Tetranuclear bimetallic complexes of cobalt (II) and copper (II) with biadetylazinedihydrazone

Abstract

Binuclear cobalt (II) complexes of biacetylazinedihydrazone (BAADH), CO₂(BAADH)₂X₄ (X = Cl^-, Br^-, SCN^-, NO) react with copper (II) halides to give tetranuclear bimetallic complexes [Co(BAADH)₂X₄][CuN₂Y₂)(Y=Cl^-, Br^-). IR and electronic spectra point to the presence of chromophores (CoN₄X₂) and (CuN₂Y₂) implying coordination of terminal NH2 groups of BAADH with (Copper (II) Electrochemical reduction of each complex occurs in two steps. The first step is a two-electron transfer process where each terminal copper (II) is transformed to copper (I) state. The more cathodic second step involve some electron where only one of the two inner core cobalt (II) ions is reduced to cobalt (I)state. The redox pattern is supported by additional evidence gathered from similar investigations on the linear trimeric [Cu(DMG)₂] (CuCl₂)₂ species (DMG = dimethylglyoximate ion) and related species.