Hartree-Fock, Post Hartree-Fock and density functional theory studies on structure and conformational stability of N-Methylen-Formamide (NMF) and substituted compounds of NMF

Theoretical Study on the Self, Water-assisted and Au-to-assisted Dimer Proton Transfer Reaction in the N-Hydroxy-Methylen-Formamide

“…The lengths of the links C=N and C= O, in the trans-cis conformer, correspond in all cases to the localized links by comparing them to the experimental data that we met for C=N in the conjugated imines [2] and the C=O in the formamide's family [3,4]. This is confirmed by the frequencies calculation which gives ν C=N = 1671.82 cm -1 and ν C=O = 1718.75 cm -1 at MP2/6-31G * level [1].…”

“…The structures and frequencies of the equilibrium geometry were discussed briefly in the introduction of this work and in detail by Brahimi et al at the HF, post-HF (MP2) and density functional theory levels for the isolated NHMF [1].…”

“…Both formamide and formamidic forms to the tautomeric equilibrium of formamide molecules are present in the smallest N-acyled imidate NHMF (Figure 1) [1]. The self-proton transfer from O 7 -H 8 to N 2 in the NHMF gives the N-Formyl Formamide (NFF) molecules.…”

“…The importance of the amide functional group is demonstrated by the fact that the amide peptide bond is the basic linkage in peptides and proteins. The NHMF (Figure 1) [1] is the smallest N-acyled Imidate which contains the two amide and oximin forms of the formamide tautomeric equilibrium.…”

“…The conformational energy reaction cis-cis to trans-cis is endothermic of 4.29 kcal/mol at B3LYP/6-31G * level. The change of configuration passes by a transition state which is situated at an energy barrier of 26.20 kcal/mol at HF/6-31G * and 30.65 kcal/mol at B3LYP/6-31G * level [1]. These energies correspond to a rotation around the double bond C 1 =N 2 and are, respectively, two and three times larger than those we find in the literature for the rotation around the bond C 2 -C 3 in the butadiene (13.23 kcal/mol) [5].…”