Theoretical Study On The Effect Of The Substituted Groups On The Activation Free Energies Of The Substituted Ethylene Catalyzed By MnSalen(O)(R')

Content: B3LYP density functional calculations were carried out to theoretical study on the effect of substituent on the reaction barrier catalyzed by organomanganese complexes. The optimal structures of reactants, transition states and products were obtained. The reaction barriers were then estimated. Our investigation can be divided in three parts:1) The first part is the comparison of the reaction of the complex 1 and 2 with ethylene in order to explain that complex 2 can represent 1 as the catalyst.2) In our second part we choose 2 and CH2=CHR(R=H, Me, Ph, NO2) as reactants to explain that the effects of the substituents of the reactants on the barriers of the first transition state, Calculations results shown that all three reactions are exothermic. The activation free energy is smallest for R=Me.3) Lastly, we choose 2 and 3 with ethylene as reactants to explain that the electronic effects of the manganese on the barriers of the first transition state. The activation free energy is smaller for R=Cl.