Cyclometalated Ir (III) Complexes Involving Functionalized Terpyridine-Based Ligands Exhibiting Aggregation -Induced Emission and Their Potential Applications in CO2 Detection

Synthesis of three novel terpyridine-based donor acceptor (D-A) ligands (TP1, TP2, TP3) and cyclometalated iridium complexes [Ir(ppy)(2)TP1]+PF6- (C1), [Ir(ppy)(2)TP2]+PF6- (C2), and [Ir(ppy)(2)TP3]+PF6- (C3) [ppy = 2-phenyl pyridine] involving these were described. The ligands and complexes were characterized by spectroscopic studies (H-1, C-13, F-19, P-31, ESI-MS, UV-vis, and fluorescence). Crucial role of intermolecular interactions in aggregation - caused quenching (ACQ; C2) and aggregation-induced emission (AIE; C3) was rationalized by X-ray single-crystal analyses. Vital role of restricted intramolecular rotation (RIR) in inducing AIE upon aggregation via pi-pi interactions in these complexes was scrutinized by various studies. Because of strong intramolecular charge transfer these D-A based AlEgens exhibited solvatochromism. Further, AIE property of the complexes Cl and C3 was exploited toward detection of CO2.