Crystal structure of an iridium(III) complex of the [C(dppm)(2)] PCP pincer ligand system and its conjugate CH acid form

After the successful creation of the newly designed PCP carbodi­phospho­rane (CDP) ligand [Reitsamer et al. (2012 ▸). Dalton Trans. 41, 3503–3514; Stallinger et al. (2007 ▸). Chem. Commun. pp. 510–512], the treatment of this PCP pincer system with the transition metal iridium and further the analysis of the structures by single-crystal diffraction and by NMR spectroscopy were of major inter­est. Two different iridium complexes, namely (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}methane-κ(3) P,C,P′)carbonyl­chlorido­hydridoiridium(III) chloride di­chloro­methane tris­olvate, [Ir(III)(CO){C(dppm)(2)-κ(3) P,C,P′}ClH]Cl·3CH(2)Cl(2) (1) and the closely related (bis­{[(di­phenyl­phosphan­yl)meth­yl]di­phenyl­phosphanyl­idene}methanide(1+)-κ(3) P,C,P′)carbonyl­chlorido­hy­dridoirid­ium(III) dichloride–hydro­chloric acid–water (1/2/5.5), [Ir(III)(CO){CH(dppm)(2)-κ(3) P,C,P′)ClH]Cl}(2) (2), have been designed and both complexes show a slightly distorted octa­hedral coordinated Ir(III) centre. The PCP pincer ligand system is arranged in a meridional manner, the CO ligand is located trans to the central PCP carbon and a hydride and chloride are located perpendicular above and below the P(2)C(2) plane. With an Ir—C(CDP) distance of 2.157 (5) Å, an Ir—CO distance of 1.891 (6) Å and a quite short C—O distance of 1.117 (7) Å, complex 1 presents a strong carbonyl bond. Complex 2, the corresponding CH acid of 1, shows an additionally attached proton at the carbodi­phospho­rane carbon atom located anti­periplanar to the hydride of the metal centre. In comparison with complex 1, the Ir—C(CDP) distance of 2.207 (3) Å is lengthened and the Ir—C—O values indicate a weaker trans influence of the central carbodi­phospho­rane carbon atom.