Comparative electrochemiluminescence studies about bis-tridentate iridium(III) complexes comprising Nheterocyclic carbene

Abstract

Exploring novel efficient electrochemiluminescent (ECL) dyes derived from transition metal complexes with new skeletons is always one of the hot and important topics of ECL-related studies. Herein, three bis-tridentate iridium(III) complexes (BisL_T-Ir-NHC-R, where R represents H, CH₃ and CF₃) with N-heterocyclic carbenes (NHC) ligands have been prepared in this work. Beside photophysics (PL), theoretical calculations and cyclic voltammetry (CV), ECL properties have been comparatively investigated in this work. Notably, not only did the BisL_T-Ir-NHC- CF₃ have the highest photoluminescence efficiency value of 13.26 %, but most importantly, the ECL efficiency of bis-tridentate iridium(III) complexes in this work was up to 3.4 times than the benchmark of Ru(bpy)₃²⁺ under the same experimental conditions. These results demonstrates that bis-tridentate iridium(III) complexes with NHC ligands have great potential applications in ECL-based analysis technology and could open a new avenue to develop highly efficient ECL dyes derived from bis-tridentate iridium complexes in the future.