In contrast to their three-dimensional counterparts, porous molecular assemblies have shown limited utility for gas storage and separation applications. Among these, they have nearly entirely involved porous organic cages (POCs). These all-organic solids, however, lack the strong binding sites that endow hybrid organic/inorganic materials with selective adsorption. Porous coordination cages are particularly promising in this regard. A challenge here, however, is the synthesis of soluble, permanently porous materials. Here, structural modifications on 5-hydroxy isophthalic acid-based materials allowed for the study of the effect of linear alkoxide groups on the synthesis, solubility, and selective gas uptake of porous cages. The tuning of reaction conditions allowed for the isolation of tetragonal or hexagonal two-dimensional materials or porous molecular cages. The solubility of the porous molecular cages increased by extending the length of the functionalized alkoxide group. The isolated porous molecules display BET surface areas ranging from 125 to 545 m<sup>2</sup>/g. The pentoxide-based molecular assembly shows considerable promise for the separation of hydrocarbons with average isosteric heats of adsorption of –48 and –31 kJ/mol for ethylene and ethane, respectively.

Ligand-based phase control in porous molecular assemblies

256th National Meeting (2018)

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