Dual colorimetric sensoring bis(indolyl)calix[4]crown-6

Calix-chromophore, bis(indolyl)calix[4]crown-6 (1) in an oxidized form showing selective colorimetric changes for both alkaline earth cations and F− in CH3CN, has been newly synthesized. It is observed that the binding ability of 1 for the Ca2+ binding enhances in the presence of F−. Compound 1 can operate three independent combinational NOR logic gates toward metal cations and anions.