A ferrocene functionalised macrocyclic receptor for cations and anions

Abstract

The isolation and characterisation of a new macrocyclic hexaamine trans-6,13-bis(ferrocenylmethylamino)-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane (L²) bearing two ferrocenyl groups appended to its exocyclic amines is reported. The crystal structures of L² and its dihydrochloride salt L²·2HCl·2H₂O have been determined. In the latter case cation–anion hydrogen bonding is observed in the solid state. Substrate binding by the electroactive L² in MeCN–CH₂Cl₂ solution has been examined by cyclic voltammetry and reveals the receptor electrochemically to recognise benzoate and chloride anions. The macrocyclic N-donors may also bind transition metal cations such as Cu^II and Zn^II.