1,1,2,2-四甲基环丙基-3-甲基锂晶体结构

DJ_Tokyo

★声明：本文仅代表个人观点，笔者学识有限，资料整理过程中难免存在疏漏谬误，请不吝指正。

1,1,2,2-四甲基环丙基-3-甲基锂晶体结构

★信源★

Adalbert Maercker课题组在期刊《化学报告》（Chemische Berichte）报道了1,1,2,2-四甲基环丙基-3-甲基锂晶体结构，论文为“Chem. Ber. 1984, 117, 2547–2554. DOI [1]: 10.1002/cber.19841170802.”。

★基本信息★

中文名称：1,1,2,2-四甲基环丙基-3-甲基锂

英文名称：1,1,2,2-tetramethylcyclopropyl-3-methyllithium

化学简式：LiCH2CH(CMe2)2

CAS：92509-21-2(LiCH2CH(CMe2)2),92407-70-0([LiCH2CH(CMe2)2]6)

CCDC [2]：1128817

1H NMR (80 MHz, Ether-d10): δ/ ppm = 1.24 (s, 6H, CH3), 1.08 (s, 6H, CH3), 0.5 (t, J= 6.7 Hz, 1H, CH), –1.06 (d, J = 6.7 Hz, 1H, CH2).

★晶体合成★

根据文献“J. Am.Chem. Soc. 1964, 86, 2247–2251. DOI: 10.1021/ja01065a029.”和“J. Am. Chem. Soc. 1965, 87, 5144–5148. DOI: 10.1021/ja00950a029.”报道，环丙基甲基金属试剂存在开环平衡，因此合成1,1,2,2-四甲基环丙基-3-甲基锂时要尽可能降低反应温度，论文中在–60 ℃低温下反应仍有8%的开环产物。

▲图1 1,1,2,2-四甲基环丙基-3-甲基锂合成

★晶体结构★

其结构示意图如图2所示（由ChemBioDraw [3]绘制），其晶体结构图如图3所示（由Diamond[4]绘制）。晶体结构表明1,1,2,2-四甲基环丙基-3-甲基锂是一个六聚体，六个金属锂构成一个八面体，该八面体的六个面上各有一个1,1,2,2-四甲基环丙基-3-甲基，1,1,2,2-四甲基环丙基-3-甲基的亚甲基碳桥联三个锂金属，因此其结构式可写为[Li(μ3-η1:η1:η1-CH2CH(CMe2)2)]6，如果不写异丁基与金属之间的键合模式，则可写为[LiCH2CH(CMe2)2]6。

▲图2 1,1,2,2-四甲基环丙基-3-甲基锂结构示意图

▲图3 1,1,2,2-四甲基环丙基-3-甲基锂晶体结构图（球棍模型）

论文和晶体数据可从期刊主页下载，也可以从以下链接下载：

链接:https://pan.baidu.com/s/1m0_Nx--kdtQAPjyRNNMPjA?pwd=reda

提取码: reda

参考文献

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