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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Solvation Structures and Deactivation Pathways of Luminescent Isothiazole-Derived Nucleobases: (tz)A, (tz)G, and I-tz

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de Araujo, Adalberto Vasconcelos Sanches [1] ; Valverde, Danillo [2] ; Canuto, Sylvio [2] ; Borin, Antonio Carlos [1]
Total Authors: 4
[1] Univ Sao Paulo, Dept Fundamental Chem, Inst Chem, BR-05508000 Sao Paulo, SP - Brazil
[2] Univ Sao Paulo, Inst Phys, BR-05508090 Sao Paulo, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Journal of Physical Chemistry A; v. 124, n. 34, p. 6834-6844, AUG 27 2020.
Web of Science Citations: 0

The photophysical relaxation pathways of (tz)A, (tz)G, and I-tz luminescent nucleobases were investigated with the MS-CASPT2 quantum-chemical method and double-zeta basis sets (cc-pVDZ) in gas and condensed phases (1,4-dioxane and water) with the sequential Monte Carlo/CASPT2 and free energy gradient (FEG) methods. Solvation shell structures, in the ground and excited states, were examined with the pairwise radial distribution function (G(r)) and solute-solvent hydrogen-bond networks. Site-specific hydrogen bonding analysis evidenced relevant changes between both electronic states. The three luminescent nucleobases share a common photophysical pattern, summarized as the lowest-lying 1(pi pi{*}) bright state that is populated directly after the absorption of radiation and evolves barrierless to the minimum energy structure, from where the excess of energy is released by fluorescence. From the (1)(pi pi{*})(min) region, the conical intersection with the ground state ((pi pi{*}/GS)(CI)) is not accessible due to the presence of high energetic barriers. By combining the present results with those reported earlier by us for the pyrimidine fluorescent nucleobases, we present a comprehensive description of the photophysical properties of this important class of new fluorescent nucleosides. (AU)

FAPESP's process: 17/02612-4 - Dynamics of excited states and spectroscopic properties of natural and synthetic DNA and RNA derivatives in solvent environment
Grantee:Danillo Pires Valverde
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 14/50983-3 - INCT 2014: complex fluids
Grantee:Antonio Martins Figueiredo Neto
Support type: Research Projects - Thematic Grants
FAPESP's process: 18/19454-5 - Structure and Photochemistry of Fluorescent Nucleobaseas and Metal Mediated Base Pairs
Grantee:Antonio Carlos Borin
Support type: Regular Research Grants