Crystal structures of two PCN pincer iridium complexes and one PCP pincer carbodi-phospho-rane iridium inter-mediate: substitution of one phosphine moiety of a carbodi-phospho-rane by an organic azide.

The structure of [Ir{(4-Cl-C6H4N3)C(dppm)-κ3 P,C,N}(dppm-κ2 P,P')]Cl·1.5CH2Cl2·0.5C7H8 (C57H48Cl2IrN3P4·1.5CH2Cl2·0.5C7H8) (2), dppm = bis-(di-phenyl-phosphino)methane {systematic name: [7-(4-chloro-phen-yl)-1,1,3,3-tetra-phenyl-5,6,7-tri-aza-κN 7-1,3λ4-diphospha-κP 1-hepta-4,6-dien-4-yl][methyl-ene-bis(di-phenyl-phosphine)-κ2 P,P']iridium(I) chloride-di-chloro-methane-toluene (2/3/1)}, resulting from the reaction of [IrClH{C(dppm)2-κ3 P,C,P)(MeCN)]Cl (1a) with 1-azido-4-chloro-benzene, shows a monocationic five-coordinate IrI complex with a distorted trigonal-bipyramidal geometry. In 2, the iridium centre is coordinated by the neutral triazeneyl-idene-phospho-rane (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-κ3 P,C,P)]·CH3CN, (C52H45ClIrNP4·CH3CN) (1b) [systematic name: chlorido-cyanidohydrido(1,1,3,3,5,5,7,7-octa-phenyl-1,3λ5,5λ4,7-tetra-phospha-κ2 P 1,P 7-hept-3-en-4-yl)iridium(III) aceto-nitrile monosolvate], prepared from 1a and KCN, reveals an octa-hedral IrIII central atom with a meridional PCP pincer carbodi-phospho-rane (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)-κ3 P,C,N)(dppm-κ2 P,P')]·2CH3OH, (C58H48ClIrN4P4·2CH3OH) (3) (systematic name: {4-[3-(4-chloro-phen-yl)triazenido-κN 3]-1,1,3,3-tetra-phenyl-1,3λ5-diphospha-κP 1-but-2-en-4-yl}cyanido[methyl-enebis(di-phenyl-phosphine)-κ2 P,P']iridium(III) methanol disolvate), formed via prolonged reaction of 1-azido-4-chloro-benzene with 1b, features a six-coordinate IrIII 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 mol-ecules show occupational disorder, with the toluene mol-ecule exhibiting additional 1:1 positional disorder with some nearly overlying carbon atoms.