Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 67. Reactions of the salts [X][W(CR)(CO)2(η5-C2B9H9Me2)][X = P(CH2Ph)Ph3, R = C6H4Me-4; X = NEt4, R = Ph] with bis(cyclo-octa-1,5-diene)platinum

Abstract

The salts [X][W(CR)(CO)₂(η⁵-C₂B₉H₉Me₂)][X = NEt₄, R = Ph; X = P(CH₂Ph)Ph₃ or PPh₄, R = C₆H₄Me-4] have been prepared, and an X-ray diffraction study has been carried out on the tetraphenylphosphonium compound. There are two very similar crystallographically independent anions, together with their associated counter ions, in the asymmetric unit of the structure. In the anion the tungsten atom carries two terminally bound carbonyl ligands (W–CO mean 2.019 Å, W–C–O mean 176.9°), a p-tolylmethylidyne ligand [WCC₆H₄Me-4 mean 1.83(3)Å], and the η⁵-7,8-C₂B₉H₉Me₂ cage [mean W–ligated cage atoms, 2.424 Å(mean of 10)]. Treatment of the species [X][W(CR)(CO)₂(η⁵-C₂B₉H₉Me₂)][X = P(CH₂Ph)Ph₃, R = C₆H₄Me-4; X = NEt₄, R = Ph] in thf (tetrahydrofuran) with [Pt(cod)₂](cod = cyclo-octa-1,5-diene) affords the complexes [P(CH₂Ph)Ph₃][PtW(µ-CC₆H₄Me-4)(CO)₂(cod)(η⁵-C₂B₉H₉Me₂)](2a) and [NEt₄][PtW(µ-CPh)(CO)₂(cod)(η⁵-C₂B₉H₉Me₂)](2b), respectively. The cod ligand in the compounds (2) may be displaced with tertiary phosphines, but crystalline products were not obtained. Moreover, protonation of (2) led to decomposition. However, treatment of (2a) with [AuCl(PPh₃)] and TIPF₆, and (2b) with the gold reagent and KPF₆, in thf, affords the trimetal compounds [AuPtW(µ₃-CR)(CO)₂(PPh₃)(cod)(η⁵-C₂B₉H₉Me₂)](R = C₆H₄Me-4 or Ph), which were fully characterised. The n.m.r. data (¹H, ¹³C-{¹H}, ¹⁹⁵Pt-{¹H}, and ³¹P-{¹H}) for the complexes are reported.