Cluster build-up using the [Ru(η5-C5H5)(MeCN)3 ]+ cation; synthesis and structural characterisation of some cyclopentadienyl-substituted hexa- and hepta-nuclear ruthenium carbido clusters

Abstract

The reaction of the dianion [Ru ₅ C(CO) ₁₄ ] ^2- with 2 equivalents of [Ru(η ⁵ -C ₅ H ₅ )(MeCN) ₃ ] ⁺ afforded two new clusters, the hexanuclear anion [Ru ₆ C(CO) ₁₄ (η ⁵ -C ₅ H ₅ )] ^- 1 and the neutral heptanuclear cluster [Ru ₇ C(CO) ₁₄ (η ⁵ -C ₅ H ₅ ) ₂ ] 2 in high yields. In a similar reaction the hexanuclear dianion [Ru ₆ C(CO) ₁₆ ] ^2- may be ‘capped’ by [Ru(η ⁵ -C ₅ H ₅ )(MeCN) ₃ ] ⁺ to afford good yields of both the heptanuclear monoanion [Ru ₇ C(CO) ₁₆ (η ⁵ -C ₅ H ₅ )] ^- 3 and the neutral cluster 2. The clusters 1, 2 and 3 have been fully characterised by both spectroscopic and crystallographic methods. The crystal structures show that the metal framework of all three clusters is based on a central Ru ₆ C octahedral core. In 1 one of the core atoms is co-ordinated to an η ⁵ -C ₅ H ₅ ligand, while in 2 an additional Ru(η ⁵ -C ₅ H ₅ ) group caps one triangular face of the octahedron to give a capped octahedral framework. In 3 the single η ⁵ -C ₅ H ₅ ligand is co-ordinated to the capping Ru atom in the capped octahedral framework.