Crystal transformation synthesis of a highly stable phosphonate MOF for selective adsorption of CO₂

Abstract

A 2D phosphonate MOF {[Ni(Hptz)2]·7H2O}n (H2ptz = 4-(1,2,4-triazol-4-yl)phenylphosphonic acid) (2) is obtained through crystal transformation from a trinuclear compound [Ni3(Hptz)6·(H2O)6]·9H2O (1). Studies of chemical stability show that 2 retains its crystallinity in boiling water and organic solvents. 2 also exhibits high adsorption capacity for CO2 (80 cm3(STP) g−1) and selective separation of CO2 over N2.