Research data for paper: Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single-Molecule Magnets

Data for paper published in Angewandte Chemi (vol. 61, issue 17) published April 2022 CIF files and checkcif files Abstract Replacing a monoanionic cyclopentadienyl (Cp) ligand in dysprosium single-molecule magnets (SMMs) with a dianionic cyclobutadienyl (Cb) ligand in the sandwich complexes [(η4-Cb′′′′)Dy(η5-C5Me4tBu)(BH4)]− (1), [(η4-Cb′′′′)Dy(η8-Pn†)K(THF)] (2) and [(η4-Cb′′′′)Dy(η8-Pn†)]− (3) leads to larger energy barriers to magnetization reversal (Cb′′′′=C4(SiMe3)4, Pn†=1,4-di(tri-isopropylsilyl)pentalenyl). Short distances to the Cb′′′′ ligands and longer distances to the Cp ligands in 1–3 are consistent with the crystal field splitting being dominated by the former. Theoretical analysis shows that the magnetic axes in the ground Kramers doublets of 1–3 are oriented towards the Cb′′′′ ligands. The theoretical axiality parameter and the relative axiality parameter Z and Zrel are introduced to facilitate comparisons of the SMM performance of 1–3 with a benchmark SMM. Increases in Z and Zrel when Cb′′′ replaces Cp signposts a route to SMMs with properties that could surpass leading systems.本数据集对应2022年4月发表于《德国应用化学》（Angewandte Chemie）第61卷第17期的研究论文，包含CIF文件（晶体学信息文件，Crystallographic Information File）与checkcif校验文件。【摘要】在夹心配合物[(η⁴-Cb′′′′)Dy(η⁵-C5Me4tBu)(BH4)]⁻（化合物1）、[(η⁴-Cb′′′′)Dy(η⁸-Pn†)K(THF)]（化合物2）与[(η⁴-Cb′′′′)Dy(η⁸-Pn†)]⁻（化合物3）中，将镝基单分子磁体（single-molecule magnets, SMMs）中的单阴离子型环戊二烯基（cyclopentadienyl, Cp）配体替换为双阴离子型环丁二烯基（cyclobutadienyl, Cb）配体，可获得更高的磁化反转能垒（其中Cb′′′′=C4(SiMe3)4，Pn†=1,4-二（三异丙基硅基）戊搭烯基）。化合物1至3中与Cb′′′′配体的较短配位距离以及与Cp配体的较长配位距离，与晶体场分裂主要由Cb′′′′配体主导的结论相符。理论分析表明，化合物1至3的基态克拉默斯二重态（Kramers doublets）的磁轴均指向Cb′′′′配体。为便于将化合物1至3的单分子磁体性能与基准单分子磁体进行对比，研究引入了理论轴向性参数Z与相对轴向性参数Zrel。当以Cb′′′替换Cp配体后，Z与Zrel值均有所提升，这为开发性能可超越现有顶尖体系的单分子磁体指明了方向。