Fluorescence enhancement upon gelation and thermally-driven fluorescence switches based on tetraphenylsilole-based organic gelators

Two new organic gelators 1 and 2 based on the silole (silacyclopentadiene) framework were designed with the end to develop switchable fluorescent organogels, by making use of the aggregation-induced emission (AIE) feature of silole derivatives. As for other silole derivatives, compounds 1 and 2 exhibited AIE behavior as indicated by the significant fluorescence enhancement by introducing water to the THF solutions. Compounds 1 and 2 can gel hexane, methylcyclohexane and heptane. Large fluorescence enhancement was observed for compounds 1 and 2 after gelation. Moreover, their fluorescence intensities can be changed reversibly accompanying the gel–solution transition through alternating cooling and heating. Therefore, thermally-driven fluorescence switches can be achieved with organogels based on 1 and 2.