Two new coordination compounds of CoII based on pyrazin-2,3-dicarboxylic acid formulated as (Base)2[CoII(pyzdc)2(H2O)2]·6H2O, (where Base = 2-amino- 4-methyl pyridinium (1); 2-amino-4-methyl pyrimidin-3-ium (2); and pyzdcH2 = pyrazin-2,3-dicarboxylic acid), have been synthesized and structurally characterized by elemental analyses, IR spectroscopy and single crystal X-ray diffraction. These two title compounds are iso-structure. In 1 and 2, the metal center have distorted octahedral coordination geometries and chelated by two N atoms of the pyrazine ring, two monodentate carboxylate O atoms, and two O atoms from two coordinated water molecules, forming a distorted octahedral N2CoO4. Through hydrogen bonding (such as O−H···O and N−H···O) and/or slipped or offset - stacking interactions, 3D supramolecular networks are constructed in these complexes. So the hydrogen bond interactions play an important role in sustaining of the supramolecular solid-state architectures in compound 1 and 2.

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