The α₂-polymorph of salicylideneaniline

Abstract

N-Salicylideneaniline (SA), C13H11NO, belongs to the large family of aromatic Schiff bases. It is of particular importance owing to its reversible photoreactivity. SA forms two photochromic polymorphs, both with two non-coplanar benzene rings. In addition, we have recently discovered a planar polymorph, named the beta-polymorph, which will be discussed in a subsequent paper. We report here the structure of the alpha2-polymorph in the orthorhombic crystal system. This compound exhibits a strong intramolecular O-H...N hydrogen bond and the dihedral angle between the two rings varies with temperature.

4-Fluoro-2-[(3-methylphenyl)iminomethyl]phenol

“…The title compound ( Figure 1) is essentially co-planar with a dihedral angle of 9.28 (7)° between the aromatic rings. The bond distances and angles in the title compound are in accord with those reported for related salicylaldimine-based ligand systems (Karakaş et al, 2004;Arod et al, 2005;Cheng et al, 2005;Brink et al, 2009). …”

“…For related structures, see: Karakaş et al (2004); Arod et al (2005); Cheng et al (2005); Brink et al (2009). For related rhenium tricarbonyl complexes containing salicylaldimines, see: Brink et al (2011).…”

Polymorphism inN-Salicylideneaniline Reconsidered

“…Indeed, we observed that distances and angles of 1 are similar to those found in the nonplanar R 2 -polymorph. 15 The molecule is quite planar with a angle (Scheme 1) of 2.27(15)°, but ()6.93(27)°) is larger than ψ ()4.77(26)°). It appeared interesting to study (CrystalMaker) 33 other near-planar ( < 10°) SA derivatives found in the CCDC database.…”

Tetra(o-phenyldiazo-p-methylphenoxy)silane – A silicon complex with a fourfold capped-tetrahedral [4+4] coordination sphere

“…1 and 2, respectively) [6]. The molecular conformation (E) of 1 is similar to that found in the crystal structure of the Schiff base Nphenylsalicylaldimine [7]. Fig.…”