Click synthesis, Hg2+ sensor and Intramolecular fluorescence resonance energy transfer in novel BODIPY dendrons

Two novel intramolecular fluorescence resonance energy transfer (FRET) dendritic compounds RhB-BODIPY and NPI-BODIPY have been synthesized utilizing click reaction and characterized. The fluorescence intensity of RhB-BODIPY at 580 nm was amplified with 10.7-fold on addition of Hg2+ and the fluorescence resonance energy transfer efficiency between the energy donor (BODIPY) and the energy acceptor (rhodamine) is 67%. In compound NPI-BODIPY, the naphthalimide serves as donor and BODIPY serves as acceptor. The energy transfer efficiency of NPI-BODIPY is 72%. The comparative sensing abilities of RhB-BODIPY toward a range of metal ions have been investigated and it exhibited appreciable selectivity towards He. Job's plot clearly indicated that the binding ratio of RhB-BODIPY with He2+ is 1:2. The H-1 NMR titration of RhB-BODIPY with He2+ confirmed that tertiary amines and triazoles were involved in the binding event. The detection limit estimated from the titration results were 3.34 x 10(-7) M for RhB-BODIPY. The fluorescence quantum yield of RhB-BODIPY and NPI-BODIPY at 510 nm were 53% and 88% respectively. In addition, both two compounds were successfully applied to living cell imaging. (C) 2016 Elsevier B.V. All rights reserved.