New Supercage Metal-Organic Framework Based on Allopurinol Ligands Showing Acetylene Storage and Separation.

ABSTRACT

To develop efficient adsorbent materials for storage and separation of C2 H2 , an unprecedented supercage MOF, [Me2 NH2 ]⋅[Zn3 (ALP)(TDC)2.5 ]⋅3.5DMF⋅2 H2 O (1) was constructed through medicinal molecule allopurinol (ALP) and S-containing 2,5-thiophenedicarboxylic acid (H2 TDC). 1 contains a novel linear trinuclear cluster that is composed by ALP and carboxylates and forms a final uncommon 5-connected yfy topological framework. The framework possesses three types of interlinked cages decorated by rich functional sites, and reveals not only high adsorption capacity for C2 H2 but also excellent selective separation for C2 H2 /CO2 and C2 H2 /CH4 at 298 K. Dynamic breakthrough experiments on C2 H2 /CO2 (11) mixture and C2 H2 /CH4 (11) mixture also demonstrated the potential of the material to separate C2 H2 from CO2 or CH4 mixtures. Molecular simulations were also studied to identify the different CO2 - and C2 H2 - binding sites in 1, such as carboxylate groups, S atoms and carbonyl groups.