Selective Dendritic Fluorescent Sensors for Zn(II)

A series of dendritic 8-hydroxyquinoline (8-HQ) and 5-dialkyl(aryl)amino-methyl -8-HQ derivatives were synthesized and their fluoroionophoric properties toward representative alkali, alkaline earth, group IIIA and transition metal ions were investigated. Among the selected ions, Zn(II) enhanced the fluorescence of N-di- (methoxycarbonylethyl)aminoethyl-3-[4-(8-hydroxyquinolin-5-ylmethyl)piperazin-1-yl]-propanoic amide] (7) by 31-fold, while Al(III) caused enhancement to some extent. The absence of any significant fluorescence enhancement by the other ions examined renders 7 a highly useful Zn(II)-selective fluorescent sensor.