Molecular taekwondo. 2. A new calix[4]azacrown bearing two different binding sites as a new fluorescent ionophore

Synthesis and binding studies of a new calixarene-based fluoroionophore were made. Calix[4]azacrown having an anthracenyl unit displayed large chelation-enhanced fluorescence effects with Cs⁺, Rb⁺, and K⁺ over other metal ion tested. Interesting "molecular taekwondo" processes between Cs⁺-Cu²⁺ and Cs⁺-Ag⁺ pairs were monitored via fluorescent changes.