Abstract：
A new Co(II) complex, [Co(NCS)2(L)2] (1) has been synthesized based on levamisole (L) as a new ligand. Single-crystal X-ray diffraction analyses confirm that the Co(II) ion is having a distorted tetrahedral coordination geometry in the complex. Notably strong intramolecular S⋅⋅⋅S and S⋅⋅⋅N interactions has been confirmed by employing Quantum Theory of Atoms in Molecules (QTAIM). These intramolecular interactions occur among the sulfur and nitrogen atoms of the levamisole ligands and also the nitrogen atoms of the thiocyanate. Direct current (dc) magnetic analyses reveal presence of zero field splitting (ZFS) and large magnetic anisotropy on Co(II). Detailed ab initio ligand field theory calculations quantitatively predicted the magnitude of ZFS. Prominent field-induced single-ion magnet (SIM) behavior was observed for 1 from dynamic magnetization measurements. Slow magnetic relaxation follows an Orbach mechanism with the effective energy barrier Ueff=29.6 (7) K and relaxation time τo=1.4 (4)×10-9 s.
摘要：
一种新的Co(II)复合体，[Co（NCS）2（L）2]（1）是基于左旋咪唑（L）作为新的配体合成的。单晶X射线衍射分析证实，Co（II）离子在配合物中具有扭曲的四面体配位几何形状。通过采用分子中原子的量子理论（QTAIM），已经证实了显着的分子内S.这些分子内相互作用发生在左旋咪唑配体的硫和氮原子以及硫氰酸盐的氮原子之间。直流（dc）磁分析显示Co（II）上存在零场分裂（ZFS）和大的磁各向异性。详细的从头算配体场论计算定量地预测了ZFS的大小。从动态磁化强度测量中观察到1的显着场诱导的单离子磁体（SIM）行为。慢磁弛豫遵循Orbach机制，有效能垒Ueff=29.6（7）K，弛豫时间为=1.4（4）×10-9s。
