A reversible fluorescent Hg2+/K+ switch that works as keypad lock in the presence of F− ion

Abstract

A thiacalix[4]arene based fluorescent chemosensor 3 of 1,3-alternate conformation bearing two dansyl groups and a crown-5 ring behaves as an “On–Off” reversible switch for two chemical inputs Hg²⁺ and K⁺ ions and mimics a molecular level keypad lock in the presence of F⁻ ions.