Cystine-derived bis-naphthalimides as stimuli-responsive fluorescent gelatorsElectronic supplementary information (ESI) available: Details of synthesis, characterisation; SEM images for L1; 1H NMR studies of L1 with NaBF4; fluorescence titration plots of L1 and chloride, bromide and acetate. See DOI: 10.1039/c4nj01755b

• Main Authors: Sarma, Rupam J, Devi, Kakali
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c4nj01755b

Two cystine-derived bis-naphthalimide gelators ( L1 , L2 ) were synthesised and characterised. Both L1 and L2 exhibited similar absorptions and emission spectra in solvents such as acetonitrile and DMF. The fluorescence spectra of both the compounds featured a distinct monomer and long-wavelength excimer emissions in the aforementioned solvents. It was found that the excimer emissions for the two compounds could be preferentially quenched by triethylamine, and subsequently restored with hydrofluoric acid. The stimuli-responsive nature of the excimer emissions was demonstrated using anion stimuli in solution and in the gel phase. Thus, the excimer emission for L1 (or L2 ) could be switched 'off' using fluoride anions, and subsequently re-activated using tetrafluoroborate anions as the chemical stimulus. Stimuli-responsive fluorescence modulation of two cystine-derived bis-naphthalimide gelators was demonstrated using fluoride/tetrafluoroborate anions as the chemical inputs.