Crystal structures of [IrCl 2 (NHCHPh)((dppm)(C(N 2 dppm))-κ 3 P , C , P ')]Cl·5.5MeCN and [IrI(NHCHPh)(((dppm)C(N 2 ))-κ 2 P , C )(dppm-κ 2 P , P ')]I(I 3 )·0.5I 2 ·MeOH·0.5CH 2 Cl 2 : triazene fragmentation in a PCN pincer iridium complex.

The structure of [IrCl2 (C58 H51 N3 P4 )]Cl·5.5CH3 CN or [IrCl2 (NHCHPh)(((dppm)C(N2 dppm)) - κ 3 P,C,P )]Cl·5.5CH3 CN [ 3 , dppm = bis-(di-phenyl-phos-phino)methane; systematic name: di-chlorido(1,1,3,3,7,7,9,9-octa-phenyl-4,5-di-aza-1,3λ5 ,7λ4 ,9-tetra-phosphanona-3,5-dien-6-yl-κ2 P 1 , P 9 )-(phenyl-methanimine-κ N )iridium(III) chloride aceto-nitrile hemihendeca-solvate], resulting from an oxygen-mediated cleavage of a triazeneyl-idene-phospho-rane ligand producing a diazo-methyl-ene-phospho-rane and a nitrene moiety, which in turn rearrange via a Staudinger reaction and a 1,2-hydride shift to the first title complex, involves a six-coordinate IrIII complex cation coordinated by a facial PCP pincer ligand, a benzaldimine and two chlorido ligands. The pincer system features a five- and a seven-membered ring, with the central divalent carbon of the PCP pincer ligand being connected to a phosphine and a diazo-phospho-rane. The chlorido ligands are positioned trans to the central carbon atom and to the phospho-rus donor of the seven-membered ring of the pincer system, respectively. A chloride ion serves as counter-ion for the monocationic complex. The structure of [IrI(C26 H22 N2 P2 )(C26 H22 P2 )(C6 H7 N)]I(I3 )·0.5I2 ·CH3 OH·0.5CH2 Cl2 or [IrI(NHCHPh)((dppm)C(N2 )-κ 2 P,C )(dppm - κ 2 P,P' )]I(I3 )·0.5I2 ·CH3 OH·0.5CH2 Cl2 { 4 , systematic name: (4-diazo-1,1,3,3,-tetra-phenyl-1,3λ4 -diphosphabutan-4-yl-κ P 1 )iodido[methyl-enebis(di-phenyl-phosphine)-κ2 P , P '](phenyl-methanimine-κ N )iridium(III) iodide-triiodide-di-chloro-methane-iodine-methanol (2/2/1/1/2)}, accessed via treatment of the triazeneyl-idene-phospho-rane complex [Ir((BnN3 )C(dppm)-κ 3 P,C,N )(dppm-κ 2 P,P ')]Cl with hydro-iodic acid, consists of a dicationic six-coordinate IrIII complex, coordinated by a bidentate diazo-methyl-ene-phospho-rane, a benzaldimine, a chelating dppm moiety and an iodido ligand. The phospho-rus atoms of the chelating dppm are trans to the central carbon atom of the diazo-methyl-ene-phospho-rane and the iodide ligand, respectively. Both an iodide and a triiodide moiety function as counter-ions. The aceto-nitrile solvent mol-ecules in 3 are severely disordered in position and occupation. In 4 , the I3 - anion is positionally disordered (ratio roughly 1:1), as is the I- anion with a ratio of 9:1. The di-chloro-methane solvent mol-ecule lies near a twofold rotation axis (disorder) and was refined with an occupancy of 0.5. Another disorder occurs for the solvent methanol with a 1:1 ratio.