Peel Andrew J, Tezuka Noriyuki, D'Rozario James M, Uchiyama Masanobu, Wheatley Andrew E H
Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , UK . Email:
Cluster of Pioneering Research (CPR) , Advanced Elements Chemistry Laboratory , RIKEN , 2-1 Hirosawa, Wako-shi , Saitama 351-0198 , Japan.
Chem Sci. 2019 Feb 5;10(11):3385-3400. doi: 10.1039/c8sc04325f. eCollection 2019 Mar 21.
The synthesis and isolation of a novel bimetallic species formed by reacting two equivalents of TMPLi with CuCl in the presence of EtO are reported. X-ray crystallography reveals the EtO-free tetranuclear aggregate (TMPCu)(TMPLi) , which formally results from the catenation of dimers of TMPLi and TMPCu. NMR spectroscopy confirms that, upon dissolution in hydrocarbon media, the crystals fail to form a conventional Gilman cuprate dimer. Instead they exhibit a spectrum which is consistent with that recently proposed for an of dimeric Gilman cuprate. Moreover, while pre-isolated Gilman cuprate is inert to benzene solvent, this new isomer smoothly affects aromatic deprotonation to give mainly Ph(TMP)CuLi , which is formally a heterodimer of Gilman cuprate TMPCu(μ-TMP)Li and PhCu(μ-TMP)Li . Attempts to synthesise through explicit combination of pre-isolated and were successful; additionally, this permitted the preparation of Ph(TMP)CuLi and Ph(TMP)CuLi when was combined in 1 : 2 ratios with TMPCu or TMPLi, respectively. was characterised as metallacyclic in the solid-state, its structural features resembling those in but with reduced Li-π interactions. It also proved possible to perform Cu/Li exchange on (using BuOCu) to give a novel mixed organo(amido)copper species Ph(TMP)Cu . Remarkably, the unprecedented reactivity of towards benzene is reproduced by heating a 1 : 1 mixture of TMPLi and TMPCu in the same solvent; this gives predominantly . On the other hand, mixtures which are rich in either Cu or Li can lead to the selective formation of or . Though crystallographic data on could not be obtained, DFT calculations accurately corroborated the observed structures of and and could be used to support having the same structure type, albeit with enhanced Li-π interactions. This was consistent with NMR spectroscopic data. However, in contrast to and , for which 2D NMR spectroscopy indicated only conformational changes, was additionally found to exhibit fluxionality in a manner consistent with a dissociative process.
报道了在EtO存在下，通过两当量的TMPLi与CuCl反应形成的新型双金属物种的合成与分离。X射线晶体学揭示了不含EtO的四核聚集体(TMPCu)(TMPLi)，它正式由TMPLi和TMPCu的二聚体的链化产生。核磁共振光谱证实，在烃类介质中溶解时，晶体不会形成传统的吉尔曼铜酸盐二聚体。相反，它们表现出的光谱与最近提出的二聚体吉尔曼铜酸盐的光谱一致。此外，虽然预先分离的吉尔曼铜酸盐对苯溶剂呈惰性，但这种新异构体能顺利地影响芳环去质子化，主要生成Ph(TMP)CuLi，它正式是吉尔曼铜酸盐TMPCu(μ-TMP)Li和PhCu(μ-TMP)Li的异二聚体。通过预先分离的和的明确组合成功合成了；此外，当分别以1:2的比例与TMPCu或TMPLi组合时，这允许制备Ph(TMP)CuLi和Ph(TMP)CuLi。在固态中被表征为金属环，其结构特征类似于中的那些，但Li-π相互作用减弱。还证明可以对(使用BuOCu)进行Cu/Li交换，得到新型混合有机(酰胺基)铜物种Ph(TMP)Cu。值得注意的是，通过在相同溶剂中加热TMPLi和TMPCu的1:1混合物，可以重现对苯前所未有的反应性；这主要生成。另一方面，富含Cu或Li的混合物可导致选择性地形成或。虽然无法获得关于的晶体学数据，但密度泛函理论计算准确地证实了观察到的和的结构，并可用于支持具有相同的结构类型，尽管Li-π相互作用增强。这与核磁共振光谱数据一致。然而，与2D核磁共振光谱仅表明构象变化的和相比，还发现以与解离过程一致的方式表现出流动性。
