Nodal equivalence of (O–H)6 and aromatic rings: a supramolecular cousin of Dianin's compound and β-hydroquinone

Abstract

The simple dialcohol endo-4,endo-8-dimethylbicyclo[3.3.1]nonane-endo-2,endo-6-diol 2 yields inclusion compounds (diol)₃.(guest) from nearly all recrystallisation experiments. These crystals have a hydrogen bonded network structure in cubic space group Ia, in which the disordered guest molecule occupies a spherical cage enclosed by eight (O–H)₆ cycles positioned at the corners of a cube. Comparison of this structure with the inclusion crystals formed by Dianin's compound 1, and the β-form of hydroquinone 3, reveals familial supramolecular behaviour between the three cases. The nodal relationship of their (O–H)₆ cycles or aromatic rings creates allied crystal engineering assemblies despite their dissimilar molecular structures.