Background: The energetic properties and relative aromaticity of some derivatives of Benzamide
(BEA) structure were investigated in which the BEA was substituted by CH3, NO2, CN, Cl and
OCH3 groups in two meta and para positions. For this purpose, density functional theory (DFT) calculations
were applied using B3LYP/6-31+G (d, p) method. The obtained results indicated that the
stability of on the derivatives changed in the order of Cl> NO2> OCH3> CN> CH3 for para and meta
Methods: Density functional theory (DFT) calculations of BEA structure with different para and meta substitutions were
conducted in which geometries, energies, electrophilicity HOMA, HOSE, Aj, and HOMED values were obtained at the
B3LYP/6-31+G(d, p) level.
Results: To calculate the stability of various derivatives of BEA we investigated the electronic energy levels, the values of
relative energy. If the structure with the lowest energy is considered zero, and other structures are measured in term that,
the para and meta stability for both position is obtained as the following: Cl> NO2> OCH3> CN> CH3 (Fig. 3 and 4).
These results suggest that with the increasing of atomic radius of substituted and the reducing of the electronic attraction
power of substituted, at the viewpoint of energy, the structure will be more stable.
Conclusion: Density functional theory calculations in B3LYP/6-31+G (d, p) level of theory on the structure of BEA structure
with various substituent in the para and meta position indicate that from the viewpoint of energy, all of the meta
structures with ER-substituent are more stable than the para structures and BEA structure with EW-substituent are more
stable than the meta structure. Aromaticity indices of BEA derivatives including HOMA, HOMED, HOSE, Aj, NICS (0)
and NICS (1) were calculated in which the aromaticity increased in the order of NO2> CN> Cl> OCH3> CH3 for meta position
whereas, this order for para substitutions was as NO2> CN> Cl> CH3> OCH3. Finally, it was included that placing
EW substituents at both meta and para positions enhance the aromaticity while substituting BEA by ER groups, weakens