Interface host-guest interaction between calixpyrrole and neutral derivatives of phenol as the base for their potentiometric discrimination
Radecki, J × Radecka, H Piotrowski, T Depraetere, S Dehaen, Wim Plavec, J #
Wiley-v c h verlag gmbh
Electroanalysis vol:16 issue:24 pages:2073-2081
Calixpyrrole liquid membrane electrodes display a potentiometric response towards the neutral form of phenol derivatives. They do not respond towards the corresponding anionic forms. The mechanism of the generation of the potentiometric signal relies on: (1) The creation of supramolecular complex calixpyrrole-nitrophenol at the organic/aqueous interface; (2) The increasing of the acidity of OH group from nitrophenol molecules due to formation of hydrogen bond between calixpyrrole-nitrophenol at the interface; (3) The dissociation of the OH group from calixpyrrole-nitrophenol complex and the ejection of H+ to the aqueous layer adjusted to the membrane organic phase boundary. The sensitivity and selectivity of the calixpyrrole liquid membrane electrodes are governed by the lipophilicity and acidity of the phenolic guests. Also, the affinity to create a hydrogen bond between the host and the target molecule is a parameter which has a strong influence on the phenomena studied.