title: Isomorphism in 1-(2-halidobenzyl)-4-[(E)-2-(3-hydroxyphenyl)ethenyl]pyridinium halide hemihydrates (halide = Cl, Br).
abstract: The crystal structures of two (E)-stilbazolium salts, namely 1-(2-chlorobenzyl)-4-[(E)-2-(3-hydroxyphenyl)ethenyl]pyridinium chloride hemihydrate, C(20)H(17)ClNO(+) x Cl(-) x 0.5 H(2)O, (I), and 1-(2-bromobenzyl)-4-[(E)-2-(3-hydroxyphenyl)ethenyl]pyridinium bromide hemihydrate, C(20)H(17)BrNO(+) x Br(-) x 0.5 H(2)O, (II), are isomorphous; the isostructurality index is 99.3%. In both salts, the azastyryl fragments are almost planar, while the rings of the benzyl groups are almost perpendicular to the azastyryl planes. The building blocks of the structures are twofold symmetric hydrogen-bonded systems of two cations, two halide anions and one water molecule, which lies on a twofold axis. In the crystal structure, these blocks are connected by means of weaker interactions, viz. van der Waals, weak hydrogen bonding and stacking. This study illustrates the robustness of certain supramolecular motifs created by a spectrum of intermolecular interactions in generating these isomorphous crystal structures.
authors.affiliation: Department of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland.
authors.forename: Wiesław
authors.initials: W
authors.lastname: Prukała
authors.forename: Dorota
authors.initials: D
authors.lastname: Prukała
authors.forename: Maciej
authors.initials: M
authors.lastname: Kubicki