Dynamics of H/sub 2/ elimination from the methaniminium cation, (CH/sub 2/NH/sub 2/)/sup +/. Isotope effects, translational energy release, and molecular orbital calculations
Various molecular orbital methods have been used to examine possible reaction mechanisms for the unimolecular decomposition (CH/sub 2/NH/sub 2/)/sup +/ ..-->.. (HCNH)/sup +/ + H/sub 2/. Measurements of deuterium isotope effects on the translational energy release indicate the nonequivalence of the two departing hydrogen atoms, as does the reported absence of hydrogen scrambling in the products of this decomposition. The semiempirical calculations and the ab initio calculations up to and including the 6-31G** level predict that the departing hydrogen atoms do become equivalent and indistinguishable and that there will be significant hydrogen scrambling. This paradox is resolved on the grounds that geometries corresponding to stationary points in these calculations would not be stationary were a degree of configuration interaction to be included. The overall conclusion reached is that the transition state for elimination for H/sub 2/ from (CH/sub 2/NH/sub 2/)/sup +/ is an asymmetric nonplanar structure with a geometry not far distant from (CH/sub 3/NH)/sup +/, which is not a stable minimum on the potential surface.
- Research Organization:
- Univ. of New South Wales, Kensington, Australia
- OSTI ID:
- 5419373
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 110:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM
ISOTOPE EFFECTS
ORGANIC NITROGEN COMPOUNDS
DECOMPOSITION
CATIONS
HYDROGEN
MATHEMATICAL MODELS
MOLECULAR ORBITAL METHOD
MOLECULAR STRUCTURE
POTENTIAL ENERGY
THEORETICAL DATA
VIBRATIONAL STATES
CHARGED PARTICLES
CHEMICAL REACTIONS
DATA
ELEMENTS
ENERGY
ENERGY LEVELS
EXCITED STATES
HYDROGEN ISOTOPES
INFORMATION
IONS
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
STABLE ISOTOPES
400201* - Chemical & Physicochemical Properties
400202 - Isotope Effects
Isotope Exchange
& Isotope Separation