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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >7-Hydroxyflavone Revisited. 2. Substitution Effect on Spectral and Acid-Base Properties in the Ground and Excited States
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7-Hydroxyflavone Revisited. 2. Substitution Effect on Spectral and Acid-Base Properties in the Ground and Excited States

机译：再谈7-羟基黄酮。 2.取代对基态和激发态光谱和酸碱性质的影响

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摘要

Three derivatives of 7-hydroxy-2-phenyl-4H-chro-men-4-one (7-hydroxyflavone), containing chloro, methoxy, and dimethylamino substituents at position 4', were synthesized and investigated from the view of their ground-state and electronically excited-state behavior. Spectral and fluorescent properties in a Wide range of pH/H-0, thermodynamics of the ground and S-1 states, and: kinetics of the excited-state deactivation of the compounds were investigated by means of steady-state electronic absorption, steady-state, and time-resolved fluorescent spectroscopies as well as by computational methods. The results are rationalized from the point of view of the substituent effect. In spite of a similar structure and the same acid base centers, the compounds strongly differ in fluorescence characteristics as well as in the dependence of fluorescent properties on pH/H-0 of the media. Various protolytic/tautomeric forms of the compounds investigated absorb light in the 300-500 nm range and fluoresce in the whole visible range of spectra. The electron-releasing substituents at position 4' of 7-hydroxyflavone immensely affect spectral properties as well as the excited-state thermodynamics and kinetics, whereas the electron-withdrawing Ones cause minimal effect.
机译：合成了7-羟基-2-苯基-4H-色烯-4-酮（7-羟基黄酮）的三个衍生物，它们在4'位置含有氯，甲氧基和二甲基氨基取代基，并从其基础上进行了研究。状态和电子激发态行为。在广泛的pH / H-0范围内具有光谱和荧光性质，基态和S-1状态的热力学以及：化合物的激发态失活动力学是通过稳态电子吸收，状态，时间分辨荧光光谱以及计算方法。从取代作用的观点来看，结果是合理的。尽管具有相似的结构和相同的酸碱中心，但这些化合物的荧光特性以及荧光特性对介质的pH / H-0的依赖性差异很大。所研究化合物的各种蛋白水解/互变异构形式吸收300-500 nm范围内的光，并在整个可见光谱范围内发出荧光。 7-羟基黄酮的4'位置的释放电子的取代基极大地影响光谱性质以及激发态的热力学和动力学，而吸电子的取代基的影响最小。

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