Spectroscopic and quantum chemical studies on 4-acryloyl morpholine

Fourier transform infrared (FTIR) and FT-Raman spectra have been recorded and an extensive spectroscopic investigations have been carried out on 4-acryloyl morpholine (4AM). Theoretical quantum chemical studies have also been performed. From the ab initio and DFT analysis using HF, B3LYP and B3PW91 methods with 6-31G(d,p) and 6-311G++(d,p) basis sets the energies, structural, thermodynamical and vibrational characteristics of the compound were determined. The energy difference between the chair equatorial and chair axial conformers of 4AM have been calculated by density functional theory (DFT) method. The optimized geometrical parameters, theoretical wavenumbers and thermodynamic properties of the molecule are compared with the experimental values. The effect of acryloyl group on the characteristic frequencies of the morpholine ring has been analysed. The mixing of the fundamental modes with the help of potential energy distribution (PED) through normal co-ordinate analysis has been discussed.

Graphical abstract. FTIR and FT-Raman spectroscopic investigations and the theoretical quantum chemical studies on 4-acryloyl morpholine (4AM) have been carried out. From ab initio and DFT analysis the energy, structural, thermodynamical and vibrational properties of the compound were determined. The compound exists in the most stable chair-equatorial conformer. The potential energy scan confirms the most stable chair-equatorial conformer of 4AM. The energy difference between the chair equatorial and chair axial conformers of 4AM have been calculated by DFT method.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► FTIR and FT-Raman investigations of 4-acryloyl morpholine (4AM) were carried out. ► Energy, structural and thermodynamical characteristics of 4AM were determined. ► The potential energy scan confirms the stable chair-equatorial conformer of 4AM. ► Energy difference between chair-equatorial and chair-axial conformers was calculated. ► Effect of acryloyl group on the frequencies of the morpholine ring has been analysed.