Raman and infrared spectra, conformational stability and Ab initio calculations for n‐propylamine

Abstract

The Raman (3500-10 cm-') and infrared (3500-50 cm-') spectra of gaseous and solid n-propylamine, CH,CH,CH,NH, , and its deuterated analog, CH,CH,CH,ND, , were recorded. Additionally, the Raman spectra of the liquids were measured and qualitative depolarization values were obtained. From the fact that several distinct Raman lines disappear on going from the fluid phases to the solid state, it is concluded that the molecule exists as a mixture of several conformers, with the trans-trans conformer being the most stable form in the solid. The first term indicates the position of the methyl group relative to the CN bond, whereas the second term indicates the position of the lone electron pair on the nitrogen relative to the central CC bond Relying mainly on group frequencies, depolarization data and relative intensities of Raman and infrared bands, a complete vibrational assignment is proposed for the trans-trans conformer. Ab initio calculations were carried out on these molecules, employing both 3-21G and 6-31G* basis sets. The results obtained using these basis sets are compared, and used in normal coordinate calculations. The results of the ab initio calculations support the vibrational assignment, and also indicate that it is the trans-trms and trans-gauche conformers which are the more stable forms of npropylamine and have nearly equal energies. ~~~

FT-IR, NMR spectroscopic and quantum mechanical investigations of two ferrocene derivatives

“…The calculated bond lengths and angles for piperidine, propylamine and ferrocene molecules in Fc-3ppa compound are compared with their previously reported experimental data. The optimized geometric parameters of Fc-3ppa obtained by B3LYP/6-31G(d) method are in good agreement with previously reported data [46][47][48][49][50] as given in Table 1. A brief discussion of the experimental and theoretical NMR and vibrational properties of the title compounds is presented.…”

Molecular mechanics (MM4) study of amines

“…The experimental gas phase vibrational spectra of ammonia, 18 methylamine, [19][20][21][22][23][24] dimethylamine, [25][26][27] trimethylamine, 28,29 ethylamine, 30-33 n-propylamine, [31][32][33] and isopropylamine 24 were used for the optimization of the force parameters in the present work. Many of these have several conformations, all of which were examined, together with the rotational barriers that separate them.…”

Crystal structure and thermal behavior of two new organic monosulfates NH3(CH2)5NH3SO4 1.5H2O and NH3(CH2)9NH3SO4 H2O

“…2). The coordination of sulfurous atoms is (Table 3) 5), respectively, indicating the presence of 'gauche' conformations as shown in n-propylamine [18]. C-C or C-N distances and C-C-C or C-C-N angles in these organic cations are similar to those observed in compounds containing the same organic molecule [19,20].…”