α,β-Diarylation on β-Diketo-BF₂ Complexes: Strong Intrinsic Aggregation-Induced Emission and Organic Self-Recovering Electrochromism

A novel one-step synthetic strategy was developed to synthesize α,β-diaryl β-diketone-BF 2 complexes ( 2a – 2g ) using readily available building blocks (1,2-diarylethanones). The complexes were further transformed to π-extended α,β-diaryl-β′-styryl-β-diketo-BF 2 ( 3a – 3c ) via Knoevenagel condensation with aromatic aldehydes. All the complexes exhibit strong intrinsic aggregation-induced emission, with fluorescence colors tuning from cyan (λ em = 470 nm) to red (λ em = 652 nm) and the quantum yields reaching up to 90%. The complexes were demonstrated for electrochromism, which exhibits a drastic color change from colorless to purple upon applying a reduction potential of −1.3 V with spontaneous self-oxidation from the reduced state.