The ring stretching vibrations are very much important in
Subashchandrabose et al.  assigned the C–N out-of-plane bending vibration at 664 cm−1 (FT-IR)/666 cm−1 (FT-Raman). The in-plane and out-of plane-bending vibrations of C–N bonds are observed at 988, 743, 674, 619, 529 and 373 cm−1 in B3LYP. The band observed at 634 cm−1 in FT-IR spectrum and band observed at 708 cm−1 in FT-Raman spectrum shows good agreement with the theoretical wavenumber. The TED of C–N bending vibrations lies in the range 10–92%.
In our present study, the band observed at 976 and 1013 cm−1 in B3LYP theoretical wavenumber is assigned to trigonal bending and breathing mode of the phenyl ring and it SKLB1002 shows good agreement with experimental FT-IR medium band at 1014 cm−1 (mode No: 25). It is spores evident from Table 1, in our present study the C–C–C in-plane bending vibrations are observed at 976, 740, 609 and 577 cm−1. The out-of-plane bending vibrations are observed at 486 and 106 cm−1 in theoretically calculated wavenumber. The torsional modes of C–C–C–C in theoretical wavenumber is observed at 674, 486, 404 and 358 cm−1. The vibration observed very strongly at 675 cm−1/FT-IR and 673 cm−1/FT-Raman shows good agreement with calculated torsional modes. The rest of the observed, calculated wavenumber and the corresponding assignment of the title molecule are shown in Table 1.