Intermediates in the Rh-catalysed dehydrocoupling of phosphine-borane.

Active species, product distributions and a suggested catalytic cycle are reported for the dehydrocoupling of the phosphine–borane H3B·PtBu2H to give HPtBu2BH2PtBu2BH3 using the [Rh(COD)2][BArF4] pre-catalyst.