Ethylene And Cis -2 - Butene Into The Detailed Reaction Mechanism Of The Two Cyclopentadienyl Zirconium Hydride In Zirconium Hydrogen Bond,

In this paper,the model reaction mechanisms of Cp₂ZrH₂(derived from Cp₂ZrH₂)with ethylene and cis-2-butene were investigated,respectively,by using B3LYP level of density functional theory(DFT)calculations.The molecular structures and bonding involved in the reaction mechanisms were analyzedThe mechanistic study on insertion of ethylene into the Zr-H bond of Cp₂ZrH₂ to give Cp₂Zr(H)(CH₂CH₃)is performed,with the aid of density functional theory calculations.Two possible insertion pathways are proposed.One is the side-insertion and the other is the central-insertion. For the side-insertion path,the rate-determining step is the ethylene insertion step.For the central-insertion path,the rate-determining step is formation of the adduct by Cp₂ZrH₂ and ethylene. Our results of calculations predicted that the central-insertion path is preferred kinetically over the side-insertion path.Two types of Zr…H-C agostic interactions having different stability are described.The detailed mechanisms for reaction of Cp₂ZrH₂ with cis-2-butene were explored with the aid of density functional theory calculations.Two possible pathways for olefin insertion into the Zr-H of Cp₂ZrH₂ were proposed.One is the side-insertion and the other is the central-insertion. The central-insertion is theoretically predicted to be more favorable kinetically than the side-insertion.It is revealed that formation and cleavage of Zr…H-C agostic interaction,andβ-hydrogen elimination are requisite steps in addition to the olefin insertions.The side-agostic and the central-agostic interactions are found to be involved in some intermediates.The former agostic is less stable than the latter,which plays a role in describing which path is preferred.