CHELATING ETHER-PHOSPHINE COMPLEXES OF THE COBALT GROUP-METALS - CRYSTAL-STRUCTURES OF HOSPHINE]-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 poten tially 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 geo metry, but in the latter it acts as an O,P chelate. The crystal struct ure 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 s pecies 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 resp ectively, where L acts as a monodentate P-bonding ligand in 4 and 5. C omplex;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 che late in the other. The crystal structure of 3 has been determined and shows the metal to have a slightly distorted-octahedral mer arrangemen t with cis phosphorus donors. The fluxional nature of this complex has been monitored by variable-temperature P-31-(H-1) and H-1 NMR spectro scopy which shows that these ligands readily interchange at high tempe ratures. 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 w ith cyclohexene gave an unstable alkene complex 7 which could not be i solated. but was identified by variable-temperature P-31-{H-1} NMR stu dies.