Stabilized germylenes based on dialkanolamines: Synthesis, structure, chemical properties

A series of novel low valent germanium compounds RN(CHR2CR1R3O)(CHR4CHR5O)Ge 1–13 (R = Me, Ph, Bn; R1, R2, R3, R4, R5 = H, Me, Ph, (CH2)3, (CH2)4, CH2(C6H4)) was obtained via the reaction between Ge[N(SiMe3)2]2 and various dialkanolamines. All new compounds were characterized by elemental analysis, 1H and 13C NMR spectroscopy and in several cases by X-ray diffraction analysis (1, 3, 8, 10). The compounds 1, 3, 8 are dimeric in the solid state due to the formation of intermolecular Ge–O bonds, the complex 10 is monomeric, all compounds possess a transannular Ge–N bond. The reactivity of the germylenes synthesized was investigated in reactions of oxidative insertion (with halogenation reagents, MeI, disulfides), [1 + 4]-cycloaddition, oxidation and in reactions with water and acetic anhydride. Some reactions were investigated by DFT calculations.

Graphical abstractIn the course of this work the new germylenes 1–13 were obtained. Four complexes were investigated by X-ray analysis. In the solid state three of these compounds are dimeric due to intermolecular Ge–O contacts(1, 3, 8) and one compound is monomeric (10).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A series of germylenes based on substituted dialkanolamines was synthesized. ► The germylenes exist as monomers or dimers depending on ligand structure. ► The reactivity of germylenes synthesized was investigated. ► Some reactions were investigated by DFT calculations.