Short communication Synthesis and fluorescence behaviour of crown and azacrown ethers carrying the dansyl fluorophore as a pendant in acetonitrile solution

AbstractThe influence of Li + ,Na,K + ,Cs,Mg 2 ,Ca 2+ ,Sr 2+ ,Ba 2 ,Co,Ni,Cu,Zn,Pb 2 + and Al 3 ions on the spectroscopicproperties of the dansyl group covalently linked to crown ether or diazacrown ethers was investigated by means of absorption and emissionspectrophotometry. Interaction of the alkali metal ions with all fluoroionophores studied is weak, while alkaline earth metal ions interactstrongly causing about 50% quenching of dansyl fluorescence of A21C5-Dns and A 2 18C6-Dns. The Cu 2+ ,Pb 2+ and Al 3+ cations interactvery strongly with dansyl chromophore regardless the crown ether type, causing a major change in absorption spectrum of the chromophoreandformingnon-fluorescentcomplexes.TheCo 2+ ,Ni ,Zn 2 ,Mg andAg + cationsinteractmoderatelywithallfluoroionophoresstudiedcausing about 20% of fluorescence quenching of dansyl, except for a strong dansyl fluorescence quenching of 15C5-Dns by Co 2+ ion. Thequenchingefficiencyofdidansylatedfluoroionophoresbythealkalimetalionsandalkalineearthmetalionsisweakerthanmonodansylatedones. © 2002 Elsevier Science B.V. All rights reserved.