Solvent effect on 1,2-O-(1-ethylpropylidene)-alpha-D-glucofuranose organogel properties

The solvent effect on organogel formation in nitrobenzene and chlorobenzene using 1,2-O-(1-ethylpropylidene)-alpha-d-glucofuranose (1) as the gelator is presented. Fourier transform infrared (FTIR) spectroscopy revealed that hydrogen bonding between the molecules of gelator 1 is the main driving force for gelator self-aggregation. The gels are characterized by different hydrogen-bonding patterns, which are reflected in a different microstructure of the networks. The morphology of fibers of nitrobenzene organogel consists of straight, rod-like, and thinner fibers, in comparison to the elongated but generally not straight and thicker fibers in chlorobenzene organogel. The thermal stability of gels also differs, and the DeltaH is equal to 50.1 and 65.0 kJ/mol for nitrobenzene and chlorobenzene gels, respectively. The properties of the gels reported here were compared to benzene and toluene gels of 1 presented in previous work and correlated with different solvent parameters: epsilon, delta, and E(T)(30). We have shown that the polarity of the solvent influences the thermal stability of the gel, the hydrogen-bonding network, and finally the structure of gel network. Therefore, in the studied sugar-based gelator, the hydrogen bonding alone is insufficient to fully describe the gelation process.