Abstract
A novel copper(I) metal-organic framework (MOF), {[Cu-2(I)(py-pzpypz)(2)(mu-CN)(2)]center dot MeCN}(n) (1 center dot MeCN), with an unusual topology is shown to be robust, retaining crystallinity during desolvation to give 1, which has also been structurally characterized [py-pzpypz is 4-(4-pyridyl)-2,5-dipyrazylpyridine)]. Zigzag-shaped channels, which in 1 center dot MeCN were occupied by disordered MeCN molecules, run along the c axis of 1, resulting in a significant solvent accessible void space (9.6% of the unit cell volume). These tight zigzags, bordered by ((CuCN)-C-I)(n) chains, make 1 an ideal candidate for investigations into shape-based selectivity. MOF 1 shows a moderate enthalpy of adsorption for binding CO2 (-32 kJ mol(-1) at moderate loadings), which results in a good selectivity for CO2 over N-2 of 4.8:1 under real-world operating conditions of a 15:85 CO2/N-2 mixture at 1 bar. Furthermore, 1 was investigated for shape-based selectivity of small hydrocarbons, revealing preferential uptake of linear acetylene gas over ethylene and methane, partially due to kinetic trapping of the guests with larger kinetic diameters.