Bimetallic synergistic catalysis in MOFs toward transforming CO2 into carbonates with a record turnover number

Abstract

The synthesis of asymmetric carbonates from renewable CO₂ is important for sustainable chemistry but often suffers from low efficiency, harsh reaction conditions, and noble metal catalysts. Achieving this efficient transformation under mild conditions by non-noble metal catalysts remains a great challenge. Herein, a framework {[In₃(μ₃-O)(H₂O)Cu₄(CPT)₄I₂]⋅(NO₃)⋅1.5H₂O⋅3DMF}_n (CuIn-CPT, CPT = 3,5-bis(4′-carboxyphenyl)-1,2,4-triazole) was synthesized, assembled from a [Cu₁₂In₁₈] nanocage with multiple Cu^I and In^III Lewis acid sites, and it exhibits good thermal and chemical stabilities. It achieves up to 98% yield in multicomponent reactions of CO₂, propargyl alcohols, and primary alcohols without solvent under mild conditions, with a record turnover number of 4,844—ten times higher than top Ag-based catalysts—and excellent recyclability over 10 cycles. Density functional theory (DFT) calculations and mechanistic studies confirm that the synergistic effect between [Cu₄] and [In₃] clusters enhances catalytic efficiency. This work provides an inspiration for developing efficient non-noble metal heterogeneous catalysts in CO₂ conversion.