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