Chiral paramagnetic closo-ruthenacarboranes via phosphine–diphosphine displacement reaction of 'three-bridge' exo-nido-ruthenacarboranes: Molecular Structure of (−)-[closo-3-Cl-3,3-{(Ph2PCHCH3)2CH2}-3,1,2-RuC2B9H11] and its ortho-cycloboronated derivative

Treatment of [exo-nido-{Cl(Ph3P)2Ru}-μ-(H)3-10-H-7,8-C2B9H8] (1) with the (2S,4S)-(−)-2,4-bis(diphenylphosphino)pentane (3, BDPP) while heating in toluene results in the formation of three novel optically active diphosphine–ruthenium closo complexes, 18e diamagnetic (−)-[closo-3-Cl-3,3-{(S,S)-BDPP}-3-H-3,1,2-RuC2B9H11] (4), and 17e paramagnetic (−)-[closo-3-Cl-3,3-{(S,S)-BDPP}-3,1,2-RuC2B9H11] (5) along with its ortho-cycloboronated derivative (−)-[closo-3-Cl-3,3-{(S,S)-Ph2PCH(CH3)CH2CH(CH3)PPh- (6). Both odd-electron complexes 5 and 6 were characterized by single-crystal X-ray diffraction analysis.