Crown ether-containing Schiff base as a highly efficient "turn-on" fluorescent sensor for determination and separation of Zn2+ in water.

A highly efficient Zn(2+) "turn-on" fluorescent sensor, [4'-benzo-15-crown-5]N=CH-(2-OH-C(6)H(4)) (HL), has been synthesized. In the presence of Zn(NO(3))(2), displays high selectivity and sensitive enhancement of fluorescence intensity in water with the formation of [ZnL(2)]. Addition of an equimolar amount of KNO(3) to [ZnL(2)] leads to the formation of {[KZnL(2)]NO(3)}(n).