Identification of structural and spectral properties of synthesized 3-(p-isopropylphenyl)-5-(o,m,p-nitrophenyl)-1-phenylformazans: A combined experimental and DFT study

The fomazan compounds 3-(p-isopropylphenyl)-5-(o,m,p-nitrophenyl)-5-phenylformazans (1-3) have been synthesized and characterized by FTIR, UV-Vis and ¹H NMR spectroscopic techniques and elemental analysis. Quantum chemical calculations of the molecular structures, vibrational frequencies, gauge including atomic orbital ¹H chemical shift values were carried out using the density functional B3LYP method with the 6-311 + G(d,p) basis set. The TD-DFT calculations were carried out using the B3LYP, CAM-B3LYP and PBE1PBE functionals with the 6-311 + G(d,p) basis set to determine the maximum absorbtion wavelength of the UV-Vis spectra for (1-3). The non-linear optical properties are addressed theoretically. Besides, DFT calculations of the molecular electrostatic potential, the natural bond orbital and thermodynamic properties of (1-3) were carried out at the B3LYP/6-311 + G(d,p) level of theory.