Novel acid mono azo dye compound: Synthesis, characterization, vibrational, optical and theoretical investigations of 2-[(E)-(8-hydroxyquinolin-5-yl)-diazenyl]-4,5-dimethoxybenzoic acid

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• 作者：Mustafa Sa?mac? ; Hatice Kanbur ?avu? ; Hatice Ar? ; Recep ?ahing?z ; Talat ?zpozan
• 关键词：Azo dye ; Azo-hydrazone tautomerism ; Vibrational analysis ; Geometry optimization ; DFT ; Optical properties
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2012
• 出版时间：November, 2012
• 年：2012
• 卷：97
• 期：Complete
• 页码：88-99
• 全文大小：964 K

文摘

Novel acid mono azo dye, 2-[(E)-(8-hydroxyquinolin-5yl)-diazenyl]-4,5-dimethoxybenzoic acid (HQD), was synthesized by coupling diazonium salt solution of 2-amino-4,5-dimethoxybenzoic acid (DMA) with 8-hydroxyquinoline (HQ). This dye was characterized by UV-vis, IR & Raman, ¹H and ¹³C NMR spectroscopic techniques and elemental analysis. The normal coordinate analysis of HQD was also performed to assign each band in vibrational spectra. DFT (B3LYP and B3PW91) calculations were employed to optimize the geometry, to interpret NMR spectra, to calculate and to determine the stable tautomeric structure of the compound. Natural Bond Orbital (NBO) analysis was performed to investigate intramolecular interactions. The vibrational spectral data obtained from solid phase IR & Raman spectra were assigned based on the results of the theoretical calculations. UV-vis spectroscopic technique was employed to obtain the optical band gap of HQD. The analysis of the optical absorption data revealed the existence of direct and indirect transitions in the optical band gaps. The optical band gaps of HQD have been found 1.95 and 1.90 eV for direct and indirect transitions, respectively.