Preparation and gelling properties of sugar-contained low-molecular-mass gelators: Combination of cholesterol and linear glucose

Four novel amphiphilic cholesterol-based and sugar-contained low-molecular-mass gelators (LMMGs) were designed and prepared. According to the structures of the linkers, which are ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,6-hexane- diamine, these compounds are denoted as 1, 2, 3 and 4, respectively. Gelation tests revealed that 2, 3 and 4 start to gel xylene at concentrations of 0.090%, 0.022%, and 0.016% (w/v), respectively, which are typical ‘super-gelators’. Moreover, these xylene gel systems also possess film formation property. Scanning electron microscopy (SEM) measurements demonstrated that the aggregation behaviors of the compounds are greatly affected by the structures of the linkers. ¹H NMR spectroscopy studies revealed that intermolecular hydrogen bonding formation plays an important role for the formation of the gels. X-ray diffraction (XRD) studies showed that 1 possesses a layered structure in its 1-pentanol gel, a similar structure to that of it in solid state. Gelator 3 also possesses a similar structure in its THF gel, but different from that of it in solid state. Transmission electron microscopy (TEM) observation revealed the helical nature of the nanobelt assemblies of 1 in its 1-pentanol gel.