Separation of Dielectric Nonideality from Preferential Solvation in Binary Solvent Systems: An Experimental Examination of the Relationship between Solvatochromism and Local Solvent Composition around a Dipolar Solute
Separation of Dielectric Nonideality from Preferential Solvation in Binary Solvent Systems: An Experimental Examination of the Relationship between Solvatochromism and Local Solvent Composition around a Dipolar Solute
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二元溶剂体系中介电非理想性与优先溶剂化的分离：偶极溶质周围溶剂化显色性与局部溶剂组成之间关系的实验检验
DOI：
10.1021/jp010825a
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发表时间：
2001
影响因子：
2.9
通讯作者：
J. Kauffman
中科院分区：
文献类型：
--
作者：
Mazdak Khajehpour;Carrie M. Welch;K. A. Kleiner;J. Kauffman
二元溶剂体系的介电非理想性是指在溶剂混合物的极性摩尔分数中Onsager反应场函数与线性的偏差。偶极荧光团溶解在一个理想的电介质混合物表现出溶剂化变色位移是线性的溶剂极性摩尔分数在它的溶剂化球。结果，可以容易地从峰位移确定“局部组成”。在这里，我们确定的条件下，这种线性近似是适当的估计偶极溶质周围的本地组合物。在先前的研究中（Khajehpour，M. H.的;考夫曼，J.F. J. Phys. Chem. A 2000，104，7151 - 7159），我们已经证明了介电非理想性对在己烷-乙醇混合物中观察到的ADMA [1-（9-蒽基）-3-（4-N，N-二甲基苯胺）丙烷]的电荷转移激发态的发射峰位移的影响。这种二元溶剂的线性近似失败，和一个更复杂的分析方法，如苏潘的非线性r…
Dielectric nonideality of a binary solvent system refers to the deviation of the Onsager reaction field function from linearity in the polar mole fraction of the solvent mixture. A dipolar fluorophore dissolved in an ideal dielectric mixture exhibits a solvatochromic shift that is linear in the solvent polar mole fraction in it's solvation sphere. As a result, the “local composition” can be easily determined from the peak shift. Here we identify the conditions under which this linear approximation is appropriate for estimating local compositions around dipolar solutes. In a previous study (Khajehpour, M. H.; Kauffman, J. F. J. Phys. Chem. A 2000, 104, 7151−7159), we have demonstrated the influence of dielectric nonideality on the observed emission peak shifts of the charge-transfer excited state of ADMA [1-(9-anthryl)-3-(4-N,N-dimethylaniline)propane] in hexanes−ethanol mixtures. The linear approximation fails for this binary solvent, and a more elaborate method of analysis such as Suppan's nonlinearity r...