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Construction of intermolecular σ-hole interactions in rare earth metallocene complexes using a 2,3,4,5-tetraiodopyrrolyl anion
Chemical Science ( IF 7.6 ) Pub Date : 2024-07-26 , DOI: 10.1039/d4sc03786c
Francis Delano 1 , Florian Benner 1 , Seoyun Jang 1 , Samuel M Greer 2 , Selvan Demir 1
Affiliation  

The generation of noncovalent intermolecular interactions represents a powerful method to control molecular vibrations and rotations. Combining these with the axial ligand field enforced by the metallocene ligand scaffold provides a dual-pronged approach in controlling the magnetic-relaxation pathways for dysprosium-based single-molecule magnets (SMMs). Here, we present the first implementation of 2,3,4,5-tetraiodopyrrole (TIPH) in its anionic form [TIP] as a ligand in three isostructural rare-earth metal complexes Cp*2RE(TIP) (1-RE, RE = Y, Gd, and Dy; Cp* = pentamethylcylopentadienyl), where the TIP ligand binds through the nitrogen and one iodine atom κ2(N,I) to the metal centre. The shallow potential energy surface of the intermolecular σ-hole interaction yields distortions of the interatomic distances at elevated temperatures which were investigated by variable-temperature SCXRD. 1-RE constitute the first crystallographically characterized molecules containing TIP as a ligand for any metal ion, and 1-Dy is the first SMM that employs the TIP ligand. The structural dependence on temperature allowed the mechanism of magnetic relaxation to be explored through ab initio calculations at different temperatures. The electronic influence of the coordinated iodine substituent was probed via magnetometry and cw-EPR spectroscopy on 1-Gd. To further scrutinize the impact of the iodine substituents on the physical properties, a second set of new complexes Cp*2RE(DMP) (2-RE, RE = Y, and Dy) where DMP = 2,5-dimethylpyrrolyl were synthesized. Here, the DMP ligand binds similarly to the TIP ligand and represents an all-hydrocarbon analogue to 1-RE. 2-Dy constitutes the first SMM bearing a DMP ligand.

中文翻译:


使用 2,3,4,5-四碘吡咯基阴离子构建稀土茂金属配合物中的分子间 σ-空穴相互作用



非共价分子间相互作用的产生代表了控制分子振动和旋转的有效方法。将这些与茂金属配体支架强制的轴向配体场相结合,提供了一种双管齐下的方法来控制基于镝的单分子磁体(SMM)的磁弛豫路径。在这里,我们首次实现了阴离子形式 [TIP] 的 2,3,4,5-四碘吡咯 (TIPH) -作为三种同构稀土金属配合物 Cp* 2 RE(TIP) ( 1-RE ,RE = Y、Gd 和 Dy;Cp* = 五甲基环戊二烯基),其中 TIP 配体通过氮和一个碘原子 κ 2 (N,I) 与金属中心结合。分子间 σ-空穴相互作用的浅势能面在高温下会产生原子间距离的扭曲,这通过变温 SCXRD 进行了研究。 1-RE构成第一个含有 TIP 作为任何金属离子配体的晶体学特征分子, 1-Dy是第一个采用 TIP 配体的 SMM。结构对温度的依赖性使得可以通过不同温度下的从头计算来探索磁弛豫机制。通过磁力测定和1​​-Gd连续波 EPR 光谱探讨了配位碘取代基的电子影响。 为了进一步研究碘取代基对物理性质的影响,合成了第二组新配合物 Cp* 2 RE(DMP)( 2-RE 、RE = Y 和 Dy),其中 DMP = 2,5-二甲基吡咯基。此处,DMP 配体的结合与 TIP 配体类似,代表1-RE的全烃类似物。 2-Dy构成第一个带有 DMP 配体的 SMM。
更新日期:2024-07-26
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