Chemisorption of H₈Si₈O₁₂Clusters on Gold:  A Novel Si−H Bond Activation

Formation of Mixed Layers Derived from Functional Silicon Oxide Clusters on Gold

“…After the layer has assembled, the cluster is evacuated from the chamber and ∼5-10% of the layer desorbs in UHV, opening adsorption sites for another adsorbate. The new cluster, D 8 is then admitted into the chamber. It interacts (as an extrinsic precursor) with the layer until a satisfactory adsorption site is found and chemisorbs.…”

“…It interacts (as an extrinsic precursor) with the layer until a satisfactory adsorption site is found and chemisorbs. A hydrogen atom, a byproduct of the chemisorption process, may recombine with an adsorbed H 8 The ∼60% cluster displacement may be correlated with the location of the open adsorption sites that may be necessary for the reaction, those formed when the initial cluster is removed from the UHV chamber ( Figure 1). These "active sites", locations where the displacement reactions begin, may be located on finite size terraces where H (D) diffusion can occur.…”

“…For example, consider the case of an initial layer of H 8 Si 8 O 12 exposed to D 8 Si 8 O 12 clusters (Figure 9). At first, each D 8 When gold is initially exposed to C 6 H 13 -H 7 Si 8 O 12 , the chemisorbed layer is unaffected by a dynamic vacuum (Figure 9). Unlike the behavior observed for H 8 In summary, C 6 H 13 -H 7 Si 8 O 12 blocks these displacement processes.…”

“…At first, each D 8 When gold is initially exposed to C 6 H 13 -H 7 Si 8 O 12 , the chemisorbed layer is unaffected by a dynamic vacuum (Figure 9). Unlike the behavior observed for H 8 In summary, C 6 H 13 -H 7 Si 8 O 12 blocks these displacement processes. It acts as a poison to further modification of the initial layer on the gold surface.…”

“…on freshly evaporated gold surfaces in ultrahigh vacuum (UHV) has been previously characterized by soft X-ray photoelectron (XPS) and reflection-absorption infrared spectroscopies (RAIRS). 8,9 These adsorbates, commonly known as hydridosilsesquioxane clusters, are a volatile, well-defined chemical species that are easily synthesized and can be separated into several sizes of the formula (HSiO 1.5 ) n (n ) 8, 10, 12, remains intact including Cl 8 Si 8 O 12 and (CH 3 ) 8 Si 8 O 12 have also been reported in the literature. 17 Some of the dynamic properties of the silicon oxide cluster monolayer have also been previously discussed.…”