First synthesis of a ‘1,2-diquinone-calix[4]arene’. Interaction of its reduced form with Ag+

Abstract

Electrochemical oxidation of 5,11 17,23-tetra-tert-butyl-25,26-bis(diphenylphosphinoylmethoxy)-27,28-dihydroxxycalix[4]arene (3), a calixarene with two phosphoryl units appended on proximal positions, affords the corresponding ' 1,2-diquinone-calix[4]arene' (4). The formation of 4 results from nucleophilic attack of residual water on anodically generated diphenoxylium cations. Preliminary voltammetric experiments in CH 3 CN on a platinum electrode showed that 4 is suitable for electrochemical detection of the silver metal cation.

Electrochemical study of two tris-O-substituted calix[4]arenes: 25,27-Dipropoxy-26-hydroxy-28-benzoyloxycalix[4]arene(partial cone) and 25,27-dibenzyl-26-hydroxy-28-benzoyloxy-calix[4]arene(partial cone). Electrosynthesis of the corresponding calix[4]arene-monoquinones

“…As part of an ongoing programme aimed at the preparation of functionalised calixarenes, we report herein the results of the electrochemical oxidation of the partial-cone calix [4]arenes 1 and 2. The present study complements our previous investigations on the electrochemical synthesis of calixquinones, starting from partially, lower rim-functionalised calix [4]arenes [2][3][4]. It was undertaken in order to investigate whether substituents lying in the vicinity of the hydroxyl group may sterically influence the oxidation process, for example by stabilising intermediates.…”

Calixarene-Based Molecules for Cation Recognition

“…To achieve selectivity over Pb 2+ and Cu 2+ in PVC or polysiloxanebased membranes, the ligand 34 with an alternating conformation was developed (log K Cd,M = -0.7 (Pb), 1,2-Diquinone containing calixarenes were proposed for the voltammetric detection of transition metal ions due to their interaction with them as exemplified by Ag + [176].…”

Silver electrowinning from silver(I)–calixarene complexes by two-phase electrolysis

“…A few preliminary voltammetric experiments, made by the authors, with silver(I)-calixarene complexes were promising, indicating that it should be possible to reduce silver(I)-calixarene complexes in the loaded organic phase. However, it is discouraging that calixarene amides can easily be electrochemically oxidized to a calixquinone form, losing their primary properties [18,19].…”