N-(3-Chlorophenyl)-2-hydroxy-1-naphthaldimine at 200 K

Abstract

The title compound, C17H12ClNO, (I), exists as the enol–imino tautomer [Csp2—O 1.333 (2) A] in the solid state at 200 K, while NMR spectroscopy reveals the keto­amino form in di­methyl sulfoxide solution. The orientation of the Csp2—O (for the OH tautomer) and the Csp2=O bond (for the NH tautomer) towards the N-3-chloro­phenyl substituent shows that both tautomers are E isomers with respect to the imino N=C bond. The solid-state OH tautomer is benzeno­id, forming the very short resonance-assisted O—H⋯N intramolecular hydrogen bond [N⋯O 2.537 (2) A]. The mol­ecules are assembled using only van der Waals contacts. The packing of the mol­ecules within the unit cell implies π–π interactions of adjacent naphthalene and phenyl rings, respectively. The energetically more favourable non-planar geometry [the dihedral angle between the naphthalene and 3-chloro­phenyl rings is 17.2 (1)°] is in accordance with the absence of intermolecular hydrogen bonding that could compensate the formation of a less energetically favourable planar mol­ecule.