Crystal structures of [IrCl2(NHCHPh)((dppm)(C(N2dppm))-κ3 P, C, P')]Cl·5.5MeCN and [IrI(NHCHPh)(((dppm)C(N2))-κ2 P, C)(dppm-κ2 P, P')]I(I3)·0.5I2·MeOH·0.5CH2Cl2: triazene fragmentation in a PCN pincer iridium complex

Bettina Pauer; Gabriel Julian Partl; Stefan Oberparleiter; Walter Schuh; Holger Kopacka; Klaus Wurst; Paul Peringer

doi:10.1107/S2056989019000136

Crystal structures of [IrCl₂(NHCHPh)((dppm)(C(N₂dppm))-κ³ P, C, P')]Cl·5.5MeCN and [IrI(NHCHPh)(((dppm)C(N₂))-κ² P, C)(dppm-κ² P, P')]I(I₃)·0.5I₂·MeOH·0.5CH₂Cl₂: triazene fragmentation in a PCN pincer iridium complex

Acta Crystallogr E Crystallogr Commun. 2019 Jan 8;75(Pt 2):179-184. doi: 10.1107/S2056989019000136. eCollection 2019 Feb 1.

Authors

Bettina Pauer¹, Gabriel Julian Partl¹, Stefan Oberparleiter¹, Walter Schuh¹, Holger Kopacka¹, Klaus Wurst¹, Paul Peringer¹

Affiliation

¹ Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria.

Abstract

The structure of [IrCl₂(C₅₈H₅₁N₃P₄)]Cl·5.5CH₃CN or [IrCl₂(NHCHPh)(((dppm)C(N₂dppm))-κ ³P,C,P)]Cl·5.5CH₃CN [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-κN)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 Ir^III 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(C₂₆H₂₂N₂P₂)(C₂₆H₂₂P₂)(C₆H₇N)]I(I₃)·0.5I₂·CH₃OH·0.5CH₂Cl₂ or [IrI(NHCHPh)((dppm)C(N₂)-κ ²P,C)(dppm-κ ²P,P')]I(I₃)·0.5I₂·CH₃OH·0.5CH₂Cl₂ {4, systematic name: (4-diazo-1,1,3,3,-tetra-phenyl-1,3λ⁴-diphosphabutan-4-yl-κP ¹)iodido[methyl-enebis(di-phenyl-phosphine)-κ² P,P'](phenyl-methanimine-κN)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 ³P,C,N)(dppm-κ ²P,P')]Cl with hydro-iodic acid, consists of a dicationic six-coordinate Ir^III 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.

Keywords: carbodiphosphorane; crystal structure; diazomethylenephosphorane; diazophosphorane; divalent carbon; fragmentation; iridium(III); nitrene; triazene.