Rangan Sylvie, Bournel Fabrice, Gallet Jean-Jacques, Kubsky Stefan, Le Guen Karine, Dufour Georges, Rochet François, Sirotti Fausto, Piaszenski Guido, Funke Ralf, Kneppe Martin, Köhler Ulrich
Laboratoire de Chimie Physique Matière et Rayonnement, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France.
J Phys Chem B. 2005 Jul 7;109(26):12899-908. doi: 10.1021/jp051725y.
Using a combination of local -- scanning tunneling microscopy -- and spatially integrated, but chemically sensitive probes -- X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy -- we have examined how 3-butenenitrile reacts with the Si(001)-2 x 1 surface at room temperature. Electron spectroscopies indicate three different nitrogen chemical bonds: a Si-C=N-Si bond, a C=C=N cumulative double bond, and a CN moiety datively bonded to a silicon atom. All molecular imprints detected by scanning tunneling microscopy (STM) involve two adjacent silicon dimers in the same row. The three geometries we propose -- a double di-sigma bonding via the CN and the C=C, a cumulative double bond formation associated with alphaC-H bond dissociation, and a di-sigma vinyl bonding plus a CN datively bonded to a silicon atom -- are all compatible with electron spectroscopies and data. Real-time Auger yield kinetic measurements show that the double di-sigma bonding geometry is unstable when exposed to a continuous flux of 3-butenenitrile molecules, as the Si-C=N-Si unit transforms into a CN moiety. A model is proposed to explain this observation.
我们使用局部扫描隧道显微镜以及空间积分但化学敏感的探针（X射线光电子能谱和近边X射线吸收精细结构光谱）相结合的方法，研究了3-丁烯腈在室温下与Si(001)-2×1表面的反应。电子能谱表明存在三种不同的氮化学键：Si-C=N-Si键、C=C=N累积双键以及与硅原子配位键合的CN基团。扫描隧道显微镜（STM）检测到的所有分子印记都涉及同一行中相邻的两个硅二聚体。我们提出的三种几何结构——通过CN和C=C的双二σ键合、与αC-H键解离相关的累积双键形成以及二σ乙烯基键合加上与硅原子配位键合的CN——都与电子能谱和数据相符。实时俄歇产率动力学测量表明，当暴露于连续的3-丁烯腈分子流中时，双二σ键合几何结构不稳定，因为Si-C=N-Si单元会转变为CN基团。提出了一个模型来解释这一观察结果。
