Synthesis and molecular structure of mixed alkyne-cyclopentadienyl clusters via the ionic coupling of [Os 3(CO) 9(R 2C 2)] 2− with [Ru(η 5-C 5H 5)(MeCN) 3] + and the reaction [Os 3RuH(η 5-C 5H 5)(CO) 10(MeCN)] with alkynes (R 2C 2) (R = Me, Ph)

Abstract

The ionic coupling reaction of the dianion [Os 3(CO) 9(R 2C 2)] 2− (R = Me, Ph) with two equivalents of the monocation [Ru(η 5-C 5H 5)(CH 3CN) 3] + affords the neutral clusters [Os 3Ru 2(CO) 9(R 2C 2)(η 5-C 5H 5) 2] [R = Me, 1 and R = Ph, 2] in ca. 80% yield. An X-ray crystallographic study of 1 confirms that these clusters exhibit a capped pseudo-octahedral Os 3Ru 2C 2 core, with the alkyne bonded parallel to the hinge bond of the capped butterfly metal geometry in a μ 4–η 2 manner, the Ru atoms adopting the wing-tip and capping positions. Reaction of the activated cluster [Os 3RuH(η 5-C 5H 5)(CO) 10(MeCN)] ( 3) with RCCR (R = Me, Ph) affords the related clusters [Os 3RuH(CO) 9(η 5-C 5H 5)(R 2C 2)] (R = Me, 4 and R = Ph, 5) in ca. 35% yield. The reaction with PhCCPh also produces [Os 3Ru(CO) 8(η 5-C 5H 5)(PhCCPh)(PhCC(H)Ph)] ( 6) in ca. 15% yield. An X-ray crystallographic study shows that this cluster has a pseudo-octahedral Os 3RuC 2 core, with the Ru(η 5-C 5H 5) unit adopting the wing-tip position, the alkyne bonded in a μ 4–η 2 arrangement and the ethenyl ligand bridging an Os–Os edge in a μ 2–η 1:η 2 configuration.