Bjørn H. Ellingsen, K.-M. Marstokk, H. Møllendal
1978
Citations
1
Influential Citations
19
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Two conformations of 2-amino-1-propanol, CH 3 CH(NH 2 )CH 2 OH, each with an intra-molecular hydrogen bond are assigned from the microwave spectrum in the 18.6–39.7 GHz region. Rotamer I has the methyl group approximately anti to the C-O bond; this group is gauche to the C-O bond in conformer II. The OCCN angle is 54° ± 2° in form I and 61.5° ± 2° in II. Hydrogen bond parameters are more favourable in I than in II and I is energetically favoured with ΔG° = −0.58 ± 0.17 kcal mole −1 , Δ H ° = −0.50 ± 0.19 kcal mole −1 , and Δ S ° = 0.3 ± 0.1 e.u. Further conformations are at least 0.5 kcal mole −1 less stable than II. The dipole moment is μ a = 3-03 ± 0.01 D, μ b = 0.54 ± 0.03 D, μ c = 0.57 ± 0.19 D, and μ tot = 3.13 ± 0.05 D, respectively, for I, while μ a = 2.19 ± 0.03 D, μ b = 1.46 ± 0.08 D, μ c = 1.172 ± 0.003 D, and μ tot = 2.88 ± 0.07 D, respectively, for II. Four vibrationally excited states belonging to three different normal modes are assigned for I as are two vibrationally excited states for II, mode frequencies being determined by relative intensity measurements. Centrifugal distortion analyses for the ground vibrational states of the two conformers and the quartic coefficients are reported.