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

An electrochemical study of the electronic interactions occurring betw een 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 sin gle peak-wave of 2e height is observed by cyclic voltammetry and DC po larography, respectively, for the (0,0)/(0,1-) and (0,1-)/(1-,1-) redu ction processes. Although the dyine ligand gives rise to conducting po lymers, 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 bon d beyond the olefinic character, alters the linearity of the chain, an d then hinders the pi-electron delocalization.