Molecule-based magnetic materials based on dinuclear ruthenium carboxylate and octacyanotungstate

Abstract

Two structurally different polymeric complexes consisting of ruthenium(II,III) pivalate ([Ru2(piv)]4+) (Hpiv = pivalic acid) and octacyanotungstate(V) ([W(CN)8]3−) ions, [{Ru2(piv)4}3W(CN)8(H2O)] (1) and (PPh4)2[Ru2(piv)4W(CN)8]·0.5H2O (2), were synthesized. The infrared spectra as well as diffused reflectance spectra confirmed the existence of the ruthenium(II,III) pivalate dimer in 1 and 2. The X-ray crystal structure analysis of 2 showed an alternating arrangement of [Ru2(piv)]4+ and [W(CN)8]3− ions in a one-dimensional chain. The temperature-dependent magnetic susceptibility of 2 showed a ferrimagnetic-like behavior. However, the field dependent magnetization curve at 2 K indicates that this complex has an S = 0 ground state. The X-ray crystal structure analysis of 1 showed a two-dimensional layered structure made up of windmill-shaped 28 membered-rings of alternating arrangement of [Ru2(piv)]4+ and [W(CN)8]3−. The magnetic susceptibility and zero-field-cooled and field-cooled magnetization data of 1 showed that this complex is ferrimagnetic with Tc = 44 K. The field dependence of magnetization exhibited a hysteresis with a coercive field of 5600 Oe at 5 K.