6-(2-Hydroxyanilinomethylene)-4-nitrocyclohexa-2,4-dien-1-one

Abstract

The molecule of the title compound, C13H10N2O4, is nearly planar with a dihedral angle between the two aromatic rings of 2.24 (9)°. The NH group forms an intramolecular hydrogen bond with the carbonyl O atom. The mol­ecules form dimers about inversion centers in the crystal structure via inter­molecular O—H⋯O hydrogen bonds.

Excited-State Dynamics and Two-Photon Absorption Cross Sections of Fluorescent Diphenyl-TinIV Derivatives with Schiff Bases: A Comparative Study of the Effect of Chelation from the Ultrafast to the Steady-State Time Scale

“…However, as we elaborate below, for the 3 and 4 series, the aniline and salicylidene rings are not necessarily in the same plane: In the crystal phase, the structures of salicylidene- ortho -aminophenols (free ligands) are not far from complete planarity, showing small deviations between the salicylidene (nine atoms taken for plane calculations) and aniline moieties (eight atoms taken for plane calculations; see Scheme for plane measurement explanation). From a series of reported X-ray structures, ,– depending on the nature and position of the substituents, these deviations range only from 13.44° for the E -OH form of 1 to 2.24° when compound 1 has a nitro substituent at the O-para position in the salicylidene moiety and adopts a Z -NH geometry . On the other hand, in the case of tin IV derivatives, the size of the tin atom itself has been shown to be enough to distort planar geometries, even if a fused ring system is constructed. ,, From the X-ray structures of the diphenyl-tin IV derivatives of the 3 series, it was possible to measure the following angles between planes in the organic Schiff base skeleton: 17.75° ( 3a ), 25.57° ( 3a ), 10.84° ( 3c ), 17.38° ( 3d ), 25.3° ( 3e ), and 19.41° ( 3f ) .…”