Design and Characterization of a Cu(II) Coordination Polymer Based on α-Diimine: Evaluation of the Biomimetic Activity

Abstract

The copper-based polymer is synthesized using a slow evaporation method with an α-diimine chelator (1,10-phenanthroline) as the primary ligand. The synthesized polymer is characterized by various spectroscopic studies (FT-IR, UV-visible, EPR, luminescent), powder XRD and TGA techniques. Single crystal XRD studies reveal the molecular structure as a one-dimensional (1D) coordination polymer (CP) with the composition [Cu(phen)(NO₃)₂]_n. The FT-IR spectrum of CP further ascertains the binding modes of the ligand moiety. The copper ion is present in the +2 oxidation state and the geometry around the central metal ion is distorted square pyramidal. Moreover, CP shows a brilliant catecholase-like activity in methanol, which can easily oxidize the substrate 3,5-di-tert-butylcatechol (3,5-DTBC) to its respective quinone. Kinetic measurements suggest that the catechol oxidation rate follows saturation kinetics with respect to the substrate and first order kinetics with respect to the catalyst. CP shows a very good catalytic activity with K_cat = 8.28 h⁻¹.