An orthorhombic polymorph of 5-[(4-methylphenyl)diazenyl]salicylaldehyde

Abstract

The title compound, C14H12N2O2, is an orthorhombic polymorph of the previously reported monoclinic form [Bakir et al. (2005). Acta Cryst. E61, o1611–o1613]. The dihedral angle between the aromatic rings is 4.32 (13)°. The molecular structures of the two polymorphs, including short intramolecular O—H...O hydrogen bonds between the the hydroxy and keto groups, are quite similar but their crystal packings are distinct. Unlike the monoclinic form, in which centrosymmetrically related hydroxy and keto groups form {...H...O}2 synthons via weak O—H...O contacts, leading to dimeric aggregates, in the orthorhombic form, the hydrogen bonding between these groups leads to the formation of supramolecular chains orientated along the a axis.