| Monovalent silyl cations, four-valence electron reactive intermediates, are investigated. These species possess nearly degenerate two lowest unoccupied molecular orbitals (LUMOs) in addition to their highest occupied molecular orbital (HOMO). This gives them the potential of forming one, two or three bonds simultaneously. One possible route to the generation of these phenylsilicon cation reactive intermediates utilizes 2,3-benzo-1,4,5,6,7-pentaphenyl-7-silanorbornadiene cation as a precursor. Upon fragmentation of the 7-silanorbornadiene cation, 1,2,3,4-tetraphenylnaphthalene (TPN) is formed and PhSi:+ may arise as a coproduct. [Special characters omitted].;Fluoroborates were considered as potential trapping agents due to the strong Si-F bonds that would ultimately result. Trapping reactions involving difluoroborate anions F2BX2 (X = F, Me, Ph) have been screened through density functional theory computational studies. The stepwise process shown below was found to have low activation barriers for both steps in the formation of the trapping product PhSiF2BF2. The first fluoride transfer to silicon is predicted to be a barrierless reaction and insertion of the resulting silylene into the second B-F bond is predicted to proceed with 1-3 kcal/mol barrier. [Special characters omitted]. |
