Novel structural rearrangements induced by metal-metal interactions in ruthenium(II) ruthenocenyl- and (Pentamethylruthenocenyl) acetylide complexes, ReC=CRuL2(eta(5)-C5R5) and Rc'C=CRuL2(eta(5)-C5R5) [Rc equals Ruthenocenyl, Rc' equals pentamethylruthenocenyl, L-2=2PPh(3) or Ph2PCH2CH2PPh2 (dppe), R=H or Me]

The reaction of RcC=CH [Rc = (eta(5)-C5H5)Ru(eta(5)-C5H4)] with RuClL2(eta(5)-C5R5) [R = H or Me; L-2 = 2PPh(3) or Ph2PCH2CH2PPh2 (dppe)] in the presence of NH4PF6 and subsequent treatment with base gave Ru(II) ruthenocenylacetylide complexes RcC=CRuL2(eta(5)-C5R5) in good yields. In a similar manner, the pentamethylruthenocene analogues, Rc'C=CRuL2(eta(5)-C5R5) [Rc' = (eta(5)-C5Me5)Ru(eta(5)-C5H4)], were also prepared. Cyclic voltammograms of the complexes showed two reversible one-electron-oxidation processes, consisting of the processes [Ru(II)Ru'(II)] to [Ru(III)Ru'(II)] and then to [Ru(III)Ru(III)]. Chemical oxidation of the complexes induced novel structural rearrangement. The two-electron oxidation of complex RcC=CRu(PPh3)(2)(eta(5)-C5H5) afforded a kind of allenylidene complex, a cyclopentadienylidenethylidene complex, [(eta(5)-C5H5)Ru{mu-eta(6):eta(1)-C5H4C=C}Ru(PPh3)(2)(eta(5)-C5H5)](2+), in 90% yield. The one-electron oxidation of Rc'C=CRu(PPh3)(2)(eta(5)-C5H5) gave the vinylidene complex (Rc'CH=C)Ru(PPh3)(2)(eta(5)-C5H5) in 62% yield, while the two-electron oxidation led to the fulvene-vinylidene complex [(eta(6)-C5Me4CH2)Ru{mu-eta(5):eta(1)-C5H4CH=C}Ru(PPh3)(2)(eta(5)-C5R5)](2+) by an intramolecular hydrogen transfer in 59% yield.