Structural aspects of palladium and platinum complexes with chiral diphosphinoferrocenes relevant to the regio- and stereoselective copolymerization of CO with propene

A series of chiral diphosphinoferrocene ligands 3a-i, derived from josiphos (=(2R)-1-[(1R)-1-(dicyclohexylphosphino)ethyl]-2-(diphenylphosphino)ferroc ene, formerly called [(R)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl}dicy cloxexylphosphine) where the electronic properties of the ligand are system atically varied, were prepared. X-Ray studies of five of these new ligands confirmed that these compounds display very similar conformations in the so lid state and that no structural criteria could be found indicating the mod ified electronic properties. These ligands find application in the Pd-catal yzed highly regio- and stereoselective CO/propene copolymerization reaction , where the electronic properties of the ligand show a great impact on the catalyst activity. Coordination-chemical aspects of these diphosphinoferroc enes relevant to the CO/propene copolymerization reaction were addressed by the preparation and characterization of Pd- and Pt-complexes of the genera l formula [PdCl2(P-P)] (5), [PdMe2(P-P)] (6), [PdClMe(P-P)] (7), [PdMe(MeCN )(P-P)]PF6 (8), and [PtClMe(P-P)] (9) (P-P=chiral diphosphinoferrocene liga nd (3a-h), four of which were characterized by X-ray crystallography.