Mixed Crystalline Lithium Organics and Interconversion in Solution

Scrambling, but not the Humpty Dumpty way! The crystallographically
confirmed mixed lithium organic [tBuLi]4·4­[Me2NC6H4Li]4 (1) consists of independent alkyl- and
aryllithium tetramers in a 1:4 ratio. It has been employed to study
the interconversion in solution. 7Li-DOSY and 7Li-EXSY NMR spectroscopy was utilized to establish the nature of
that exchange and to determine related rate constants along the equilibria
to give [Me2NC6H4Li]4 (A), [(Me2NC6H4Li)3(tBuLi)] (B), [(Me2NC6H4Li)2(tBuLi)2] (C), [(Me2NC6H4Li)­(tBuLi)3] (D), and [tBuLi]4 (E).

无序重排，但绝非汉普蒂·邓普蒂式的随机重排！经晶体学确证的混合有机锂化合物[(叔丁基锂(tBuLi))₄·4(N,N-二甲基氨基苯基锂(Me₂NC₆H₄Li))₄]（1），以1:4的比例包含独立存在的烷基锂与芳基锂四聚体。该化合物被用于研究溶液中的分子间相互转化过程：研究人员借助锂-7扩散有序光谱(7Li-DOSY)与锂-7交换光谱(7Li-EXSY)核磁共振波谱法，明确了该交换过程的本质，并通过平衡体系测定了相关速率常数，得到了如下中间产物与终产物：[Me₂NC₆H₄Li]₄（A）、[(Me₂NC₆H₄Li)₃(tBuLi)]（B）、[(Me₂NC₆H₄Li)₂(tBuLi)₂]（C）、[(Me₂NC₆H₄Li)(tBuLi)₃]（D）以及[tBuLi]₄（E）。