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, C 15 H 12 FNO 2, (I), and (E)-1-{3-[(2-hydroxy-3-methoxybenzylidene)amino]phenyl}ethanone, C 16 H 15 NO 3, (II), which crystallizes with Z′ = 2 in space group Pca2 1, there are intramolecular O-HN 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-HO hydrogen bond to form a C(8) chain, whereas in the crystal of (II), molecules are linked by three C-HO hydrogen bonds to form sheets within which orthogonal C 2 2 (16) and C 2 2 (17) chains can be identified. Comparisons are made with some related structures.