Rhodium(I) complexes with phosphinooxathiane (POT) and phophinooxazolidine (POZ) ligands: the crystal structures of [(POT)Rh(CO)Cl] and [(POZ)Rh(CO)Cl]

The synthesis of the complexes [(POT)Rh(CO)Cl] (1) and [(POZ)Rh(CO)Cl] (2) has been achieved by reacting the ligands POT and POZ with the starting material [Rh(μ-Cl)(CO)2]2 in a 2:1 ratio. The single crystal X-ray diffraction studies show both structures to have metal centers into a slightly distorted square planar environment, the main distortion being due to the steric hindrance caused by the aromatic rings in the phosphine moiety. Preliminary results concerning the use of the catalytic systems POT/Rh and POZ/Rh in the rhodium catalyzed asymmetric hydroformylation of styrene showed that the POT/Rh system is more efficient, giving some enantiomeric enrichment of the product, a chiral branched aldehyde.