Diphosphinoazine rhodium(III) and iridium(III) octahedral complexes

Rhodium(III) and iridium(III) octahedral complexes of general formula [MCl3{R2PCH2C(But)NNC(But)CH2PR2}] (M = Rh, Ir; R = Ph, c-C6H11, Pri, But; not all the combinations) were prepared either from the corresponding diphosphinoazines and RhCl3 · 3H2O or by the oxidation of previously reported bridging complexes [{MCl(1,2-η:5,6-η-CHCHCH2CH2CHCHCH2CH2)}2{μ-R2PCH2C(But)NNC(But)CH2PR2}] with chlorine-containing solvents. Depending on the steric properties of the ligands, complexes with facial or meridional configuration were obtained. Crystal and molecular structures of three facial and two meridional complexes were determined by X-ray diffraction. Hemilability of ligand in the complex fac-[RhCl3{(C6H11)2PCH2C(But)NNC(But)CH2P(C6H11)2}] consisting in reversible decoordination of the phosphine donor group in the six-membered ring was observed as the first step of isomerization between fac and mer isomers.

New octahedral Rh(III) and Ir(III) complexes of diphosphinoazines were prepared by two independent methods and characterized by NMR and X-ray diffraction. Complexes with both facial and meridional configuration were isolated, the preference for the particular configuration being probably controlled by steric reasons. Hemilability of a diphosphinoazine ligand in one of the complexes was experimentally observed by variable temperature NMR spectroscopy.Figure optionsDownload as PowerPoint slide