An ion-pair compound based on [Pd(mnt) ₂] ^- with strong antiferromagnetically coupled interaction: Synthesis, crystal structure, magnetic property

An ion-pair compound, which constructs from the 1-(4′-F-benzyl) pyridinium with Λ-shaped (abbreviated as [FBzPy] ⁺) and planar bis(maleonitrileditholato)palladium(III) (abbreviated as [Pd(mnt) ₂] ^-), has been synthesized and structurally characterized. The cations and anions in this compound stack into well-separated columns in the solid state, the adjacent anions exist the strong trend of dimerization within an anionic column, and the contacts between the neighbor Pd(III) ions alternate as 3.39 and 4.06 Å, respectively. The weak π⋯π stacking interactions were observed between adjacent benzene rings within a cationic column. The temperature dependence of magnetic susceptibility measured in the temperature range of 1.8-330 K; indicates this compound is almost diamagnetic. The magnetic susceptibility was successfully modeled by a spin dimer magnetic exchange scheme with s=12 to give rise to g=2.1, and the energy gap between singlet ground state and triplet excited state is about 1310 K.