الفهرس 
The electronic Schr?dinger equationOnly 14 pages are availabe for public view
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Abstract
he present work presents a theoretical investigation of the electronic structure and conformational preference of a series of triazolopyrimadines, namely 1,2,4-triazole, [1,2,4]-triazole [4,3-a] pyrimidine, [1,2,4]-triazole [4,3-a] pyrimidine-5-one, 3-acetyl [1,2,4]-triazole [4,3-a] pyrimidine-5-one, 3-acetyl [1,2,4]-triazole [3,4-b] quinazolin-5-one, 3-acetyl-1-phenyl-1H- [1,2,4]-triazole [3,4-b] quinazolin-5(1H)-one, 3-acetyl-1-p-tolyl-1H- [1,2,4]-triazole [3,4-b] quinazolin-5(1H)-one, 3-acetyl-1-(4-methoxy-phenyl)-1H- [1,2,4]-triazole [3,4-b] quinazolin-5(1H)-one, 3-acetyl-1-(4-chloro-phenyl)-1H- [1,2,4]-triazole [3,4-b] quinazolin-5(1H)-one, and 3-acetyl-1-(4-nitro-phenyl)-1H- [1,2,4]-triazole [3,4-b] quinazolin-5(1H)-one.
These molecules are potentially effective and biologically active. The ground state geometries of all studied molecules are optimized at the DFT/B3LYP level of theory using the 6-31G basis set. The effect of ”d” polarization function is explored upon using the 6-31G(d) basis set. It became evident that the effect of ”d” function is very limited and can be negligted in a cost-effective computation. Ground state electronic structural properties and charge density distributions are computed analyzed and discussed. Substituent effects are examined and general trends are drown. The electronic absorption spectra of the studied compounds were measured in polar as well as non-polar solvents. Assignments of the observed transitions were facilitated via molecular orbital computations. The charge-transfer nature of the excited states, their polarizibility and σ/π-polarization were also analyzed and discussed.