ELECTRONIC INTERACTIONS IN MULTICLUSTER ARRAYS - AN ELECTROCHEMICAL APPROACH .2.

An electrochemical study of the electronic interactions occurring between the two polymetallic redox cores in the diyne dimers [Co-2(CO)(6)](2)(H=C-C6H4-C=CH), [Ru-3(CO)(9)(mu-CO)](2)(HC=C-C6H4-C=CH) and [Ru-3(CO)(9)(mu-H)](2)(-C=C-C6H4-C=C-) is reported. In all derivatives a single peak-wave of 2e height is observed by cyclic voltammetry and DC polarography, respectively, for the (0,0)/(0,1-) and (0,1-)/(1-,1-) reduction processes. Although the dyine ligand gives rise to conducting polymers, especially when doped with IZ, it behaves as an insulator when coordinated by two metallic clusters. Likely, the coordination of the acetylenic moieties by bi- or tri-metallic frames reduces the C-C bond beyond the olefinic character, alters the linearity of the chain, and then hinders the pi-electron delocalization.