Panigrahi Mallika, Dash Sukalyan, Patel Sabita, Behera P K, Mishra B K
Centre of Studies in Surface Science and Technology, Department of Chemistry, Sambalpur University, Jyoti Vihar, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Nov;68(3):757-62. doi: 10.1016/j.saa.2006.12.057. Epub 2007 Jan 8.
The influence of solvent polarity on the electronic transition of four different N-hexadecyl styrylpyridinium dyes has been investigated in 15 solvents. The E(T)(30) scale has been used to propose a quantitative approach towards the relative stability of the electronic ground and excited state species. The extents of contribution of dipolar aprotic solvents towards the solvation of the excited species have been determined to be 42-48% for some of the dyes. Instead of a steady solvatochromism, all the dyes suffer a reversal in solvatochromism. The transitions of the solvatochromism, referred to as solvatochromic switches, are found to be at E(T)(30) values of approximately 50 for methyl and N,N-dimethylamino substituted dyes while at 37.6 for hydroxyl substituted dye and approximately 45 for 4-(1-methyl-2-phenylethenyl) pyridinium dye. A reversal in the trend of solvent effect in the later dye corresponding to 4-(4-methyl styryl)pyridinium dye has been attributed to an analogy of series and parallel electron flow.
在15种溶剂中研究了溶剂极性对四种不同的N-十六烷基苯乙烯基吡啶鎓染料电子跃迁的影响。已使用E(T)(30)标度提出一种针对电子基态和激发态物种相对稳定性的定量方法。对于某些染料，已确定偶极非质子溶剂对激发态物种溶剂化的贡献程度为42 - 48%。所有染料均未呈现稳定的溶剂化显色现象，而是出现了溶剂化显色反转。溶剂化显色反转（称为溶剂化显色开关）被发现，对于甲基和N,N-二甲基氨基取代的染料，其发生在E(T)(30)值约为50时；对于羟基取代的染料，发生在E(T)(30)值为37.6时；对于4-(1-甲基-2-苯乙烯基)吡啶鎓染料，发生在E(T)(30)值约为45时。与4-(4-甲基苯乙烯基)吡啶鎓染料对应的后一种染料中溶剂效应趋势的反转归因于串联和并联电子流的类比。
