Some unusual iridium-(I), -(II), and -(III) complexes formed from 2-methoxyphenyl- or 2-hydroxyphenyl-di-t-butylphosphine

Abstract

O-Metallated yellow iridium(I) complexes, [[graphic omitted])}{PBu^t₂(C₆H₄OX–2)}](I; X = H or Me), are described. ¹H–, ³¹P–, And ¹H–{³¹P}-INDOR studies show a complex behaviour with temperature, probably due in part to the complexity of the spin systems and to the presence of rotational isomers. A benzene solution of (I; X = H) in air gives, after an induction period, the blood-red paramagnetic iridium(II) complex trans-[[graphic omitted])}₂]. The latter reacts with hydrogen to give the dark purple iridium(III) hydride [[graphic omitted])}₂], (IV), also prepared from hydrated iridium(III) chloride and (2-hydroxyphenyl)di-t-butylphosphine in isopropyl alcohol. Complex (IV) in benzene slowly reacts with air to give the Ir^II complex or rapidly with carbon monoxide to give colourless [[graphic omitted])}₂]. A benzene solution of trans-[[graphic omitted])}₂] in air slowly (24 h) gives the purple five-co-ordinate C-metallated Ir^III complex [[graphic omitted])}]; this readily takes up carbon monoxide in the sixth co-ordination position to give a colourless adduct. Various other reactions to give unidentified products are described. ¹H and ³¹P n.m.r. and i.r. data are given.