Solid State Structure and Intermolecular Interactions of twoN-Benzylidenephenylethylamines

This article describes single crystal X-ray diffraction studies of two Schiff bases containing hydroxyl groups in aromatic rings: N-(4-hydroxybenzylidene)phenylethylamine (1) and N-(4-hydroxy-3-methoxybenzylidene)tyramine (2). Molecules of compound 1, with just one phenolic OH group, adopted an anti conformation, and were associated in zigzag chains with O-H...N hydrogen bonds between the azomethine fragment and the hydroxyl group. However, a gauche conformation was preferred by compound 2, which contained two hydroxyl groups in aromatic rings. Molecules of 2 were arranged in a three-dimensional array through O-H...N and O-H...O hydrogen bonding interactions. The results highlighted the importance of OH positions in the aromatic ring for the structural behaviour of the Schiff bases derived from phenylethylamines.Graphical AbstractMolecules of Schiff bases containing the moiety ArCH=N-CH2CH2Ar with one or two hydroxyl groups in the para position in the aromatic rings are associated in zigzag chains in the solid state through O-H...N hydrogen bonding interactions.