Synthesis, molecular structure and reactivity of the first secondary carbaboranylbisphosphine 1,2-bis (phenylphosphino)-1,2-dicarba-closododecaborane(12)

Article abstract of DOI:10.1016/S0277-5387(97)00426-9

The reaction of a diastereomeric mixture of 1,2-bis(phenylchlorophosphino)-1,2-dicarba-closododecaborane(12) (1) with LiA1H₄, followed by hydrolysis with H₂O, gives a 4:1 mixture of rac- and meso-1,2-bis(phenylphosphino)-1,2-dicarba-closo-dodecaborane(12) (2a, b) or 1-phenylphosphino-1,2-dicarbacloso-dodecaborane(12) (3), depending on the stoichiometry employed. A mixture of 2a, b reacts with sulfur in undecane at 190°C or without solvent at 105-110°C to give exclusively the cyclic anhydride of 1,2-bis(phenylthiophosphoryl)-1,2-dicarba-closo-dodecaboranyl(12)- dithiodiphosphinic acid (6). 2, 3 and 6 were characterised spectroscopically (¹H, ³¹P, ¹¹B, ¹³C NMR, IR, MS) and X-ray structure determinations were carried out on the racemic isomers 2a and 6.