A complimentary study of calixarene based bifunctional receptors for alkali or transition metal cations and Cr2O72- anions

The article describes the syntheses and extraction properties of two new ca lixarene based receptors (3 and 4); the receptor 3 was synthesized from 25, 27-diacetonyloxy-26,28-dihydroxy-5,11,17,23-tetra-tert-butylcalix [4] arene 2 by treatment with tetraethylene glycol ditosylate and then the compound 3 was converted to its Schiff base derivative 4 by refluxing 3 with 1,8-dia mino-3,6-dioxaoctane. In the synthesis, the lower rim of p-tert-butylcalix[ 4]arene has been modified in order to acquire soft and hard binding sites f or the recognition of metal cations and Cr2O7-2 selected alkali, transition metal cations and Cr2O7-2 anions are reported. It has been observed that r eceptor 4 is a better extractant 7 for all metal cations, but not selective as compared to the receptor 3. The protonated alkylinium form of 4 is an e ffective anions from an aqueous into a dichloromethane layer. (C) 2001 Else vier Science BN. All extractant for transferring the Cr2O7-2 rights reserve d.