Efficient gas and alcohol uptake and separation driven by two types of channels in a porous MOF: an experimental and theoretical investigation

Utilizing the self-assembly strategy between the paddle-wheel Cu-2(COO)(4) cluster and a terephthalic acid ligand modified by a triazolyl group, namely H(2)tztp = 2-(1H-1,2,4-triazol-1-yl)terephthalic acid, a porous MOF, [Cu-0.5(tztp)(0.5)]center dot 0.5DMA (1), has been successfully designed and built. 1 is a three-dimensional self-interpenerated framework with a (3,6)-connected rtl topology, and contains hydrophilic and hydrophobic channels decorated with rich uncoordinated triazolyl N atoms and benzene rings from tztp ligands, respectively. The unique porous environment leads not only to high gas adsorption amounts of CO2, C2H6, C2H4 and C2H2 but also to a good separation ability of C-2 hydrocarbons over CH4, CO2 over CH4, and C2H2 over CO2 in the MOF. The specific adsorption sites of CO2 and C-2 hydrocarbons were explored by a molecular simulation. The breakthrough experiments demonstrated excellent dynamic separations for CO2 and CH4, C-2 hydrocarbons and CH4 as well as C2H2 over CO2. The MOF also revealed excellent adsorption and separation ability for CH3OH over other bulkier alcohol molecules.