Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 80. Mixed-metal tungsten and ruthenium compounds

Abstract

Treatment of the compounds [W(CC₆H₄Me-4)(CO)₂L]{L =η-C₅H₅ or HB (pz)₃[hydrotris(pyrazol-1-yl)borate]} with a three-fold excess of [Ru(CO)₄(η-C₂H₄)] in light petroleum affords as the only products the tetranuclear metal cluster complexes [WRu₃(µ₃-CC₆H₄Me-4)(CO)₁₁L]. In contrast, a similar reaction (L =η-C₅H₅) employing a W : Ru mol ratio of 2:1 gives in high yield the trinuclear metal complex [W₂Ru{µ₃-C₂(C₆H₄Me-4)₂}(CO)₇(η-C₅H₅)₂], which in refluxing cyclohexane releases CO and affords the electronically unsaturated species [W₂Ru(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₅(η-C₅H₅)₂]. With hydrogen and with diazomethane the latter compound affords the complexes [W₂RuH(µ-H)(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₄(η-C₅H₅)₂] and [W₂Ru(µ-CH₂)(µ-CH₂)(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₄(η-C₅H₅)₂], respectively, whereas alkynes yield the species [W₂Ru(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(µ₃-R¹C₂R²)(CO)₃(η-C₅H₅)₂](R¹= R²= Me or Ph; R¹= H, R²= Ph). Reactions of [W₂Ru(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₅(η-C₅H₅)₂] with the alkylidyne–tungsten complexes [W(CC₆H₄Me-4)(CO)₂L](L =η-C₅H₅ or η-C₅Me₅) afford the tetranuclear metal compounds [W₃-Ru(µ-CO)(µ₃-η-CO)(µ-CC₆H₄Me-4)₂(µ₃-CC₆H₄Me-4)(CO)₂(η-C₅H₅)₂L]. The n.m.r. data for the new compounds are reported and discussed in relation to their structures.