We performed reactions between zinc chloride or zinc acetate dihydrate and pyrazinoic acid (pyzaH) in different solvents, ethanol or acetonitrile. In some experiments, water was added for better dissolution. The mol ratio between zinc ions and pyzaH was 1 : 2. Crystals of the new compound [ZnCl$_2$(pyzaH)$_2$·2H$_2$O] and crystals of the already known compound [Zn(H$_2$O)$_2$(pyza)$_2$] were isolated, which was confirmed by X-ray structural analysis. Infrared spectroscopy, CHN and thermal analysis were used to further characterize the resulting products. We found that the deprotonation of pyzaH and the binding of the anionic ligand pyza$^−$ to the zinc ion took place when water was added to the organic solvent.
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