Carbon−Sulfur and Carbon−Phosphorus Bond Cleavage and Subsequent Carbon−Carbon Bond Formation Promoted by an Active Ruthenium(0) Species

Reaction of RuH₂(CO)(PPh₃)₃ (1) with thiophene in the presence of styrene gives the novel diruthenium complex (Ph₃P)(OC)Ru(μ-(1Z,3Z)-PhCHCHCHCHS)(μ-PPh₂)Ru(CO)(PPh₃) (2) with a unique bridging 4-phenyl-1,3-butadienethiolato moiety made up of the 1-thiapenta-2,4-dien-1,5-diyl and phenyl groups, which are derived from the thiophene and triphenylphosphine, respectively. Treatment of 2 on a preparative thin-layer chromatography plate of alumina or silica gel causes Z−E isomerization of the bridging moiety to give (Ph₃P)(OC)Ru(μ-(1Z,3E)-PhCHCHCHCHS)(μ-PPh₂)Ru(CO)(PPh₃) (5). The molecular structures of 2 and 5 have been determined by X-ray structure analyses.