Synthesis and Anion Recognition Properties of Thiosemicarbazone Based Molecular Tweezers

Abstract

A series of novel thiosemicarbazone based molecular tweezers were synthesized and studied as anion-binding receptors. Contrasting our former work, some of these receptors not only have considerable selectivity to H₂PO₄ ⁻, as well as F⁻ and CH₃COO⁻. When adding F⁻, CH₃COO⁻ and H₂PO₄ ⁻ anions to their solutions respectively, the color has shown striking changes from colorless to yellow or dark yellow. The binding abilities of the receptors are according with the acidities of the N-H groups on the thiourea moiety, which are determined by the electronegativity of subgroups on them. Job plot indicated that 1:1 stoichiometry complex are formed between receptors and anions.

Keywords:

• Anion recognition
• molecular tweezers receptor
• thiosemicarbazone

Acknowledgments

This work is supported by NSFC (No. 20671077), the Key Project of Chinese Ministry of Education (No. 205161), Gansu Provincial Natural Science Found of China (No. 3ZS061-A25-027), Scientific Research Fund for youth of Gansu province in China (No. 3YS051-A25-010), Scientific Research Fund of Gansu Provincial Education Department (No. 0601-24), and Key Laboratory of Eco-Environment-Related Polymer Materials (Northwest Normal University) Ministry of Education.