%0 Journal Article
%T MNDO and DFT Computational Study on the Mechanism of the Oxidation of 1,2-Diphenylhydrazine by Iodine
%A Gideon A. Shallangwa
%A Adamu Uzairu
%A Victor O. Ajibola
%A Hamza Abba
%J ISRN Physical Chemistry
%D 2014
%R 10.1155/2014/592850
%X The reaction mechanisms of the oxidation of 1,2-diphenylhydrazine by iodine have been examined using semiempirical and density functional theory methods, the oxidation proceeded via two independent pathways that can be separately monitored. One pathway involved the chain multistep mechanism. The other pathway occurred via a one-step mechanism in which a ¡°cyclic¡± activated complex was formed which on disproportionation gave the products. The one-step ¡°cyclic¡± activated complex mechanism proceeds more rapidly than the chain multistep mechanism. The results were explained by analyses based on computational energetics of the optimised reactants, intermediates, transition states, and products of the reaction of iodine with 1,2-diphenylhydrazine. 1. Introduction 1,2-Diphenylhydrazine is used as an antisludging additive to motor oil, a desuckering agent for tobacco plants, a reductant in the reclamation of rubber, a component of experimental organometallic polymers, an ingredient in photochromic resin compositions, and a component in polymerization reactions [1, 2]. It is also used in the manufacture of hydrogen peroxide [1, 2]. Some 1,2-diphenylhydrazine derivatives are used as flame-retardant agents [3]. Several aryl hydrazine interactions in small molecule complexes have been studied to see how they might react with iron and other substances [4]. Some of the studies found that a 3£¿mM solution of benzene completely disproportionate 6 equivalents of 1,2-diphenylhydrazine into aniline and azobenzene. The effort of study to shift the chemistry in a different direction was only partially successful. Several others [5¨C9] have also reported that the reactions of 1,2-diphenylhydrazine and its derivatives were pH dependent and would yield different products depending on the PH of the reaction medium. These studies [4¨C9] concluded that 1,2-diphenylhydrazine and its derivatives enjoy complicated chemistries that include structural rearrangement and disproportionation and that their interactions with metal ions or inorganic substances are complex and incompletely understood. Although 1,2-diphenylhydrazine is known to be oxidized readily by many oxidants [10¨C17], only in a few other cases have the reaction mechanisms been examined, especially its reaction mechanisms with iodine [14]. It is also noteworthy to state that the various mechanisms proposed were not conclusive and needed to be revisited. Iodine, on the other hand, is an essential component of the human diet, and in fact, appears to be the heaviest required element in a diet. Iodine compounds are useful in
%U http://www.hindawi.com/journals/isrn.physical.chemistry/2014/592850/