Syntheses, crystal structures, and magnetic properties for two spin-ladder complexes based on bis(2-thioxo-1,3-dithiole-4,5-dithiolato)nickelate monoanion building block

Two isostructural complexes based on bis(2-thioxo-1,3-dithiole-4,5- dithiolato)nickelate monoanion ([Ni(Dmit)₂]^-) building block, (C₁₉H₁₁NNiF₃S₁₀ (I) and C₁₈H₁₀N₂F₃NiS₁₀ (II)), have been synthesized and characterized structurally and magnetically. Two complexes crystallize in monoclinic space group P1 with very similar cell parameters and packing structures. The planar [Ni(Dmit)₂]^- monoanions form face-to-face π-type dimer, and the neighboring dimers are aligned into a ladder-type arrangement via lateral-to-lateral S.S contacts along x axis in the crystals of I and II. Two complexes exhibit similar magnetic behaviors, and their magnetic susceptibility data can be fitted to a Heisenberg antiferromagnetic two-legged spin ladder formula in high-temperature region and reproduced well by the Troyer expression in low-temperature region. The spin-gap values, obtained, respectively, from the fits of magnetic susceptibility data in high- and low-temperature regions, are closed to each other, indicating the chose magnetic exchange model and the results of fits are reasonable.