Hyo-Suk Kim

Germanium Compounds Containing Ge═E Double Bonds (E = S, Se, Te) as Single-Source Precursors for Germanium Chalcogenide Materials

New germanium chalcogenide precursors, S═Ge(dmamp)2 (3), S═Ge(dmampS)2 (4), Se═Ge(dmamp)2 (5), Se═Ge(dmampS)2 (6), Te═Ge(dmamp)2 (7), and Te═Ge(dmampS)2 (8), were synthesized from Ge(dmamp)2 (1) and Ge(dmampS)2 (2) using sulfur, selenium, and tellurium powders (dmamp = 1-dimethylamino-2-methyl-2-propanolate, dmampS = 1-dimethylamino-2-methylpropane-2-thiolate). Complexes 1 and 2 were synthesized from metathesis reactions of GeCl2·dioxane with 2 equiv of aminoalkoxide or aminothiolate ligands. Thermogravimetric analysis of complex 1 displayed good thermal stability and volatility. The molecular structures of complexes 2-8 from X-ray single crystallography showed distorted trigonal bipyramidal geometry at the germanium centers. Germanium chalcogenide materials (GeSe and GeTe) were obtained from the thermal decomposition of complexes 5, 6, and 8 in hexadecane. X-ray diffraction patterns exhibited that GeSe and GeTe had orthorhombic and rhombohedral phases, respectively. This study affords a facile method to easily prepare germanium chalcogenide materials using well-designed and stable complexes by thermal decomposition of single-source precursors in solution.

Trinuclear magnesium complexes stabilized by aminoalkoxide ligands

Abstract New magnesium complexes, [Et2Mg3(dmamp)4] (1) and [(CH2=CH)2Mg3(dmamp)4] (2), were prepared by the reaction of alkylmagnesium bromide with sodium 1-dimethylamino-2-methyl-2-propoxide [Na(dmamp)] in THF. Complexes 1 and 2 were characterized by 1H and 13C NMR spectroscopies, FTIR spectroscopy, elemental analysis, and single-crystal X-ray diffraction (XRD) analysis. The XRD analysis showed that these complexes are trinuclear where the alkoxy O is the μ2-O bridge between the Mg ions. Among the three metal centers, the two terminal Mg ions are five coordinate and have a square–pyramidal geometry, whereas the central Mg is four coordinate with a distorted tetrahedral geometry. The combination of ethyl and vinyl groups with sterically bulky aminoalkoxide ligands plays an important role in stabilizing the molecule.