Investigation of Intramolecular Hydrogen Bond in Malonaldehyde Derivatives: An AIM and NBO Study

All the plausible conformations of tautomeric structures (Keto and Enol) of malonaldehyde (MA) havebeen investigated by the Bekes-Lee-Yang-Parr (B3LYP) nonlocal density functional with extended 6-311++G basis set for studying the stability order of conformers and the various possibilities ofintramolecular hydrogen bonding formation. The results show that the chelated enol structur (E11) ismore stable than the order conformers. This is mainly due to the formation of intramolecular hydrogenbond. Furthermore, the effect of halogen substitution (F,Cl and Br) on intramolecular hydrogen bond andπ-electron delocalization were also investigated. The contribution of resonance to the stability of chelatedMA conformers is greater than that of the hydrogen bond energy. Finally, the computational results withAIM and NBO analyses were compared. The topological properties of the electron density contributionsfor various type of intramolecular hydrogen bond have been analyzed in term of the Bader theory ofatoms in molecules (AIM).

کلیدواژه ها:

malonaldehyde (MA) ، intramolecular hydrogen bond ، halogen substitution ، AIM ، NBO