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Ab Initio Studies Of Abstraction Reactions Xhn + Hydrogen (H2) → Xhn+1 + Hydrogen (H) (X = Carbon, Nitrogen, Silicon, Or Phosphorus), Mark S. Gordon, David R. Gano, Jerry A. Boatz
Ab Initio Studies Of Abstraction Reactions Xhn + Hydrogen (H2) → Xhn+1 + Hydrogen (H) (X = Carbon, Nitrogen, Silicon, Or Phosphorus), Mark S. Gordon, David R. Gano, Jerry A. Boatz
Mark S. Gordon
The abstraction reactions CH3 + H2 --+ CH4 + H, SiH3 + H2 --+ SiH4 + H, NH2 + H2 --+ NH3 + H, and PH2 + H2--+ PH3 + H have been studied with a variety of methods, including MCSCF, POL-CI, UMP2, and UMP3. In agreement with the observed thermochemistry, abstraction by methyl radical is found to proceed more easily than by silyl, and the reverse of the last reaction occurs with a very small ( ~ 5.6 kcal/mol) barrier. POL-CI appears to be a consistently reliable approach for this type of reaction.
Are The Silacyclopentadienyl Anion And The Silacyclopropenyl Cation Aromatic?, Mark S. Gordon, Philip Boudjouk, Freidun Anwari
Are The Silacyclopentadienyl Anion And The Silacyclopropenyl Cation Aromatic?, Mark S. Gordon, Philip Boudjouk, Freidun Anwari
Mark S. Gordon
Stabilization energies attributable to aromaticity in the silacyclopentadienyl anion and the silacyclopropenyl cation were found to be small in the former and absent in the latter when calculated from bond-separation reactions employing 3-21G and ST0-2G basis sets. The silacyclopentadienyl anion is approximately 25% as aromatic as the all-carbon analogue whereas silabenzene is more than 80% as aromatic as benzene. The introduction of diffuse functions into the basis sets has only a small effect on these results. The silacyclopropenyl cation is actually destabilized but strain is probably a key factor in the comparison. Also found was that the ST0-2G basis set …