Tuning porosity via control of interpenetration in a zinc isonicotinate metal organic framework

Abstract

Metal organic frameworks (MOFs) are a class of porous solids formed by linking metal centres or metal clusters by suitable organic ligands capable of generating porosity in the microporous and mesoporous regimes. They have been investigated extensively for their gas storage applications in the last two decades. Interpenetration is nature’s way of avoiding excessive free-space within the large porous networks by growing identical but independent networks within a parent network to decrease the solvent accessible voids and increase stability. A major challenge in MOF synthesis involves minimizing or completely eliminating the extent. In this paper, we report a zinc isonicotinate (or pyridyl-4-carboxylate, 4-PyC) MOF, 1, prepared by tuning the synthesis conditions to minimize interpenetration. The three-fold interpenetration presented in this material is unusual and has been compared to the other zinc isonicotinates to identify the differences contributing to the improved porosity. In addition, the thermal decomposition of 1 in an oxygen-deficient medium has been shown to yield significantly porous carbon embedded with ZnO nanoparticles.