Synthesis, characterization and density functional theory study of some new 2-anilinothiazoles

We report here a comparative theoretical and experimental study of anilinothiazoles. The anilinothiazoles are synthesized by acid catalyzed condensation of N-phenylthioureas and 2-chloro-1,1-dimethoxyethane. Substituted anilines were employed to introduce substitution in 2-anilinothiazoles. The experimental geometric and spectroscopic properties of the anilinothiazoles are compared with the theoretically calculated ones. The model developed here comprises of geometry optimization at B3LYP method of DFT at 6-31+G(d) basis set. The optimized geometric parameters of anilinothiazoles show nice correlations with values obtained from X-ray crystal structure. Differences of up to 0.02 Å in bond length and 1.0° in bond angles are observed except SC2N6 and C7N6C2 where this difference is 1.77° and 6.01°, respectively. The vibrational spectra are calibrated with a common scaling factor of 0.9613 and show nice correlations with the experimental IR spectra. The UV–Vis spectra calculated at 190–450 nm range show 20–25 nm difference from the experimental spectra. The consistent difference may be attributed to the condensed phase nature of anilinothiazoles however the theoretical spectra are for single molecules. In addition HOMO, LUMO and the associated band gaps are also calculated and depicted.