New dimeric cholesteryl-based A(LS)2 gelators with remarkable gelling abilities: Organogel formation at room temperature

Abstract

Three new dimeric cholesterol-based compounds of A(LS)2 type, where A stands for aromatic component, S steroid moiety, and L a linker connecting the two units, have been designed and prepared. Gelation test in 30 solvents demonstrated that the compounds can gel some of the solvents and form 37 gels, of which 16 form spontaneously at room temperature (∼25°C). These gels possess smart thixotropic properties as revealed by rheological studies. FTIR and 1H NMR measurements revealed that hydrogen bonding is an important driving force for the formation of the gel networks. XRD analysis demonstrated that unlike commonly found layered structures adopted by dimeric cholesterol-based low-molecular mass gelators (LMMGs), one of the gelators created in this study adopts a hexagonal packing structure in its benzene gel.