Synthesis, characterization, fluorescence and computational studies of new Cu, Ni and Hg complexes with emissive thienylbenzoxazolyl-alanine ligands |
| |
Authors: | Elisabete Oliveira M.M.M. Raposo Carlos Lodeiro |
| |
Affiliation: | a REQUIMTE, Department of Chemistry, FCT-UNL, 2829-516 Monte de Caparica, Portugal b CQ-UM, Center of Chemistry, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal c Faculty of Science, Organic-Chemistry Department, Campus Ourense, University of Vigo, 32004 Ourense, Spain d BIOSCOPE Research Team, Faculty of Science, Physical-Chemistry Department, Campus Ourense, University of Vigo, 32004 Ourense, Spain |
| |
Abstract: | 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 reveal 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 the protonated carboxylic groups present in the amino acid residue while a second metal ion is 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. |
| |
Keywords: | Mercury(II) Copper(II) Benzoxazole Thiophene Alanine derivatives Emissive compounds |
本文献已被 ScienceDirect 等数据库收录! |
|