Isonitrile μ-carbido complexes.

The μ-carbido complex [WPt(μ-C)Br(CO)(PPh)(Tp*)] (Tp = hydrotris(dimethylpyrazolyl)borate) undergoes substitution of one phosphine ligand with isonitriles to afford complexes [WPt(μ-C)Br(CNR)(CO)(PPh)(Tp*)] (R = Bu, CHMe-2,6, CHMe-2,4,6). For aryl but not alkyl isocyanides disubstitution follows to afford [WPt(μ-C)Br(CNR)(CO)(Tp*)] (R = CHMe-2,6, CHMe-2,4,6). The bis(isonitrile) derivatives, including [WPt(μ-C)Br(CNBu)(CO)(Tp*)], may also be prepared from the reactions of -[Pt(CNR)] with [W(CBr)(CO)(Tp*)]. Bis- and tris(dimethylpyrazolyl)borate pro-ligand salts replace the bromide and one phosphine in [WPt(μ-C)Br(CNCHMe)(CO)(PPh)(Tp*)] or the bromide and one isonitrile in [WPt(μ-C)Br(CNCHMe)(CO)(Tp*)] to afford [WPt(μ-C)(CNCHMe)(CO)(Tp*)(L)] (L = κ-Tp*, dihydrobis(pyrazolyl)borate). Structural, spectroscopic and computational data for the complexes are discussed to interrogate the nature of the WC-Pt carbido bridge by analogy with a range of other sp-C and sp-B ligands (CN, CCH, CP, CAs, CSb, CNO, BO, BNH and BCH).