Synthesis, crystal structures, molecular simulations for hydrogen gas adsorption, fluorescent and antimicrobial properties of pyrazine-2,3-dicarboxylate complexes

Eight new pyrazine-2,3-dicarboxylate complexes have been synthesized and structurally characterized. The pzdc ligand bridges two neighboring metal atoms to form a 1D chain in complexes 1, 3–8. The structure of the complex 2 is mononuclear. It is noted that when dimethylformamide was replaced by methanol, a 1-D double-chain structure of 3 was formed instead of the mononuclear structure of 2. The most interesting feature of 3 is the presence of C–H⋯Cu close hydrogen bonding interactions. In complexes, the pzdc ligand exhibits four kinds of coordination modes. The adjacent chains are held together by hydrogen bonds, C–H⋯π and π⋯π interactions, forming three-dimensional network. Complexes 4–8 exhibit strong fluorescent emission bands in the solid state at room temperature. Atomically detailed simulations were used to assess the potential of complexes in gas storage applications. Complexes 2 and 7 have showed antimicrobial activity on studied microorganisms.