Room-temperature ferromagnetic organic magnets derived from fluoro-graphite via facile halide exchange

Room-temperature ferromagnetic organic magnet is developed via a facile halide exchange process using fluoro-graphite (FG) as a starting material. Structural and chemical analysis reveals that heterogeneous C–F bond cleavage in the defect sites of FG is essentially related to the formation of ferromagnetic hydroxyl-graphene (HG). Pyrolysis of FG in a polar solvent with iodine ions induces a formation of metastable C–I bond and subsequent replacement of the I sites with the hydroxyl groups. Specifically, defective sites can be formed in FG due to nucleophile attack where the OH groups can be easily generated. As a result, the FG can be transformed into the HG with a network of sp²-conjugated carbon motifs in a sp³-based graphene matrix. Hence, the paramagnetic centers in the π-electron system of FG can be transformed to the long-range ordered ferromagnetic centers in the sp²-conjugated system of HG. Electron paramagnetic resonance data demonstrate the weak ferromagnetic property of HG stable at room temperature.