NMR, UV, FT-IR, FT-Raman spectra and molecular structure (monomeric and dimeric structures) investigation of nicotinic acid N-oxide: A combined experimental and theoretical study
| Autor: | Mehmet Karabacak, Ahmet Atac, Caglar Karaca, Etem Kose |
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| Rok vydání: | 2012 |
| Předmět: |
Models
Molecular Magnetic Resonance Spectroscopy Absorption spectroscopy Analytical chemistry Spectrum Analysis Raman Niacin Analytical Chemistry Cyclic N-Oxides symbols.namesake Spectroscopy Fourier Transform Infrared Instrumentation HOMO/LUMO Conformational isomerism Spectroscopy Molecular Structure Chemistry Chemical shift Carbon-13 NMR Atomic and Molecular Physics and Optics Molecular vibration symbols Quantum Theory Physical chemistry Spectrophotometry Ultraviolet Density functional theory Raman spectroscopy Dimerization |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 85:145-154 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2011.09.048 |
| Popis: | In this work, the experimental and theoretical UV, NMR, and vibrational features of nicotinic acid N-oxide (abbreviated as NANO, C(6)H(5)NO(3)) were studied. The ultraviolet (UV) absorption spectrum of studied compound that dissolved in water was examined in the range of 200-800nm. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400cm(-1) and 3500-50cm(-1), respectively. The (1)H and (13)C NMR spectra in DMSO were recorded. The geometrical parameters, energies and the spectroscopic properties of NANO were obtained for all four conformers from density functional theory (DFT) B3LYP/6-311++G(d,p) basis set calculations. There are four conformers, C(n), n=1-4 for this molecule. The computational results identified the most stable conformer of title molecule as the C1 form. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. (13)C and (1)H nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies, were performed by CIS approach. Finally the calculation results were applied to simulate infrared, Raman, and UV spectra of the title compound which show good agreement with observed spectra. |
| Databáze: | OpenAIRE |
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