ESIPT-modulated HBT–o-carborane dyads with efficient aggregation-induced emission and acid-induced discolouration properties

Abstract

Non-ESIPT C-HBTP and ESIPT C-HBTO were designed and synthesized through nickel-catalyzed cross-coupling reactions, utilizing o-carborane and 2-(2′-hydroxy-phenyl)benzothiazole (HBT) as substrates. The photophysical characteristics of these compounds were thoroughly investigated through UV-vis absorption spectroscopy, fluorescence spectroscopy, and DFT calculations. C-HBTO, with its ESIPT properties, undergoes a structural transformation from an enol structure to a more stable ketone configuration. Additionally, C-HBTP and C-HBTO exhibited excellent aggregation-induced emission (AIE) properties and good quantum yields of 39.1% and 33.8% in the solid state, respectively.