Crystal and molecular structures of six-coordinate germanium difluorides and dibromides containing lactamomethyl C,O-chelating ligands

The structures of (O−Ge)-bischelate bis(lactamomethyl)difluoro- and-dibromogermanes L⁽ⁿ⁾]₂GeX₂, where L is the bidentate lactamomethyl C,O-chelating ligand,n=5–7 (the size of the lactam ring), and X=F or Br, were studied by X-ray diffraction analysis. The six-coordinate Ge atom in these compounds is involved in two hypervalent X−Ge−O bonds whose parameters are compared with the corresponding values in analogous dichlorides and five-coordinate Ge derivatives. On going from difluorides to dichlorides and then to dibromides, the coordination environment about the Ge atom approaches the ideal octahedron. An analogous effect is observed as the size of the lactam ring increases. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1799–1805, October, 2000.