Preparation and structure of [7-(η5-C5Me5)-8-Cl-11-(PMe2Ph)-nido-7-RhB10H11], a metallaborane analogue of the fluxional borane anion nido-B11H14–

Abstract

[(C₅Me₅)RhB₁₀H₁₁Cl(PMe₂Ph)] has a novel type of nido-7-metallaundecaborane structure which uniquely has one B–H–B and two M–H–B bridging H atoms rather than the usual two B–H–B bridging H atoms: these three H_µ mutually exchange (ΔG^‡ca. 33 kJ mol^–1) and this, together with the crystallographically determined molecular structure, suggests that the parent borane nido-B₁₁H₁₄^– has a conventional B–H–B bridge styx 3730 structure rather than one with an H₃⁺ triangle perpendicular to the molecular axis.