ION-RESPONSIVE FLUORESCENT COMPOUNDS - V - PHOTOPHYSICAL AND COMPLEXING PROPERTIES OF COUMARIN-343 LINKED TO MONOAZA-15-CROWN-5

The photophysical and complexing properties of a fluoroionophore consi sting of coumarin 343 linked to monoaza-15-crown-5 are reported in ace tonitrile and ethanol. The amide link between the coumarin and the cro wn precludes pH sensitivity of the tertiary amine bridging group. Upon complexation by calcium and magnesium cations, the photophysical prop erties undergo marked changes. whereas the effects are insignificant o r very weak with alkali metal ions. I.R, spectra were recorded in deut erated acetonitrile in order to unravel the participation of the carbo nyl groups in the complexation. The stoichiometry of the complexes is 1:1 apart from the case of complexation with calcium in acetonitrile w here two complexes can be formed. The stability constants of the compl exes were determined in acetonitrile and ethanol. (C) 1998 Elsevier Sc ience S.A. All rights reserved.