Molecular recognition directed self-assembly of supramolecular cylindrical channel-like architectures from 6,7,9,10,12,13,15,16-octahydro-1,4,7,10,13-pentaoxabenzocyclopentadecen-2-ylmethyl 3,4,5-tris(p-dodecyloxybenzyloxy)benzoate

Abstract

Complexation of the crown ether receptor of the benzo-15-crown-5 benzoate 6[6,7,9,10,12,13,15,16octahydro-1,4,7,10,13-pentaoxabenzocyclopentadecen-2-ylmethyl 3,4,5-tris(p-dodecyloxybenzyloxy)benzoate]6 with NaCF₃SO₃ and KCF₃SO₃ destabilizes the crystalline phase of 6 and induces the self-assembly of a supramolecular cylindrical channel-like architecture which displays an enantiotropic thermotropic disordered hexagonal columnar (Φ_h) mesophase. Characterization of this supramolecular architecture was performed by a combination of differential scanning calorimetry (DSC), X-ray scattering, thermal optical polarized microscopy, DC conductivity and molecular modelling. A model is proposed in which a stratum of the column is formed by ca. 5.8 molecules of 6 with their benzo-15-crown-5 receptors placed side-by-side in the centre of the column and their melted alkyl tails radiating towards its periphery. endo-Recognition generated via the benzo-15-crown-5 receptor upon complexation, and exo-recognition provided by the tapered 3,4,5-tris(p-dodecyloxybenzyloxy)benzoate fragment of 6(most probably functioning via hydrophobichydrophobic interactions) provide the driving force for the self-assembly of this channel-like supramolecule. This mechanism of self-assembly resembles that of tobacco mosaic virus (TMV).