Achieving Diverse CO2 Conversions through On-Demand Installation of Multivariate Catalytic Sites into One Prototypical Metal–Organic Framework

Abstract

The programmable design and construction of multirole or swing-role metal–organic frameworks (MR/SR-MOFs) for variable CO₂ conversions are appealing for green and sustainable chemistry. Herein, we describe a facile MR/SR-MOF synthetic strategy for on-demand engineering of the catalytic pore spaces in a primitive MOF for diverse CO₂ chemical fixation. Distinct functional groups can be precisely and quantitively immobilized into prototypical LIFM-28 (proto-LIFM-28) by virtue of postsynthesis based on its solid-state dynamic attribute, generating different catalytic pore spaces suitable for hydrosilylation, N-methylation, cycloaddition, and cyclization reactions of CO₂. Remarkably, the resultant LIFM-DSL-3 carrying amino and CO₂-masked N-heterocyclic carbene (NHC–CO₂) sites presents an excellent hydrosilylation performance with complete Ph₂SiH₂ conversion (>99%) and high silyl methoxide (SMO) selectivity (95%) under atmospheric CO₂ pressure, achieving an extraordinary turnover number (TON) of 4367 and a turnover frequency (TOF) of 6221 h^–1 beneficial for efficient methanol release upon hydrolysis. Moreover, an exceptionally high N-methylation efficiency is obtained for CO₂ transformation via N-methylation. This work demonstrates how to design MR/SR-MOFs as a multivariate catalytic platform for the cost-saving multirole and swing-role applications through on-demand manipulation and installation of active sites into a single MOF matrix without de novo synthesis.