کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1231138 1495273 2012 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Vanillin and isovanillin: Comparative vibrational spectroscopic studies, conformational stability and NLO properties by density functional theory calculations
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Vanillin and isovanillin: Comparative vibrational spectroscopic studies, conformational stability and NLO properties by density functional theory calculations
چکیده انگلیسی

This study is a comparative analysis of FT-IR and FT-Raman spectra of vanillin (3-methoxy-4-hydroxybenzaldehyde) and isovanillin (3-hydroxy-4-methoxybenzaldehyde). The molecular structure, vibrational wavenumbers, infrared intensities, Raman scattering activities were calculated for both molecules using the B3LYP density functional theory (DFT) with the standard 6-311++G∗∗ basis set. The computed values of frequencies are scaled using multiple scaling factors to yield good coherence with the observed values. The calculated harmonic vibrational frequencies are compared with experimental FT-IR and FT-Raman spectra. The geometrical parameters and total energies of vanillin and isovanillin were obtained for all the eight conformers (a–h) from DFT/B3LYP method with 6-311++G∗∗ basis set. The computational results identified the most stable conformer of vanillin and isovanillin as in the “a” form. Non-linear properties such as electric dipole moment (μ), polarizability (α), and hyperpolarizability (β) values of the investigated molecules have been computed using B3LYP quantum chemical calculation. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecules.

Figure optionsDownload as PowerPoint slideHighlights
► Geometrical parameters of both vanillin and isovanillin structures were predicted.
► The complete assignments are performed on the basis of the PED.
► Experimental spectra were compared with theoretically simulated spectra.
► HOMO and LUMO energies were calculated.
► Polarizability and first hyperpolarizability of vanillin and isovanillin were calculated.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 95, September 2012, Pages 354–368
نویسندگان
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