Crystal structures of two PCN pincer iridium complexes and one PCP pincer carbodiphosphorane iridium intermediate: Substitution of one phosphine moiety of a carbodiphosphorane by an organic azide

Abstract

The structure of [Ir{(4-Cl-C6H4N3)C(dppm)-κ 3 P,C,N}(dppm-κ 2 P,P′)]Cl·1.5CH2Cl2·0.5C7H8 (C57H48Cl2IrN 3P4 ·1.5CH2Cl2·0.5C7H8) (2), dppm = bis(diphenylphosphino)methane {systematic name: [7-(4-chlorophenyl)-1,1,3,3-Tetraphenyl-5,6,7-Triaza-κN 7-1,3λ 4-diphospha-κP 1-hepta-4,6-dien-4-yl][methylenebis(diphenylphosphine)-κ 2 P,P′]iridium(I) chloride-dichloromethane-Toluene (2/3/1)}, resulting from the reaction of [IrClH{C(dppm) 2-κ 3 P,C,P)(MeCN)]Cl (1a) with 1-Azido-4-chlorobenzene, shows a monocationic five-coordinate Ir I complex with a distorted trigonal-bipyramidal geometry. In 2, the iridium centre is coordinated by the neutral triazeneylidenephosphorane (4-Cl-C6H4N3)C(dppm) acting as a PCN pincer ligand, and a chelating dppm unit. The structure of the coordination compound [IrCl(CN)H(C(dppm) 2-κ 3 P,C,P)]·CH3CN, (C52H45ClIrNP4 ·CH 3 CN) (1b) [systematic name: chloridocyanidohydrido(1,1,3,3,5,5,7,7-octaphenyl-1,3λ 5,5λ 4,7-Tetraphospha-κ 2 P 1,P 7-hept-3-en-4-yl)iridium(III) acetonitrile monosolvate], prepared from 1a and KCN, reveals an octahedral Ir III central atom with a meridional PCP pincer carbodiphosphorane (CDP) ligand; the chloride ligand is located trans to the central carbon of the CDP functionality while the hydrido and cyanido ligands are situated trans to each other. The chiral coordination compound [Ir(CN)((4-Cl-C6H4N3)CH(CH(P(Ph) 2) 2)-κ 3 P,C,N)(dppm-κ 2 P,P′)]·2CH 3 OH, (C58H48ClIrN4P4·2CH3OH) (3) (systematic name: {4-[3-(4-chlorophenyl)triazenido-κN 3 ]-1,1,3,3-Tetraphenyl-1,3λ 5-diphospha-κP 1-but-2-en-4-yl}cyanido[methylenebis(diphenylphosphine)-κ 2 P,P′]iridium(III) methanol disolvate), formed via prolonged reaction of 1-Azido-4-chlorobenzene with 1b, features a six-coordinate Ir III central atom. The iridium centre is coordinated by the dianionic facial PCN pincer ligand [(4-Cl-C6H4N3)CH(CH(P(Ph2)2)2)], a cyanido ligand trans to the central carbon of the PCN pincer ligand and a chelating dppm unit. Complex 2 exhibits a 2:1 positional disorder of the Cl-anion. The CH2Cl2 and C7H8 solvent molecules show occupational disorder, with the toluene molecule exhibiting additional 1:1 positional disorder with some nearly overlying carbon atoms.