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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Tautomerism and behavior of 3-hydroxy-2-phenyl-4H-chromen-4-ones (flavonols) and 3,7-dihydroxy-2,8-diphenyl-4H,6H-pyrano[3,2-g]chromene-4,6- diones (Diflavonols) in basic media: Spectroscopic and computational investigations
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Tautomerism and behavior of 3-hydroxy-2-phenyl-4H-chromen-4-ones (flavonols) and 3,7-dihydroxy-2,8-diphenyl-4H,6H-pyrano[3,2-g]chromene-4,6- diones (Diflavonols) in basic media: Spectroscopic and computational investigations

机译：3-羟基-2-苯基-4H-chromen-4-ones（黄酮醇）和3,7-二羟基-2,8-diphenyl-4H，6H-吡喃并[3,2-g] chromene-4的互变异构和行为基本介质中的，6-二酮（Diflavonols）：光谱和计算研究

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摘要

Absorption and emission spectroscopic investigations and computational predictions have shown that neutral molecules of flavonols and diflavonols can exist in the ground and excited states in one or two tautomeric forms stabilized by intramolecular (in aprotic media) or intermolecular (with solvent molecule(s), in protic media) hydrogen bonds. Electronic excitation creates conditions for the transformation of tautomeric forms, accompanied by proton transfer, reflected in fluorescence spectra. Proton transfer is also probable in monoanions of diflavonols in protic media. The OH groups involved in hydrogen bonds exhibit a proton-donating ability characterized by the respective acidity constants. The electronically excited diflavonols are relatively strong acids if they lose one proton. With increasing basicity of the medium, anionic forms occur, which exhibit spectral characteristics and emission abilities different from those of neutral molecules. These features open up possibilities for the analytical use of these compounds as spectral probes sensitive to the properties of liquid phases - from neutral to strongly basic. The less intensively studied diflavonols seem to be more promising than flavonols for these purposes, since they are more lipophilic, polarizable, polar, and sensitive to basic features of the environment.
机译：吸收和发射光谱研究和计算预测表明，黄酮醇和二黄酮醇的中性分子可以一种或两种互变异构形式存在于基态和激发态，这些互变异构形式由分子内（在非质子介质中）或分子间（与溶剂分子一起）稳定。质子介质）氢键。电子激发为互变异构形式的转化创造条件，伴随着质子转移，反映在荧光光谱中。质子介质中二黄酮醇的单阴离子中也可能发生质子转移。涉及氢键的OH基团表现出以各自的酸度常数表征的质子给体能力。如果电子激发的二黄酮醇失去一个质子，则它们是相对强酸。随着介质碱性的增加，出现阴离子形式，其表现出与中性分子不同的光谱特征和发射能力。这些功能为将这些化合物用作对液相特性敏感的光谱探针（从中性到强碱性）的分析可能性提供了可能性。出于这些目的，较少研究的二黄酮醇似乎比黄酮醇更有希望，因为它们更具亲脂性，可极化性，极性且对环境的基本特征敏感。

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