Mechanism Study On Mn,Cu Catalyzed Coupling Reactions And Design Of Metal-Free Hydrogenation Catalysts

Transition-metal complexes are powerful catalysts and are widely applied in organic synthesis,materials chemistry,biochemistry and nanochemistry.Among many transition-metal catalysts,the catalysts with 3d metal as their center developed rapidly in recent years.Compared with the traditional noble metal catalysts,3d metal catalysts are cheaper,less toxic and more environmentally friendly.Therefore,3d metal catalysts are widely concerned in recent years.Transition-metal catalyzed coupling reaction is an important method to construct chemical bonds.In general,there are two mechanisms of C-N coupling reactions:the cross coupling amination and the C-H amination.Compared with the former,C-H amination is more atom economical and environmentally friendly.However,how to realize high regioselective C-H amination is a major challenge for this mechanism.Similar to C-N coupling reactions,transition-metal catalyzed C-C coupling reactions also have different reaction mechanisms.Rearrangement reaction is an important reaction mechanism for C-C coupling reactions.Different from the cross coupling reactions,theoretical studies about the transition-metal catalyzed rearrangement reactions are rare,and the reaction mechanism of the rearrangement reactions remains to be further explored.By means of computational chemistry,we can study the reaction cycle of C-N coupling and C-C coupling,analyze the electronic structures of key structures,understand the source of reaction selectivity,and provide theoretical support for future experimental design.Based on the deep understanding of the experimental mechanism,designing catalysts by using computational methods is also the focus of computational chemistry.Using computational chemistry to design catalysts can easily construct the catalyst's structure and avoid the extensive use of the experimental substrates,which is more environmentally friendly and convenient.For the above content,this paper mainly includes the following three parts:1.The reaction mechanism of Mn^III(ClPc)SbF₆ catalyzed C-H amination was studied.At the same time,we also compared the Mn^III(ClPc)SbF₆ catalytic system with the traditional[Co]NCOOMe catalytic system.The source of the different regioselectivities in the two systems was explained through the analysis of electronic structure and thermodynamics.The hydride transfer(HYT)mechanism which is different from the traditional hydrogen atom transfer(HAT)mechanism was proposed.It is pointed out that the key of the new transfer mechanism lies in the redox active ligand Cl Pc ring in Mn^III(ClPc)SbF₆ catalyst.2.The[2,3]-?rearrangement of allyliciodides and sulfides catalyzed by chiral Cu complex was systematically studied.The catalytic cycle of the two reactions was described in detail,and the similarities and differences between the catalytic mechanisms of the two reactions were compared.On the basis of mechanism study,we also use charge analysis,NCI analysis and energy decomposition analysis to explore the sources of stereoselectivity and regioselectivity of the two reactions.3.Based on the deep understanding of the reaction mechanism,a series of hydrogenation catalysts were designed by using the FLP strategy.Meanwhile,we also took the hydrogenation of acetone to isopropanol as a template,analyzing whether the designed catalysts can successfully catalyze the hydrogenation reaction.