Fig. 6: Rotational speed control and fluorescence switch of WP5-M.
From: Cation controlled rotation in anionic pillar[5]arenes and its application for fluorescence switch
a Cation switch between Li+ and NH4+. b Partial NMR of switching control of rotors. c Switching of rate for WP5 in D2O at 298 K with multiple cycles of cation exchange. d Fluorescence emission spectrum of WP5-M (c = 5.0 mM, λex = 365 nm; insert: fluorescence of WP5-Li and WP5-NH4 under 365 nm UV irradiation). e Fluorescence response of WP5 (5.0 mM) at 471 nm upon multiple cycles of cation switch between Li+ and NH4+ in D2O (λex = 365 nm). f Revealing and erasing information with WP5 inks: the image written with WP5-NH4 under 365 nm light (I), and the image could be observed upon adding LiOH on the pre-existing images (II), which could be erased by painting NH4F (III).
