Carbazole incorporated ratiometric chemosensor for Zn2+.

An electron donating carbazole incorporated thiazole (3) based Zn(2+) selective intrinsic chemosensor has been synthesized and investigated. It was found that electron donating substituents such as methyl and carbazole on chemosensor (1) produce remarkable red shift in emission upon complexation with Zn(2+). The sensor shows a selective fluorescence response with Zn(2+) over biologically relevant cations (Ca(2+), Mg(2+), Na(+), and K(+)) and biologically non-relevant cations (Cd(2+), In(3+) and Ga(3+)) in an aqueous ethanol system. It also produce an enhancement in the quantum yield and a longer emission wavelength shift on Zn(2+) binding with the potential of a ratiometric assay.