A mixed-valence CuI/CuII metal–organic framework for CO2 conversion

Abstract

The development of noble-metal-free and efficient metal–organic frameworks (MOFs) as heterogeneous catalysts for carbon dioxide (CO₂) conversion is of particular interest, but remains challenging. In this study, a Cu^I/Cu^II mixed-valence MOF (1) was synthesized, consisting of copper(I) cyclic trinuclear units (Cu^I-CTUs) and Cu^II-paddlewheel units. The MOF featured a (3,4,4)-c network topology, which is rarely reported in the literature. Interestingly, 1 demonstrated efficient catalytic activity in the cyclization reaction of epoxides or propargyl amines with CO₂ with excellent yields (i.e., 81% to 99% for 12 examples). Additionally, it showed high reusability, maintaining the catalytic performance for at least five cycles without a loss in efficiency. Of significant note, MOF 1 delivered high catalytic activity with a turnover frequency of 142.8 h⁻¹ (23.8 h⁻¹ based on Cu) for the synthesis of oxazolidinones at ambient temperature, showcasing its potential as an effective catalyst for CO₂ conversion reactions.