REACTIONS OF TRI(HYDRIDO)(P-TOLYL ISOCYANIDE)BIS(TRIPHENYLARSINE)IRIDIUM-(III) WITH CHELATING LIGANDS - SPECTROSCOPIC AND MAGNETIC STUDY

Reactions of [IrH3(AsPh3)2(CNC6H 4Me-p)] with chelating ligands yield substitution products having the metal in various oxidation states depending on the nature of the ligand. Carboxylic acids, pentane-2,4-dione, and quadridentate Schiff bases give iridium(II) monomeric paramagnetic complexes; amino- and hydroxy-acids and o-amino- and o-hydroxy-phenols give paramagnetic iridium(IV) products. The presence of highly electron-attracting groups in the co-ordination sphere keeps Ir in the oxidation state III. All the complexes have been characterised by their vibrational, electronic, and magnetic properties, and in some cases the most probable ground-state electronic configuration of Ir has been suggested. Ligand-field properties favourable to each oxidation state are discussed.