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Molecular structure of 1,5-diazabicyclo[3.1.0]hexane as determined by gas electron diffraction and quantum-chemical calculations.
- Source :
-
The journal of physical chemistry. A [J Phys Chem A] 2008 Jun 12; Vol. 112 (23), pp. 5243-50. Date of Electronic Publication: 2008 May 20. - Publication Year :
- 2008
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Abstract
- The equilibrium molecular structure and conformation of 1,5-diazabicyclo[3.1.0]hexane (DABH) has been studied by the gas-phase electron-diffraction method at 20 degrees C and quantum-chemical calculations. Three possible conformations of DABH were considered: boat, chair, and twist. According to the experimental and theoretical results, DABH exists exclusively as a boat conformation of C s symmetry at the temperature of the experiment. The MP2 calculations predict the stable chair and twist conformations to be 3.8 and 49.5 kcal mol(-1) above the boat form, respectively. The most important semi-experimental geometrical parameters of DABH (r(e), A and angle)e), deg) are (N1-N5) = 1.506(13), (N1-C6) = 1.442(2), (N1-C2) = 1.469(4), (C2-C3) = 1.524(7), (C6-N1-C2) = 114.8(8), (N5-N1-C2) = 107.7(4), (N1-C2-C3) = 106.5(9), and (C2-C3-C4) = 104.0(10). The natural bond orbital (NBO) analysis has shown that the most important stabilization factor in the boat conformation is the n(N) --> sigma*(C-C) anomeric effect. The geometry calculations and NBO analysis have been performed also for the bicyclohexane molecule.
Details
- Language :
- English
- ISSN :
- 1520-5215
- Volume :
- 112
- Issue :
- 23
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry. A
- Publication Type :
- Academic Journal
- Accession number :
- 18491847
- Full Text :
- https://doi.org/10.1021/jp801346v