Crystal engineering using polyphenols. Host-guest behaviour of planar ribbons in C-methylcalix[4]resorcinarene-4,4′-trimethylenedipyridine-methanol (1/2/0.5), and capture of 2,2′-bipyridyl molecules by paired calixarene bowls in C-methylcalix[4]-resorcinarene-2,2′-bipyridyl-methanol-water (1/1/1/1.16)

Abstract

Co-crystallisation of the rccc isomer of C-methylcalix[4]resorcinarene 1 with 4,4′-trimethylenedipyridine from methanol yields a solvated 1:2 adduct 2 in which the resorcinarene acts as a quadruple donor and the dipyridines both act as double acceptors, in O-H‥N hydrogen bonds. The supramolecular structure consists of linear and nearly planar ribbons with the bowls of the resorcinarene units in one ribbon acting as hosts towards the -(CH ₂ ) ₃ - spacer units of a neighbouring ribbon, acting as guests. Co-crystallisation of the same resorcinarene 1 with 2,2′-bipyridyl yields a doubly solvated 1:1 adduct resorcinarene-2,2′-bipyridyl-methanol-water (1/1/1/1.16) 3. The resorcinarene, methanol and water molecules combine by means of multiple O-H‥O hydrogen bonds to form paired, essentially-planar two-dimensional nets in which centrosymmetric pairs of resorcinarene bowls act as self-assembled carcerands to form large cavities in which pairs of 2,2′-bipyridyl molecules are held by a combination of O-H‥N and C-H‥O hydrogen bonds.