Synthesis, structural and electrochemical properties of a new family of amino-acid-based coordination complexes

Abstract

Metalloproteins involved in oxidation–reduction processes in metabolism are fundamental for the wellbeing of every organism. The use of amino-acid-based compounds as ligands for the construction of biomimetic coordination systems represents a promising alternative for the development of new catalysts. Herein is presented a new family of copper, zinc and nickel coordination compounds, which show four-, five- and six- coordination geometries, synthesized using Schiff base ligands obtained from the amino acids L-alanine and L-phenylalanine. Structural analysis and property studies were performed using single-crystal X-ray diffraction data, spectroscopic and electrochemical experiments and DFT calculations. The analysis of the molecular and supramolecular architectures showed that the non-covalent interactions developed in the systems, together with the identity of the metal and the amino acid backbone, are determinants for the formation of the complexes and the stabilization of the resultant geometries. The CuII complexes were tested as candidates for the electrochemical conversion reduction of nitrite to NO, finding that the five-coordinate L-phenylalanine complex is the most suitable. Finally, some insights into the rational design of ligands for the construction of biomimetic complexes are suggested.

Phenylalanine-Based Co2+ and Cd2+ 1D Coordination Polymers: Structural Properties and Catalytic Application for Solvent-Free Aerobic Oxidation of Cycloalkene

“…In our previous studies, we showed that this derivative is a suitable platform for obtaining crystalline materials and organogels 34 and can also act as a ligand for the synthesis of discrete Cu 2+ , Ni 2+ , and Zn 2+ coordination compounds with different structural features and properties. 20,35 Herein, we continue exploring the applications of L, but for the synthesis of Co 2+ and Cd 2+ coordination compounds. In this case, one-dimensional coordination polymers (CP) with metal centers bearing distorted octahedral geometries were obtained (Figures 1 and 2).…”