二过碘酸合镍(IV)氧化酒石酸钠的动力学

1 引言近年来,关于超常价态过渡金属氧化还原反应动力学的研究逐渐增多。四价镍的各种配合物氧化有机物和低价金属离子的动力学及机理在文献中也有报导.但对Ni(Ⅳ)和高碘酸根的配合物(DPN)氧化有机物的动力学研究尚处于起步阶段.本文采用停止流动分光光度法对DPN在碱性介质中的动力学机理进行了研究。提出了一个包括两组相互平行的两步单电子转移连串反应的反应机理。据此导出了能够解释本文全部实验事实的速率方程,并求得了表观活化参数。

Kinetics of Oxidation of Sodium Tartrate by Ni(IV) Periodate Complex in Aqueous Alkaline Medium

The kinetics and mechanism of electron transfer from sodium tartrate to Ni(Ⅳ) periodate complex have been studied in aqueous alkaline medium using spectroscopic and stopped-flow method. The kinetics exhibits a pseudo first order for the disap-pearance of Ni(Ⅳ) periodate complex when substrate is present in excess. The order for the substrate found is not an integer. Additon of NaIO_4 and NaOH affects the reaction rates. Results are interpreted in terms of a mechanism involving two separated steps of one-electron transfer from the substrate to the species containing Ni(IV). The activation parameters of this reaction have been calculated.