Intermolecular Interactions in Dihydrothymine Derivatives Form Two-Dimensional and Three-Dimensional Networks

Abstract

In this paper, inter- or intra-molecular induced oxazolidine ring opening of two bicyclic nucleosides during recrystallisation are presented. The structures of these two compounds, azide derivative 2 and –NHBz derivative 3, as well as bicyclic O-trityl derivative 1, have been determined by single crystal X-ray diffraction method. The aim of this work was to understand the influence of structural differences of dihydrothymines on their supramolecular assemblies. In the crystal structure of 1, which crystallized with one ethanol molecule in the asymmetric unit, O–H···N and C–H···O intermolecular hydrogen bonds form two-dimensional network. One C–H···π interaction extends two-dimensional network into three-dimensional. Supramolecular structure of 2 is a three-dimensional network formed by N–H···O, O–H···O, C–H···N and C–H···O hydrogen bonds. Compound 3 crystallized with two independent molecules and two water molecules in the asymmetric unit and displays the greatest number of intermolecular interactions. Interestingly, although N–H···O, O–H···N, O–H···O and C–H···O hydrogen bonds are formed, as well as two C–H···π interactions, the result is only a two-dimensional network.

Graphical Abstract

In this paper crystal structures of three dihydrothymine derivatives which built different supramolecular architectures are presented and it is shown how weak interaction, such as C−H···π interaction, can form higher-order supramolecular structure, from two-dimensional to three-dimensional network.