A Porous Copper–Organic Framework Assembled by [Cu₁₂] Nanocages: Highly Efficient CO₂ Capture and Chemical Fixation and Theoretical DFT Calculations

Abstract

A new porous copper-organic framework assembled from 12-nuclear [Cu₁₂] nanocages {[Cu₂(L^4-)(H₂O)₂]·4DMA·2H₂O}_<i>n</i> (<b>1</b>) (H₄L = 5,5'-(butane-1,4-diyl)-bis(oxy)-diisophthalic acid) was successfully prepared and structurally characterized. Compound <b>1</b> feathering of a 3D framework with two types of 1D nanotubular channels and a large specific surface area can effectively enrich various harmful dyes. Additionally, due to the carbon dioxide (CO₂) interactions with open Cu(II) sites and the electron-rich ether oxygen atoms of ligand in <b>1</b>, it exhibits a highly selective CO₂ uptake. Interestingly, <b>1</b> can effectively catalyze the cycloaddition reaction of CO₂ with various epoxides under mild conditions, which is ascribed to the Lewis acid Cu(II) sites in the framework of <b>1</b>. Importantly, <b>1</b> acting as a heterogeneous catalyst can be recycled at least 10 times without an obvious loss of catalytic activity, and the CO₂ cycloaddition mechanism was further uncovered by density functional theory (DFT) calculations. This study can greatly enrich the MOF catalysts system of CO₂ conversion and also provide a valuable guidance for the design of efficient MOFs catalysts.