Title: 1-Aza-2,4-disilabicyclo[1.1.0]butanes with Superelongated C–N σ-Bonds

Authors: Jiancheng Li*, Daniel J. Goffitzer, Meiyu Xiang, Yilin Chen, Wenjun Jiang, Martin Diefenbach, Hongping Zhu*, Max C. Holthausen*, and Herbert W. Roesky*

Abstract: Two silylene molecules oxidatively react under formal [1 + 2 + 1]-cycloaddition to the C≡N bond of nitriles to yield 1-aza-2,4-disilabicyclo[1.1.0]butanes (L)(Cl)Si[μ-η^1,2-NC(p-RC₆H₄)]Si(Cl)(L) (L = PhC(NtBu)₂, R = CF₃ (2), F (3), Cl (4), Br (5)). The strongly folded bicyclic SiCNSi cores in 2–5 feature inverted bridgehead carbon atoms and superelongated C–N bonds [1.745(12) to 1.801(2) Å], exceeding the lengths of C–N single bonds in known silaaziridines by up to 23%. Detailed bonding analysis discloses C–N bonding interactions, sharing far-reaching similarities with the central C–C bond in [1.1.1]propellane.

Full-Link: https://pubs.acs.org/doi/10.1021/jacs.1c03149