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Pyrrolyl-Bridged Metallocene Complexes: From Synthesis, Electronic Structure, to Single-Molecule Magnetism
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2023-08-28 , DOI: 10.1021/acs.inorgchem.3c01724
Francis Delano 1 , Florian Benner 1 , Seoyun Jang 1 , Selvan Demir 1
Affiliation  

The π- and σ-basicity of the pyrrolyl ligand affords several coordination modes. A sterically encumbering coordination sphere around metal centers may foster new coordination modes for the pyrrolyl ligand. Here, we present three dinuclear rare earth complexes [Cp*2RE(μ-pyr)]2, [RE = Y (1), La (2), Dy (3); Cp* = pentamethylcyclopentadienyl, pyr = pyrrolyl], which were synthesized through a protonolysis reaction between allyl complexes and H-pyrrole. Each metal is ligated by two Cp* ligands and the N atom of the pyrrolyl ring while interacting with the π-system of the other pyrrolyl ligand, yielding an unprecedented coordination mode for pyrrolyl best described as [((η5-Cp*)2RE)2(μ-1η2-pyr-2κN)(μ-2η2-pyr-1κN)]. The steric congestion implemented by the Cp* ligands forces this asymmetric coordination of the pyrrolyl ligand. 13 were characterized by crystallography, electrochemistry, and spectroscopy. Density functional theory calculations on 1 uncovered the bonding situation between the pyrrolyl ligand and the yttrium(III) ion. Excitingly, 3 displays slow magnetic relaxation under zero dc field with Ueff = 98.9(7) cm–1 and τo = 6.7(1) × 10–8 s, placing it among coveted dinuclear metallocene single-molecule magnets. CASSCF calculations provided the energy of the crystal field states of DyIII and confirmed the barrier height.

中文翻译:

吡咯桥茂金属配合物:从合成、电子结构到单分子磁性

吡咯基配体的π-和σ-碱性提供了多种配位模式。金属中心周围的空间阻碍配位球可能会促进吡咯基配体的新配位模式。在这里,我们提出了三种双核稀土配合物 [Cp* 2 RE(μ-pyr)] 2、[RE = Y ( 1 )、La ( 2 )、Dy ( 3 );Cp*=五甲基环戊二烯基,pyr=吡咯基],通过烯丙基配合物与H-吡咯之间的质子解反应合成。每种金属由两个 Cp* 配体和吡咯环的 N 原子连接,同时与另一个吡咯配体的 π 系统相互作用,产生前所未有的吡咯配位模式,最好描述为 [((η 5 -Cp * ) 2 RE) 2 (μ-1η 2 -pyr-2κN)(μ-2η 2 -pyr-1κN)]。Cp* 配体实现的空间拥挤迫使吡咯基配体的这种不对称配位。13通过晶体学、电化学和光谱学进行了表征。1 的密度泛函理论计算揭示了吡咯基配体与钇(III)离子之间的键合情况。令人兴奋的是,3在零直流场下表现出缓慢的磁弛豫,U eff = 98.9(7) cm –1和 τ o = 6.7(1) × 10 –8 s,使其跻身令人垂涎的双核茂金属单分子磁体之列。CASSCF 计算提供了 Dy III晶体场态的能量并确认了势垒高度。
更新日期:2023-08-28
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