Selective zinc sensor based on pyrazoles and quinoline used to image cells

Abstract

The synthesis, Zn2+ binding, crystal structure, and cell imaging studies of a new pyrazole amine quinoline receptor with a flexible binding pocket are described. Upon coordination to Zn2+, the absorption of the receptor increases at 364 nm and it fluoresces at 500 nm. The fluorescence response to Zn2+ is selective for Zn2+ and does not occur with other metal ions, not even Cd2+. In solution, the receptor forms 1:1 complexes with Zn2+, but in the solid-state two Zn2+ ions coordinate to the receptor. The aqueous solubility of the receptor allows for imaging of Zn2+ in living cells. Cells exposed to receptor and Zn2+ fluoresce when excited with visible light. © 2014 Elsevier Ltd. All rights reserved.