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 = PF_6′(1a) or SbF_6′(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)Å, 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.