Rozina Khattak started services in April 2012 as an Assistant Professor in the National Center of Excellence in Physical Chemistry, University of Peshawar in Peshawar, Pakistan. She then joined the Department of Chemistry, Shaheed Benazir Bhutto Women University in Peshawar, Pakistan as an Assistant Professor. She also serves as the Head of Department. She graduated (MSc) in 2003 from the Department of Chemistry, University of Karachi in Karachi, Pakistan. She worked as a research officer in the same department for two years after her graduation. She acquired her PhD degree from the same university in January 2012 with a split PhD experience in 2009 from the Department of Chemistry, Durham University in Durham, UK. She has her expertise in the synthesis of Organic and Inorganic Compounds, kinetics and mechanism. Her research mainly revolves around the kinetic studies of the redox reactions, and to propose their mechanisms.
Structural variation exhibits effects on the properties of transition metal complexes, more specifically, reduction potential and reactivity patterns. A change in the reactivity pattern may lead to alter the redox mechanism and biochemical application of the compounds. This study reveals the mechanisms of the oxidation of acetylferrocene, methylferrocenemethanol, and hexacyanoferrate (II), by dicyanobis (phenanathroline)iron(III), and through comparison, it highlights the effect of structural variation upon the redox behaviour. The reactions were observed to undergo a complex kinetics. The reactions completed in three phases. First phase, when an overall zeroth order kinetics was observed. The reactions followed an overall second order kinetics in the second phase. The third phase was named as a competition phase, because, the rate of reactions and the rate of decrease in the solubility of dicyanobis(phenanthroline)iron(II) competed each other. The reactions, although followed same kinetic orders, but, the rate-controlling species were specific to each phase in each reaction. The medium of reaction(s) and protonation play a vital role in the oxidation process. Protonation of acetylferrocene, methylferrocenemethanol, and hexacyanoferrate(II) yielded FcC+OHMe, FcCHO+H2Me, [HFeII(CN)6]3–, and [H2FeII(CN)6]2–, which oxidized during the reactions. The rate-determining step involved FcC+OHMe during the oxidation of FcCOMe by [FeIII(phen)2(CN)2]+, effect of protons revealed. A reverse phenomenon during the oxidation of FcCHOHMe and [FeII(CN)6]4– by [FeIII(phen)2(CN)2]+, however, helped to demonstrate participation of FcCHO+H2Me, and, [HFeII(CN)6]3– and [H2FeII(CN)6]2– as the rate retarding entities, whilst FcCHOHMe and [FeII(CN)6]4– as the rate controlling species. The influence of ionic strength, dielectric constant, and thermodynamic parameters of activation justified the consequences by providing authentic clues. The rate law(s) has been proposed for each reaction in the view of the results and literature.
Audience Take away:
• The audience will be able to know the detailed kinetics of the three selected redox reactions between iron complexes.
• They will learn the mechanisms of the electron transfer of the three selected systems.
• They will become known that how the structure affects the mechanism of certain process?
• Their knowledge will be enhanced through the highlights of the effects of various factors upon the reactions.
• This study will help them in their research and teaching in Physical Chemistry.