Abstract

A spectrophotometric study of the solubilization of crown-substituted magnesium phthalocyaninate (I) has been carried out in an aqueous solution of sodium dodecyl sulfate (II). The experiments have been performed with saturated solutions of I at a thermodynamic equilibrium of a solution with a precipitate of I. The known transition from dimers of I to monomers upon solubilization has been studied in detail. It has been found that monomerization of I begins at concentrations much lower than the critical micelle concentration (CMC) of II, while specific micelles of II are formed with involvement of I dimers at still lower surfactant concentrations. The presence of dimers is also observed when I is dissolved in pure water; the solubility of I has appeared to be 7.38 μM (chemists usually suppose I to be insoluble in water). Extinction coefficients of monomers and dimers of I have been determined in the methodological part of the work. The following thermodynamic characteristics of solubilization have been found on the basis of experimental data: solubilization capacity of micelles, coefficient of solubilizate partition between micelles and an ambient solution, and the standard solubilization affinity of I. The found value of the solubilization capacity as calculated per one molecule of I in a micelle leads to an abnormally large aggregation number (309). One explanation of this fact is the possible development of a bimodal distribution of micelles, at which solubilisate-containing micelles coexist with “empty” micelles; as a result, the average number of solubilizate molecules in a micelle can appear to be smaller than unity.

中文翻译：

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十二烷基硫酸钠溶液中冠取代酞菁镁溶解的热力学研究

摘要

在十二烷基硫酸钠（II）的水溶液中进行了冠取代的酞菁镁（I）增溶的分光光度研究。已经在具有I沉淀的溶液的热力学平衡下用I的饱和溶液进行了实验。已经详细研究了I的二聚体在增溶后向单体的过渡。已经发现，I的单体化开始于比II的临界胶束浓度（CMC）低得多的浓度，而II的特定胶束在更低的表面活性剂浓度下与I二聚体一起形成。当我溶于纯净水中时，也会观察到二聚体的存在。I的溶解度似乎为7.38μM（化学家通常认为I不溶于水）。I的单体和二聚体的消光系数已在工作的方法论部分确定。根据实验数据发现了以下增溶热力学特性：胶束的增溶能力，胶束与环境溶液之间的增溶物分配系数以及I的标准增溶亲和力。胶束中的一个I分子会导致异常大的聚集数（309）。对这一事实的一种解释是，胶束的双峰分布可能会发展，在胶束中含增溶剂的胶束与“空”胶束共存。结果，胶束中可溶物分子的平均数量似乎小于1。