A long-lived luminogenic iridium(III) complex for acetylacetone detection in environmental samples

The wide use of acetylacetone (Acac) in industries is fueling the need for the development of Acac detection methods. However, only a few nanomaterial-based fluorescent probes for Acac have been reported, and these probes either lack turn-on detection capability, and/or aqueous compatibility. Herein, a series of iridium(III) dimers were synthesized in one step and screened as luminescent probes for Acac. The candidate probe 8 exhibited a luminescence enhancement of near 160-fold in the presence of Acac in aqueous solution, with a linear relationship of Acac (0.1–10 μM) and a limit of detection (LOD) of 0.043 μM. Mechanistically, the probe chelated with Acac to form a new luminescent complex. Moreover, the long lifetime of probe 8 allowed its response to Acac to be distinguished from fluorescent interference through time-resolved emission spectroscopy (TRES). Probe 8 further demonstrated its practical application as a luminogenic probe for Acac in real water samples. In summary, because probe 8 is very easily prepared and modified compared with existing Acac luminescence probes, it serves as an ideal starting point to develop next-generation luminogenic probes for monitoring Acac in environmental and biological systems.