Departamento de Química Orgánica, CIHIDECAR - CONICET , Facultad de Ciencias Exactas y Naturales, University of Buenos Aires , 3er Piso, Pabellón 2, Ciudad Universitaria, Buenos Aires 1428 , Argentina.
Dipartimento di Chimica , University of Pavia , Sezione Chimica Organica, v.le Taramelli 12, 27100 Pavia , Italy.
J Org Chem. 2019 Apr 5;84(7):4338-4352. doi: 10.1021/acs.joc.9b00334. Epub 2019 Mar 25.
Irradiation of a series of p-substituted aryl benzoates under N atmosphere in homogeneous and micellar media was investigated by means of steady-state condition and of time-resolved spectroscopy. A notable selectivity in favor of the 2-hydroxybenzophenone derivatives was observed in micellar media. The benzophenone derivatives were the main photoproduct. On the other hand, in homogeneous media (cyclohexane, acetonitrile, and methanol) the observed product distribution was entirely different, viz. substituted 2-hydroxybenzophenones, p-substituted phenols, benzyl and benzoic acid were found. The binding constants in the surfactant were also measured and NOESY experiments showed that the aryl benzoates were located in the hydrophobic core of the micelle. Laser flash photolysis experiments led to the characterization of both p-substituted phenoxy radical and substituted 2-benzoylcyclohexadienone transients in homogeneous and micellar environment.
在氮气气氛下，通过稳态条件和时间分辨光谱法研究了一系列对取代的芳基苯甲酸酯在均相和胶束介质中的辐照。在胶束介质中观察到有利于 2-羟基二苯甲酮衍生物的显著选择性。二苯甲酮衍生物是主要的光产物。另一方面，在均相介质（环己烷、乙腈和甲醇）中，观察到的产物分布完全不同，即取代的 2-羟基二苯甲酮、对取代的苯酚、苄基和苯甲酸。还测量了表面活性剂中的结合常数，并且 NOESY 实验表明芳基苯甲酸酯位于胶束的疏水核中。激光闪光光解实验导致在均相和胶束环境中表征了取代的苯氧基自由基和取代的 2-苯甲酰环己二烯酮瞬态。
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