Langner Alexander, Panarello Anthony, Rivillon Sandrine, Vassylyev Oleksiy, Khinast Johannes G, Chabal Yves J
Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
J Am Chem Soc. 2005 Sep 21;127(37):12798-9. doi: 10.1021/ja054634n.
Immobilization of indene ligands onto two types of hydrogen-terminated surfaces, oxide-free Si [H/Si(111)] and oxidized Si [H/SiO2/Si], has been investigated by infrared absorption spectroscopy. The activity of a common catalyst (H2PtCl6) is shown to depend critically on the nature of the solvent. For instance, 2-propanol preferentially reacts with the surface, preventing any ligand attachment. Chlorobenzene is more stable, allowing some ligand attachment, but the H2PtCl6 catalyst also fosters silicon oxidation. In contrast, UV irradiation on oxide-free surfaces promotes a cleaner and more efficient reaction, leading to ligand attachment without substrate oxidation. The complete inactivity of H-terminated surfaces with a thin oxide layer [H/SiO2/Si] suggests that the UV-induced immobilization is mediated solely by the excitation of electron-hole pairs (excitons) in the substrate and is not the result of direct Si-H bond breaking.
通过红外吸收光谱研究了茚配体在两种氢封端表面（无氧化物的硅[H/Si(111)]和氧化硅[H/SiO₂/Si]）上的固定化。结果表明，常用催化剂（H₂PtCl₆）的活性严重依赖于溶剂的性质。例如，2-丙醇优先与表面反应，阻止任何配体附着。氯苯更稳定，允许一些配体附着，但H₂PtCl₆催化剂也会促进硅氧化。相比之下，对无氧化物表面进行紫外线照射可促进更清洁、更高效的反应，从而在不发生底物氧化的情况下实现配体附着。具有薄氧化层的氢封端表面[H/SiO₂/Si]完全无活性，这表明紫外线诱导的固定化仅由底物中电子-空穴对（激子）的激发介导，而不是直接Si-H键断裂的结果。
