1. gem-Dialkyl Effect in Diphosphine Ligands: Synthesis, Coordination Behavior, and Application in Pd-Catalyzed Hydroformylation
- Author
-
Charles Romain, James D. Nobbs, Andrew J. P. White, Srinivasulu Aitipamula, Martin van Meurs, George J. P. Britovsek, and Dillon W. P. Tay
- Subjects
Steric effects ,PHOSPHORUS LIGANDS ,CYCLIC SULFATES ,Denticity ,BITE-ANGLE ,0904 Chemical Engineering ,chemistry.chemical_element ,chelate ,Bite angle ,010402 general chemistry ,0305 Organic Chemistry ,01 natural sciences ,Medicinal chemistry ,Catalysis ,bidentate ,0302 Inorganic Chemistry ,Chelation ,hydroformylation ,BASIS-SETS ,ISOMERIZATION ,Science & Technology ,Chemistry, Physical ,010405 organic chemistry ,Chemistry ,Thorpe-Ingold ,METAL-CATALYSTS ,General Chemistry ,0104 chemical sciences ,Physical Sciences ,gem-dialkyl ,COMPLEXES ,diphosphine ,Isomerization ,Hydroformylation ,Palladium - Abstract
A series of palladium complexes with C3-bridged bidentate bis(diphenylphosphino)propane ligands with substituents of varying steric bulk at the central carbon have been synthesized. The size of the gem-dialkyl substituents affects the C–C–C bond angles within the ligands and consequently the P–M–P ligand bite angles. A combination of solid-state X-ray diffraction (XRD) and density functional theory (DFT) studies has shown that an increase in substituent size results in a distortion of the 6-membered metal–ligand chair conformation toward a boat conformation, to avoid bond angle strain. The influence of the gem-dialkyl effect on the catalytic performance of the complexes in palladium-catalyzed hydroformylation of 1-octene has been investigated. While hydroformylation activity to nonanal decreases with increasing size of the gem-dialkyl substituents, a change in chemoselectivity toward nonanol via reductive hydroformylation is observed.
- Published
- 2019