Isonitrile μ 2 -carbido complexes.

The μ-carbido complex [WPt(μ-C)Br(CO) 2 (PPh 3 ) 2 (Tp*)] (Tp = hydrotris(dimethylpyrazolyl)borate) undergoes substitution of one phosphine ligand with isonitriles to afford complexes [WPt(μ-C)Br(CNR)(CO) 2 (PPh 3 )(Tp*)] (R = t Bu, C 6 H 3 Me 2 -2,6, C 6 H 2 Me 3 -2,4,6). For aryl but not alkyl isocyanides disubstitution follows to afford [WPt(μ-C)Br(CNR) 2 (CO) 2 (Tp*)] (R = C 6 H 2 Me 2 -2,6, C 6 H 2 Me 3 -2,4,6). The bis(isonitrile) derivatives, including [WPt(μ-C)Br(CN t Bu) 2 (CO) 2 (Tp*)], may also be prepared from the reactions of triangulo -[Pt 3 (CNR) 6 ] with [W(CBr)(CO) 2 (Tp*)]. Bis- and tris(dimethylpyrazolyl)borate pro-ligand salts replace the bromide and one phosphine in [WPt(μ-C)Br(CNC 6 H 2 Me 3 )(CO) 2 (PPh 3 )(Tp*)] or the bromide and one isonitrile in [WPt(μ-C)Br(CNC 6 H 2 Me 3 ) 2 (CO) 2 (Tp*)] to afford [WPt(μ-C)(CNC 6 H 2 Me 3 )(CO) 2 (Tp*)(L)] (L = κ 2 -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 1 and sp-B 1 ligands (CN, CCH, CP, CAs, CSb, CNO, BO, BNH and BCH 2 ).