BINUCLEAR AND TRINUCLEAR CYANO-BRIDGED RUTHENIUM COMPLEXES CONTAINING (L-L)2RUII AND CP(EPH3)2RUII MOIETIES[(L-L) = 2,2'-BIPYRIDINE, 1,10-PHENANTHROLINE, CP = ETA-5-(C5H5)-, E = P,AS,SB]

The cyano and isonitrilo bridged di- and tri-nuclear ruthenium(II) complexes of the types, [NC(L-L)2RuCNRu(EPh3)2Cp]+Y-, [Cl(L-L)2RuNCRu(EPh3)2Cp]Y and [(L-L)2Ru{NCRu (EPh3)2 Cp}2]Y2 [where (L-L) = 2,2'-bipyridine, 1,10-phenanthroline; E = P, As, Sb; Cp = eta-5-(C5H5)-; Y = (PF6)-, (BPh4)-] have been prepared. They have been characterised by elemental analyses, spectral (IR, 1H NMR and electronic) and redox data. The redox and the spectral properties of the [(L-L)2RuII] moiety have been rationalised in terms of the competitive pi-back bonding by the second RUII ion centered at [RuCp(EPh3)2]+. The (L-L)2CIRUII group in isonitrile bridged complexes is more easily oxidised than that in the corresponding acetonitrile analogue which accords with the spectral behaviour of the complexes.