'Aggregation-Induced Emission' Active Mono-Cyclometalated Iridium(III) Complex Mediated Efficient Vapor-Phase Detection of Dichloromethane.

Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an 'Aggregation-induced Emission' (AIE) active mono-cyclometalated iridium(III)-based (M1) probe molecule, which detects DCM sensitively and selectively in vapor phase with a response time <30 s. It reveals a turn-on emission (non-emissive to intense yellow) on exposing DCM vapor directly to the solid M1. The recorded detection limit is 4.9 ppm for DCM vapor with pristine M1. The mechanism of DCM detection was explored. Moreover, the detection of DCM vapor by M1 was extended with a low-cost filter paper as the substrate. The DCM is weakly bound with the probe and can be removed with a mild treatment, so, notably, the probe can be reused.