A simple entry into nido-C2B10 clusters: HCl promoted cleavage of the C-C bond in ortho-carboranyl diphosphines

Treatment of the diphosphines ortho-B10H10C((PBu2)-Bu-t) C(PR2) (R = Et, Cy, Ph) with HCl gives the zwitterionic, nido-12-vertex species B10H10C((PHBu2)-Bu-t) C(PClR2); these reactions are reversed by the addition of NEt3.