A Pd( ii ) catecholato complex bearing 5,5′-divinyl-2,2′-bipyridine: synthesis, characterization, and electrochemical disproportionation in solutions and electropolymerized films

substantially changed the voltametric properties, indicating disproportionation between the electrogenerated SQ complexes to the regenerated 2 and ligand dissociation products. In contrast to previous reports on the disproportionation of chemically isolated SQ complexes, we found electrochemical features of the repeated anodic oxidation of regenerated 2 followed by disproportionation. The electropolymerized films of 2 on indium tin oxide electrodes exhibited a widely separated pair of anodic and cathodic peaks, similar to those of monomer 2 in solution. The disproportionation of the constituent complexes in the metallopolymers was spectroelectrochemically monitored by the disappearance of the characteristic LL'CT absorption, indicative of ligand dissociation. These findings provide new insights into the fabrication of redox-active metallopolymer films and their applications, which exploit their electrochemical reactivity and bistability in molecular devices.