A ferrocene redox-active triazolium macrocycle that binds and senses chloride

A ferrocene bis(triazole) macrocycle was synthesised in good yield by the Eglinton coupling of an acyclic bis(alkyne) precursor and characterised in the solid state by X-ray crystallography. Alkylation gives the corresponding triazolium macrocycle, which binds chloride and benzoate strongly in CD ₃CN solution through favourable charge-assisted C- H···anion interactions, as evidenced by ¹H NMR titration experiments. Preliminary electrochemical studies reveal that the redox-active macrocycle is capable of sensing chloride in CH ₃CN solution.