Senz A, Gsponer HE
Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Rio Cuarto, 5800, Argentina
J Colloid Interface Sci. 1997 Nov 1;195(1):94-100. doi: 10.1006/jcis.1997.5141.
The luminescence quenching of tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+) by 2-, 3-, and 4-nitrophenol (NO2PhOH), in their protonated forms, has been studied by static and time-resolved techniques in water and sodium dodecyl sulfate (SDS) aqueous solution. In water, the bimolecular rate constants were obtained separately from both techniques and they were coincident. The values were close to the diffusional limit. In the presence of SDS micelles at a fixed detergent concentration, the Stern-Volmer plots of tau0/tau vs quencher total concentration ([Q]t) were linear in the whole range of [Q]t used. However, the Stern-Volmer plots of the ratio I0/I vs [Q]t in SDS micelles showed an upward deviating curve. From these plots of I0/I, the concentrations of the NO2PhOHs in the micellar pseudophase were measured. The treatment of the data of both types of measurements let us determine the association constants (K) of the NO2PhOHs to SDS micelles and the exit (k-) and entrance (k+) rate constants of NO2PhOHs to the micelles. The K values obtained from either static or time-resolved luminescence techniques were in agreement within experimental error. An electron-transfer mechanism was also proposed for the quenching reaction of the excited state Ru(bpy)32+ by nitrophenols in which the metallic complex is oxidized. Copyright 1997 Academic Press. Copyright 1997Academic Press
采用静态和时间分辨技术，在水和十二烷基硫酸钠（SDS）水溶液中研究了质子化形式的2-、3-和4-硝基苯酚（NO2PhOH）对三（2,2'-联吡啶）钌（II）（Ru(bpy)32+）的发光猝灭作用。在水中，通过两种技术分别获得了双分子速率常数，二者一致。这些值接近扩散极限。在固定洗涤剂浓度的SDS胶束存在下，tau0/tau对猝灭剂总浓度（[Q]t）的Stern-Volmer图在所用[Q]t的整个范围内呈线性。然而，SDS胶束中I0/I对[Q]t的Stern-Volmer图显示出向上偏离的曲线。从这些I0/I图中，测量了胶束假相中NO2PhOH的浓度。对两种测量数据的处理使我们能够确定NO2PhOH与SDS胶束的缔合常数（K）以及NO2PhOH进出胶束的速率常数（k-和k+）。从静态或时间分辨发光技术获得的K值在实验误差范围内一致。还提出了一种电子转移机制，用于解释硝基苯酚对激发态Ru(bpy)32+的猝灭反应，其中金属配合物被氧化。版权所有1997年学术出版社。版权所有1997年学术出版社
