Morphology evolution and gas adsorption of porous metal–organic framework microcrystals

Abstract

A facile and controllable synthesis of porous framework [Cu₃(L)₂(DABCO)] (1) (H₃L = 1,1′:3,1′′-terphenyl]-4,4′′,5′-tricarboxylic acid; DABCO = 1,4-diazabicyclo[2.2.2]octane) microcrystals was realized with morphology evolution from a tetragonal plate to an elongated tetragonal bipyramid, and the particle size changes by tuning the volume ratio of mixed solvents of DMF and H₂O. Interestingly, the exposed high-energy {103} crystal facet can be easily tuned by controlling the supersaturation through the increase of the solution concentration, resulting in the formation of spindle microcrystals. It was found that both H₂O and HCl play important roles in the morphology evolution process. The gas adsorption properties were found to be dependent on the morphology of microcrystals, and the elongated tetragonal bipyramidal microcrystals show the largest BET surface area.