Synthesis and Structural Characterization of a Series of Novel Zn(II)-based MOFs with Pyridine-2,5-dicarboxylate Linkers

A series of novel metal–organic frameworks comprised of Zn–O–Zn dinuclear units and multidentate pyridine-2,5-dicarboxylate linkers were synthesized under mild conditions. The crystal structure and composition of the novel phases were established from synchrotron powder diffraction data. Small variations in the parameters of the synthesis led to formation of the metal–organic systems of different topologies, either 3D metal–organic frameworks (MOFs) or a 0D molecular complex. The novel MOFs feature a permanent porosity. The excess hydrogen uptake measured for the selected MOF sample was about 0.9 wt % at 77 K and 1 bar. Structural examinations indicated the phase transformation in several samples caused by the absorption of the atmospheric water molecules. The thermal stability and guest-molecule content in the pores of the novel MOFs were also characterized by TGA-DSC.