Immobilisation at an electrode surface of calix[4]arenes bearing electropolymerisable pyrrole moieties at the upper rim

The first example of electrochemical homopolymerisation of calix[4]arenes modified by grafting N-substituted pyrrole moieties at their upper rim is presented. In a first step, a preliminary study was carried out on two model compounds (i.e. pyrroles bearing a p-amido-anisyl group via an alkyl spacing arm) to determine the conditions of electropolymerisation under potentiodynamic conditions. A minute change in the alkyl spacing arm length from ethyl to butyl has a remarkable influence, allowing better electropolymerisation when longer. Moreover, we have proved that dicyclohexylcarbodiimide, a coupling reagent used during synthesis has an inhibiting effect on pyrrole electropolymerisation. Similar results were obtained in the calix[4]arene series, i.e. film growth is enhanced with the calixarene containing the butyl spacing arm. (C) 1998 Elsevier Science S.A. All rights reserved.