Systematic oligoaniline-based derivatives: ACQ-AIE conversion with a tunable insertion effect and quantitative fluorescence turn-on detection of BSA

The aggregation-induced emission (AIE) phenomenon has attracted persistent attention in recent years. Currently, the molecular design is mainly based on ring-shaped molecules. Hence, a novel strategy was put forward to achieve conversion from aggregation-caused quenching to AIE in derivatives of aniline oligomers using a new chain-insertion'' pattern. Studies of aniline oligomer derivatives indicate a tunable insertion effect on the AIE behaviors of the derivatives. Fully substituted oligoanilines exhibited typical AIE behavior, while partially substituted derivatives were AIE-inactive. In addition, luminescence wavelength and solid fluorescence in aniline derivatives can be effectively regulated by insertion and chain length. The resulting model will contribute to simplified and systematic research into oligomer-based AIEgens. Moreover, fully substituted anilines show a quantitative turn-on fluorescence response towards bovine serum albumin (BSA) with a detection limit in the order of micrograms per liter. Thus, fully substituted anilines show great potential for use as fluorescent probes in BSA sensors.