10.1021/jp801346v.s001
Yuri V. Vishnevskiy
Yuri V.
Vishnevskiy
Natalja Vogt
Natalja
Vogt
Jürgen Vogt
Jürgen
Vogt
Anatolii N. Rykov
Anatolii N.
Rykov
Vladimir V. Kuznetsov
Vladimir V.
Kuznetsov
Nina N. Makhova
Nina N.
Makhova
Lev V. Vilkov
Lev V.
Vilkov
Molecular Structure of 1,5-Diazabicyclo[3.1.0]hexane as Determined by Gas Electron Diffraction and Quantum-Chemical Calculations
American Chemical Society
2008
DABH
MP 2 calculations
boat conformation
Gas Electron Diffraction
NBO
analysis
2008-06-12 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Molecular_Structure_of_1_5_Diazabicyclo_3_1_0_hexane_as_Determined_by_Gas_Electron_Diffraction_and_Quantum_Chemical_Calculations/2934100
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 °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 <i>C<sub>s</sub></i> 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<sup>−1</sup> above the boat form, respectively. The most important semi-experimental geometrical parameters of DABH (<i>r</i><sub>e</sub>, Å and ∠<sub>e</sub>, 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 <i>n</i>(N) → σ*(C−C) anomeric effect. The geometry calculations and NBO analysis have been performed also for the bicyclohexane molecule.