the factors governing ISC in biomolecules. We propose that the intramolecular CT state observed here is a key to the excited-state dynamics of epigenetic nucleosides with modified exocyclic functional groups, paving the way to study their effects in DNA strands.
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Affiliation(s)
- Xueli Wang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, P. R. China
| | - Lara Martínez-Fernández
- Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemistry (IADCHEM), Universidad Autónoma de Madrid Campus de Excelencia UAM-CSIC Cantoblanco, 28049, Madrid, Spain
| | - Yuyuan Zhang
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio, 43210, USA
| | - Kun Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, P. R. China
| | - Roberto Improta
- Istituto di Biostrutture e Bioimmagini CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Bern Kohler
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio, 43210, USA
| | - Jianhua Xu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, P. R. China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi, 030006, P. R. China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, P. R. China.,Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi, 030006, P. R. China
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19
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Zhou P, Tang Z, Li P, Liu J. Unraveling the Mechanism for Tuning the Fluorescence of Fluorescein Derivatives: The Role of the Conical Intersection and nπ* State. J Phys Chem Lett 2021; 12:6478-6485. [PMID: 34240884 DOI: 10.1021/acs.jpclett.1c01774] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Although a large number of fluorescein derivatives have been developed and applied in many different fields, the general mechanisms for tuning the fluorescence of fluorescein derivatives still remain uncovered. Herein, we found that the fluorescence quenching of neutral form of fluorescein derivatives in acidic medium resulted from a dark nπ* state, whereas the fluorescence of the anionic form of fluorescein derivatives in the gas phase and alkaline solutions was tuned by minimal energy conical intersection (MECI). The formation of MECI involved significant rotation of benzene ring and flip-flop motion of xanthene moiety, which would be restricted by intermolecular hydrogen bonding and lowering temperature. The energy barrier for reaching MECI depended on the substituents in the benzene moiety in accordance with experimentally observed substituent effects. These unprecedented mechanisms would lead to a recognition of fluorescein derivatives and could provide a correct and instructive design strategy for further developing new fluorescein derivatives.
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Affiliation(s)
- Panwang Zhou
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, P. R. China
| | - Zhe Tang
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, P. R. China
| | | | - Jianyong Liu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, Liaoning China
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20
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Wang J, Blancafort L. Stability and Optical Absorption of a Comprehensive Virtual Library of Minimal Eumelanin Oligomer Models*. Angew Chem Int Ed Engl 2021; 60:18800-18809. [PMID: 34114313 PMCID: PMC8457142 DOI: 10.1002/anie.202106289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/09/2021] [Indexed: 12/11/2022]
Abstract
Eumelanin is responsible for photoprotection in living organisms. It is made of 5,6‐dihydroxyindole (DHI) oligomers. However, lack of detailed structural knowledge limits understanding its function and exploiting its potential in material science. To uncover the relationship between structural stability and optical properties, we have studied a virtual library of 830 DHI dimers. We find a preference for oxidized, polycyclic structures which speaks in favor of graphite‐like structures for the larger oligomers, and propose an electrocyclic formation mechanism. Besides widely considered quinone oxidation patterns, also structures with interfragment double bonds and zwitterionic resonance structures are stable. Future theoretical melanine models will have to cover this diversity, and we introduce a new representative set of 49 stable dimers. Some stable oxidized dimers have absorption energies as low as 1.3 eV. They may be present as substructures in the naturally found oligomers and contribute to the absorption spectrum of the biopolymer.
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Affiliation(s)
- Jun Wang
- Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, Jiangsu Engineering Laboratory for Environment Functional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, No.111 West Changjiang Road, Huaian, 223300, Jiangsu Province, P. R. China.,Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Facultat de Ciències, C/M. A. Capmany 69, 17003, Girona, Spain
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Facultat de Ciències, C/M. A. Capmany 69, 17003, Girona, Spain
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21
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How the stability, reactivity and optical response of the protonated base pairs differ with other biologically important adenine–thymine pairs: a DFT and TD-DFT approach. CHEMICAL PAPERS 2021. [DOI: 10.1007/s11696-020-01474-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Milovanović B, Novak J, Etinski M, Domcke W, Došlić N. Simulation of UV absorption spectra and relaxation dynamics of uracil and uracil-water clusters. Phys Chem Chem Phys 2021; 23:2594-2604. [PMID: 33475644 DOI: 10.1039/d0cp05618a] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy with nonadiabatic dynamics simulations to identify the photophysical mechanisms that can give rise to experimentally observed decay time constants. We first compute and theoretically assign the electronic spectra of uracil using the second-order algebraic-diagrammatic-construction (ADC(2)) method. The obtained electronic states, their energy differences and state-specific solvation effects are the prerequisites for understanding the photodynamics. We then use nonadiabatic trajectory-surface-hopping dynamics simulations to investigate the photoinduced dynamics of uracil and uracil-water clusters. In contrast to previous studies, we found that a single mechanism - the ethylenic twist around the C[double bond, length as m-dash]C bond - is responsible for the ultrafast component of the nonradiative decay, both in the gas phase and in solution. Very good agreement with the experimentally determined ultrashort decay time constants is obtained.
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Affiliation(s)
| | - Jurica Novak
- Department of Physical Chemistry, Ruđer Bošković Institute, Zagreb, Croatia. and Higher Medical and Biological School, South Ural State University, Chelyabinsk, Russia
| | - Mihajlo Etinski
- University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia
| | - Wolfgang Domcke
- Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Nađa Došlić
- Department of Physical Chemistry, Ruđer Bošković Institute, Zagreb, Croatia.
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23
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Pagacz-Kostrzewa M, Kochman M, Gul W, Wierzejewska M. Phototransformations of 2-aminonicotinic acid resolved with matrix isolation infrared spectroscopy and ab initio calculations. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Bühlmeyer A, Ehni P, Ullmann D, Frey W, Baro A, Laschat S. Synthesis and Liquid Crystalline Self‐Assembly of Concave Diindoles with a Hydropentalene Core. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Andrea Bühlmeyer
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Philipp Ehni
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Dustin Ullmann
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Wolfgang Frey
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Angelika Baro
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Sabine Laschat
- Institut für Organische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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25
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Léger SJ, Marchetti B, Ashfold MNR, Karsili TNV. The Role of Norrish Type-I Chemistry in Photoactive Drugs: An ab initio Study of a Cyclopropenone-Enediyne Drug Precursor. Front Chem 2020; 8:596590. [PMID: 33425854 PMCID: PMC7793749 DOI: 10.3389/fchem.2020.596590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/25/2020] [Indexed: 01/01/2023] Open
Abstract
We present a contemporary mechanistic description of the light-driven conversion of cyclopropenone containing enediyne (CPE) precusors to ring-opened species amenable to further Bergman cyclization and formation of stable biradical species that have been proposed for use in light-induced cancer treatment. The transformation is rationalized in terms of (purely singlet state) Norrish type-I chemistry, wherein photoinduced opening of one C-C bond in the cyclopropenone ring facilitates non-adiabatic coupling to high levels of the ground state, subsequent loss of CO and Bergman cyclization of the enediyne intermediate to the cytotoxic target biradical species. Limited investigations of substituent effects on the ensuing photochemistry serve to vindicate the experimental choices of Popik and coworkers (J. Org. Chem., 2005, 70, 1297-1305). Specifically, replacing the phenyl moiety in the chosen model CPE by a 1,4-benzoquinone unit leads to a stronger, red-shifted parent absorption, and increases the exoergicity of the parent → biradical conversion.
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Affiliation(s)
- Spencer J. Léger
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, United States
- Department of Chemical Engineering, University of Louisiana at Lafayette, Lafayette, LA, United States
| | - Barbara Marchetti
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, United States
| | | | - Tolga N. V. Karsili
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, United States
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26
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Lopes Jesus AJ, Rosado MTS, Fausto R, Reva I. UV-induced radical formation and isomerization of 4-methoxyindole and 5-methoxyindole. Phys Chem Chem Phys 2020; 22:22943-22955. [PMID: 33026378 DOI: 10.1039/d0cp04354k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Monomers of 4-methoxyindole and 5-methoxyindole trapped in low-temperature xenon matrices (15-16 K) were characterized by IR spectroscopy, in separate experiments. Each compound was shown to adopt the most stable 1H-tautomeric form. The photochemistry of the matrix-isolated compounds was then investigated by exciting the matrices with narrowband UV light with λ ≤ 305 nm. Two main photoproducts, similar for each compound, have been detected: (1) 4-methoxy- or 5-methoxy-indolyl radical, resulting from cleavage of the N-H bond; (2) 3H-tautomers (4-methoxy- or 5-methoxy-) with the released hydrogen atom reconnected at the C3 ring carbon atom. The presence of the two types of photoproducts in the UV-irradiated matrices was confirmed by comparison of their B3LYP/6-311++G(d,p) calculated IR spectra with the experimental spectra emerging upon the irradiations. The mechanism of the observed phototransformations was elucidated by Natural Bond Orbital and Natural Resonance Theory computations on the methoxy-substituted indolyl radicals resulting from the N-H bond cleavage. The highest natural atomic spin densities were predicted at the C3 and N1 positions of the indolyl ring, corresponding to a predominance of the resonance structures with the radical centres located at these two atoms. As a whole, the obtained experimental and theoretical data allowed establishing a general pattern for the photochemistry of methoxyindoles under matrix-isolation conditions.
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Affiliation(s)
- A J Lopes Jesus
- University of Coimbra, CQC, Department of Chemistry, 3004-535, Coimbra, Portugal.
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27
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Zhao L, Zhou G, Jia B, Teng G, Zhan K, Zheng H, Luo J, Liu B. New insight into the ultrafast excited state deactivation mechanism of guanosine in the gas phase. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Paterson MJ, Townsend D. Rydberg-to-valence evolution in excited state molecular dynamics. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1815389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
| | - Dave Townsend
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, UK
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, UK
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29
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Lamas I, Montero R, Martínez-Martínez V, Longarte A, Blancafort L. An nπ* gated decay mediates excited-state lifetimes of isolated azaindoles. Phys Chem Chem Phys 2020; 22:18639-18645. [PMID: 32789383 DOI: 10.1039/d0cp02635b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aiming to serve as a guide to understand the relaxation mechanisms of more complex aza-aromatic compounds, such as purine bases, we have studied the non-radiative channels of a set of azaindole structural isomers: 4-, 5-, 6- and 7-azaindole (AI). The relaxation of the isolated molecules, after excitation at the low energy portion of their spectra, has been tracked by femtosecond time-resolved ionization, and the decay paths have been obtained with MS-CASPT2//TD-DFT calculations. Although the ultrashort measured lifetimes for 5- and 6-AI are in contrast to the long-living excited state found in 7-AI, the calculations describe a common relaxation pathway. Along it, the initially excited ππ* states decay to the ground state through a conical intersection accessed through an nπ* state that functions as a gate state. The work reveals that the position of the nitrogen atoms in the purine ring determines the barrier to access the gate state and therefore, the rate of the non-radiative relaxation.
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Affiliation(s)
- Iker Lamas
- Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain.
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30
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Iwai R, Suzuki S, Sasaki S, Sairi AS, Igawa K, Suenobu T, Morokuma K, Konishi G. Bridged Stilbenes: AIEgens Designed via a Simple Strategy to Control the Non‐radiative Decay Pathway. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Riki Iwai
- Department of Chemical Science and Engineering Tokyo Institute of Technology 2-12-1-H-134 O-okayama, Meguro-ku Tokyo 152-8552 Japan
| | - Satoshi Suzuki
- Fukui Institute for Fundamental Chemistry Kyoto University Takano-Nishibiraki-cho 34-4, Sakyou-ku Kyoto 606-8103 Japan
| | - Shunsuke Sasaki
- Université de Nantes CNRS Institut des Matériaux Jean Rouxel IMN F-44000 Nantes France
| | - Amir Sharidan Sairi
- Department of Chemical Science and Engineering Tokyo Institute of Technology 2-12-1-H-134 O-okayama, Meguro-ku Tokyo 152-8552 Japan
| | - Kazunobu Igawa
- Institute for Materials Chemistry and Engineering Kyushu University Fukuoka 816-8580 Japan
| | - Tomoyoshi Suenobu
- Division of Advanced Science and Biotechnology Osaka University 2-1 Yamada-oka, Suita Osaka 565 Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry Kyoto University Takano-Nishibiraki-cho 34-4, Sakyou-ku Kyoto 606-8103 Japan
| | - Gen‐ichi Konishi
- Department of Chemical Science and Engineering Tokyo Institute of Technology 2-12-1-H-134 O-okayama, Meguro-ku Tokyo 152-8552 Japan
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31
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Suzuki S, Sasaki S, Sairi AS, Iwai R, Tang BZ, Konishi G. Principles of Aggregation-Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications. Angew Chem Int Ed Engl 2020; 59:9856-9867. [PMID: 32154630 PMCID: PMC7318703 DOI: 10.1002/anie.202000940] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Indexed: 12/16/2022]
Abstract
Twenty years ago, the concept of aggregation-induced emission (AIE) was proposed, and this unique luminescent property has attracted scientific interest ever since. However, AIE denominates only the phenomenon, while the details of its underlying guiding principles remain to be elucidated. This minireview discusses the basic principles of AIE based on our previous mechanistic study of the photophysical behavior of 9,10-bis(N,N-dialkylamino)anthracene (BDAA) and the corresponding mechanistic analysis by quantum chemical calculations. BDAA comprises an anthracene core and small electron donors, which allows the quantum chemical aspects of AIE to be discussed. The key factor for AIE is the control over the non-radiative decay (deactivation) pathway, which can be visualized by considering the conical intersection (CI) on a potential energy surface. Controlling the conical intersection (CI) on the potential energy surface enables the separate formation of fluorescent (CI:high) and non-fluorescent (CI:low) molecules [control of conical intersection accessibility (CCIA)]. The novelty and originality of AIE in the field of photochemistry lies in the creation of functionality by design and in the active control over deactivation pathways. Moreover, we provide a new design strategy for AIE luminogens (AIEgens) and discuss selected examples.
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Affiliation(s)
- Satoshi Suzuki
- Fukui Institute for Fundamental ChemistryKyoto UniversityTakano-Nishibiraki-cho 34-4, Sakyou-kuKyoto606-8103Japan
| | - Shunsuke Sasaki
- Université de NantesCNRSInstitut des Matériaux Jean Rouxel, IMNF-44000NantesFrance
| | - Amir Sharidan Sairi
- Department of Chemical Science and EngineeringTokyo Institute of Technology2-12-1-H-134 O-okayama, Meguro-kuTokyo152-8552Japan
| | - Riki Iwai
- Department of Chemical Science and EngineeringTokyo Institute of Technology2-12-1-H-134 O-okayama, Meguro-kuTokyo152-8552Japan
| | - Ben Zhong Tang
- Department of ChemistryThe Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong
| | - Gen‐ichi Konishi
- Department of Chemical Science and EngineeringTokyo Institute of Technology2-12-1-H-134 O-okayama, Meguro-kuTokyo152-8552Japan
- PRESTO (Japan) Science and Technology Agency (JST)Japan
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32
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Principles of Aggregation‐Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000940] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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33
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Iwai R, Suzuki S, Sasaki S, Sairi AS, Igawa K, Suenobu T, Morokuma K, Konishi GI. Bridged Stilbenes: AIEgens Designed via a Simple Strategy to Control the Non-radiative Decay Pathway. Angew Chem Int Ed Engl 2020; 59:10566-10573. [PMID: 32119188 DOI: 10.1002/anie.202000943] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/19/2020] [Indexed: 12/18/2022]
Abstract
To broaden the application of aggregation-induced emission (AIE) luminogens (AIEgens), the design of novel small-molecular dyes that exhibit high fluorescence quantum yield (Φfl ) in the solid state is required. Considering that the mechanism of AIE can be rationalized based on steric avoidance of non-radiative decay pathways, a series of bridged stilbenes was designed, and their non-radiative decay pathways were investigated theoretically. Bridged stilbenes with short alkyl chains exhibited a strong fluorescence emission in solution and in the solid state, while bridged stilbenes with long alkyl chains exhibited AIE. Based on this theoretical prediction, we developed the bridged stilbenes BPST[7] and DPB[7], which demonstrate excellent AIE behavior.
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Affiliation(s)
- Riki Iwai
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1-H-134 O-okayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Satoshi Suzuki
- Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishibiraki-cho 34-4, Sakyou-ku, Kyoto, 606-8103, Japan
| | - Shunsuke Sasaki
- Université de Nantes, CNRS, Institut des Matériaux Jean Rouxel, IMN, F-44000, Nantes, France
| | - Amir Sharidan Sairi
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1-H-134 O-okayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Kazunobu Igawa
- Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, 816-8580, Japan
| | - Tomoyoshi Suenobu
- Division of Advanced Science and Biotechnology, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565, Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, Takano-Nishibiraki-cho 34-4, Sakyou-ku, Kyoto, 606-8103, Japan
| | - Gen-Ichi Konishi
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1-H-134 O-okayama, Meguro-ku, Tokyo, 152-8552, Japan
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34
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Szkaradek KE, Stadlbauer P, Šponer J, Góra RW, Szabla R. UV-induced hydrogen transfer in DNA base pairs promoted by dark nπ* states. Chem Commun (Camb) 2020; 56:201-204. [DOI: 10.1039/c9cc06180k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Formation of an excited-state complex enables ultrafast photorelaxation of dark nπ* states in GC and HC base pairs.
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Affiliation(s)
- Kinga E. Szkaradek
- Department of Physical and Quantum Chemistry
- Wroclaw University of Science and Technology
- Faculty of Chemistry
- Wrocław
- Poland
| | - Petr Stadlbauer
- Regional Centre of Advanced Technologies and Materials
- Faculty of Science
- Palacky University
- 771 46 Olomouc
- Czech Republic
| | - Jiří Šponer
- Regional Centre of Advanced Technologies and Materials
- Faculty of Science
- Palacky University
- 771 46 Olomouc
- Czech Republic
| | - Robert W. Góra
- Department of Physical and Quantum Chemistry
- Wroclaw University of Science and Technology
- Faculty of Chemistry
- Wrocław
- Poland
| | - Rafał Szabla
- Institute of Biophysics of the Czech Academy of Sciences
- 61265 Brno
- Czech Republic
- Institute of Physics
- Polish Academy of Sciences
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35
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Sapunar M, Domcke W, Došlić N. UV absorption spectra of DNA bases in the 350-190 nm range: assignment and state specific analysis of solvation effects. Phys Chem Chem Phys 2019; 21:22782-22793. [PMID: 31595896 DOI: 10.1039/c9cp04662c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The theoretical assignment of electronic spectra of polyatomic molecules is a challenging problem that requires the specification of the character of a large number of electronic states. We propose a procedure for automatically determining the character of electronic transitions and apply it to the study of UV spectra of DNA bases in the gas phase and in the aqueous environment. The procedure is based on the computation of electronic wave function overlaps and accounts for an extensive sampling of nuclear geometries. Novelties of this work are the theoretical assignment of the electronic spectra of DNA bases up to 190 nm and a state specific analysis of solvation effects. By accounting for different effects contributing to the total solvent shift we obtained a good agreement between the computed and experimental spectra. Effects of vibrational averaging, temperature and solvent-induced structural changes shift excitation energies to lower values. Solvent-solute electrostatic interactions are state specific and strongly destabilize nRyd states, and to lesser extent nπ* and πRyd states. Altogether, this results in the stabilization of ππ* states and destabilization of nπ*, πRyd and nRyd states in solution.
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Affiliation(s)
- Marin Sapunar
- Department of Physical Chemistry, Ruder Bošković Institute, 10000 Zagreb, Croatia.
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36
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León I, Fernández JA. Influence of the solvent in the electronic excitation of aromatic alcohols: Excited state IR-UV of propofol(H 2O) 8. J Chem Phys 2019; 150:214306. [PMID: 31176335 DOI: 10.1063/1.5093813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
It is well known that water plays an important role in the reactivity and dynamics in a solution of molecules in electronic excited states. For example, electronic excitation is usually accompanied by a solvent rearrangement that may also influence the redistribution of the excitation energy. However, there is a lack of experimental data on such processes. Here, we explore the structural changes that follow electronic excitation in aggregates of propofol (2,6-diisopropylphenol) with up to eight water molecules, using a combination of mass-resolved excitation spectroscopy and density functional theory calculations. The molecules of water form a polyhedron around the hydroxyl group of propofol, also interacting with the π cloud of the aromatic ring. Electronic excitation produces a strong structural change in the water superstructure, which moves to an interaction with one of the carbon atoms of the aromatic ring, producing its distortion into a prefulvenic structure. Such deformation is not observed in smaller water clusters or in propofol-phenol aggregates highlighting the decisive role played by the solvent.
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Affiliation(s)
- Iker León
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV-EHU), Barrio Sarriena S/N, Leioa 48940, Spain
| | - José A Fernández
- Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV-EHU), Barrio Sarriena S/N, Leioa 48940, Spain
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37
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Hernández FJ, Bonafé FP, Aradi B, Frauenheim T, Sánchez CG. Simulation of Impulsive Vibrational Spectroscopy. J Phys Chem A 2019; 123:2065-2072. [DOI: 10.1021/acs.jpca.9b00307] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Federico J. Hernández
- Universidad Nacional de Córdoba. Facultad de Ciencias Quı́micas, Departamento de Quı́mica Teórica y Computacional, Córdoba Argentina
- Instituto de Investigaciones en Fisicoquímica de Córdoba, INFIQC (CONICET-Universidad Nacional de Córdoba), Córdoba 5000, Argentina
| | - Franco P. Bonafé
- Universidad Nacional de Córdoba. Facultad de Ciencias Quı́micas, Departamento de Quı́mica Teórica y Computacional, Córdoba Argentina
- Instituto de Investigaciones en Fisicoquímica de Córdoba, INFIQC (CONICET-Universidad Nacional de Córdoba), Córdoba 5000, Argentina
| | - Bálint Aradi
- Bremen Center for Computational Materials Science, Universität Bremen, Bremen 28359, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, Universität Bremen, Bremen 28359, Germany
| | - Cristián G. Sánchez
- Universidad Nacional de Córdoba. Facultad de Ciencias Quı́micas, Departamento de Quı́mica Teórica y Computacional, Córdoba Argentina
- Instituto de Investigaciones en Fisicoquímica de Córdoba, INFIQC (CONICET-Universidad Nacional de Córdoba), Córdoba 5000, Argentina
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38
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Montero R, Lamas I, León I, Fernández JA, Longarte A. Excited state dynamics of aniline homoclusters. Phys Chem Chem Phys 2019; 21:3098-3105. [PMID: 30672912 DOI: 10.1039/c8cp06416d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated the relaxation, following excitation in the 290-235 nm region, of neutral aniline homoclusters (An)n formed in a supersonic expansion by femtosecond time resolved ionization. The applied method permits isolation of the dynamics of the dimer from that originated in bigger species of the generated distribution. Interestingly, and differently from the monomer and (An)n≥3 clusters, the dimer does not present a N-H dissociative 1πσ* channel. This fact can be explained in terms of the symmetric structure adopted, in which each molecule establishes two N-Hπ interactions, destabilizing the H dissociation channel. The observations permit relating the photophysics to the interactions established by the aniline units and confirming previous observations and theoretical predictions on the structure of aniline aggregates.
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Affiliation(s)
- Raúl Montero
- SGIker Laser Facility, UPV/EHU, Sarriena, s/n, Leioa 48940, Spain
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39
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Marchetti B, Karsili TNV, Ashfold MNR. Exploring Norrish type I and type II reactions: an ab initio mechanistic study highlighting singlet-state mediated chemistry. Phys Chem Chem Phys 2019; 21:14418-14428. [DOI: 10.1039/c8cp07292b] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Norrish reactions are important photo-induced reactions in mainstream organic chemistry and are implicated in many industrially and biologically relevant processes and in the processing of carbonyl molecules in the atmosphere.
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Affiliation(s)
- Barbara Marchetti
- Department of Chemistry
- University of Louisiana at Lafayette
- Lafayette
- USA
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40
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Pepino AJ, Segarra-Martí J, Nenov A, Rivalta I, Improta R, Garavelli M. UV-induced long-lived decays in solvated pyrimidine nucleosides resolved at the MS-CASPT2/MM level. Phys Chem Chem Phys 2018; 20:6877-6890. [PMID: 29459916 DOI: 10.1039/c7cp08235e] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The most relevant 'dark' electronic excited states in DNA/RNA pyrimidine nucleosides are mapped in water employing hybrid MS-CASPT2/MM optimisations with explicit solvation and including the sugar. Conical intersections (CIs) between initially accessed bright 1ππ* and the lowest energy dark 1nπ* excited states, involving the lone pair localised on the oxygen and/or nitrogen atoms are characterised. They are found in the vicinities of the Franck-Condon (FC) region and are shown to facilitate non-adiabatic population transfer. The excited state population of the 1nOπ* state, localised in the carbonyl moiety on all pyrimidine nucleosides, is predicted to rapidly evolve to its minimum, displaying non-negligible potential energy barriers along its non-radiative decay, and accounting for the ps signal registered in pump-probe experiments as well as for an efficient population of the triplet state. Cytidine displays an additional 1nNπ* state localised in the N3 atom and that leads to its excited state minimum displaying large potential energy barriers in the pathway connecting to the CI with the ground state. Sugar-to-base hydrogen/proton transfer processes are assessed in solution for the first time, displaying a sizable barrier along its decay and thus being competitive with other slow decay channels in the ps and ns timescales. A unified deactivation scheme for the long-lived channels of pyrimidine nucleosides is delivered, where the 1nOπ* state is found to mediate the long-lived decay in the singlet manifold and act as the doorway for triplet population and thus accounting for the recorded phosphorescence and, more generally, for the transient/photoelectron spectral signals registered up to the ns timescale.
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Affiliation(s)
- Ana Julieta Pepino
- Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy.
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41
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Cooper GA, Hansen CS, Karsili TNV, Ashfold MNR. Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase. J Phys Chem A 2018; 122:9869-9878. [DOI: 10.1021/acs.jpca.8b09859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Graham A. Cooper
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Christopher S. Hansen
- School of Chemistry, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Tolga N. V. Karsili
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana 70504, United States
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42
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Concerted-asynchronous reaction path of the excited-state double proton transfer in the 7-azaindole homodimer and 6H-indolo[2,3-b]quinoline/7-azaindole heterodimer. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2017.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Cao J. The position of the N atom in the pentacyclic ring of heterocyclic molecules affects the excited-state decay: A case study of isothiazole and thiazole. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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44
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Karsili TN, Marchetti B, Ashfold MN. The role of 1πσ∗ states in the formation of adenine radical-cations in DNA duplexes. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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45
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Stange UC, Temps F. Ultrafast electronic deactivation of UV-excited adenine and its ribo- and deoxyribonucleosides and -nucleotides: A comparative study. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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46
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Martinez-Fernandez L, Prampolini G, Cerezo J, Liu Y, Santoro F, Improta R. Solvent effect on the energetics of proton coupled electron transfer in guanine-cytosine pair in chloroform by mixed explicit and implicit solvation models. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.07.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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47
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48
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Ai Y, Xing J, Zhang A, Zhao C, Liu Y, Xie B, Chen W, Cui G, Lu Z, Wang X. Computational Study on the Excited-State Decay of 5-Methylcytosine and 5-Hydroxymethylcytosine: The Common Form of DNA Methylation and Its Oxidation Product. J Phys Chem B 2018; 122:10424-10434. [DOI: 10.1021/acs.jpcb.8b07830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | | | | | | | - Binbin 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
| | | | - Xiangke Wang
- NAAM Research Group, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Collaborative Innovation Centre of Radiation Medicine of Jiangsu Higher Education Institutions, School for Radiological and Interdisciplinary Sciences, Soochow University, Suzhou 215123, P. R. China
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49
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Lischka H, Nachtigallová D, Aquino AJA, Szalay PG, Plasser F, Machado FBC, Barbatti M. Multireference Approaches for Excited States of Molecules. Chem Rev 2018; 118:7293-7361. [DOI: 10.1021/acs.chemrev.8b00244] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Hans Lischka
- School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P.R. China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
| | - Dana Nachtigallová
- Institute of Organic Chemistry and Biochemistry v.v.i., The Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Palacký University, 78371 Olomouc, Czech Republic
| | - Adélia J. A. Aquino
- School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P.R. China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
- Institute for Soil Research, University of Natural Resources and Life Sciences Vienna, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria
| | - Péter G. Szalay
- ELTE Eötvös Loránd University, Laboratory of Theoretical Chemistry, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary
| | - Felix Plasser
- Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
- Department of Chemistry, Loughborough University, Leicestershire LE11 3TU, United Kingdom
| | - Francisco B. C. Machado
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos 12228-900, São Paulo, Brazil
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50
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Affiliation(s)
- Michael S. Schuurman
- National Research Council of Canada, Ottawa, Ontario K1A 06A, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1A 0R6, Canada
| | - Albert Stolow
- National Research Council of Canada, Ottawa, Ontario K1A 06A, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1A 0R6, Canada
- Department of Physics, University of Ottawa, Ottawa, Ontario K1A 0R6, Canada
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