Supramolecular Control of Ligand Coordination and Implications in Hydroformylation Reactions

摘要

Coordination chemistry and organometallic chemistry have intensely fuelled the field of transition metal catalysis, and knowledge-based ligand design is, next to combinatorial and high-throughput experimentation, a leading approach to develop new catalytic systems. For the industrially important hydroformylation reaction, ligand effects have been studied in detail, also with the aid of high-pressure spectroscopy techniques, (for example, HP NMR and HP-IR). The active species in this reaction is a trigonal bipyramidal complex, with a hydride on the axial position. The classical Wilkinson's dissociative mechanism, based on triphenyl phosphine as ligand, is widely accepted and explains most observations made to date. Two coordination complexes have been observed with either the ligands coordinated in the equatorial-equatorial (eq-eq) or in the equatorial-axial (eq-ax) mode (Scheme 1).