Halogenation of A-frame μ-carbido complexes: synthesis of μ2-halocarbynes

The reaction of [Rh-2(mu-C)Cl-2(PPh3)(4)] with bis(diphenylphosphino)-methane (dppm) affords the A-frame mu-carbido complex [Rh-2(mu-C)Cl-2(mu-dppm)(2)], halide metathesis of which provides [Rh-2(mu-C)Br-2(mu-dppm)(2)]. The reactions of the former with PhICl2 or the latter with [pyH][Br-3] provide rare examples of mu(2)-halocarbyne ligands in the complexes [Rh-2(mu-CX)(mu-X)X-4(mu-dppm)(2)] (X = Cl, Br).