Fluorous gallic acid derivatives as versatile gelators. Self-assembly into nanosized fibers or balls

A new class of low molecular mass organogelators, the fluorous derivatives of gallic acid 1-3, is described. The gelation properties have been examined in a large variety of organic liquids. The corresponding analogs possessing alkyl instead of semiperfluoroalkyl chains (4-6) do not display any gelation properties, thus revealing the key role of perfluorinated chains in the aggregation/gelation process. Gels have been studied by scanning electron microscopy, revealing the presence of three-dimensional networks of nanosized fibers. In the case of an instable gel, SEM images showed that these elongated fibers curl up into nanoballs, failing to create the entangled network responsible for solvent entrapment.