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Figure 5
Solution UV–vis spectra of Tetdron before (red) and after (blue) irradiation with 400 nm light, followed by relaxation and re-protonation of the chromophore in the dark (yellow to grey lines).

IUCrJ
Volume 6| Part 4| July 2019| Pages 619-629
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519005761