Walz Florian, Moos Eric, Garnier Delphine, Köppe Ralf, Anson Christopher E, Breher Frank
Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131, Karlsruhe, Germany.
Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Chemistry. 2017 Jan 23;23(5):1173-1186. doi: 10.1002/chem.201605073. Epub 2016 Dec 23.
The synthesis, structure, and full characterization of a redox-switchable germylene based on a [3]ferrocenophane ligand arrangement, [Fc(NMes) Ge] (4), is presented. The mesityl (Mes)-substituted title compound is readily available from Fc(NHMes) (2) and Ge{N(SiMe ) } , or from the dilithiated, highly air- and moisture-sensitive compound Fc(NLiMes) ⋅3 Et O (3) and GeCl . Cyclic voltammetry studies are provided for 4, confirming the above-mentioned view of a redox-switchable germylene metalloligand. Although several 1:1 Rh and Ir complexes of 4 (5-7) are cleanly formed in solution, all attempts to isolate them in pure form failed due to stability problems. However, crystalline solids of [Mo(κ Ge-4) (CO) ] (8) and [W(κ Ge-4) (CO) ] (9) were isolated and fully characterized by common spectroscopic techniques (8 by X-ray diffraction). DFT calculations were performed on a series of model compounds to elucidate a conceivable interplay between the metal atoms in neutral and cationic bimetallic complexes of the type [Rh(κ E-qE)(CO) Cl] (qE=[Fc(NPh) E] with E=C, Si, Ge). The bonding characteristics of the coordinated Fc-based metalloligands (qE/qE ) are strongly affected upon in silico oxidation of the calculated complexes. The calculated Tolman electronic parameter (TEP) significantly increases by approximately 20 cm (E=C) to 25 cm (E=Si, Ge) upon oxidation. The change in the ligand-donating abilities upon oxidation can mainly be attributed to Coulombic effects, whereas an orbital-based interaction appears to have only a minor influence.
本文介绍了一种基于[3]二茂铁并苯配体排列的氧化还原可切换亚锗烯[Fc(NMes)Ge]（4）的合成、结构及全面表征。该均三甲苯基（Mes）取代的标题化合物可由Fc(NHMes)（2）和Ge{N(SiMe) }轻松制得，或由二锂化的、对空气和水分高度敏感的化合物Fc(NLiMes)·3EtO（3）和GeCl制得。对4进行了循环伏安法研究，证实了上述关于氧化还原可切换亚锗烯金属配体的观点。尽管4的几种1:1铑和铱配合物（5 - 7）在溶液中能清晰形成，但由于稳定性问题，所有将它们分离成纯形式的尝试均告失败。然而，分离出了[Mo(κGe - 4)(CO) ]（8）和[W(κGe - 4)(CO) ]（9）的晶体固体，并通过常用光谱技术对其进行了全面表征（8通过X射线衍射）。对一系列模型化合物进行了密度泛函理论（DFT）计算，以阐明[Rh(κE - qE)(CO)Cl]类型的中性和阳离子双金属配合物（qE = [Fc(NPh)E]，E = C、Si、Ge）中金属原子之间可能的相互作用。在对计算出的配合物进行计算机模拟氧化时，配位的基于Fc的金属配体（qE/qE ）的键合特性受到强烈影响。氧化后，计算出的托尔曼电子参数（TEP）显著增加，从大约20 cm（E = C）增加到25 cm（E = Si、Ge）。氧化后配体供体能力的变化主要可归因于库仑效应，而基于轨道的相互作用似乎影响较小。
