Solvent Effect on 1,2-O-(1-Ethylpropylidene)-α-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 I 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 Delta H 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.