Fig. 4. Responsive emission characteristics of 2 and 3 (5 μM) in DMEM/10% FBS solutions containing TX100. (a) Fluorescence spectra of 2 at pH ranging from 8.0 (black) to 2.0 (red); inset sigmoidal plot fit of integrated fluorescence intensity versus pH. (b) Fluorescence spectra of 3 at pH ranging from 8.0 (black) to 2.0 (red); inset sigmoidal plot fit of integrated fluorescence intensity versus pH. (c) Diagram representing FEF values from differing pH solutions of 2 (solid red bars) and 3 (crossed red bars).
