Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 98. Tri- and tetra-nuclear metal compounds with ethylidyne or p-tolylmethylidyne groups, and having both cyclopentadienyl and carbaborane ligands

Abstract

The trimetal compounds [MWAu(µ-CR)(µ-CR′)(CO)₄(η-C₅H₅)(η⁵-C₂B₉H₉Me₂)](M = Mo or W, R = R′= C₆H₄Me-4; M = W, R = R′= Me; R = Me, R′= C6H4Me-4) have been prepared by treating the complexes [MAuCl(µ-CR′)(CO)₂(η-C₅H₅)](M = Mo or W, R′= C₆H₄Me-4; M = W, R′= Me) with the reagents [NEt₄][W(CR)(CO)₂(η⁵-C₂B₉H₉Me₂)](R = C₆H₄Me-4 or Me) in CH₂Cl₂ in the presence of TIBF₄. The trimetal compounds react with [Pt(cod)₂](cod = cyclo-octa-1,5-diene) or [Pt(PMe₂Ph)₂(nb)](nb = norbornene = bicyclo [2.2.1]heptene) to afford, respectively, the complexes [W₂PtAu(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₄(cod)(η-C₅H₅)(η⁵-C₂B₉H₉Me₂)] and [MWPtAu(µ-CR′)(µ₃-CR)(CO)₄(PMe₂Ph)₂(η-C₅H₅)(η⁵-C₂B₉H₉Me₂)](M = W, R = R′= C₆H₄Me-4; R = Me, R′= C₆H₄Me-4; M = Mo, R = R′= C₆H₄Me-4). The cod complex was prepared by an alternative method, by treating [NEt₄][WPt(µ-CC₆H₄Me-4)(CO)₂(cod)(η⁵-C₂B₉H₉Me₂)] with [WAuCl(µ-CC₆H₄Me-4)(CO)₂(η-C₅H₅)], in the presence of TIBF₄. Addition of an excess of PMe₂Ph in thf (tetrahydrofuran) to [W₂PtAu(µ-CC₆H₄Me-4)(µ₃-CC₆H₄Me-4)(CO)₄(cod)(η-C₅H₅)(η⁵-C₂B₉H₉Me₂)] in the same solvent results in displacement of both cod and W(CC₆H₄Me-4)(CO)₂(η-C₅H₆) groups, and formation of the trimetal complex [WPtAu(µ₃-CC₆H₄Me- 4)(CO)₂(PMe₂Ph)₃(η₅-C₂B₉H₉Me₂)]. The i.r. and n.m.r. (¹H and ¹³C-{¹H}) data for the compounds are reported and discussed.