Escobar, Brandy

Abstract

Metal- organic frameworks (MOFs) have rapidly emerged as one of the favored crystalline porous materials (CPM) due to their compositional and geometric tunability leading to many possible applications, especially in gas storage and separation. Here, we sought to achieve efficient capture of small target molecules through a ligand insertion method to create new porous materials. Considering that the interactions between gas molecules and porous frameworks are usually not strong, it is ideal to increase the interaction between gas molecules and porous framework or to increase the density of gas binding sites by trapping gas molecules within small snug pockets or segments. Herein we have synthesized and characterized two new porous materials with different coordination chemistry and studied the adaptability of the less common, non-aromatic organic ligands and metal types within metal-organic frameworks. The first coordination network is constructed by a copper dimer, forming a copper paddlewheel that arranges into a pillar-layered structure. The second network is formed by nickel trimers creating an unusual MIL-88-type structure. Both MOFs involve the use of BCP (bicyclo[1.1.1]pentane1,3-dicarboxylic acid) as the primary ligand and DABCO as the secondary ligand. While the ligand combination is equivalent, new materials differ in their structural chemistry due to difference in metal cluster chemistry. The structures were determined from single-crystal X-ray diffraction and their thermal stability and gas sorption properties for CO2 and N2 have also been studied.

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