Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9769900 | Journal of Molecular Structure | 2005 | 14 Pages |
Abstract
The intramolecular hydrogen bond, molecular structure and vibrational frequencies of α-paramethoxyphenyl acetylacetone have been investigated by means of high-level density functional theory (DFT) methods with different basis sets. The geometrical parameters results are compared to the experimental structure obtained from X-ray diffraction experiment and with acetylacetone results. The calculated hydrogen bond strength is 17.33 kcal/mol. The Oâ¯O distance of about 2.450 Ã
in α-paramethoxyphenyl acetylacetone suggests that the hydrogen bond in this compound is stronger than acetylacetone. This conclusion is well supported by the NMR proton chemical shifts and O-H stretching mode at 2639 cmâ1. On the other hand, the results of theoretical calculations show that the paramethoxyphenyl substitution in α position of acetylacetone results in an increase of the conjugation of Ï electrons in the chelate ring. This result is in good agreement with the Gilli's symmetry coordinates. The topological properties of the electron density contributions for intramolecular hydrogen bond in α-paramethoxyphenyl acetylacetone and acetylacetone have been analyzed in term of the Bader theory of atoms in molecules (AIM).
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Heidar Raissi, Farzaneh Farzad, Alireza Nowroozi,