NMR spectroscopy of organolithium compounds, part XXXIII: <i>trans</i>
-2,3-dimethylcyclopropyllithium aggregation in diethylether: An equilibrium between three different complexes of comparable energy and the influence of LiBr on aggregate structure
作者:Thomas Fox、Harald Günther
DOI:10.1002/poc.3800
日期:2018.5
The aggregate formation of trans‐2,3‐dimethylcyclopropyllithium (2) was studied in diethylether (DEE). With the help of the isotopic fingerprint method three clusters, a monomer, a dimer, and a fluxional tetramer in the ratio 1.00:0.53:0.22 were identified at 187 K. In the presence of 1 equivalent of LiBr cyclopropyllithium (1) forms in DEE at 163 K a mixed dimer and a mixed tetramer, while in THF
在乙醚(DEE)中研究了反式-2,3-二甲基环丙基锂(2)的聚集体形成。借助同位素指纹法,在187 K处鉴定出三个簇,即单体,二聚体和流动四聚体,其比率为1.00:0.53:0.22。在DEE中存在1当量的LiBr环丙基锂(1)形式时在163 K下,混合的二聚体和混合的四聚体,而在THF中,混合的二聚体占主导。在相同条件下2和2,2,3,3- tetramethylcyclopropyllithium(3)的形式在该溶剂混合物DEE / THF(1:1)混合的二聚物,如同2也于THF中。