Chemical Fixation of CO2 Under Solvent and Co-Catalyst-free Conditions Using a Highly Porous Two-fold Interpenetrated Cu(II)-Metal-Organic Framework

A highly porous metal-organic framework (MOF) based on the Cu(II) ion, {[Cu-6(TATAB)(4)(DABCO)(3)(H2O)(3)]center dot 24DMF}(n) (Cu(II)-MOF) (where H(3)TATAB = 4,4',4 ''-s-triazine-1,3,5-triyl-tri-p-aminobenzoic acid and DABCO = 1,4-diazabicyclo[2.2.2]octane) was prepared and structurally characterized. The Cu(II)-MOF features a 2-fold interpenetrated three-dimensional, dual-walled cage with a dimension of similar to 29.8 A composed of a high density of Lewis acidic (LA) Cu(II) ions and basic -NH sites. The MOF possesses a high surface area of 2043.7 m(2)/g and exhibits selective adsorption of CO2 with a high heat of interaction (Qst) energy of 41.9 kJ mol(-1). Owing to the synergetic participation of LA and basic sites, the Cu(II)-MOF acts as an efficient heterogeneous catalyst for co-catalyst- and solvent-free chemical fixation of CO2 into cyclic carbonates. In-depth theoretical calculations were carried out using density functional theory (DFT) to elucidate the detailed mechanistic path involved in the successful co-catalyst-free conversion of CO2 into cyclic carbonates by the Cu(II)-MOF, and the results were found to be in clear agreement with the experimental findings. Further, Cu(II)-MOF exhibits recyclable catalytic activity and can be reused for several cycles without significant loss of catalytic activity. Herein, we report the rational design of a highly porous Cu(II)-MOF for the co-catalyst- and solvent-free fixation of CO2 into cyclic carbonates under environmentally friendly conditions.

Automated summary

The highly porous Cu(II)-MOF shows excellent adsorption capability and catalytic activity, efficiently converting CO2 into cyclic carbonates without the need for co-catalysts or solvents. This MOF is designed rationally, with recyclable catalytic activity, making it suitable for environmentally friendly CO2 conversion.