Barozzino-Consiglio Gabriella, Hamdoun Ghanem, Fressigné Catherine, Harrison-Marchand Anne, Maddaluno Jacques, Oulyadi Hassan
Normandie Université, UNIROUEN, INSA de Rouen, CNRS, Laboratoire COBRA (UMR 6014 & FR 3038), 76000, Rouen, France.
Chemistry. 2017 Sep 12;23(51):12475-12479. doi: 10.1002/chem.201702990. Epub 2017 Aug 9.
Despite its common use in synthesis, the structure of isopropylliyhium in THF has never been determined, a dimer being generally proposed but not supported. This paper fills this data gap through a sophisticated NMR study that shows that, in THF at low-temperature, isopropyllithium is in the form of a 1:2 mixture of a trisolvated monomer and a disolvated dimer in equilibrium. The presence of the monomer, never evoked before, together with a hypo-solvation of the dimer hinted by DFT calculations, provides a rational explanation to the remarkable reactivity of this organolithium reagent in ethereal solvents.
尽管异丙基锂在合成中常用，但它在四氢呋喃（THF）中的结构从未被确定，一般认为其为二聚体，但并未得到证实。本文通过一项精密的核磁共振研究填补了这一数据空白，该研究表明，在低温下的四氢呋喃中，异丙基锂是以三溶剂化单体和二溶剂化二聚体的1:2混合物形式处于平衡状态。此前从未提及的单体的存在，以及密度泛函理论计算所暗示的二聚体的低溶剂化作用，为这种有机锂试剂在醚类溶剂中显著的反应活性提供了合理的解释。
