OXIDATIVE ADDITIONS OF I2 AND CH3I TO [RH(QUIN)(CO)BROKEN-VERTICAL-BAR-P(R-C6H4)3-BROKEN-VERTICAL-BAR] COMPLEXES - CRYSTAL-STRUCTURE OF [RH(I)(CH3)(QUIN)(CO)BROKEN-VERTICAL-BAR-P(4-CH3-C6H4)3-BROKEN-VERTICAL-BAR].1/2ET2O .4.

The oxidative additions of homo- and heteronuclear molecules XI (X = I, CH3) to the [Rh(quin)(CO)\P(R-C6H4)3\] complexes [quin = 2-quinaldinate anion (C9H6 NCOO-), R = 4-CH3O, 4-CH3, 4-F, 4-Cl, 3-CH3] were studied. Various phosphine ligands with different electronic properties and the same steric characteristics (R = 4-CH3O, 4-CH3, 4-F, 4-Cl) were used to determine their effect on the metal centre towards the oxidative addition reactions. Different sequences of the net electrodonation of the phosphine ligands for the square-planar rhodium(I) starting compounds and oxidated rhodium(III) products were deduced from the DELTAdelta(P-31) values. The spectroscopic data, IR, H-1 and P-31 NMR, indicated that in all cases only one isomer was formed. The crystal structure of one of these species, [Rh(I)(CH3)(quin)(CO)\P(4-CH3-C6H4)3\].1/2Et2O was resolved, indicating a pseudo-octahedral environment in the rhodium atom with the methyl and iodide ligands in cis positions.