Publicação
Synthesis, characterization, fluorescence and DFT studies of new Cu2+, Ni2+ and Hg2+ complexes with emissive thienylbenzoxazolyl-alanine ligands
| Resumo: | The interaction of four fluorescent compounds containing thiophene and benzoxazole moieties combined with an alanine residue with alkaline, alkaline-earth, transition and post-transition metal ions was explored. The highly fluorescent heterocyclic alanine derivatives are strongly quenched in the solid state after complexation with the paramagnetic metal ions Cu2+ and Ni2+, and with the diamagnetic Hg2+. Absorption and steady-state fluorescence titrations reveals a selective interaction with Cu2+, Ni2+ and Hg2+. In all cases the formation of mononuclear or dinuclear metal complexes in solid state and in solution are postulated. DFT calculations on the mercury(II) complexes confirm the formation of dinuclear species. Our results suggest that one metal ion is coordinated by the chelate group formed by the amine and carboxylic groups presents in the amino acid residue and the second metal ion directly linked to the chromophore. As parent compound, L4 shows no interaction with Cu2+ and Ni2+ salts. However, the interaction with Hg2+ induces a strong quenching and a red shift of the fluorescence emission. |
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| Autores principais: | Oliveira, Elisabete |
| Outros Autores: | Costa, Susana P. G.; Raposo, M. Manuela M.; Faza, Olalla Nieto; Lodeiro, Carlos |
| Assunto: | Mercury(II) Copper(II) Benzoxazole Thiophene Alanine derivatives Emissive compounds |
| Ano: | 2011 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The interaction of four fluorescent compounds containing thiophene and benzoxazole moieties combined with an alanine residue with alkaline, alkaline-earth, transition and post-transition metal ions was explored. The highly fluorescent heterocyclic alanine derivatives are strongly quenched in the solid state after complexation with the paramagnetic metal ions Cu2+ and Ni2+, and with the diamagnetic Hg2+. Absorption and steady-state fluorescence titrations reveals a selective interaction with Cu2+, Ni2+ and Hg2+. In all cases the formation of mononuclear or dinuclear metal complexes in solid state and in solution are postulated. DFT calculations on the mercury(II) complexes confirm the formation of dinuclear species. Our results suggest that one metal ion is coordinated by the chelate group formed by the amine and carboxylic groups presents in the amino acid residue and the second metal ion directly linked to the chromophore. As parent compound, L4 shows no interaction with Cu2+ and Ni2+ salts. However, the interaction with Hg2+ induces a strong quenching and a red shift of the fluorescence emission. |
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