Density functional theory calculations of vibrational frequencies and molecular structure of S-methyl β-N-(4-nitro benzal) methylene dithiocarbazate

The vibrational frequencies and molecular geometry of the title compound are examined theoretically using the density functional theory (DFT) B1LYP, B3LYP, B3P86 and B3PW91 methods. For vibrational frequencies, the correlation coefficients obtained for B1LYP, B3LYP, B3P86, and B3PW91 methods are 0.998, 0.999, 0.998 and 0.998, respectively. B3LYP method provides most satisfactory correlation (CC=0.999) between experimental and calculated fundamental vibrational frequencies. For bond length correlation coefficients for B1LYP, B3LYP, B3P86 and B3PW91 methods are 0.997, 0.996, 0.994 and 0.995, respectively. For bond angle correlation coefficients for B1LYP, B3LYP, B3P86 and B3PW91 methods are 0.954, 0.952, 0.978 and 0.976, respectively. B1LYP and B3P86 yields highest correlation (CC=0.997 and 0.978) for bond length and bond angle, respectively.