Co-crystalline hydrogen bonded solids formed by helical tubuland diols

Abstract

The helical tubulands are a group of alicyclic dialcohols whose inclusion compounds crystallise in the chiral space group P3₁21 (or enantiomorph P3₂21) with a hydrogen bonded network structure containing parallel guest-filled tubes. Protic organic guest molecules are also included within these host tubes, with the exception of phenols which form co-crystalline adducts. The diol 3 includes non-protic guests within the usual tubular lattice, but forms a 1∶1 adduct with hydroquinone in space group C2/c whose crystal structure is entirely different from typical diol–phenol compounds like (2)₂·(hydroquinone) in space group P2₁/c. Unexpectedly, diol 3 also forms the unprecedented co-crystalline diol–alcohol compound (3)·(methanol). This substance does have close structural similarities to the earlier co-crystalline diol–phenol compounds in space group P2₁/c.