Synthesis and characterization of porphyrin-based metal-organic frameworks for gas adsorption

Abstract

In this research, synthesis of porphyrinic linkers, porphyrin-based Metal-Organic Frameworks construction and their physical properties were concerned. For the first one, four porphyrin derivatives, including dicarboxyphenylporphyrin, 1,4-phenylene-bridged meso–meso linked diporphyrin, meso-meso β-β β-β triply linked (fused) diporphyrin and tetracarboxybiphenylporphyrin were synthesized. However, only the last porphyrin derivative was used as organic linker for MOFs synthesis in the presence of M(NO3)2 (M= Zn, Cu) with or without 4,4’-bipyridine (as pillar) by using dimethylformamide as solvent. The obtained porphyrin-based MOFs were investigated their morphologies and gas adsorption properties for the potential use in gas storage. Morphology of synthesized MOFs exhibited as micro-particles of MOFs in various forms, such as cubic, rod and platelet shapes. The nitrogen adsorption-desorption isotherms performed as type I adsorption isotherm which was typical for microporous materials. Total specific surface areas were in range 400-600 m2/g and the quite narrow pore size distribution was found with the average pore diameter of 0.6 nm. Moreover, the stability of this framework was investigated by TGA with the temperature not over than 300°C. It should be concluded that the synthesized MOFs via pathway B, using M-TCBPP as organic linkers with 4,4’-bipyridine as a pillar between the porphyrin plane, was the suitable pathway to synthesize MOFs.