Experimental and DFT studies on the vibrational and electronic spectra of 9-p-tolyl-9H-carbazole-3-carbaldehyde

•The FT-IR, FT-Raman spectra and UV–Vis of the title compound have been recorded experimentally.•Optimized geometry, vibrational frequencies, IR and Raman intensities are obtained with RHF and six DFT methods.•The absorption spectra of the compound were computed both in gas-phase and in DMF solution.•The hybridization and covalent effects in polyatomic wave functions has been studied by analysis the NBO.

The compound 9-p-tolyl-9H-carbazole-3-carbaldehyde (HCCD) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV–Vis spectra. The X-ray diffraction study showed that HCCD has a Z-configuration. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°, which is comparable with the calculated result 65° for B3LYP/6-311++G(d, p) method. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with B-based DFT (BLYP, B3LYP and cam-B3LYP) methods, and WB-based DFT (WB97, WB97X and WB97XD) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-(cam)B3LYP/6-311++G(d, p) and PCM-(cam)B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide good descriptions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100–1000 K was determined. The natural atomic hybrids were calculated and discussed.

Graphical abstractDFT study of the structural and spectroscopic properties of HCCD has been reported.Figure optionsDownload full-size imageDownload as PowerPoint slide