Biomimetic caged platinum catalyst for hydrosilylation reaction with high site selectivity.

Natural enzymes exhibit unparalleled selectivity due to the microenvironment around the active sites, but how to design artificial catalysts to achieve similar performance is a formidable challenge for the catalysis community. Herein, we report that a less selective platinum catalyst becomes highly active and selective for industrially relevant hydrosilylation of a broad range of substrates when a porous cage ligand is used for confinement around the catalytic active site. The catalyst is more than ten times more active than Karstedt's catalyst while being recyclable. Properties such as size-selective catalysis and Michaelis-Menten kinetics support the proposed enzyme-like model. This biomimetic catalyst exhibits remarkable site-selectivity through the cage's confining effect, which amplifies small steric differences into dramatic reactivity changes for similar functional groups within a molecule.