Crystallization of five new supramolecular networks with both bipyridyl and dicyanamide ligands

Abstract

Supramolecular materials are important due to their distinct physical and chemical properties. Here we report the synthesis and structural determination, by single-crystal X-ray diffraction, of five new supramolecular networks, namely {[Fe(bpy)3OH][dca·4H2O]}n (1), {[Fe(bpy)3][Zn(dca)3]2}n (2), {Zn(bpy)2(dca)2}n (3), {Zn(bpy)(dca)2}n (4) and {[Zn(bpy)3][Fe(dca)3]2}n (5), where bpy=bipyridine and dca=dicyanamide. Compound 1 is made up of a [Fe(bpy)3OH]+ cation layer and a [dca·4H2O]− anion layer. Water clusters are present in the anionic sheet which link adjacent layers of the supramolecular assembly of compound 1. The anionic layer consists of randomly orientated dca anions and water clusters, while the cationic layer has randomly occupied OH groups. Compounds 2 and 5 have similar molecular connectivity to a previously reported structure, but with a different combination of metal centres. They contain a two-dimensional {[M′(dca)3−}n network which provides perfect hexagonal pockets for [M(bpy)3]2+ cations. Compound 3 consists of neutral distorted octahedral monomeric units and these monomeric units are connected through intermolecular hydrogen bonding, forming a 3D network. One of anionic dca ligands in compound 3 is also randomly orientated. Compound 4 possesses a zig-zag 1D chain structure and a 3D framework is generated through weak interactions between aromatic rings of adjacent layers. All five compounds contain both bpy and dca. The crystallization of these compounds depends highly on the experimental conditions.