SYNTHESIS, STRUCTURAL CHARACTERIZATION, AND REACTIVITY OF THE (ETA(2)-BENZOATO)IRIDIUM(III) HYDRIDE COMPLEX [MER-(ME3P)3IR(ETA(2)-O2CC6H5)(H)][PF6]

mer-(Me3P)3Ir(H)(O2CC6H5)(Cl) (1) reacts with Tl[PF6] to form the unus ual (eta2-benzoato)iridium(III) hydride complex [mer-(Me3P)3Ir(eta2-O2 CC6H5)(H)][PF6] (2). Compound 2 was crystallographically characterized and found to belong to the monoclinic space group P2(1)/n with a = 6. 899(2) angstrom, b = 11.783(3) angstrom, c = 32.303(8) angstrom, beta = 92.89(2)degrees, and V = 2622.7(13) angstrom3 for Z = 4. The Ir-O(1) and Ir-O(2) distances are 2.244(8) and 2.198(8) A, respectively. The coordinated oxygen-carbon distances are O(1)-C(7) = 1.294(15) angstrom and O(2)-C(7) = 1.284(15) angstrom, respectively. Compound 2 reacts w ith dimethyl acetylenedicarboxylate (DMAD) to yield (Me3P)3-Ir{(MeOC(O )C=C(H)(C(O)OMe)}(eta2-O2CC6H5)] [PF6] (3). Compound 3 crystallizes in the monoclinic space group P2(1)/n with a = 13.129(4) angstrom, b = 1 7.837(8) angstrom, c = 16.939(4) angstrom, beta = 109.81(2)degrees, an d V = 3732(2) angstrom3 for Z = 4. The synthesis and reactivity of 2 a re discussed with respect to the nature of the Ir-O linkage.