Figure 6.
(a) Chemical structure of FRET-capable [3]heterorotaxane; (b) Schematic illustration of the equilibria involving R4•4Cl as its Cl− salt in the presence of γ-CD and CBAs; (c) Solid-state fluorescence spectra (λex = 347 nm) of R4•4Cl upon adding 0–200 equiv. of γ-CD, followed by 200 equiv. of Ad•Cl as the CBA; (d) Powders obtained from homogeneous mixtures of R4•4Cl and ascending amounts (0–200 equiv) of γ-CD and Ad•Cl (200 equiv) under UV light; (e) Surface-dependent fluorescence ink on different paper media (newsprint, coated and uncoated rag paper, banknotes, copy, matte and glossy white paper) under UV light. Copyright 2015 Nature. Reproduced with permission from [58].