Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
Inorg Chem. 2023 Apr 10;62(14):5854-5862. doi: 10.1021/acs.inorgchem.3c00689. Epub 2023 Mar 29.
The high reactivity accessible from the reduction of the tris(amide) complexes Ln(NR) (R = SiMe) with potassium graphite in the presence of a variety of ethers is demonstrated by crystal structures of six different types of products of C-O bond cleavage reactions with Ln = Y, Ho, Er, and Lu. Specifically, 1,2-dimethoxyethane (DME) can be cleaved in Ln(NR)/KC reactions as shown by three different types of crystals: [K (crypt)][(RN)Y(OCHCHOCH)], , [(RN)Y(μ-OCHCHOCH-κO,κO')], , and [K(18-c-6)]{[(RN)Lu][(μ-OCHCHO)]}, (18-c-6 = 18-crown-6; crypt = 2.2.2-cryptand). THF can be ring opened by the Y(NR)/KC reaction system, as shown by crystals of the butoxide, [K(crypt)][(RN)Y(OCHCHCHCH)], . The cyclic ether, oxetane, OCH, ring opens in Ln(NR)/KC reactions to form crystals of the propoxide, [K(18-c-6)(OCH)][(RN)Ln(OCHCHCH)], , for Ln = Ho and Er. In EtO, the Y(NR)/KC reactions do not attack the solvent, but C-O cleavage of 18-c-6 is observed to form {[(RN)]Y[μ-η:-O(CHO)K]}, . These Ln(NR)/KC C-O cleavage reactions are typically accompanied by C-H bond activation reactions, which form cyclometalates such as [K(crypt)]{(RN)Ln[N(SiMe)(SiMeCH)-κC,κN]}, (Ln = Y, Ho, Er), and [K(18-c-6)]{(RN)Y[N(SiMe)(SiMeCH)-κC,κN]}, , which are common decomposition products of Ln(NR) reactions. In addition, in this study, the hydride complex, [K(18-c-6)][(RN)YH], , was isolated. NMR analysis indicates that the yttrium reactions form mixtures that consistently contain the yttrium cyclometalates and as major components. These results show the diversity of available reaction pathways for the Ln(NR)/KC system and highlight the inherent difficulties in isolating Ln(II) complexes containing the [Ln(NR)] anion.
六类不同结构的 C-O 键断裂产物的晶体结构证实了三（酰胺）配合物 Ln(NR)（R = SiMe）在钾石墨存在下还原后具有高反应活性，Ln 包括 Y、Ho、Er 和 Lu。具体而言，1,2-二甲氧基乙烷（DME）可在 Ln(NR)/KC 反应中裂解，产生三种不同类型的晶体：[K（crypt）][（RN）Y（OCHCHOCH）]，[（RN）Y（μ-OCHCHOCH-κO，κO'）]，和[K(18-c-6)]{[(RN)Lu][(μ-OCHCHO)]}，（18-c-6=18-冠-6；crypt=2.2.2- 穴醚）。THF 可被 Y(NR)/KC 反应体系开环，产物晶体为丁氧基盐，[K(crypt)][（RN）Y（OCHCHCHCH）]。环状醚环氧化物 OCH 开环形成丙氧基盐，[K(18-c-6)(OCH)][(RN)Ln(OCHCHCH)]，（Ln=Ho 和 Er）。在 EtO 中，Y(NR)/KC 反应不攻击溶剂，但观察到 18-c-6 的 C-O 断裂，形成{[(RN)]Y[μ-η:-O(CHO)K]}。这些 Ln(NR)/KC C-O 断裂反应通常伴随着 C-H 键活化反应，形成环金属配合物，如[K(crypt)]{(RN)Ln[N(SiMe)(SiMeCH)-κC，κN]}，（Ln=Y、Ho、Er）和[K(18-c-6)]{(RN)Y[N(SiMe)(SiMeCH)-κC，κN]}，这些都是 Ln(NR)反应的常见分解产物。此外，在这项研究中，分离得到了氢化物配合物[K(18-c-6)][(RN)YH]。NMR 分析表明，钇反应形成的混合物主要包含钇环金属配合物和作为主要成分。这些结果表明 Ln(NR)/KC 体系具有多种可供选择的反应途径，并突出了分离含有[Ln(NR)]阴离子的 Ln(II)配合物的固有困难。
