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Lifetime and fluorescence quantum yield of two fluorescein-amino acid-based compounds in different organic solvents and gold colloidal suspensions
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Orientador(es)
Resumo(s)
Fluorescein and its derivatives are yellowish-green emitting dyes with outstanding potential in advanced molecular probes for different applications. In this work, two fluorescent compounds containing fluorescein and an amino acid residue (compounds 1 and 2) were photophysically explored. Compounds 1 and 2 were previously synthesized via ester linkage between fluorescein ethyl ester and Boc-ser (TMS)-OH or Boc-cys(4-methyl benzyl)-OH. Studies on the time-resolved fluorescence lifetime and relative fluorescence quantum yield (ϕ) were performed for 1 and 2 diluted in acetonitrile, ethanol, dimethyl sulfoxide, and tetrahydrofuran solvents. The discussion considered the dielectric constants of the studied solvents (range between 7.5 and 47.2) and the photophysical parameters. The results of the lifetime and ϕ were compared with those obtained for compounds 1, 2 and fluorescein without an amino acid residue in alkaline aqueous solutions. Moreover, as a preliminary result compound 2 (S-cysteine) was tested in the presence of gold nanoparticles as an aggregation colorimetric probe.
Descrição
V.P. and A.C.G. thank Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)/Brazil for postdoctoral and Ph.D. Grants, respectively. C.L. thanks the CNPq program Science without borders 2014-2016 for the "Special Visitant Researcher" Grant (Brazil), CNPq and Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG). Financial support from the Scientific PROTEOMASS Association (Portugal), LAQV/REQUIMTE is acknowledged. All authors are also grateful for the financial and structural support provided by the University of Sao Paulo through the NAP-CatSinQ (Research Core in Catalysis and Chemical Synthesis), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES). We thank Javier Fernandez-Lodeiro for synthesizing the gold nanoparticles used in this study.
Palavras-chave
Fluorescein Fluorescence quantum yield Gold nanoparticles Lifetime Physical and Theoretical Chemistry Analytical Chemistry