Electrochemical synthesis, characterization and magnetic studies of Ni/TCNQ salts

Two new materials, Ni(TCNQ) and Ni3(TCNQ)2, have been obtained by an electroplating technique and characterized by SEM, XPS, vibrational spectroscopy, X-ray diffraction and magnetic techniques. The compound Ni(TCNQ), obtained at lower applied voltages, contains paramagnetic Ni(II) cations and diamagnetic TCNQ−2 anions. In contrast, the material obtained at higher applied voltages, Ni3(TCNQ)2, contains diamagnetic Ni(II) cations and S=1/2TCNQ−3 anions. Thus, the higher oxidation states of the organic ligand have been stabilized by control of the applied electroplating voltage. Magnetic studies of polycrystalline samples of both compounds show the presence of dominant ferromagnetic interactions at higher temperatures, but antiferromagnetic interactions dominate at low temperatures.