Transition states for the abstraction reactions of triplet methylene with hydrogen and methane

Journal Article · Wed May 26 04:00:00 EDT 1976 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00427a002· OSTI ID:7185341

Bauschlicher, Jr, C W; Bender, C F; Schaefer, F III

The transition states and barrier heights for the reactions CH/sub 2/(/sup 3/B/sub 1/) + H/sub 2/ ..-->.. CH/sub 3/ + H and CH/sub 2/(/sup 3/B/sub 1/) + CH/sub 4/ ..-->.. CH/sub 3/ + CH/sub 3/ have been predicted using nonempirical electronic structure theory. Earlier work on the CH/sub 2/(/sup 3/B/sub 1/) + H/sub 2/ reaction has been extended by the addition of polarization functions to the earlier double zeta basis set, and the consideration of five additional degrees of freedom in the potential surface. The earlier conclusions remain essentially unchanged; the transition state occurs for a C/sub 2v/ structure and the barrier height is approximately 15 kcal/mole. For the methane abstraction reaction a barrier height approximately 7 kcal/mole higher was found, implying that neither reaction should occur to a significant degree at room temperature. This conclusion is consistent with the bond-energy bond-order (BEBO) calculations of Carr but in disagreement with the modified intermediate neglect of differential overlap (MINDO) predictions of Dewar.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 7185341
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 98:11; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKANES
BOND ANGLE
BOND LENGTHS
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
ELECTRONIC STRUCTURE
ELEMENTS
FLUIDS
HYDROCARBONS
HYDROGEN
INTERMEDIATE STRUCTURE
METHANE
METHYLENE RADICALS
MULTIPLETS
NONMETALS
ORGANIC COMPOUNDS
RADICALS
SADDLE-POINT METHOD
TRIPLETS