Rhodium(I) mixed CO/phosphine/amine complexes: Synthesis, structure, and reactivity

A series of new complexes of the general formula Rh(CO)(Cl)(PPh3)(NRR'R ") have been prepared via the bridge-splitting reactions of [Rh(mu-Cl)(CO)(PPh3)](2) with primary, secondary, and tertiary amine ligands, The Rh(I) complexes, Rh(CO)(Cl)(PPh3)(H2NCy) (3) and Rh(CO)(Cl)(PPh3)(HNEt2) (6) were crystallographically characterized and were found to possess a local square-planar geometry with a triphenylphosphine ligand trans to the amine, There is evidence for inter- and intramolecular hydrogen bonding between the amine hydrogen and the chloride ligand in 3 and 6, Complex 6 adds CX4 (X = Cl, Br, I) resulting in the formation of Rh(III) anionic complexes of the type [RhClnX4-n(PPh3)(CO)](-)(NH2R2)(+). The complex [RhCl4(PPh3)(CO)](-)(NH2Et2)(+.1/2) C6H6 (19) was characterized by X-ray diffraction and was found to crystallize in the monoclinic C2/c space group. The crystal structure of complex 20, which is synthesized from the reaction of 6 with CBr4, indicates that: the compound corresponds to the formula [RhBr2.85Cl1.15(CO)(PPh3)](-)(H(2)Net(2))(+. /2) C6H6. Rh(CO)(Cl)(PPh3)(HNEt2) catalyzes hydrosilation of l-hexene and polymerization of styrene and methyl methacrylate in the presence of perhaloalkanes.