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首页> 外文期刊>Chemistry: A European journal >Heavy Grignard Reagents;Challenges and Possibilities of Aryl Alkaline Earth Metal Compounds
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Heavy Grignard Reagents;Challenges and Possibilities of Aryl Alkaline Earth Metal Compounds

机译：重型格氏试剂;芳族碱土金属化合物的挑战和可能性

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摘要

Compounds of the type aryl-M-X,with M=Ca,Sr,Ba and X as any kind of ligand (such as halide,phosphanide,amide,aryl),are presented.The low reactivity of the heavy alkaline earth metals calcium,strontium,and barium enforces an activation prior to use for the direct synthesis.The insertion of these metals into C-I bonds of aryl iodides (direct synthesis) yields aryl metal iodides and has to be performed at low temperatures and in THF.Aryl alkaline-earth-metal compounds show some characteristics;1) the ease of ether cleavage enforces low reaction temperatures,2) for Sr and Ba the Schlenk equilibrium is shifted towards homoleptic MI_2 and MPh_2,3) high solubility of diaryl alkaline-earth-metal derivatives in THF even at low temperatures initiated quantum chemical investigations on the aggregation behavior,and 4) a strong low field shift of the ~(13)C resonances of the ipso carbon atoms in NMR spectra was observed.First results from quantum chemical calculations on diaryl dicalcium(I) suggest a long Ca-Ca bond with a considerable Ca-Ca bond dissociation energy.Initial results on a selection of applications such as metallation,metathesis,and addition reactions of aryl calcium compounds are presented as well.
机译：提出了以M = Ca，Sr，Ba和X为任何配体（例如卤化物，膦酸酯，酰胺，芳基）的芳基-MX型化合物。重碱土金属钙，锶的低反应性这些金属插入芳基碘化物的CI键中（直接合成）会生成芳基金属碘化物，必须在低温和THF中进行。芳基碱土-金属化合物具有某些特征; 1）醚易于裂解，从而降低了反应温度; 2）对于Sr和Ba，Schlenk平衡向均相MI_2和MPh_2转移; 3）即使在THF中，二芳基碱土金属衍生物的溶解度也很高在低温下启动了对聚集行为的量子化学研究，以及4）在NMR光谱中观察到ipso碳原子的〜（13）C共振的强低场移。二芳基二钙的量子化学计算的第一结果（I ） 建议较长的Ca-Ca键具有相当大的Ca-Ca键解离能。还提出了一些应用的初步结果，如金属化，复分解和芳族钙化合物的加成反应。

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