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Crespo-Hernández CE, Martínez-Fernández L, Rauer C, Reichardt C, Mai S, Pollum M, Marquetand P, González L, Corral I. Electronic and structural elements that regulate the excited-state dynamics in purine nucleobase derivatives. J Am Chem Soc 2015; 137:4368-81. [PMID: 25763596 PMCID: PMC4410903 DOI: 10.1021/ja512536c] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Indexed: 12/20/2022]
Abstract
The excited-state dynamics of the purine free base and 9-methylpurine are investigated using experimental and theoretical methods. Femtosecond broadband transient absorption experiments reveal that excitation of these purine derivatives in aqueous solution at 266 nm results primarily in ultrafast conversion of the S2(ππ*) state to the vibrationally excited (1)nπ* state. Following vibrational and conformational relaxation, the (1)nπ* state acts as a doorway state in the efficient population of the triplet manifold with an intersystem crossing lifetime of hundreds of picoseconds. Experiments show an almost 2-fold increase in the intersystem crossing rate on going from polar aprotic to nonpolar solvents, suggesting that a solvent-dependent energy barrier must be surmounted to access the singlet-to-triplet crossing region. Ab initio static and surface-hopping dynamics simulations lend strong support to the proposed relaxation mechanism. Collectively, the experimental and computational results demonstrate that the accessibility of the nπ* states and the topology of the potential energy surfaces in the vicinity of conical intersections are key elements in controlling the excited-state dynamics of the purine derivatives. From a structural perspective, it is shown that the purine chromophore is not responsible for the ultrafast internal conversion in the adenine and guanine monomers. Instead, C6 functionalization plays an important role in regulating the rates of radiative and nonradiative relaxation. C6 functionalization inhibits access to the (1)nπ* state while simultaneously facilitating access to the (1)ππ*(La)/S0 conical intersection, such that population of the (1)nπ* state cannot compete with the relaxation pathways to the ground state involving ring puckering at the C2 position.
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Affiliation(s)
- Carlos E. Crespo-Hernández
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United
States
| | - Lara Martínez-Fernández
- Departamento
de Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Módulo 13, Cantoblanco, 28049 Madrid, Spain
| | - Clemens Rauer
- Institute
of Theoretical Chemistry, University of
Vienna, Währinger
Str. 17, 1090 Vienna, Austria
| | - Christian Reichardt
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United
States
| | - Sebastian Mai
- Institute
of Theoretical Chemistry, University of
Vienna, Währinger
Str. 17, 1090 Vienna, Austria
| | - Marvin Pollum
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United
States
| | - Philipp Marquetand
- Institute
of Theoretical Chemistry, University of
Vienna, Währinger
Str. 17, 1090 Vienna, Austria
| | - Leticia González
- Institute
of Theoretical Chemistry, University of
Vienna, Währinger
Str. 17, 1090 Vienna, Austria
| | - Inés Corral
- Departamento
de Química, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Módulo 13, Cantoblanco, 28049 Madrid, Spain
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Bekçioğlu G, Allolio C, Sebastiani D. Water Wires in Aqueous Solutions from First-Principles Calculations. J Phys Chem B 2015; 119:4053-60. [DOI: 10.1021/jp5121417] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Gül Bekçioğlu
- Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Christoph Allolio
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám 2, CZ-16610 Prague 6, Czech Republic
| | - Daniel Sebastiani
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
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Guo X, Zhao Y, Cao Z. Ab Initio Study on Ultrafast Excited-State Decay of Allopurinol Keto-N9H Tautomer from Gas Phase to Aqueous Solution. J Phys Chem A 2014; 118:9013-20. [DOI: 10.1021/jp5020115] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xugeng Guo
- State Key Laboratory for
Physical Chemistry of Solid Surfaces and Fujian Provincial Key Lab
of Theoretical and Computational Chemistry, College of Chemistry and
Chemical Engineering, Xiamen University, No. 422, South Siming Road, Xiamen 361005, P. R. China
| | - Yuan Zhao
- State Key Laboratory for
Physical Chemistry of Solid Surfaces and Fujian Provincial Key Lab
of Theoretical and Computational Chemistry, College of Chemistry and
Chemical Engineering, Xiamen University, No. 422, South Siming Road, Xiamen 361005, P. R. China
| | - Zexing Cao
- State Key Laboratory for
Physical Chemistry of Solid Surfaces and Fujian Provincial Key Lab
of Theoretical and Computational Chemistry, College of Chemistry and
Chemical Engineering, Xiamen University, No. 422, South Siming Road, Xiamen 361005, P. R. China
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