[Ir(acac)(η2-C8H14)2]: A precursor in the synthesis of cyclometalated iridium(III) complexes

A new convenient synthesis and the crystallographic characterization of [Ir(acac)(coe)2] (2, acac = acetylacetonato; coe = cis-cyclooctene) are described. The title compound crystallized from THF/ethanol in two modifications (monoclinic P21/c, 2a, and triclinic P 1 ¯ , 2b). Complex 2 represents an efficient starting material in the synthesis of mononuclear iridium(III) complexes containing cyclometalated 2-phenylpyridinato ligands using oxidative addition reactions of the corresponding ligands towards 2. Thus [Ir(acac)(ppy)2] (3, ppy = 2-phenylpyridinato) and [Ir(ppy)3] (4) (mer, 4a; fac, 4b) were prepared in excellent yields and short reaction times in a kind of one-pot procedure starting from [{Ir(μ-Cl)(coe)2}2] (1). Furthermore a convenient synthesis of [{Ir(μ-Cl)(ppy)2}2] (5) from 1 and Hppy is described.