Molecular polarizability-induced covalently enhanced hydrogen bonds to achieve rapid conversion of CO2 and mechanism study

In the context of carbon peaking and carbon neutrality goals, the efficient conversion of CO 2 into cyclic carbonates represents a key pathway for carbon circular utilization. Hydrogen-bond donor (HBD) catalysts are widely applied in CO 2 cycloaddition reactions, and their mechanistic role in the rate-determining step has long been a central research focus. However, most existing studies primarily focus on hydrogen-bonding effects alone, while overlooking electron transfer processes and the evolution of intermolecular interactions, thereby failing to elucidate the intrinsic mechanism at an electronic level. This work employs the cycloaddition reaction between styrene oxide (SO) and CO 2 as a model system, integrating experimental investigations with theoretical calculations. The polarizabilities of a series of HBD catalysts were computed, and the catalyst-substrate polarizability difference (|Δα|) was introduced as an electronic coupling descriptor, enabling a systematic investigation of the structure–activity relationship with catalytic performance. The results indicate that a smaller catalyst-substrate |Δα| facilitates the formation of covalent-enhanced hydrogen bonds between the two components, which significantly enhances charge-transfer capability within the HBD-substrate complex, thereby substantially lowering the energy barrier of the rate-determining ring-opening step and leading to a pronounced enhancement in catalytic performance. This study highlights the role of catalyst-substrate polarizability regulation, providing new theoretical insights for the rational design of HBD catalysts.