الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The optimized geometrical parameters (bond length, angles and dihedral angles) are computed by DFT/B3LYP with 6-31G** as basis set. It is found that the aryl-oxygen bond is shorter and stronger than acyl-oxygen bond. This can be attributed to larger contribution of the lone pair of O9 with the trinitro groups of the picryl ring in resonance. Thus, the aryl-oxygen fission will be more difficult and require higher activation energy compared to the acyl-oxygen bond when subjected to nucleophilic reactions. The presence of electron donating groups such as (p-OMe, p-Me, m-Me) shorten the bond distance of C1-C7 . While the presence of electron withdrawing groups such as (m-Cl, p-NO2) lengthen this bond distance. The calculated dihedral angles between the plane of the aromatic rings and the ester group indicate that the two phenyl rings are neither in same plane nor perpendicular to each other. The ground state properties, namely: energies of the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) levels and the dipole moments of compounds (3a-g) are calculated by B3LYP with 6-31G** basis set. It showed that presence of electron donating group push up the frontier molecular orbitals, while the powerful electron withdrawing nitro group pushes them down. The electron donating groups (e.g. p-OMe, p-Me or m-Me) cause an increase in orbital energy, while the electron withdrawing groups (e.g. p-Cl, m-Cl or NO2) cause decreasing orbital energy. Also the calculations showed that the titled esters have a dipole with positive end at the O9 and a negative end at the aroyl ring except for compound (3g, x = p-NO2) where the negative end is oriented toward the picryl group. Both The Mulliken and NBO charges showed that the carbonyl carbon (C7) is more positively charged than the ipso carbon (C10). The coefficient on the carbonyl carbon and the ipso carbon atom shows that its value is greater for C10 compared to C7.