American Chemical Society, Journal of the American Chemical Society, 25(137), p. 8150-8160, 2015
DOI: 10.1021/jacs.5b02448
Full text: Download
The self-assembly and self-organisation behaviour of uracil-conjugated enantiopure (R) or (S) BINOLs and an hydrophobic oligo(para-phenylene ethynylene) (OPE) chromophore exposing 2,6-di(acetylamino)pyridine termini are reported. Systematic spectroscopic (UV-Vis, CD, fluorescence, NMR and SAXS) and microscopic studies (TEM and AFM) showed that BINOL and OPE compounds undergo triple H-bonding recognition generating different organic nanostructures in solution. Depending on the solvophobic properties of the liquid medium (Toluene, CHCl3, CHCl3/CHX and CHX/THF), spherical, rod-like, fi-brous and helical morphologies were obtained, with the latter being the only nanostructures expressing chirality at the microscopic level. SAXS analysis combined with molecular modelling simulations showed that the formation of the helical superstructures is composed of dimeric double-cable tape-like structures that, in turn, are supercoiled at the microscale. This behaviour is interpreted as a consequence of an interplay between the degree of association of the H-bonded recognition, the vapour pressure of the solvent and the solvophobic/solvophilic character of the supramolecular adducts in the different solutions under static and dynamic conditions, namely during solvent evaporation conditions at room temperature.