Ferromagnetism in Charge Transfer Salts Based on Metallocenes and Nickel Bis-Dithiolenes

Abstract The synthesis and preliminary structural and magnetic studies of several compounds based on [M(Cp*)2], with M = Fe; Mn; Cr, and on [Ni(L)2], where L is a 1,2-dithiolate, as bdt = benzenedithiolate, edt = ethylenedithiolate and tcdt = tetrachlorobenzenedithiolate, are reported. In the charge transfer salts, [M(Cp*)2][Ni(L)2], both 1D and layered structures are observed. From the magnetic behavior of the several charge transfer salts apparently ferro and antiferromagnetic interactions are competing in most compounds. Generally AFM interactions dominate at high temperatures, but in several cases FM interactions become dominant at low temperatures. However magnetic ordering was only clearly observed for [Fe(Cp*)2][Ni(edt)2] and [Mn(Cp*)2][Ni(bdt)2], both presenting metamagnetic transitions with TN= 3.2 K and Hc∽ 4 kG, at 2 K, for the first and with TN = 2.3 K and Hc ∽ 200 G, at 2 K, for the second.