Monomeric germanium(II) amides bearing β-diketiminato ligands: Synthesis, structural characterization, and thermal properties

Germanium(II) compounds featuring β-diketiminate-type ligands are attractive for applications as nanoparticle precursors, imaging agents, and components of electronic devices. In this work, we report the synthesis of β-diketiminatogermanium(II) amides LGe(NHPh) [1, L = {HC(CMeN-2,4,6-Me₃C₆H₂)₂}^-], LGe(4-NHPy) (2), LGe(2-NHPy) (3), and LGe(2-NHPy) (4), L = {HC(CMeN-2,6-iPr₂C₆H₃)₂}^-], which were obtained by the reaction of a low-valent organogermanium halide (LGeCl or LGeCl) with a lithium salt of the respective aromatic amine (LiNHPh) or aminopyridine [Li(4-NHPy) and Li(2-NHPy)]. Compounds 1-4 were characterized with several techniques such as melting point, FTIR, ¹H and ¹³C NMR spectroscopy, elemental analysis, X-ray diffraction, and thermogravimetric analysis (TGA). Compounds 1-3 and 4 crystallized in the orthorhombic (space group Pnma) and monoclinic (space group P2₁/c) crystal systems, respectively. In all cases, the geometry around the central germanium atom was highly tetrahedrally distorted. According to TGA data, 1-4 do not sublime intact but rather exhibit thermal decomposition.