Synthesis, structural characterization and quantum chemical calculations on 1-(isomeric methylbenzoyl)-3-(4-trifluoromethylphenyl)thioureas

The 1-(isomeric methylbenzoyl)-3-(4-trifluoromethylphenyl)thioureas (1–3) have been synthesized using the reaction of 2-methylbenzoyl isothiocyanate, 3-methylbenzoyl isothiocyanate and 4-methylbenzoyl isothiocyanate with 4-aminotrifluorotoluene in dry tetrahydrofuran in good yields. The series of compounds were characterized by FT-IR and Raman (vibrational spectra), multinuclear (1H and 13C) NMR, mass spectrometry and elemental analyses techniques. Structural and conformational properties of compounds 1 and 3 were determined by the X-ray single crystal diffraction. A detailed analysis of the intermolecular actions in the two crystal structures has been performed based on the Hirshfeld surfaces and their two-dimensional fingerprint plots. Different hydrogen bonds were formed in the compounds 1 and 3, which have important impact to the FT-IR spectrum. In addition, vibrational spectral characteristics of compounds 1–3 have been studied by FT-IR and Raman, along with the quantum chemical calculations at the B3LYP/6–311++G (d, p) level of approximation.