Synthesis of Polymeric Calix[4]arene Dinitrile and Diamino‐Derivatives: Exploration of Their Extraction Properties Towards Dichromate Anion

Abstract

The article describes the syntheses and extraction properties of new alkylnitrile and alkylamino substituted calix[4]arene based copolymers. These compounds have been synthesized via nucleophilic substitution reactions involving 5,11,17,23‐tetra‐tert‐butyl‐25,27‐bis(cyanomethoxy)‐26,28‐dihydroxycalix[4]arene (3), or 25,27‐bis(cyanomethoxy)‐26,28‐dihydroxycalix[4]arene (4) with 1,5‐dibromopentane and bisphenol‐A, followed by their reduction with sodium borohydride in the presence of CoCl₂ · 6H₂O. In addition an oligomer containing pendant calix[4]arene units with nitrile functionalities on its lower rim has been synthesized via nucleophilic reaction involving 5,11,17,23‐tetra‐tert‐butyl‐25,27‐bis(cyanomethoxy)‐26,28‐dihydroxycalix[4]arene 3 with p‐dibromoxylene. The extraction properties of polymers 5–9 toward the HCr₂O₇ ⁻ anion are also reported. Due to the higher oxidative stability of nitrile groups, polymers 5–7 have been developed as good extractants for transferring the HCr₂O₇ ⁻ anion from an aqueous into a dichloromethane phase.

Keywords:

• Copolymer
• Calixarene
• Solvent extraction
• Phase transfer
• Dichromate anions

Acknowledgments

We are grateful the US National Science Foundation (NSF), the Welch Foundation and the Scientific and Technical Research Council of Turkey (TUBITAK) for the financial support of this work. We thank Dr. Bruce Moyer (ORNL) for helpful discussions.