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

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 mu m 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.