Metal-induced conformational change in pyrene-appended calix[4]crown-4 which is useful for metal sensing and guest tweezing
摘要:
Calix[4]crown (1) bearing an ionophoric cavity on the lower rim and two pyrene groups on the upper rim was synthesized. The metal-binding to the ionophoric cavity changed the distance between two pyrene moieties, which was reflected by a large change in the monomer/excimer fluorescence intensity ratio. This phenomenon was applied to (i) fluorescence sensing of alkali metal cations and (ii) metal-controlled tweezing of a guest (trinitrobenzene). It was shown that the ionophoric cavity can accept only Li+ and Na+ (Na+ > Li+) but not at all K+.