SYNTHESIS, CHARACTERIZATION AND REACTIVITIES OF DINUCLEAR RHODIUM(I) COMPLEXES OF A HEXADENTATE LIGAND,N,N,N′,N′-TETRAKIS[2-(DIPHENYLPHOSPHINO) ETHYL] ETHANE-1,2-DIAMINE

Abstract

Abstract A number of square planar dinuclear rhodium(I) complexes, [Rh2LX2] (X[dbnd]Cl, I, N3) and [Rh2L][ClO4]2 have been prepared with a hexadentate ligand having N2P4 donor sites, N,N,N′,N′-tetrakis[2-(diphenylphosphino) ethyl]ethane-1,2-diamine (L). The compound [Rh2LCl2] readily undergo oxidative addition reactions with Cl2, Br2, I2 and MeI which result in the formation of octahedral dinuclear complexes with additional ligands in axial positions. [Rh2LCl2] with NOBF4 forms a pentacoordinate complex [Rh2L(NO)2Cl2][BF4]2. Reaction of [Rh2LX2] (X[dbnd]Cl,N3) with CO gives pentacoordinate dinuclear complexes [Rh2L(CO)2X2] with trigonal bipyramidal geometry. However, a CO adduct [Rh2L(CO)4I]2 is obtained when [Rh(cod)I]2 reacts with L in CO-saturated dichloromethane solution. All CO adducts react with O2 to give octahedral carbonato complexes, [Rh2L(O)4(CO3)2X2] (X[dbnd]Cl, I, N3) in which CO3 2- acts as a bidentate ligand and PPh2 of L is oxidised to Ph2P[dbnd]O which coordinates to rhodium through oxyge...