Vinylidene (H2C=C) is a member of the family of compounds of composition CH (and isomeric with ethyne, HC≡CH), but it has been observed only transiently—with a lifetime in the region of 0.1 ns. Indeed, no simple (non-base-stabilized) compounds of the type R2E=E have been characterized structurally for any of the group 14 elements. Here we show that by employing the bulky and strongly electron-donating boryl ligand (HCDippN)2B (Dipp, 2,6-iPr2C6H3), a simple monomeric digermavinylidene compound, (boryl)2GeGe, can be synthesized and is stable at room temperature. Both its formation via the two-electron chemical oxidation of the symmetrical Ge0 compound K2[(boryl)GeGe(boryl)] and its subsequent reaction chemistry (for example, with H2), are consistent with a high substituent lability and the accessibility of both 1,1- and 1,2-substitution patterns. Structural and computational studies of [(HCDippN)2B]2GeGe reveal a weak Ge–Ge double bond—the π component of which contributes to the highest occupied molecular orbital (HOMO)—with a Ge-centred lone pair as the HOMO–1.
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This work was supported by the Marie Curie Intra-European Fellowships programme of the European Union (PIEF-GA-2013-622806) and the Engineering and Physical Sciences Research Council (EP/L025000/1).
The authors declare no competing financial interests.
Supplementary information (PDF 1046 kb)
Crystallographic data for compound 1 (CIF 34 kb)
Structure factors file for compound 1 (FCF 547 kb)
Crystallographic data for compound 2 (CIF 8685 kb)
Crystallographic data for compound 3.1/2(C7H8) (CIF 1658 kb)
Crystallographic data for compound 4 (CIF 1630 kb)
Crystallographic data for compound 5 (CIF 1137 kb)
Crystallographic data for compound 6 (CIF 643 kb)
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Rit, A., Campos, J., Niu, H. et al. A stable heavier group 14 analogue of vinylidene. Nature Chem 8, 1022–1026 (2016). https://doi.org/10.1038/nchem.2597
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