2-[4-Phenyl-5-(2-pyridyl)-4H-1,2,4-triazol-3-yl]nicotinic acid: a case of solvent-dependent polymorphism

Acta Crystallogr C. 2008 Oct;64(Pt 10):o574-7. doi: 10.1107/S0108270108029806. Epub 2008 Sep 25.

Abstract

The title compound, C(19)H(13)N(5)O(2), 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 P2(1) 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.

MeSH terms

  • Crystallization
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Niacin / analogs & derivatives*
  • Niacin / chemistry*
  • Solvents / chemistry
  • Triazoles / chemistry*

Substances

  • 2-(4-phenyl-5-(2-pyridyl)-4H-1,2,4-triazol-3-yl)nicotinic acid
  • Solvents
  • Triazoles
  • Niacin