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

摘要

The influence of Li~+, Na~+, K~+, Cs~+, Mg~(2+), Ca~(2+), Sr~(2+), Ba~(2+), Co~(2+), Ni~(2+), Cu~(2+), Zn~(2+), Pb~(2+) and Al~(3+) ions on the spectroscopic properties of the dansyl group covalently linked to crown ether or diazacrown ethers was investigated by means of absorption and emission spectrophotometry. Interaction of the alkali metal ions with all fluoroinophores studied is weak, while alkaline earth metal ions interact strongly causing about 50% quenching of dansyl fluorescence of A21C5-Dns and A_218C6-Dns. The Cu~(2+), Pb~(2+) and Al~(3+) cations interact very strongly with dansyl chromophore regardless the crown ether type, causing a major change in absorption spectrum of the chromophore and forming non-fluorescent complexes. The Co~(2+), Ni~(2+), Zn~(2+), Mg~(2+) and Ag~+ cations interact moderately with all fluoroionophores studied causing about 20% of fluorescence quenching of dansyl, except for a strong dansyl fluorescence quenching of 15C5Dns by Co~(2+) ion. The quenching efficiency of didansylated fluoroionophores by the alkali metal ions and alkaline earth metal ions is weaker than monodansylated ones.