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

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 CO2. 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.

Automated summary

This study reveals that spatial constraints imposed on molecular catalysts can be utilized as a handle to enhance intrinsic activity in bifunctional catalysis. By controlling the geometry of the active site, the catalytic activity of frustrated Lewis pairs (FLPs) in the hydrogenation of CO2 can be greatly increased. This can be achieved by fixing the donor-acceptor centers at specific distances and orientations.