Synthesis, structures, and characterization of benzildiimine complexes of rhodium(III) and iridium(I)

The reactions of trans-[(PPh3)2M(CO)Cl] (M = Rh and Ir) with benzildiimine (H2BDI = 2) derived from benzil-bis(trimethylsilyl)diimine (Si2BDI) (1) in a 1:2 and 1:1 molar ratio afforded the cationic bis-benzildiiminato complexes [Rh(PPh3)2(HBDI)2]Cl (3) and the mono-benzildiimine complex [Ir(PPh3)2(CO)(H2BDI)]Cl (4), respectively. Both complexes are fully characterized using IR, FAB-MS, NMR spectroscopy and elemental analysis. The single crystal X-ray structure analysis reveals a distorted octahedral coordination geometry for the Rh(III) in 3 and a highly distorted square pyramidal geometry for Ir(I) in 4. In addition, the solid-state structure of Si2BDI is reported here for the first time showing the substituents highly twisted because of steric reasons.