Synthesis of heterobinuclear Cu(II) [sbnd]Zn(II) complexes derived from lateral macrobicyclic tricompartmental ligands: Spectral, electrochemical and kinetic studies

Abstract

Novel macrobicyclic heterobinuclear Cu(II) Zn(II) complexes have been synthesized from the corresponding mononuclear copper(II) complexes using the precursor compound 3,4:9,10-dibenzo-1,12[ N, N′-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}diaza]-5,8-dioxocyclotetradecane via template method by Shiff’s base condensation. Electrochemical and kinetic studies of the complexes have been carried out on the basis of macrocyclic ring size. Cyclic voltammetry and controlled electrolysis studies indicate that the copper(II) metal ion in the heterobinuclear complexes undergo quasireversible one electron reduction whereas the zinc(II) metal ion does not undergo any reduction in the potential range. The examination of kinetics of catechol oxidation and hydrolysis of 4-nitrophenyl phosphate vindicates that the catalytic activities of the complexes are found to increase with macrocyclic ring size of the complexes. As, the macrocyclic ring size increases, the spectral, electrochemical and catalytic studies of the complexes show remarkable variation due to distortion in the geometry of metal centre.