Conformational studies of substituted nitroanilines: geometry of 2-methyl-5-nitroaniline

The title compound (C₇H₈N₂O₂), is monoclinic, space group P2₁/n, witha=9.552(2),b=5.677(2),c=13.586(3)Å, =92.68(2)⁰, andD_x=1.374 g-cm^–3 forZ=4. The refinement converged toR=0.043,wR=0.038. The molecule is approximately planar, with dihedral angles of 3.7(2.1)⁰ between the amino group and the aromatic ring, and 3.2(2)⁰ between the nitro group and the ring. According to the UV spectrum in solution, the molecular geometry indicates weak intramolecular charge transfer. The three-dimensional structure is stabilized by three intermolecular H bonds. A bifurcated one induces the formation of chains along, while the other two link molecules that belong to adjacent chains and are related by an inversion center.