Unusual hydrogen bonded (OH)4 tetrahedral nests organize zinc(ii) coordination complexes in a non covalent diamondoid network

Abstract

The crystal organization of Zn(LOH)₂X₂ (LOH = α-(4-pyridyl)benzhydrol) shows an abrupt change on passing from X = Cl (1) and X = Br (2) to X = I (3). The smaller and more electronegative halides (1, 2) participate in –OH⋯X hydrogen bonds giving an overall arrangement of the structures in bidimensional sheets where the zinc atoms behave as distorted square nodes in the network topology. In 3 the iodine atom switches the basic supramolecular synthon from –OH⋯X to a tetrahedral –(OH)₄ nest assembled by –OH⋯OH hydrogen bonds, giving a non-covalent diamondoid network where the metal acts as a spacer. This (OH)₄ nest constitutes a relatively robust supramolecular synthon whose tetrahedral topology arises from self recognition between the molecules, without the need of a central templating element.