On the electronic origins of barriers to methyl rotation: CNDO/2 calculations on (CH3)2XHn (X = C, Si, N, P, O, S) molecules
✍ Scribed by G. Robinet; C. Leibovici; J.-F. Labarre
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 605 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
CNDO calculations are performed
for the homogeneous series of (CI13)2XH,I compounds (X = C, Si, N, P. 0, S) in order to dererminc the molecular equilibrium configuration.
In agreement with available experimental data, for aI1 investigated molecules, the theoretical energy minimum is found for the (0 = 60", ,& = 60") conformation in which one hydrogen of each methyl group is in the X heavy atoms phne but pointing outside the CXC angle. i\ partitioning of total energy shows that the variations of this quantity arc completely reflected by the wriationm of the interaction energy between non-bonded terms. A more detailed analysis reveals, only for the third-row compounds, the essential role of the interactions between central atom and methyl hydrogens.
* This research VAX partly suggested to us by the works of Gordon [9] about ethane, methylaminc and methyl alcohol. We shall use quite the same approach, mainly from the viewpoint of energy curves analysis.