Formation of a ruthenium mu-carbide complex with acetylene as the carbon source

Reactions of the dinuclear ruthenium complex [(p-cymene)Ru(mu-Cl)(3)RuCl(C2H4)(PCY3)] with phenylacetylene or tertbutylacetylene gave the vinylidene complexes [(p-cymene)Ru(mu-Cl)(3)RuCl(=C=CHR)(PCY3)] (R=tBu, Ph), which were characterized crystallographically. With acetylene, however, a tetranuclear mu-carbide complex was obtained as evidenced.