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到 THF 中并合成铒单分子磁体。
DOI：
10.1002/anie.202317678
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发表时间：
2024
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De S
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作者：
De S
硅杂环戊烯钾K2[SiC 4 - 2，5-（SiMe 3）2 - 3，4-Ph 2]与[M（η8-COT）（THF）4][BPh 4]（M=Er，Y; COT=环辛四烯基）在THF中反应，得到前所未有的亲核硅中心插入THF碳氧键的产物。主要产物[（μ-η8：η8-COT）M（μ-L1）K]∞（1 M）的结构由夹心复合物的聚合物链组成，其中螺双环硅吡喃配体[C4 H8 OSiC 4（SiMe 3）2 Ph 2]2−（L1）通过氧与钾配位。次要产物[（μ-η8：η8-COT）M（μ-L1）K（THF）]2（2 M）的特征在于硅吡喃与稀土金属的配位。在形成1 Mand 2 M时，噻咯插入THF中仅在钾和稀土金属存在下发生，突出了协同作用的重要性。锗（II）的较低亲核性导致钾锗摩尔K2[GeC 4 - 2，5-（SiMe 3）2 - 3，4-Me 2]对[M（η8-COT）（THF）4][BPh 4]的相反反应性，其中锗摩尔的完整转移发生以得到配位聚合物[{η5-GeC 4（SiMe 3）2 Me 2}M（η8-COT）K]∞（3 M）。尽管14族杂原子引起的反应性不同，但1 Er、2 Er和3Er的单分子磁体性质相似，通过第一激发的Kramers双重态发生热激活弛豫，分别受到122、80和91 cm−1的有效能垒。 还通过高达106 Hz的高频动态磁化率测量来分析化合物1 Er。
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.