New organogelators based on cyclotriveratrylene platforms bearing 2-dimethylacetal-5-carbonylpyridine fragments

Abstract

Gelators, compounds able to solidify solvents, and in particular hydrogelators are interesting soft materials. In this paper we have synthesized cyclotriveratrylene (CTV) platforms symmetrically end-substituted with pendent primary amines or nicotamic substituents. These non-amphiphilic structures induce self-assembly in a large variety of solvents forming robust and opaque gels. Cyclotriveratrylene gels have for the first time been formed and characterized using FT-IR and freeze fracture electron microscopy. Two hierarchical events are responsible for the gel structure. Individual fibres of 4–5 nm diameter are formed by aggregation of the functionalised CTV molecules. These fibres then further self-assemble into large ribbons several µm long and 20 to 40 nm wide. Within the ribbons the fine striations observed by FFEM are due to individual straight chains organized in a highly compacted state. Within the fibres the individual CTV molecules are held together by hydrogen bonding of the amide function as probed by infra-red spectroscopy.