Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
Department of Chemistry, Chungnam National University , Daejeon 34134, Republic of Korea.
J Am Chem Soc. 2017 Jun 28;139(25):8758-8765. doi: 10.1021/jacs.7b04755. Epub 2017 Jun 15.
Reactions of the (100) surfaces of Ge and Si with organic molecules have been generally understood within the concept of "dimers" formed by the 2 × 1 surface reconstruction. In this work, the adsorption of tert-butyl isocyanide on the Ge(100)-2 × 1 surface at large exposures is investigated under ultrahigh vacuum conditions. A combination of infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments along with dispersion-corrected density functional theory calculations is used to determine the surface products. Upon adsorption of a dense monolayer of tert-butyl isocyanide, a product whose structure resembles a germa-ketenimine (N=C=Ge) with σ donation toward and π back-donation from the Ge(100) surface appears. Formation of this structure involves divalent-type surface Ge atoms that arise from cleavage of the Ge(100)-2 × 1 surface dimers. Our results reveal an unprecedented class of reactions of organic molecules at the Ge(100) surface.
锗和硅的（100）表面与有机分子的反应通常在由 2×1 表面重构形成的“二聚体”的概念内得到理解。在这项工作中，在超高真空条件下研究了在大暴露下叔丁基异氰酸酯在 Ge(100)-2×1 表面上的吸附。红外光谱、X 射线光电子能谱和程序升温脱附实验以及色散校正密度泛函理论计算的结合用于确定表面产物。在吸附单层的叔丁基异氰酸酯后，出现了一种产物，其结构类似于锗亚甲酮亚胺（N=C=Ge），具有向 Ge(100)表面的σ供体和来自 Ge(100)表面的π反馈。这种结构的形成涉及二价类型的表面 Ge 原子，它们是从 Ge(100)-2×1 表面二聚体的裂解中产生的。我们的结果揭示了在 Ge(100)表面上有机分子反应的一个前所未有的类别。
