Electrochemical behaviour polymeric complexes of monosubstituted squarate ligands. 1. Cyclic and square wave voltammetry of methylsquarate and diphnylaminosquarate complexes of cobalt and nickel

摘要

Cyclic voltammetric analysis of cobalt(II) methylsquarate in N,N-dimethylformamide (DMF) and dimethylsulphyoxide (DMSO) reveals the occurrence of similar redox processes in each solvent. In DMF, one cathodic and two anodic redox processes, which are characteristic of the methylsquarate ligand, occur at -1188, + 1094 and + 1398 mV, respectively. Co(I)/Co(II) and Co(II)/Co(III) redox processes are also apparent. For cobalt(II) diphenylaminosquarate in DMF and DMSO, similar electrochemical processes occur but oxidation of Co(I) to Co(II) is more facile than for the methylsquarate complex in both solvents. Nicke(II) methylsquarate also shows ligand-based redox processes similar to the respective cobalt(II) complexes. Ni(I)/Ni(O) and Ni(II)/Ni(II) have been identified in the CV of this complex. In DMSO, there is evidence for partial dissociation of the nikel(II) methylsquarate complex. The results suggest that electron transfer occure along the polymer chains in all three complexes.