Pseudopolymorph and Charge-Transfer Co-Crystal of Disubstituted Adamantane containing Dimethoxyphenol Moieties

Abstract

A disubstituted adamantane containing dimethoxyphenol moieties was synthesized by an acid-condensation reaction. The disubstituted adamantane is a new building block, designed particularly for the rational construction of supramolecular structures that are capable of encapsulating and aligning guest molecules, leading to the formation of extended polymeric networks. Single crystal X-ray analysis revealed that the binary molecule based on adamantane has three types of crystal forms, 1a, 1b, and 1c, containing no additional molecule, water and benzene, and 1,3,5-trinitrobenzene, respectively. In crystal 1a, each hydroxyl group of dimethoxyphenol moieties participates in two intermolecular hydrogen bonds as both donor and acceptor, producing infinite one-dimensional (1D) zigzag chains. Individual chains assemble into a two-dimensional (2D) layered structure via C−H···O interactions between protons of adamantane and oxygen atoms of methoxy groups. Crystal 1b, which is pseudopolymorph of crystal 1a, has a cyclic network consisting of two molecules of disubstituted adamantane and two molecules of water, generated by hydrogen bonds, a benzene molecule accommodated in the cavity. This stacks into a tubular structure via water molecules, which again align into a 2D layered structure through water molecules. Crystal 1c shows a discrete cyclic network accomplished through hydrogen bonds between two molecules of disubstituted adamantane and two molecules of 1,3,5-trinitrobenzene. The finite cyclic network stacks to form 1D columnar aggregates due to van der Waals interactions among the adamantyl groups, resulting in the formation of a channel structure. Individual columns are intermolecularly interdigitated via donor−acceptor interactions between the dimethoxyphenol moieties and 1,3,5-trinitrobenzene, resulting in the formation of a 2D layered structure. The three types of crystals are produced by multiple hydrogen bonding, C−H···O, and donor−acceptor interactions.