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.本数据集为2022年4月发表于《应用化学》（Angewandte Chemie）第61卷第17期的论文配套数据，包含CIF文件与checkcif文件。 摘要：在三明治配合物[(η⁴-Cb′′′′)Dy(η⁵-C₅Me⁴ᵗBu)(BH₄)]⁻ (1)、[(η⁴-Cb′′′′)Dy(η⁸-Pn†)K(THF)] (2)与[(η⁴-Cb′′′′)Dy(η⁸-Pn†)]⁻ (3)中，以二阴离子型环丁二烯基（cyclobutadienyl，Cb）配体取代镝系单分子磁体（single-molecule magnets，SMMs）中的单阴离子型环戊二烯基（cyclopentadienyl，Cp）配体，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。配合物1~3中与Cb′′′′配体的配位距离更短，而与Cp配体的配位距离更长，这表明晶体场分裂主要由该环丁二烯基配体主导。理论分析显示，1~3的基态克莱默二重态的磁轴朝向Cb′′′′配体。为便于将1~3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参数Z与相对轴向参数Zrel。当以Cb′′′取代Cp配体后，Z与Zrel均有所提升，这为开发性能可超越现有领先体系的单分子磁体指明了可行路径。