Magnetic Phase Switching Performance in an Fe-Tetraoxolene-Layered Metal-Organic Framework via Electrochemical Cycling.

The iron-based tetraoxolene honeycomb-layered compound (NPr4)2[Fe2(Cl2An)3] (1; NPr4+ = tetrapropylammonium cation; Cl2An2- = 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinonate) was used as the cathode material for lithium-ion batteries. We observed a charge-cycling performance (∼16 times) with three electrons/Li+ ion insertion and extraction, corresponding to the stoichiometry redox of Cl2An2- + e- ↔ Cl2An·3- and Fe3+ + e- ↔ Fe2+. The generation/annihilation of radicals, Cl2An·3-, enables the significant improvement/deterioration of the magnetic phase transition temperature with Tc = 100 K.