Cation complexing of crown ethers using fluorescence spectroscopy, part II

The complex formations of benzo[12]crown-4, benzo[15]crown-5 and benzo[18]crown-6 with perchlorate salts of Mg2+, Li+ and Na+ were investigated using the steady state fluorescence emission spectroscopy in acetonitrile. The complexation enhanced quenched fluorescence spectra, (CEQFS) exhibited the ion complexation role of the macrocyclic ethers and equilibrium constant, Ke of 1:1 stoichiometry were estimated. The Ke were found in the order of Mg+>Na+>Li+ for benzo[15]crown-5 whilst Na+>Mg+>Li+ order was found with benzo[12]crown-4 at 298 K.