Abstract:

In this work, we carried out theoretical calculations to determine the structureactivity relationship and the properties of two benzoisoxazole derivatives. For the quantum chemical calculations, the Density Functional Theory (DFT) with B3LYP (Becke threeparameter hybrid correlation functional combined with Lee–Yang–Parr correlation functional) and 6-311+G(d,p) basis set were employed both in the gas phase and in different solvents such as toluene, chloroform, THF, DCM, acetone, DMSO. The CPCM (conductorlike polarizable continuum) solvation model was also used to compute condensed-phase energies in solvent systems. The structural parameters (bond lengths, bond angles, and dihedral angles), energetics (the total energies, the zero-point vibrational energies, the frontier orbital energies (EHOMO, ELUMO), and the bandgap energies) and the spectroscopic characteristics (UV, IR, 1H-NMR, and 13C-NMR) of the target molecules were also determined. The results of the calculations were compared with experimental values for molecule 1, which exists in literature. The calculated geometries (bond length, bond angle and dihedral angle) were in a good agreement with the experimental data. In the case of IR frequencies, the scaled calculated frequencies agreed reasonably well with the experimental results. Moreover, there is a good correlation between experimental and calculated proton signals (R² = 0.9769) and carbon signals (R² = 0.9972) of molecule 1.

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