title: Crystal structure of a new monoclinic polymorph of N-(4-methyl-phen-yl)-3-nitro-pyridin-2-amine.
abstract: The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z' = 4) of the previously reported monoclinic (P21/c, with Z' = 2) form [Akhmad Aznan et al. (2010 ▶). Acta Cryst. E66, o2400]. Four independent mol-ecules comprise the asymmetric unit, which have the common features of a syn disposition of the pyridine N atom and the toluene ring, and an intra-molecular amine-nitro N-H⋯O hydrogen bond. The differences between mol-ecules relate to the dihedral angles between the rings which range from 2.92 (19) to 26.24 (19)°. The geometry-optimized structure [B3LYP level of theory and 6-311 g+(d,p) basis set] has the same features except that the entire mol-ecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C-H⋯O, C-H⋯π, nitro-N-O⋯π and π-π inter-actions [inter-centroid distances = 3.649 (2)-3.916 (2) Å].
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Aina Mardia Akhmad
authors.initials: AM
authors.lastname: Aznan
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Zanariah
authors.initials: Z
authors.lastname: Abdullah
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Vannajan Sanghiran
authors.initials: VS
authors.lastname: Lee
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink
keywords: amine; conformation; crystal structure; polymorph; pyridine