An AIE-active phosphorescent Ir(iii) complex with piezochromic luminescence (PCL) and its application for monitoring volatile organic compounds (VOCs)

Abstract

A neutral multifunctional dinuclear Ir(III) complex 1 with a Schiff base bridging ligand is shown to combine aggregation-induced emission (AIE), piezochromic luminescence (PCL) and vapochromism. The complex displays a reversible colour change in its phosphorescence in the solid state between faint red and bright orange with high contrast intensity, triggered by high polarity volatile organic compounds (VOCs) or by mechanical grinding within 10 s. Notably, unlike many known vapochromic systems, complex 1 exhibits ultrahigh stability, with the orange colour remaining unchanged in air for several months at room temperature. A simple and efficient monitoring device has been fabricated in which highly polar VOCs act as a switch to “turn on” the device by changing the aggregation state of complex 1.