2‐[4‐Phenyl‐5‐(2‐pyridyl)‐4H‐1,2,4‐triazol‐3‐yl]nicotinic acid: a case of solvent‐dependent polymorphism |
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Authors: | Liliana Mazur Anna E. Koziol Bozena Modzelewska‐Banachiewicz |
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Abstract: | The title compound, C19H13N5O2, crystallizes in two monoclinic forms depending on the solvent used. From methanol or acetone, a yellow form [(Ia), m.p. 533 K] in the space group P21 is obtained, while with ethanol as the solvent, an orange form [(Ib), m.p. 541 K] in the space group Cc results. The conformers observed in the two polymorphs differ primarily in the relative orientation of pyridine/phenyl and triazole rings. Molecules of both polymorphs form chains through carboxyl O—H...N hydrogen bonding; however, in each crystal structure, a different group acts as acceptor, viz. a triazole and a pyridyl N atom for (Ia) and (Ib), respectively. This is the first case of polymorphism observed for crystals of a 3,4,5‐trisubstituted 1,2,4‐triazole derivative. |
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