Molecular beam photochemistry of organopolysilanes and organopolygermanes
The molecular beam photochemistry of various polysilanes and polygermanes was investigated. In most cases, the precursor compounds were photolyzed in the nozzle region of a supersonic jet by a 193 nm laser and the photoproducts analyzed downstream by 118 nm photoionization pulses followed by time-of-flight mass spectrometry. The polysilane and polygermane compounds included in this study were PhMeSi(SiMe{sub 3}){sub 2}, PhSi(SiMe{sub 3}){sub 3}, (Me{sub 2}Si){sub 6}, (Me{sub 2}Ge){sub 6}, and 1,3-diphenyl-1,2,2,3-tetramethyl-1,2,3-trisilacycloheptane. The 193 nm photoproducts of PhSiMe{sub 3}, Me{sub 3}SiSiMe{sub 3}, and vinyltrimethylsilane were also examined for comparison purposes. Dimethylsilylene (Me{sub 2}Si:) was directly observed as the major one-photon photoproduct from the cyclic precursors (Me{sub 2}Si){sub 6} and 1,3-diphenyl-1,2,2,3-tetramethyl-1,2,3-trisilacycloheptane. Likewise, dimethylgermylene (Me{sub 2}Ge:) was directly observed in the photolysis of (Me{sub 2}Ge){sub 6}. One-photon photolysis of the noncyclic polysilanes PhMeSi(SiMe{sub 3}){sub 2} and PhSi(SiMe{sub 3}){sub 3}, however, gave radical products derived from the homolytic scission of a single Si-Si bond with little or no evidence of silylene being generated directly. A mechanism explaining the difference in photochemical outcome for cyclic vs noncyclic molecules is presented. Finally, molecular Si{sub 2}C is found to be a ubiquitous product resulting from the multiphoton photochemistry of a number of organosilicon precursors.
- Research Organization:
- Tulane Univ., New Orleans, LA (US)
- Sponsoring Organization:
- US Department of Energy; National Science Foundation
- OSTI ID:
- 20015205
- Journal Information:
- Organometallics, Journal Name: Organometallics Journal Issue: 2 Vol. 19; ISSN 0276-7333; ISSN ORGND7
- Country of Publication:
- United States
- Language:
- English
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