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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Photophysics of Emissive C-tz[Isothiazolo-Cytidine] and U-tz[Isothiazolo-Uridine] Pyrimidine Analogues

Texto completo
Autor(es):
Valverde, Danillo [1] ; Sanches de Araujo, Adalberto Vasconcelos [2] ; Canuto, Sylvio [1] ; Borin, Antonio Carlos [2]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Phys, Rua Matao 1371, BR-05508090 Sao Paulo, SP - Brazil
[2] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, Ave Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: CHEMPHOTOCHEM; v. 3, n. 9, SI, p. 916-924, SEP 2019.
Citações Web of Science: 0
Resumo

The C-tz and U-tz emissive properties were investigated with the MS-CASPT2 method and CASSCF/CASPT2 protocol, with inclusion of solvent effects with the aid of the PCM and Sequential QM/MM, the Free Energy Gradient methods. Theoretical vertical emission energies and Stokes shifts, using the ASEC-FEG method, are in a good agreement with the experimental data, within the expected accuracy of CASPT2 method. Their emissive properties can be understood in analogy to the photophysical behaviour of the canonical uracil and cytosine pyrimidine nucleobases, for which the twisting of the C5C6 bond is the key for understanding their ultrashort radiationless decay times. For both C-tz and U-tz, the computed photophysical deactivation pathway, shows that the bright state 1(pi pi{*}) goes directly to a minimum structure on its potential energy hypersurface (1(pi pi{*})min), from where no conical intersection with the ground state can be reached, due to the steric hindrance of the C5C6 position, which forms the bridge between the rings in both molecules. Solvent effects place the conical intersection in higher energy region, reinforcing their emissive nature. (AU)

Processo FAPESP: 17/02612-4 - Dinâmica de estados excitados e propriedades espectroscópicas de derivados de RNA e DNA naturais e sintéticos em meio solvente
Beneficiário:Danillo Pires Valverde
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 14/50983-3 - INCT 2014: fluidos complexos
Beneficiário:Antonio Martins Figueiredo Neto
Linha de fomento: Auxílio à Pesquisa - Temático