CHELATING ETHER-PHOSPHINE COMPLEXES OF THE COBALT GROUP-METALS - CRYSTAL-STRUCTURES OF BIS[BENZYLBIS(2-ETHOXYETHYL)-PHOSPHINE]-BIS(TRIFLUOROMETHANESULFONATO)COBALT(II) AND -TRICHLORORHODIUM(III)

New Group 9 metal complexes have been prepared using the trifunctional ligand benzylbis(2-ethoxyethyl)phosphine (L). Reactions of this potentially hemilabile ligand with CoCl2, and CoCl2 . 6H(2)O with AgCF3SO3, have been studied, resulting in the isolation of [CoCl(2)L(2)] 1 and [CoL(2)(O3SCF3)(2)] 2 respectively. In the former complex L acts as a monodentate P-bonding ligand with the metal adopting a tetrahedral geometry, but in the latter it acts as an O,P chelate. The crystal structure for 2 has been determined and shows the metal to have a distorted-octahedral geometry with trans ligands (P and O) and trans triflates. The P-31-{H-1} NMR spectrum of 2 suggests the formation of a dimeric species in solution, Reactions of L with RhCl3 . 3H(2)O, [{RhCl(CO)(2)}(2)] and [{RhCl(cod)}(2)] (cod = cycloocta-1,5-diene) resulted in the isolation of [RhCl(3)L(2)] 3, [RhCl(CO)L(2)] 4 and [RhCl(cod)L] 5 respectively, where L acts as a monodentate P-bonding ligand in 4 and 5. Complex;4 is shown to be trans by NMR studies. In 3 the ligand bonds as a monodentate phosphorus donor in one case and as a bidentate O,P chelate in the other. The crystal structure of 3 has been determined and shows the metal to have a slightly distorted-octahedral mer arrangement with cis phosphorus donors. The fluxional nature of this complex has been monitored by variable-temperature P-31-(H-1) and H-1 NMR spectroscopy which shows that these ligands readily interchange at high temperatures. The iridium analogue of 5 has been prepared from [{IrCl(cod)}(2)] resulting in the isolation of [IrCl(cod)L] 6. The reaction of 3 with cyclohexene gave an unstable alkene complex 7 which could not be isolated. but was identified by variable-temperature P-31-{H-1} NMR studies.