Fig. 5. Stability of 50 µM Rubpy at pH 12.65 under continuous flashing with 532 nm at 10 Hz; intensity per flash, 352 mJ cm–2. Graph (a), without Asc2–; graph (b), with 45 mM Asc2– in the solutions. Solid lines, absorption spectra; dashed lines, emission spectra (excitation wavelength, 453 nm; filter effects and quenching avoided by 15-fold dilution and acidification to pH 1, compare ESI-1.1†). Colour code and illumination time in minutes (values corrected for aliquot removal in brackets) for all spectra: black, 0 (0); blue, 5 (5); cyan, 10 (10.35); green, 15 (16.11); yellow, 20 (22.34); orange, 25 (29.12); red, 30 (36.58). The insets give the normalized luminescence intensities as functions of the irradiation duration; the solid lines are smoothing spline fits to guide the eye.
