Crystal structures of (E)-1-{3-[(5-fluoro-2-hydroxybenzylidene)amino]phenyl}ethanone and of a fourth polymorph of (E)-1-{3-[(2-hydroxy-3-methoxybenzylidene)amino]phenyl}ethanone

Abstract

In the molecules of both (E)-1-{3-[(5-fluoro-2-hydroxybenzylidene)amino]phenyl}ethanone, C15H12FNO2, (I), and (E)-1-{3-[(2-hydroxy-3-methoxybenzylidene)amino]phenyl}ethanone, C16H15NO3, (II), which crystallizes with it Z′ = 2 in space group it Pca21, there are intramolecular O—H···N hydrogen bonds, and the non-H atoms in each molecule are essentially coplanar. In the crystal of (I), molecules are linked by a single C—H···O hydrogen bond to form a it C(8) chain, whereas in the crystal of (II), molecules are linked by three C—H···O hydrogen bonds to form sheets within which orthogonal it C22(16) and it C22(17) chains can be identified. Comparisons are made with some related structures.