Homoleptic cyclometalated iridium(III) complex nanowires electrogenerated chemiluminescence sensors for high-performance discrimination of proline enantiomers based on the difference of electron-transfer capability

Abstract

Chiral molecules can generally exhibit different physiological and biological activities, thus triggering wide interest in chiral discrimination. Herein, we demonstrate a sensitive homoleptic cyclometalated iridium(III) complexes nanowires (Ir(piq)3 NWs) electrogenerated chemiluminescence (ECL) sensor for high-performance discrimination of chiral molecules based on the difference in electron-transfer ability between different radicals. The developed Ir(piq)3 NWs/ITO sensor exhibits high ECL signal and satisfying stability without the presence of co-reactant based on hot electron-induced ECL, which would spur its further application in detecting proline enantiomers. Obvious difference on the ECL intensity towards L-Pro and D-Pro is observed under the presence of high concentration of proline enantiomers, which attributes to the different electron-transfer capability between Ir+(piq)3 and L-pro•/D-pro•. In order to attain high-performance discrimination, we construct the Ir(piq)3 NWs/TPrA sensor to achieve chiral discrimination for trace amounts of proline enantiomers (1.0 × 10−9 M), which attributes to the strong molecular interactions enhanced by introduction of active radical TPrA•.