Synthesis and Dichromate Anion Extraction Ability of Calix[4]arene Schiff Base Derivatives

Abstract

This study reports the synthesis and complexation properties of five new Schiff base derivatives of calix[4]arene (4–8), which have been synthesized from the condensation of bis(3-aminopropoxy)calix[4]arene with respective aldehyde (2-pyrrolecarbaldehyde, 2-thiophenecarboxaldehyde, furfural, 1-methylpyrrol-2-carboxaldehyde, or biphenyl-4-carboxaldehyde). In this synthesis, the role of a different binding site of calix[4]arene in the extraction of dichromate anions has been observed. The complexation properties of the new Schiff base derivatives of calix[4]arene toward HCr₂O₇ ⁻/Cr₂O₇ ⁻ ions were studied by liquid–liquid extraction experiment. The results showed that the receptor 8 is more effective than other compound (4–7) for the removal of dichromate anion. The protonated Schiff base forms of the receptors were effective for transferring the HCr₂O₇ ⁻ anion from aqueous phase to a dichloromethane phase.

Keywords:

• Calix[4]arene
• Schiff Base
• Dichromate Anions
• Extraction

Acknowledgements

We would like to thank the Research Foundation of Selcuk University (BAP) for financial support of this work