A Study On The Reactions Of3d Transition Metal Monoxides With Benzene And Monochloromethane

The reactions of3d transition metal monoxides MO with benzene andmonochloromethane have been investigated by density functional theoreticalcalculations. By theoretical calculations, the geometry configurations of reactants,products, intermediates and transition states are optimized to find out the ground statestructures of molecular reaction system. We use theoretical calculation method to findout the transition states that may exit in the process, the frequency analysis find thatvarious transition state has a unique virtual frequency. In order to explore thecoordinates to the transition states in the reactions, the intrinsic reaction coordinatemethod （IRC） is used to verify the correlation between the intermediate, transitionstate and product. The reaction mechanism of3d transition metal monoxides reactwith benzene are summarized in Scheme1:The initial step of the early transition metal monoxides and benzene reaction isthe formation of the C6H5MOH metallo hydroxyl molecule with lower energies.Because of the bond energy of early transition metal monoxides is high, when the MOmolecule migrate to the benzene above, these molecules can further isomerized toform high valent products OM-（η6-C₆H₆）. For the later transition metal monoxides,the initial step of the reaction is to generate the OM-（η2-C₆H₆）（M=Cr，Mn，Fe，Cu，Zn） and OM-（η6-C₆H₆）（M=Co，Ni） molecules with lower energy. The bonds of latertransition metal monoxides are weaker than those of early transition metal monoxides.After then, the MO molecule is inserted into the C-H bond of the benzene to form thedivalent complex C6H5MOH with the hydrogen being transferred from the benzene to the O atom of MO.The geometry configurations of reactants, products, intermediates and transitionstates are optimized on the reactions of MnO and FeO with monochloromethane.After then, the calculated results are verified by the method of FTIR in Ar matrixisolation. We find out that the reacts of MnO and FeO with monochloromrthane willspontaneously ot form OM-（ηCl-CH3Cl）（M=Mn，Fe） molecules on annealing. Upon300nm <λ<580nm irradiation, these molecules will finally isomerizes to CH3MOClproducts, which agrees well with the potential energy surfaces that are calculated. Thereaction mechanism of transition metal monoxides MnO and FeO react withmonochloromethane are summarized in Scheme2:MO+CH3Clâ†'OM-（ηCl-CH3Cl）â†'CH3MOCl（M=Mn, Fe）Scheme2...