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.

本研究合成了一系列新型硫族化锗前驱体：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)及Te=Ge(dmampS)₂(8)。该系列前驱体以Ge(dmamp)₂(1)与Ge(dmampS)₂(2)为原料，通过单质硫、硒及碲粉参与的反应制得，其中dmamp（1-二甲基氨基-2-甲基-2-丙醇盐，1-dimethylamino-2-methyl-2-propanolate）、dmampS（1-二甲基氨基-2-甲基丙烷-2-硫醇盐，1-dimethylamino-2-methylpropane-2-thiolate）。
配合物1与2可通过GeCl₂·dioxane与2当量的氨基醇盐或氨基硫醇盐配体的复分解反应合成得到。
对配合物1的热重分析结果显示，其具备良好的热稳定性与挥发性。
通过X射线单晶衍射表征的配合物2~8的分子结构表明，锗中心均呈现畸变三角双锥配位几何构型。
以配合物5、6及8为单源前驱体，在十六烷中进行热分解，可制备得到硫族化锗材料GeSe与GeTe。
X射线衍射图谱证实，所得GeSe与GeTe分别具有正交晶相与菱面晶相。
本研究提供了一种简便高效的合成策略，通过设计稳定的单源前驱体，在溶液中经热分解即可便捷制备硫族化锗材料。