Controlled silicon surface functionalization by alkene hydrosilylation.
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.
Langner
Alexander
A
Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
Panarello
Anthony
A
Rivillon
Sandrine
S
Vassylyev
Oleksiy
O
Khinast
Johannes G
JG
Chabal
Yves J
YJ
D000475:Alkenes / Q000737:chemistry* / Q000528:radiation effects; D008024:Ligands; D015394:Molecular Structure; D012821:Silanes / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects; D012825:Silicon / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D014466:Ultraviolet Rays
D000475:Alkenes; D008024:Ligands; D012821:Silanes; D012825:Silicon