synthesis, characterization and h2 adsorption performances of polymeric co(ii) and ni(ii) complexes of pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole

We studied the synthesis and characterization of polymeric coordination complexes of co(ii) and ni(ii) ions with pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole. the e lemental analysis, infrared spectroscopy, powder x-ray diffraction, magnetic susceptibility, thermal analysis and x-ray single crystal techniques were used in the characterization. the x-ray single crystal analysis suggests that the pyrazine-2,3-dicarboxylato ligand acts as a bridging ligand through the oxygen atoms of the carboxylate groups and the nitrogen atoms on the pyrazine ring. the 1-vinylimidazole ligand behaves as a monodentate ligand via the ring nitrogen atom. further, the h2 adsorption studies were carried out at 75 k for various increasing pressures and the highest h2 adsorption performances for co(ii) and ni(ii) complexes were estimated as 2.66 and 2.99 wt% at 87 bar. the theoretical calculations using the crystal data were also performed to determine the voids in the structure of co(ii) complex.