Decomposition of 1,1-dimethyl-1-silacyclobutane on a tungsten filament - evidence of both ring C-C and ring Si-C bond cleavages

作者：Tong L; Shi Y J^*

来源：Journal of Mass Spectrometry, 2010, 45(2): 215-222.

DOI：10.1002/jms.1712

• reaction mechanisms
• 1,1-dimethyl-1-silacyclobutane
• vacuum ultraviolet laser ionization mass spectrometry
• tungsten
• chemical vapor deposition

The decomposition of 1,1-dimethyl-1-silacyclobutane (DMSCB) on a heated tungsten filament has been studied using vacuum ultraviolet laser single photon ionization time-of-flight mass spectrometry. It is found that the decomposition of DMSCB on the W filament to form ethene and 1,1-dimethylsilene is a catalytic process. In addition, two other decomposition channels exist to produce methyl radicals via the Si-CH(3) bond cleavage and to form propene (or cyclopropane)/dimethylsilylene. It has been demonstrated that both the formation of ethene and that of propene are stepwise processes initiated by the cleavage of a ring C-C bond and a ring Si-C bond, respectively, to form diradical intermediates, followed by the breaking of the remaining central bonds in the diradicals. The formation of ethene via an initial cleavage of a ring C-C bond is dominant over that of propene via an initial cleavage of a ring Si-C bond. When the collision-free condition is voided, secondary reactions in the gas-phase produce various methyl-substituted 1,3-disilacyclobutane molecules. The dominant of all is found to be 1,1,3,3-tetramethyl-1,3-disilacyclobutane originated from the dimerization of 1,1-dimethylsilene.

• 出版日期2010-2