Mapping Active Site Geometry to Activity in Immobilized Frustrated Lewis Pair Catalysts

Abstract

The immobilization of molecular catalysts imposes spatial constraints on their active site. We reveal that in bifunctional catalysis such constraints can also be utilized as an appealing handle to boost intrinsic activity through judicious control of the active site geometry. To demonstrate this, we develop a pragmatic approach, based on nonlinear scaling relationships, to map the spatial arrangements of the acid–base components of frustrated Lewis pairs (FLPs) to their performance in the catalytic hydrogenation of CO ₂. The resulting activity map shows that fixing the donor–acceptor centers at specific distances and locking them into appropriate orientations leads to an unforeseen many‐fold increase in the catalytic activity of FLPs compared to their unconstrained counterparts.

Abstract

A many‐fold increase in the catalytic performance of frustrated Lewis pairs is attainable through judicious control of the spatial arrangement of the acid and base components. This is demonstrated for CO ₂ hydrogenation by mapping the active site geometry to catalyst activity and identifying the optimal distance and orientation of the donor–acceptor centers using nonlinear scaling relationships.