Crystal structure of 8-hy-droxy-quinoline: a new monoclinic polymorph.

ABSTRACT: In an attempt to grow 8-hy-droxy-quinoline-acetamino-phen co-crystals from equimolar amounts of conformers in a chloro-form-ethanol solvent mixture at room temperature, the title compound, C9H7NO, was obtained. The mol-ecule is planar, with the hy-droxy H atom forming an intra-molecular O-H?N hydrogen bond. In the crystal, mol-ecules form centrosymmetric dimers via two O-H?N hydrogen bonds. Thus, the hy-droxy H atoms are involved in bifurcated O-H?N hydrogen bonds, leading to the formation of a central planar four-membered N2H2 ring. The dimers are bound by inter-molecular ?-? stacking [the shortest C?C distance is 3.2997?(17)?Å] and C-H?? inter-actions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space group P21/n. The mol-ecular structure of the present monoclinic polymorph is very similar to that of the ortho-rhom-bic polymorph (space group Fdd2) studied previously [Roychowdhury et al. (1978 ?). Acta Cryst. B34, 1047-1048; Banerjee & Saha (1986 ?). Acta Cryst. C42, 1408-1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the ortho-rhom-bic polymorph possess twofold axis symmetry, with the central N2H2 ring adopting a butterfly conformation.

SUBMITTER: Castaneda R 

PROVIDER: S-EPMC4186174 | biostudies-other | 2014 Sep

REPOSITORIES: biostudies-other