Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single-Molecule Magnets
Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single-Molecule Magnets
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双金属协同作用使噻咯插入四氢呋喃中并合成铒单分子磁体
DOI：
10.1002/ange.202317678
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发表时间：
2024
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通讯作者：
De S
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文献类型：
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作者：
De S
钾硅溶胶K2[SiC4‐2,5‐（SiMe3）2‐3,4‐Ph2]在THF中与[M(η - 8‐COT)(THF)4][BPh4] （M=Er， Y； COT=环八烷基四烯基）反应，得到具有前所未有的将亲核硅中心插入THF碳-氧键的产物。主要产物[(μ‐η8: η8‐COT)M(μ‐L1)K]∞(1M)的结构由夹层配合物的聚合链组成，其中螺旋双环硅吡喃配体[C4H8OSiC4(SiMe3)2Ph2]2−(L1)通过氧与钾配位。次要产物[(μ‐η8: η8‐COT)M(μ‐L1)K(THF)]2（2M）表征了硅吡喃与稀土金属的配位。在形成mand2m的过程中，硅孔插入THF只发生在钾和稀土金属存在的情况下，这突出了双金属协同作用的重要性。锗（II）较低的亲核性导致钾锗K2[GeC4‐2,5‐（SiMe3）2‐3,4‐Me2]对[M(η8‐COT)(THF)4][BPh4]的反应活性形成对比，而锗的完整转移发生在配位聚合物[{η5‐GeC4(SiMe3)2Me2}M(η8‐COT)K]∞(3M)上。尽管14族杂原子引起的反应性不同，但1er、2er3和3er3的单分子磁性是相似的，热激活弛豫是通过第一激发的Kramers双重态发生的，有效能垒分别为122、80和91 cm−1。化合物1eris还通过高达106Hz的高频动态磁化率测量进行了分析。
The potassium silole K2[SiC4‐2,5‐(SiMe3)2‐3,4‐Ph2] reacts with [M(η8‐COT)(THF)4][BPh4] (M=Er, Y; COT=cyclo‐octatetraenyl) in THF to give products that feature unprecedented insertion of the nucleophilic silicon centre into a carbon‐oxygen bond of THF. The structure of the major product, [(μ‐η8: η8‐COT)M(μ‐L1)K]∞(1M), consists of polymeric chains of sandwich complexes, where the spiro‐bicyclic silapyran ligand [C4H8OSiC4(SiMe3)2Ph2]2−(L1) coordinates to potassium via the oxygen. The minor product [(μ‐η8: η8‐COT)M(μ‐L1)K(THF)]2(2M) features coordination of the silapyran to the rare‐earth metal. In forming1Mand2M, silole insertion into THF only occurs in the presence of potassium and the rare‐earth metal, highlighting the importance of bimetallic synergy. The lower nucleophilicity of germanium(II) leads to contrasting reactivity of the potassium germole K2[GeC4‐2,5‐(SiMe3)2‐3,4‐Me2] towards [M(η8‐COT)(THF)4][BPh4], with intact transfer of the germole occurring to give the coordination polymers [{η5‐GeC4(SiMe3)2Me2}M(η8‐COT)K]∞(3M). Despite the differences in reactivity induced by the group 14 heteroatom, the single‐molecule magnet properties of1Er,2Erand3Erare similar, with thermally activated relaxation occurring via the first‐excited Kramers doublet, subject to effective energy barriers of 122, 80 and 91 cm−1, respectively. Compound1Eris also analysed by high‐frequency dynamic magnetic susceptibility measurements up to 106Hz.