Formation, Structure and Reactivity of a Beryllium(0) Complex with Mgδ+−Beδ− Bond Polarization
Berthold C, Maurer J, Klerner L, Harder S, Buchner MR (2024)
Publication Type: Journal article
Publication year: 2024
Journal
DOI: 10.1002/anie.202408422
Abstract
Attempts to create a novel Mg−Be bond by reaction of [(DIPePBDI*)MgNa]2 with Be[N(SiMe3)2]2 failed; DIPePBDI*=HC[(tBu)C=N(DIPeP)]2, DIPeP=2,6-Et2C-phenyl. Even at elevated temperatures, no conversion was observed. This is likely caused by strong steric shielding of the Be center. A similar reaction with the more open Cp*BeCl gave in quantitative yield (DIPePBDI*)MgBeCp* (1). The crystal structure shows a Mg−Be bond of 2.469(4) Å. Homolytic cleavage of the Mg−Be bond requires ΔH=69.6 kcal mol−1 (cf. CpBe−BeCp 69.0 kcal mol−1 and (DIPPBDI)Mg−Mg(DIPPBDI) 55.8 kcal mol−1). Natural-Population-Analysis (NPA) shows fragment charges: (DIPePBDI*)Mg +0.27/BeCp* −0.27. The very low NPA charge on Be (+0.62) compared to Mg (+1.21) and the strongly upfield 9Be NMR signal at −23.7 ppm are in line with considerable electron density on Be and the formal oxidation state assignment of MgII−Be0. Despite this Mgδ+−Beδ− polarity, 1 is extremely thermally stable and unreactive towards H2, CO, N2, cyclohexene and carbodiimide. It reacted with benzophenone, azobenzene, phenyl acetylene, CO2 and CS2. Reaction with 1-adamantyl azide led to reductive coupling and formation of an N6-chain. The azide reagent also inserted in the Cp*−Be bond. The inertness of 1 is likely due to bulky ligands protecting the Mg−Be unit.
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APA:
Berthold, C., Maurer, J., Klerner, L., Harder, S., & Buchner, M.R. (2024). Formation, Structure and Reactivity of a Beryllium(0) Complex with Mgδ+−Beδ− Bond Polarization. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202408422
MLA:
Berthold, Chantsalmaa, et al. "Formation, Structure and Reactivity of a Beryllium(0) Complex with Mgδ+−Beδ− Bond Polarization." Angewandte Chemie International Edition (2024).
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