The recently reported compound [Dy^IIILF](CF₃SO₃)₂·H₂O (L = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane) displays a strong axial magnetic anisotropy, due to the short axial Dy–F bond, and single-molecule magnet (SMM) behavior. Following our earlier [Dy^IIILF]²⁺ work, herein we report the systematic structural and magnetic study of a family of [Ln^IIILF](CF₃SO₃)₂·H₂O compounds (Ln(III) = 1-Ce, 2-Pr, 3-Nd, 4-Eu, 5-Tb, 6-Ho, 7-Er, 8-Tm, and 9-Yb). From this series, the Ce(III) and Nd(III) analogues show slow relaxation of the magnetization under an applied direct current magnetic field, which is modeled using a Raman process. Complete active space self-consistent field theoretical calculations are employed to understand the relaxation pathways in 1-Ce and 3-Nd and also reveal a large tunnel splitting for 5-Tb. Additional computational studies on model compounds where we remove the axial F^– ligand, or replace F^– with I^–, highlight the importance of the F^– ligand in creating a strong axial crystal field for 1-Ce and 3-Nd and for promoting the SMM behavior. Importantly, this systematic study provides insight into the magnetic properties of these lighter lanthanide ions.

中文翻译：

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镧系元素中轴向 LnIII-F 键的重要性以及 Ce 和 Nd 类似物中的单分子磁体行为

最近报道的化合物[Dy ^III LF](CF ₃ SO ₃ ) ₂ ·H ₂ O (L = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane)由于短的轴向 Dy-F 键和单分子磁体 (SMM) 行为，显示出强烈的轴向磁各向异性。继我们早期的[Dy ^III LF] ²⁺工作之后，我们在此报告了[Ln ^III LF](CF ₃ SO ₃ ) ₂ ·H ₂ O 化合物家族(Ln(III) = 1 - Ce, 2 -Pr , 3 -Nd, 4-Eu、5 -Tb、6 -Ho 、7 -Er、8 -Tm 和9 -Yb )。在该系列中，Ce(III) 和 Nd(III) 类似物在使用拉曼过程建模的施加直流磁场下显示出磁化的缓慢弛豫。采用完整的活性空间自洽场理论计算来了解1 -Ce 和3 -Nd 中的弛豫路径，并揭示5 -Tb的大隧道分裂。对模型化合物进行额外的计算研究，我们去除轴向 F ^-配体，或用 I ^{-替换 F -}，突出了 F 的重要性^–为1 -Ce 和3 -Nd创建强大的轴向晶体场并促进 SMM 行为的配体。重要的是，这项系统研究提供了对这些较轻镧系离子的磁性的洞察。