StatusThe thesis was presented on the 17 March, 2017
Approved by NCAA on the 31 May, 2017
Abstract– 1.20 Mb / in romanian
3.54 Mb /
The present thesis is exposed on 115 pages of basic text, inclusively introduction, three chapters, general conclusions and recommendations, bibliography with 235 references, an annex, 65 figures, 17 tables and 43 equations.The results have been published in 13 scientific papers.
The field of study: 144.01 – Physical Chemistry
The aim of scientific work. This dissertation is dedicated to the theoretic identification of mechanisms controlling the process of hydrogen peroxide decomposition under action of tranzition metal compounds in several intermediate chemical reactions, which are of great significance in biology, medicine and environment.
The research objectives. Quantum chemical modeling of reaction mechanisms in the process of H2O2 decomposition which leads to water and oxygen. Theoretic investigation of catalytic properties of the studied manganese and iron complexes. Theoretic study of different reactions with participation of H2O2 and HO2●, HO● radicals. Identification of mechanisms for H2O2 catalytic decomposition reaction. In order to achieve the proposed objectives, ab initio and DFT theoretical methods have been applied.
Scientific originality and novelty. The theoretic model of hydrogen peroxide decomposition process under the influence of biochemical catalysts [MnII(HCO3)2(H2O)4], [FeII(H2O)6]2+ and [MnIII2(L)2(CH3COO)2(OH)2]2+ has been elaborated by investigation of reaction energy profiles, localization of corresponding transition states and calculation of the hydrogen peroxide O-O bond activation energy. The interaction modality (by direct approach) of species participating in intermediate reactions with free radicals generation (HO● and HO2●), which are active in the general process of hydrogen peroxide decomposition, has been studied.
Scientific problem solved consists in developing original calculation procedures for different quantum systems participating in chemical interactions of complexes of manganese and iron (enzyme) with small molecules and identifying mechanisms of reactions, practical importance. The verification of the methods has been achieved by ab initio and DFT quantum-chemical calculations for some active complexes of Fe(II), Mn(II) and Mn2(III) and also for intermediate reactions which occur during the hydrogen peroxide decomposition process.
Theoretical significance. The results of the thesis provide a profound theoretical knowledge of the mechanisms of studied chemical reactions, which allows to explain the general scheme of the H2O2 decomposition process in the presence of Fe(II), Mn(II) and Mn2(III) complexes with a number of ligands. The original schemes of the mechanism of hydrogen peroxide decomposition have been identified and developed. The hydrogen peroxide activation energy was determined according to developed models.
Applicative value of the present work. On the basis of profound knowledge of investigated mechanisms of the molecular oxygen formation at the cellular level (living cells) a controlled synthesis of materials with desired properties becomes achievable. The studied metal complexes (biochemical catalysts) can be applied in various fields of scientific research and in other areas of human activity such as medicine, enviroment protection, especially for waste water purification, chemical industry, cathalysis, taking into account the high catalytic activity in the process of H2O2 decomposition.
Implementation of scientific results. Modeling of the catalytic hydrogen peroxide decomposition process was included in the curriculum courses „Chemical modeling” and „Information technology in chemistry” and it is used in practical activities at the Biology and Chemistry Faculty of the Tiraspol State University.