Developing the Kharasch Reaction in Aqueous Media: Dinuclear Group 8 and 9 Catalysts Containing the Bridging Cage Ligand Tris(1,2‐dimethylhydrazino)diphosphane

The dinuclear complexes [{RuCl 2 (η 6 ‐ p ‐cymene)} 2 (μ‐THDP)] ( 4 ) and [{MCl(η 4 ‐cod)} 2 (μ‐THDP)] [M = Rh ( 5 ), Ir ( 6 )], containing the bridging cage‐type ligand tris(1,2‐dimethylhydrazino)diphosphane (THDP), have been synthesized in high yields (89–95 %) by treatment of dimers [{RuCl(μ‐Cl)(η 6 ‐ p ‐cymene)} 2 ] ( 1 ) and [{M(μ‐Cl)(η 4 ‐cod)} 2 ] [M = Rh ( 2 ), Ir ( 3 )] with one equivalent of THDP. The structure of the (η 6 ‐arene)ruthenium(II) derivative 4 has been unequivocally confirmed by means of X‐ray diffraction methods. All these complexes have been found to be active catalysts for the atom‐transfer radical addition of bromotrichloromethane to olefins (Kharasch reaction) in heterogeneous aqueous media under mild conditions (room temp.).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)