Study on the structure and vibrational spectra of efavirenz conformers using DFT: Comparison to experimental data

Mishra, Soni and Tandon, Poonam and Ayala, AP (2012) Study on the structure and vibrational spectra of efavirenz conformers using DFT: Comparison to experimental data. In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 88 . pp. 116-123.

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Abstract

Efavirenz, (S)-6-chloro-4-(cyclopropylethynyl)-1,4-dihydro-4-(trifluoromethyl)-2H-3 ,1-benzoxazin-2-one, is an anti HIV agent belonging to the class of the non-nucleoside inhibitors of the HIV-1 virus reverse transcriptase. A systematic quantum chemical study of the possible conformations, their relative stabilities and vibrational spectra of efavirenz has been reported. Structural and spectral characteristics of efavirenz have been studied by vibrational spectroscopy and quantum chemical methods. Density functional theory (DFT) calculations for potential energy curve, optimized geometries and vibrational spectra have been carried out using 6-311++G(d,p) basis sets and B3LYP functionals. Based on these results, we have discussed the correlation between the vibrational modes and the crystalline structure of the most stable form of efavirenz. A complete analysis of the experimental infrared and Raman spectra has been reported on the basis of wavenumber of the vibrational bands and potential energy distribution. The infrared and the Raman spectra of the molecule based on OFT calculations show reasonable agreement with the experimental results. The calculated HOMO and LUMO energies shows that charge transfer occur within the molecule. (C) 2011 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Efavirenz;IR;Raman spectroscopy;HOMO;LUMO
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	29 Mar 2012 11:37
Last Modified:	29 Mar 2012 11:37
URI:	http://eprints.iisc.ac.in/id/eprint/44078

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