Theoretical Study On The Structure-function Of Intermidates In Two Typical Reactions In Nonheme Biomimetic Research

Mononuclear nonheme has widely application value in the field of biology,environment, and medicine etc which can catalyze many reactions such ascarbon-carbon bond cleavage of aliphatic hydrocarbon， aromatic hydrocarbon、hydroxylation of alkanes and aromatic hydrocarbons, olefin halogenation, epoxidation，hydroxylation, sulphide oxidation reaction and so on. Although a series of experimentaland theoretical research which can fill a lot of missing details have been conducted, alot of controversies still exist in the mechanism of enzyme catalytic reaction. Theenzymatic mechanisms of two typical mononuclear nonheme enzymes have beenanalyzed in the paper. One is the mechanism of the sulfoxidation of sulfide by nickelacylperoxo complex [Ni-(TpCF3Me)(κ2-mCPBA)] under the coexist of them-chloroperbenzoic acid(mCPBA). The other is the oxidative decarboxylation of [(TpPh)-FeII(benzilate)] in the presence of benzilic acid and oxygen. Density functional theory(DFT)calculations have been performed for the two typical system and the conflict onthe mechanism have been deeply studied and solved. Beside, the fast step of thereaction and mainly spin multiplet have been predicted. The mechanism would havevital significance for the synthesis of corresponding bionic compound as well as thedevelopment of related medicine. The main contents are as follows:In the first chapter the general research situation of the nonheme enzyme as well asthe research situation of two major enzymes including Rieske dioxygenase enzyme andP450enzyme have been mainly summarized. The main research content、topic selectionbasis were also listed.In the second chapter the quantum chemistry calculation method including thedensity functional theory、transition state theory and the two-state reactivity theory(TSR)have been mainly summarized.In the third chapter the mechanism of the sulfoxidation by nickel acylperoxocomplex has been studied and the mechanism research development with and without acid has been summarized. The DFT methods was applied to study the mechanism ofthe sulfoxidation in the presence of sulfide by nickel acylperoxo complex[Ni-(TpCF3Me)(κ2-mCPBA)] under the addition of the m-chloroperbenzoicacid(mCPBA). Both the concerted and radical stepwise mechanisms have been studied.The results indicated that the former was much favored to the latter due to its lowerenergy barriers.In the fourth chapter the mechanism of oxidative decarbonylation reaction ofbiomimic Fe(II) compounds has been studied in the presence of oxygen and benzilicacid. Two kinds of basis set level were performed. The calculation results at two basislevels were discussed which showed that the oxidative decarbonylation reaction ofbiomimic Fe(II) compounds in the presence of oxygen and benzilic acid was aconcerted reaction at both basis levels. The hydrogen transfer and carbon-carbon bondsbroken were taken place at the same time. Then two controversial oxidant wereconducted with sulfoxidation reaction in the presence of sulfide in the solvent benzeneand the real oxidant was figured out. Besides, the two kinds of basis set level werecompared and discussed which found that larger basis set should be chose for atomswhich have larger electronegativity.In the fifth chapter the main contents of the paper have been summarized. Besides,the deficiency of this article and late work are expounded and prospected.