Heterobimetallic μ 2 -halocarbyne complexes.

The halocarbyne complexes [M(CX)(CO) 2 (Tp*)] (M = Mo, W; X = Cl, Br; Tp* = hydrotris(dimethylpyrazolyl)borate) react with [AuCl(SMe 2 )], [Pt(η 2 -H 2 CCH 2 )(PPh 3 ) 2 ] or [Pt(η 2 -nbe) 3 ] (nbe = norbornene) to furnish rare examples of μ 2 -halocarbyne complexes [MAu(μ 2 -CX)Cl(CO) 2 (Tp*)], [MPt(μ 2 -CCl)(CO) 2 (PPh 3 ) 2 (Tp*)] and [W 2 Pt(μ 2 -CCl) 2 (CO) 4 (Tp*) 2 ]. The complex [WPt(μ 2 -CCl)(CO) 2 (PPh 3 ) 2 (Tp*)] spontaneously rearranges to the μ 2 -carbido complex [WPt(μ 2 -C)Cl(CO) 2 (PPh 3 ) 2 (Tp*)] during silica-gel chromatography. One phosphine ligand of [WPt(μ 2 -CCl)(CO) 2 (PPh 3 ) 2 (Tp*)] is readily substituted by CO to afford [WPt(μ 2 -CCl)(CO) 3 (PPh 3 )(Tp*)]. These μ 2 -halocarbyne complexes have been interrogated by spectroscopic, crystallographic and computational methods, the latter by reference to data for terminal halocarbyne precursors [M(CX)(CO) 2 (Tp*)].