Heat-set supramolecular organogels composed of β-cyclodextrin and substituted aniline in N,N-dimethylformamide

This paper describes a new class of heat-set organogels based on β-cyclodextrin (β-CD) and para-substituted anilines (ps-An) connected by supramolecular interactions. The organogel is prepared by mixing β-CD, ps-An and lithium chloride in N,N-dimethylformamide (DMF). The heat-set organogel is a thermo-reversible gel system which turns into a clear solution upon cooling to room temperature and is re-formed when heated to the gelling temperature (Tgel). It is very interesting that the ps-An gelator, as well as other gelators, can be gelated at high temperature but dissolved as the temperature in the system decreases. The organogel is a multi-component system, in which the gelators are small commercially available organic molecules that can self-assemble into fibrous structures based on supramolecular interactions. Further studies showed the Tgel can be influenced and controlled by the substituents of ps-An. The Tgel of the system is higher when the aniline is substituted with electron-donating substituents rather than electron-withdrawing substituents.