Synthesis, characterisation and adsorption properties of a porous copper(ii) 3D coordination polymer exhibiting strong binding enthalpy and adsorption capacity for carbon dioxide

Abstract

The synthesis and characterisation of microporous coordination polymers containing copper(II) or cobalt(II) and 2-(pyridin-4-yl)malonaldehyde (Hpma) is described and the gas adsorption properties evaluated. Single-crystal X-ray structure determinations identified the structures as ³_∞[M(pma)₂]·2X (M = Cu, 1; Co, 2; X = MeOH, MeCN), which contain 3D networks with rutile topology and continuous 1D rectangular channels with diameters ranging from 3 to 4 Å. The materials exhibit low BET surface areas of 143 m² g⁻¹, but possess large capacities for carbon dioxide capture of 14.1 wt%. The small pore channels are shown to account for this, delivering a particularly strong binding enthalpy to adsorbed CO₂ of 38 kJ mol⁻¹, and a very large adsorption capacity relative to the low surface area.