Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single-Molecule Magnets
Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single-Molecule Magnets
复制标题
镝单分子磁体晶体场分裂中环丁二烯基相对于环戊二烯基的优势
DOI：
10.1002/ange.202200525
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发表时间：
2022
影响因子：
--
通讯作者：
Durrant J
中科院分区：
文献类型：
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作者：
Durrant J
用二阴离子环丁二烯基（Cb）配体取代镝单分子磁体（SMMs）中的单阴离子环戊二烯基（Cp）配体[（η4‐Cb””）Dy(η5‐C5Me4tBu)(BH4)]−(1),[（η4‐Cb””）Dy（η8‐Pn†）K(THF)](2)和[（η4‐Cb””）Dy（η8‐Pn†）]−(3)导致更大的磁化反转能量障碍(Cb“”=C4（SiMe3)4, Pn†=1,4‐di（三‐异丙基）戊烯基）。在1 - 3中，与Cb配体的距离较短，与Cp配体的距离较长，晶体场分裂以前者为主。理论分析表明，1 - 3基克莱默斯重态的磁轴向Cb配体取向。引入了理论轴向参数和相对轴向参数zandzrelre，以便将1 - 3的SMM性能与基准SMM进行比较。当Cb“’”取代Cp标志时，增加了inzandzrell，这是通往具有可能超越领先系统的smm的路线。
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 in1–3are consistent with the crystal field splitting being dominated by the former. Theoretical analysis shows that the magnetic axes in the ground Kramers doublets of1–3are oriented towards the Cb′′′′ ligands. The theoretical axiality parameter and the relative axiality parameterZandZrelare introduced to facilitate comparisons of the SMM performance of1–3with a benchmark SMM. Increases inZandZrelwhen Cb′′′ replaces Cp signposts a route to SMMs with properties that could surpass leading systems.