Development of a NIR iridium(III) complex for self-calibrated and luminogenic detection of boron trifluoride

Boron trifluoride (BF₃) is a potential environmental pollutant, and excess exposure to it may cause human diseases. However, the sensitive, rapid and accurate detection of BF₃ for on-site purposes is still a challenge. In this work, we developed the first NIR iridium(III)-based probe with dual emission and a Stokes shift of 370 nm for self-calibrated and luminogenic detection of BF₃. This probe exhibited a strong luminescence enhancement at around 650 nm to BF₃ (0-100 μM) with almost no change in luminescence at 475 nm, displaying a 220-fold I_{650 nm}/I_{475 nm} enhancement at 100 μM of BF₃ with a detection limit of 0.35 μM. Moreover, the probe showed a fast response time of less than 5 s to BF₃ along with an obvious color change under UV irradiation for visual detection. Importantly, the desirable photophysical properties of the iridium(III)-based probe can be harnessed for time-resolved detection of BF₃ in the presence of the fluorescence background. The applicability of the probe was further verified in an organic solvent waste-spiked system and on a glass pane. This work will provide a solid basis for the development of sensitive and on-site BF₃ sensing toolkits for environmental monitoring.