Synthesis of bis[N-(p-aryl)-carbamoyloxy]alkanes as new low-molecular weight organogelators

Abstract

A series of bis-carbamate-based low-molecular-weight organogelators were synthesized, and their structure–property relationships with respect to their gelation abilities in organic solvents were investigated. The self-aggregation behavior of the thermoreversible organogels was investigated by FTIR, temperature-dependent NMR, and SEM studies. The results revealed that the self-assembly into fibrous structures is driven by hydrogen bonding, π–π stacking, and hydrophobic interactions. It was found that para-aryl substitution and the number of methylene units connecting two carbamate groups had a significant influence on gelation. The effect of temperature on gel formation was also investigated for all compounds. The most interesting feature was observed for p-hexyl derivative, which gels at −18 °C but not room temperature. Furthermore, thermal properties of the gels were studied by dropping ball experiments and DSC. para-Alkoxyphenyl derivatives were also found to be good organogelators for olive oil, sunflower oil, corn oil, and ethyl laurate, isopropyl myristate, n-butyl palmitate.