Quantum mechanical and spectroscopic (FT-IR, 13C, 1H NMR and UV) investigations of potent antiepileptic drug 1-(4-chloro-phenyl)-3-phenyl-succinimide

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 117; pp. 42 - 53
• Main Authors: Vitnik, Vesna D., Vitnik, Željko J., Banjac, Nebojša R., Valentić, Nataša V., Ušćumlić, Gordana S., Juranić, Ivan O.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 03.01.2014
• Subjects: 1-(4-Chloro-phenyl)-3-phenyl-succinimide; NBO; NMR; TD-DFT; UV–Vis; Vibrational spectra; NMR; NBO; UV–Vis; Vibrational spectra; 1-(4-Chloro-phenyl)-3-phenyl-succinimide; TD-DFT
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2013.07.099

[Display omitted] •Experimental and theoretical vibrational and NMR spectra are investigated.•The PED calculation regarding the normal modes provides a strong support for the frequency assignment.•The absorption spectrum has been calculated in solvent environment using CPCM model.•HOMO–LUMO, NBO and chemical reactivity analysis were also performed.•Molecular electrostatic potential of the title compound was calculated. This study represents an integrated approach towards understanding the vibrational, electronic, NMR, and structural aspects, and reactivity of 1-(4-chloro-phenyl)-3-phenyl-succinimide (CPPS). A detailed interpretation of the FT-IR, UV and NMR spectra were reported. The equilibrium geometry, bonding features, and harmonic vibrational frequencies have been investigated with the help of density functional theory (DFT) B3LYP method using 6-31G(d,p) and 6-311++G(d,p) basis set. The scaled theoretical wavenumber showed very good agreement with the experimental values. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the Gauge-Invariant Atomic Orbital (GIAO) method. Stability of the molecule, arising from hyperconjugative interactions and charge delocalization, has been analyzed using Natural Bond Orbital (NBO) analysis. The results show that ED in the σ* and π* antibonding orbitals and second order delocalization energies E(2) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. UV–Vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were calculated by Time-Dependent DFT (TD-DFT) approach. To estimate chemical reactivity of the molecule, the molecular electrostatic potential (MEP) surface map is calculated for the optimized geometry of the molecule.