Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 94. Synthesis of di- and tri-metal compounds via the reagents [M(C–CCBut)(CO)2(η-C5H5)](M = Mo or W)

Abstract

The alkynylmethylidynemetal compounds [M(C–CCBu^t)(CO)₂(η-C₅H₅)](M = Mo or W) react with [Fe₂(CO)₉] in thf (tetrahydrofuran) at ambient temperatures to afford via alkylidyne group coupling the trimetal complexes [M₂Fe{µ₃-C₂(CCBu^t)₂}(CO)₇(η-C₅H₅)₂] in good yield. The reaction between the alkynylmethylidynetungsten reagent and [Fe₂(CO)₉] also gives small quantities of [Fe₂{µ-Bu^tC₂CW(CO)₂(η-C₅H₅)}(CO)₆], a product in which a Fe₂(CO)₆ fragment is attached to the terminal CCBu^t group of the [W(C–CCBu^t)(CO)₂(η-C₅H₅)] molecule. Treatment of [Mo(C–CCBu^t)(CO)₂(η-C₅H₅)] in light petroleum with [Rh(CO)₂(η⁵-C₉H₇)](C₉H₇= indenyl) affords a chromatographically separable mixture of the compounds [MoRh(µ-C–CCBu^t)(CO)₃(η-C₅H₅)(η⁵-C₉H₇)], [Mo₂Rh{µ₃-C₂(CCBu^t)₂}(CO)₄(η-C₅H₅)₂(η⁵-C₉H₇)], and [MoRh₂{µ³-C–CC-Bu^t}(µ-CO)(CO)₂(η-C₅H₅)(η⁵-C₉H₇)₂]. The corresponding tungsten–rhodium species [WRh(µ-C–CCBu^t)(CO)₃(η-C₅H₅)(η⁵-C₉H₇)], and [WRh₂{µ₃-C–CCBu^t}(µ-CO)(CO)₂(η-C₅H₅)(η⁵-C₉H₇)₂] have also been prepared. The dimetal compound [MoRh(µ-C–CCBu^t)(CO)₃(η-C₅H₅)(η⁵-C₉H₇)] reacts with [W(C–CCBu^t)(CO)₂(η-C₅H₅)] to give the trimetal complex [MoWRh{µ₃-C₂(CCBu^t)₂}(CO)₄(η-C₅H₅)₂(η⁵-C₉H₇)], while [WRh(µ-C–CCBu^t)(CO)₃(η-C₅H₅)(η⁵-C₉H₇)] with [Fe₂(CO)₉] and [Co(η-C₂H₄)₂(η-C₅Me₅)] affords, respectively, the compounds [WFeRh(µ₃-C–CCBu^t)(µ-CO)(CO)₅(η-C₅H₅)(η⁵-C₉H₇)] and [WCoRh(µ₃-C–CCBu^t)(µ-CO)(CO)₂(η-C₅H₅)(η-C₅Me₅)(η⁵-C₉H₇)]. The ¹H and ¹³C-{¹H} n.m.r. data for the new compounds are reported and discussed.