1,4,8,11-Tetrakis(4-ferrocenyl-3-azabutyl)-1,4,8,11- Tetraazacyclotetradecane as a Ferrocene-functionalised Polyammonium Receptor for Electrochemical Anion Sensing

The interaction of the ferrocene-functionalised polyaza receptor 1,4,8,11-tetrakis(4-ferrocenyl-3-azabutyl)-1,4,8,11-tetraazacyclotetradecane (L1) with sulfate, phosphate and ATP has been studied potentiometrically in THF-water 70:30 v/v (0.1 mol dm-3 tetrabutylammonium perchlorate, 25°C). The molecular structure of the free receptor has been determined by single-crystal X-ray procedures. An electrochemical study on L1 as a function of the pH has been carried out in THF-water 70:30 v/v in the presence of the sulfate, phosphate and ATP anions. The potential use of L1 as an anion sensing receptor is discussed in terms of the electrochemical and potentiometric data and its behaviour is compared with those of related redox-active polyammonium receptors