A binary copper(II) complex having a stepped polymeric structure: Synthesis, characterization, DNA-binding and anti-fungal studies

Abstract

A rarely found polymeric complex of copper(II) was obtained in the reaction of 2-(4-methylphenyl)acetate and copper sulfate and crystallized in quantitative yield. The complex was characterized using FT-IR, electron spin resonance, absorption spectroscopy, electrochemistry and powder and single crystal XRD studies. The structure was found to consist of interconnected pad­dlewheel units without an intervening ligand resulting in a stepped polymeric arrangement of the structure. The purity of the sample was judged from powder XRD data while ESR spectroscopy indicated a weak signal between 3000 and 4000 G values, indicating the presence of Cu(II) in the complex. Electro­chemistry revealed an irreversible, predominantly diffusion controlled Cu^IICu^II/ /Cu^IICu^I process with a D0 value calculated to be 3.032×10-8 cm2 s-1. The complex was screened for its DNA-binding ability through cyclic voltam­metry, absorption and florescence spectroscopy and viscometry; the former two yield­ing Kb values of 3.34×103 and 6.90×103 M-1, respectively. The complex exhi­bited significant activity against fungal strain Mucor piriformis, moderate activity against Aspergillus niger and slight activity against Helminthosporium solani. These preliminary findings revealed the excellent biological potential of the syn­thesized complex.