Grueso E, Alcantara D, Martinez J, Mancera M, Penades S, Sanchez F, Pradogotor R
Department of Physical Chemistry, Faculty of Chemistry, University of Sevilla, C/Profesor García GonzAlez s/N 41012 Sevilla, Spain.
J Phys Chem A. 2007 Oct 4;111(39):9769-74. doi: 10.1021/jp073577c. Epub 2007 Sep 12.
Gold nanoparticles (AuNPs) capped with N-(2-mercaptopropionyl)glycine have been used to study the strength and character of the binding of a cationic metal complex, [Ru(NH3)5pz]2+ (pz = pyrazine), at pH = 8, to these nanoparticles. The strength of the binding has been studied using a kinetic approach consisting of the study of the kinetics of the oxidation of this ruthenium complex by S2O82- at different NaCl concentrations. When the ionic strength increases, the strength of the binding decreases, as a consequence of the partial neutralization of the charge on the AuNPs which, at pH = 8, has the tiopronin residue negatively charged. The increase of the ionic strength also produces a change in the character of the binding, which changes from anticooperative to noncooperative when the ionic strength increases. The nonelectrostatic and electrostatic components of the free energy of binding are determined. From the latter, we have obtained the values of the electrostatic potential differences at the AuNPs/solutions interface.
用N-(2-巯基丙酰基)甘氨酸包覆的金纳米颗粒（AuNPs）已被用于研究阳离子金属配合物[Ru(NH₃)₅pz]²⁺（pz = 吡嗪）在pH = 8时与这些纳米颗粒结合的强度和特性。通过一种动力学方法研究了结合强度，该方法包括研究在不同NaCl浓度下，该钌配合物被S₂O₈²⁻氧化的动力学。当离子强度增加时，结合强度降低，这是由于AuNPs上的电荷部分被中和所致，在pH = 8时，硫普罗宁残基带负电荷。离子强度的增加还会导致结合特性发生变化，当离子强度增加时，结合特性从反协同变为非协同。确定了结合自由能的非静电和静电成分。从后者，我们获得了AuNPs/溶液界面处的静电势差的值。
