Thermal and solvatochromic effects on the emission properties of a thienyl-based dansyl derivative

Made available in DSpace on 2020-12-10T17:39:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-04 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) FINEP FAPEAL (Alagoas State Research Agency) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Environmental conditions have a profound effect on the photophysical behavior of highly conjugated compounds, which can be exploited in a large variety of applications. In this context, we use a combination of experimental and computational methods to investigate thermal and solvatochromic effects on the fluorescence properties of a dansyl derivative bearing a thienyl substituent, namely 2-(3-thienyl)ethyl dansylglycinate (TEDG). In particular, we analyze how the solvent polarity and temperature affect the ground and excited state energies of TEDG by using time-resolved and steady-state fluorescence techniques. We determine the changes in dipole moment of the TEDG molecule upon photoexcitation, as well as the solvent polarity effects on the excited state lifetime. Besides, we provide theoretical modeling of the HOMO-LUMO orbitals and the vertical absorption and emission energies using time-dependent density functional theory (TDDFT) as well as the polarizable continuum model (PCM) to include the solvent contribution to the absorption and emission energies. Our results show that the emission mechanism of TEDG involves locally excited states derived from hybrid molecular orbitals, accompanied by a moderate variation of the molecular dipole moment upon light excitation. Our findings demonstrate that TEDG exhibits desirable fluorescence properties that make it a promising candidate for use as a photoactive material in electrochromic, optical thermometry, and thermography applications. Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, BR-14040901 Ribeirao Preto, SP, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, Dept Fis, BR-19060900 Presidente Prudente, SP, Brazil Univ Fed Alagoas, Inst Quim & Biotecnol, BR-57072970 Maceio, Alagoas, Brazil Univ Fed Alagoas, Inst Fis, BR-57072970 Maceio, Alagoas, Brazil Univ Fed Pernambuco, Dept Quim Fundamental, CCEN, BR-50670901 Recife, PE, Brazil Inst Fed Piaui, Campus Angical, BR-64410000 Angical, PI, Brazil Univ Estadual Paulista, Fac Ciencias & Tecnol, Dept Fis, BR-19060900 Presidente Prudente, SP, Brazil CNPq: 438198/2018-2 CNPq: 305771/2016-7