Synthesis, characterization and electronic structures of Rh and co analogs of decaborane-14

We report the synthesis, isolation and structural characterization of several crystalline, moderately air stable nido-metallaboranes which represent novel metal rich open cage systems.The reaction of [Cp*CoCl]2, (Cp* = ν5-C5Me5), with [LiBH 4·thf] in toluene at-78 °C, followed by thermolysis with [BH3·thf] in boiling toluene yielded clusters, [(Cp*Co)3B6H8O] (1) and [(Cp*Co)2B8H11Me] (2). Under the similar reaction condition, [Cp*RhCl2]2 yielded [(Cp*Rh)3B7H11] (3) and [(Cp*Rh)2B8H12] (4). All the new compounds, 1-4 have been characterized by elemental analysis, IR, 1H, 11B, 13C NMR spectroscopy, and the geometric structures were unequivocally established byX-ray diffraction analysis of compound 1-4. Quantum chemical calculation by using density functional theory method is implemented on model compounds 10-40 (10-40 are the Cp analogs of 1-4 respectively, Cp = C5H5) and yields geometries in agreement with the X-ray detaermined geometries. Large HOMO-LUMO gaps are in tally with the higher stabilities of 10 and 30. © The National Academy of Sciences, India 2014.