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Tuning Molecular Rigidity with Seven-Membered Ring Fusion: A Strategy toward Bright Near-Infrared azaBODIPY
Wanle Sheng1, Guoao Wu1, Zhangcui Wang1
1School of Pharmacy, Bengbu Medical University, 2600 Donghai Avenue, Bengbu 233030, China.
None:
A streamlined synthesis of structurally unprecedented, seven-membered-ring-fused azaBODIPYs has been developed. Single-crystal X-ray analysis and calculations for this seven-membered-ring-fused azaBODIPY revealed severely twisted 1,3,5,7-aryl substituents. The twisted, rigidified structure dramatically enhances photophysical performance. Suppressing internal conversion yields bright near-infrared fluorescence (molar extinction coefficient ε up to 1.3 × 105 M-1 cm-1 and fluorescence quantum yield ΦF up to 74.2%). For a derivative bearing 1,7-dithiophenes, rapid intersystem crossing instead leads to efficient reactive oxygen species generation (ΦΔ = 28% in toluene), demonstrating its potential applications as a photosensitizer.
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