A highly selective ratiometric chemosensor for Hg2+ based on the anthraquinone derivative with urea groups

Anthraquinone derivatives with different substituents 1-3 were synthesized by introducing the urea group. Their cations' binding properties were investigated by UV-vis absorption spectroscopy. Compared with 1 and 2, 3 with electron-withdrawing group (-NO2) showed a remarkable absorption change for Hg2+ over the other metal ions. The anthraquinone moiety and the N-H fragment of the urea moiety played key roles in sensing Hg2+. The different acidity of N-H fragments of the urea moiety, caused by electron push-pull properties of the substituents on the phenyl para position, is the main reason for recognition. (c) 2007 Elsevier Ltd. All rights reserved.