Effector responsive hydroformylation catalysis

Herein, we report a supramolecular rhodium catalyst that can form dimeric or monomeric Rh-complexes, depending on the binding of effectors within the integrated DIM-receptor. X-ray crystal structures, in situ (high-pressure (HP)) spectroscopy studies, and molecular modelling studies show that in the absence of effectors, the preferred Rh-species formed is the dimer, of which two ligands coordinate to two rhodium metals. Importantly, upon binding guest molecules, -effectors-, to the DIM-receptor under hydroformylation conditions, the monomeric Rh-active species is formed, as evidenced by a combination of in situ HP NMR and IR spectroscopy studies and molecular modelling. As the monomeric complex has different catalytic properties from the dimeric structure, we effectively generate a catalytic system of which the properties respond to the presence of effectors, reminisent of how proteins are regulated in nature. Indeed, catalytic and kinetic experiments show that both the selectivity and activity of this supramolecular catalytic system can be regulated in the hydroformylation of 1-octene using acetates as effectors that shift the equilibrium from the dimeric to monomeric species.