Structures and properties of ferrocene derivatives with different kinds of nitroxide radicals

Abstract

Three ferrocene derivatives carrying different kinds of nitroxide radicals (1–3) were prepared as dual redox compounds. All of them have distorted molecular conformations between a Cp unit of a ferrocene group and a nitroxide group and the largest dihedral angle between the units is observed in the PO derivative 3. A unique magnetic behavior with a spin gap is disclosed in the derivative 3, reflecting two-dimensional interactions between the paired spins. Each derivative has two oxidation potentials based on both ferrocene and nitroxide groups and multi-step charge–discharge processes are found for all derivatives with the first discharge capacity over 200 A h kg⁻¹.