Isonitrile μ2-Carbido Complexes

Abstract

The μ-carbido complex [WPt(μ-C)Br(CO)2(PPh3)2(Tp*)] (Tp = hydrotris(dimethylpyrazolyl)borate) undergoes substitution of one phosphine ligand with isonitriles to afford complexes [WPt(μ-C)Br(CNR)(CO)2(PPh3)(Tp*)] (R = tBu, C6H3Me2-2,6, C6H2Me3-2,4,6). For aryl but not alkyl isocyanides disubstitution follows to afford [WPt(μ-C)Br(CNR)2(CO)2(Tp*)] (R = C6H2Me2-2,6, C6H2Me3-2,4,6). The bis(isonitrile) derivatives, including [WPt(μ-C)Br(CNtBu)2(CO)2(Tp*)], may also be prepared from the reactions of triangulo-[Pt3(CNR)6] with [W([triple bond, length as m-dash]CBr)(CO)2(Tp*)]. Bis- and tris(dimethylpyrazolyl)borate pro-ligand salts replace the bromide and one phosphine in [WPt(μ-C)Br(CNC6H2Me3)(CO)2(PPh3)(Tp*)] or the bromide and one isonitrile in [WPt(μ-C)Br(CNC6H2Me3)2(CO)2(Tp*)] to afford [WPt(μ-C)(CNC6H2Me3)(CO)2(Tp*)(L)] (L = κ2-Tp*, dihydrobis(pyrazolyl)borate). Structural, spectroscopic and computational data for the complexes are discussed to interrogate the nature of the W[triple bond, length as m-dash]C–Pt carbido bridge by analogy with a range of other sp-C1 and sp-B1 ligands (C[triple bond, length as m-dash]N, C[triple bond, length as m-dash]CH, C[triple bond, length as m-dash]P, C[triple bond, length as m-dash]As, C[triple bond, length as m-dash]Sb, C[triple bond, length as m-dash]NO, B[triple bond, length as m-dash]O, B[triple bond, length as m-dash]NH and B[double bond, length as m-dash]CH2). Show more