Iridium(III) hydrido complexes with 2-pyridinaldazines. Crystal structure of [IrH2(mpaa)(PPh3)2]SbF6. Synthesis and characterization of homo- and hetero-nuclear complexes

Abstract

The reactivity of the hydrido complexes [IrH2(Me2CO)2(PPh3)2]X [X = PF6′(1a) or SbF6′(1b)] with 2-pyridinaldazines [2-pyridinecarbaldehyde azine (paa) and 6-methyl-2-pyridinecarbaldehyde azine (mpaa)] is reported. The molecular structure of both mononuclear complexes which form form (1b), [IrH2(N–N)(PPh3)2]SbF6[N–N = paa, (2b); or mpaa(3b)], comprises an octahedral iridium(III) centre with apical PPh3 and cis hydrido ligands, as shown by an X-ray analysis of (3b). The mononuclear species react further with the homologous parent compound (1a) or (1b) to afford the homobinuclear species [{IrH2(PPh3)2}2(µ-N–N)]X2(X = PF6 or SbF6). Moreover, the reaction of (2a) with CuCl2·2H2O, [PdCl2(PhCN)2] or [PtMe2(dmso)2] leads to heterobimetallic complexes. The iridium(III)—palatinum(II) compound undergoes oxidative addition with MeI, giving rise to the iridium(III)—platinum(IV) species [(Ph3P)2H2lr(paa)PtMe3I]PF6. All the new complexes have been characterized by elemental analysis, conductivity measurements, i.r., and 1H and 31P-{1H} n.m.r. spectroscopy. Crystals of (3b) are triclinic, space group P, with a= 14.017(6), b= 15.673(7), c= 12.452(6)A, α= 99.60(1), β= 112.78(2), γ= 97.88(2)°, and Z= 2. The structure has been solved from diffractomer data by Patterson and Fourier methods and refined by full-matrix least squares to R= 0.049 for 5 675 observed reflections.