Anion recognition and sensing by neutral and charged transition metal co-ordinated ferrocene phosphine amide receptors

Abstract

A new bis(phosphine) amide linked ferrocene ligand [Fe{η-C₅H₄CONH(CH₂)₃PPh₂}₂] and molybdenum, chromium, rhodium and ruthenium transition metal chelated receptors of it have been prepared. Proton NMR anion-binding investigations revealed that in general the combination of the Lewis acid transition metal centre and the ferrocene amide moiety enhances the strength of anion binding. Electrochemical studies showed all receptors can electrochemically sense halide, dihydrogenphosphate and hydrogensulfate anions via significant cathodic perturbations of the respective ferrocene and transition metal oxidation wave.