BODIPY appended cone-calix[4]arene: selective fluorescence changes upon Ca2+ binding

BODIPY appended new calix[4]arene diethyl ester (1) has been synthesized in the cone conformation. With respect to fluorescence intensity changes upon metal ion complexation, 1 shows a Ca2+ ion selectivity over other metal cations. Presence of two proximal hydroxyl groups and two facing ethyl esters in BODIPY-calix[4]arene were observed to play an important role in exhibiting its selective Ca2+ ion binding.