Spectroscopic Characterization, Hirshfeld Surface, DFT, and TD-DFT of tert-Butyl Phenethylcarbamate and 1,1-Dimethyl-3-Phenethylurea

• Published in: Journal of applied spectroscopy 2020-09, Vol.87 (4), p.736-744
• Main Authors: Alshammari, M. B., Anouar, E. H., El-Hiti, G. A.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Atomic/Molecular Structure and Spectra; Comparative analysis; Computational chemistry; Conformational analysis; Continuum modeling; Density functional theory; Density functionals; Hydrogen; Hydrogen atoms; Integral equations; Mass spectrometry; NMR; Nuclear magnetic resonance; Physics; Physics and Astronomy; Solvation; Solvent effect; Spectroscopy; Surface analysis (chemical); Time dependence
• ISSN: 0021-9037; 1573-8647
• DOI: 10.1007/s10812-020-01063-6

Tert-butylphenethylcarbamate ( 1 ) and 1,1-dimethyl-3-phenethylurea ( 2 ) were synthesized, and their structures were confi rmed by NMR, FTIR, and mass spectrometry techniques. The experimental spectroscopic data of 1 and 2 were compared with the corresponding calculated ones obtained by density functional theory (DFT) and time-dependent DFT methods, for which the hybrid functionals B3LYP, B3P86, and PBE0 combined with the 6-311++G(d,p) basis set were tested. The solvent effect was considered using the implicit model — integral equation formalism-polarizable continuum model (IEFPCM). Relatively good correlation (R 2 > 90%) was obtained between the experimental and predicted spectral data. The conformational effect on the absorption maximum λ max was negligible, that is, λ max of different conformers varied by less than 0.01 nm. Hirshfeld surface analysis and electrostatic potential calculations of the closest intermolecular contacts between active atoms of 1 and 2 revealed that the closest interactions were between hydrogen atoms of 39.6 and 46.3%, respectively.