title: Structure and vibrational analysis of methyl 3-amino-2-butenoate.
abstract: The molecular structure and vibrational spectra of methyl 3-(amino)-2-butenoate (MAB) and its deuterated analogous, D(3)MAB, were investigated using density functional theory (DFT) calculations. The geometrical parameters and harmonic vibrational wavenumbers of MAB and D(3)MAB were obtained at the B3LYP/6-311++G(d,p) level. The calculated vibrational wavenumbers were compared with the corresponding experimental results. The assignment of the IR and Raman spectra of MAB and D(3)MAB was facilitated by calculating the anharmonic wavenumbers at the B3LYP/6-311G(d,p) level as well as recording and calculating the MAB spectra in CCl(4) solution. The assigned normal modes were compared with a similar molecule, 4-amino-3-penten-2-one (APO). The theoretical results were in good agreement with the experimental data. All theoretical and experimental results indicate that substitution of a methyl group with a methoxy group considerably weakens the intramolecular hydrogen bond and reduces the π-electron delocalization in the chelated ring system. The IR spectra also indicate that in the solid state, MAB is not only engaged in an intramolecular hydrogen bond, but also forms an intermolecular hydrogen bond. However, the intermolecular hydrogen bond will be removed in dilute CCl(4) solution.
authors.affiliation: Department of Chemistry, Ferdowsi University of Mashhad, Mashhad 91779, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Berenji
authors.forename: Sayyed Faramarz
authors.initials: SF
authors.lastname: Tayyari
authors.forename: Mohammad
authors.initials: M
authors.lastname: Rahimizadeh
authors.forename: Hossein
authors.initials: H
authors.lastname: Eshghi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Vakili
authors.forename: Ali
authors.initials: A
authors.lastname: Shiri
mesh_terms: D000588:Amines / Q000737:chemistry; D003437:Crotonates / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D000588:Amines; D003437:Crotonates; D003903:Deuterium