| Abstract
| - A detailed mechanism for the trimerization reaction of ethylene to give selectively 1-hexene using a [(η5-C5H4CMe2C6H5)TiCl3/MAO] catalyst has been explored by DFT simulations. It was found that the rate-determining step is the ring-opening reaction of the seven-membered metallacycle, exhibiting a barrier ΔG⧧(298.15 K) of 18.4 kcal/mol.
- In this computational study, we propose a detailed mechanism, which has been exploredby density functional theory simulations, for the trimerization reaction of ethylene to giveselectively 1-hexene using a [(η5-C5H4CMe2C6H5)TiCl3/MAO] catalyst. For ring-openingreactions we distinguish between agostic assisted β-hydrogen transfer and hydride formation.With the B3LYP functional it was found that the rate-determining step is the ring-openingreaction of the seven-membered metallacycle, exhibiting a barrier ΔG⧧(298.15 K) of 18.4kcal/mol. It appears that the selectivity of the reaction results from two effects: the stabilizingeffect of the hemilabile phenyl ligand and the ring size of the metallacycle. Upon interchangeof the phenyl group by the labile methyl group, the calculations predict the formation ofpolyethylene, which is in agreement with the experimental data.
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