Synthesis, Characterization, and Application of Platinum(II) Complexes Incorporating Racemic and Optically Active 4-Chloro-5-Methyl-1-Phenyl-1,2,3,6-Tetrahydrophosphinine Ligand

An efficient resolution method was elaborated for the preparation of (+)-4-chloro-5-methyl-1-phenyl-1,2,3,6-tetrahydrophosphinine oxide using the acidic Ca2+ salt of (-)-O,O-di-p-toluoyl-(2R,3R)-tartaric acid. Crystal structure of the diastereomeric complex was evaluated by single crystal X-ray analysis. Beside this, the absolute P-configuration was also determined by a circular dichroism (CD) spectroscopic study including theoretical calculations. The tetrahydrophosphinine oxide was then converted to the corresponding platinum complex whose stereostructure was investigated by high-level quantum chemical calculations. The Pt complex was tested as a catalyst in the hydroformylation of styrene.