Effect of molecular environment on the formation kinetics of complexes of malvidin-3-O-glucoside with caffeic acid and catechin.
Effect of molecular environment on the formation kinetics of complexes of malvidin-3-O-glucoside with caffeic acid and catechin.
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DOI：
10.1021/jp811040g
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发表时间：
2009-05
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影响因子：
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通讯作者：
S. Kunsági-Máté;Ashok Kumar;Pratibha Sharma;L. Kollár;M. Nikfardjam
中科院分区：
文献类型：
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作者：
S. Kunsági-Máté;Ashok Kumar;Pratibha Sharma;L. Kollár;M. Nikfardjam
通过记录malvidin的光致发光（PL）信号，研究了malvidin-多酚共色素配合物在水-乙醇混合物中的形成动力学。根据络合物形成的顺序，考察了两种反应通道。两个通道的末端都是由水-乙醇二元混合物形成的相同的malvidin-多酚复合物。然而，在第一种情况下，malvidin-多酚配合物首先在水中形成，然后在用乙醇稀释水溶液后，根据本体溶液组成的变化，其溶剂化壳发生变化。在第二种情况下，将原液配制成二元溶剂混合物；因此，相互作用的物种的双组分溶剂化壳在分子结合之前形成。我们的结果表明，在前一种情况下，络合物的形成速度更快。反应的Arrhenius参数评价表明，第一反应通道的活化能较低，频率因子较高，支持较高的反应速率。这些观察结果适用于分子环境由二元溶液组成的广泛化学领域。特别是，它对酿酒过程产生了重大影响，其中一种改善颜色的方法是基于本工作中所检查的物种的关联。
The formation kinetics of malvidin-polyphenol copigmentation complexes was studied in water-ethanol mixtures by time-dependent recording of the photoluminescence (PL) signal of malvidin. Two reaction channels were examined according to the order of complex formation. Both channels end with the same malvidin-polyphenol complexes formed in binary mixtures of water-ethanol. However, in the first case, the malvidin-polyphenol complexes are formed in water first, and then their solvation shells are altered according to the changed composition of the bulk solutions after the aqueous solution is diluted with ethanol. In the second case, the stock solutions are prepared as binary solvent mixtures; therefore, the bicomponent solvation shells of the interacted species are formed prior to molecular association. Our results show a faster formation of the complexes in the former case. Evaluation of the Arrhenius parameters of the reaction shows that the activation energy of the first reaction channel is lower and the frequency factor is higher, supporting a higher reaction rate. These observations are applicable to a wide range of chemistry where the molecular environment is composed of binary solutions. In particular, it has significant consequences for winemaking procedures, where one method of color improvement is based on the association of the species examined in this work.