(S)-1,1′-Binaphtho(monoaza)crown-5,-6 and-7 ionophores carrying photochromic indolospirobenzopyran (SP), naphthoxazine (NO) and naphthopyran (NP) signalling groups were synthesized and their cation-induced isomerisation to the colored merocyanine or quinone forms was studied by UV/Vis spectroscopy in the presence of alkali and alkaline earth metal ions. Under dark conditions the equilibrium of SP and NO dyes were remarkably shifted to the colored form by cations of high positive charge density (Li+ and alkaline earth metal ions). The same effects were observed with crowned NPs after UV irradiation. The stability of some merocyanine-cation complexes were evaluated by calculating the kinetic parameters of the coloration process.
- Cation recognition
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