Fig. 59. (a) Furusho and Yashima's acid and ZnII responsive catenane.131 (b) CD and absorption spectra (CDCl3, 0.1 mm, ca. 20 °C) of the [2]catenane 115 before (blue) and after the addition of TFA 1 equiv. (orange), 10 equiv. (red), and further neutralization with 10 equiv. of iPr2NEt (dashed light blue). CD and absorption spectra of the TFA salt of 115 are also shown (black). Counter ions omitted for clarity. R* = (R)-CH(CH3)Ph. Reproduced with permission from ref. 130. Copyright 2010 John Wiley and Sons.
