Cation complexing of crown ethers using fluorescence spectroscopy, part II

The complex formations of benzo12]crown-4, benzo15]crown-5 and benzo18]crown-6 with perchlorate salts of Mg(2+), 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, K(e) of 1:1 stoichiometry were estimated. The K(e) were found in the order of Mg(+)>Na(+)>Li(+) for benzo15]crown-5 whilst Na(+)>Mg(+)>Li(+) order was found with benzo12]crown-4 at 298 K.