Novel derivatives of hypervalent germanium: synthesis, structure, and stability

Abstract

Syntheses of a series of novel germanium complexes, viz. RN(CH₂CH₂NC₆F₅)₂GeHal₂ (1, R = Me, Hal = Cl; 2, R = Me, Hal = Br; 3, R = PhCH₂, Hal = Cl; 4, R = PhCH₂, Hal = Br), as well as MeN[CH₂(2-C₄H₃N)]₂GeHal₂ (5, Hal = Cl; 6, Hal = Br), by the reaction of GeHal₄ with dilithium salts of corresponding triamines 7–9 are presented. PhCH₂N(CH₂CH₂NSiMe₃)₂GeCl₂ (10) was prepared analogously from triamine 11. Other approaches to the synthesized compounds were also tested. Unexpected complexes [N(CH₂CH₂NSiMe₃)₂Ge(Hal)]₂ (12, Hal = Cl; 13, Hal = Br) were obtained by the reaction of GeHal₄ with dilithium salt of Me₃SiN(CH₂CH₂NHSiMe₃)₂ (14). DFT calculations on this reaction were carried out and discussed. Composition and structures of the novel compounds were established by elemental analyses, ¹H, ¹³C, and ¹⁹F NMR spectroscopy. The X-ray structural studies of 1–4 and 12 clearly indicated the presence of a transannular interaction N(ax)→Ge for all studied compounds.