A Study of the Polymerization of Ethylene
on Ti(III) Monocyclopentadienyl Compounds
by the Density Functional Theory Method

D. V. Besedin^†, L. Yu. Ustynyuk, and I. E. Nifant’ev

Faculty of Chemistry, Moscow State University, Leninskie gory, Moscow, 119992 Russia

e-mail: leila_ust@mail.ru

Received June 18, 2007

Abstract—Density functional theory was used to study model ethylene reactions with CpTi^IIIEt⁺A (A =
CH₃B(C₆F₅, or B(C₆F₅; A can be absent) compounds. The polymerization of ethylene on an isolated
CpTiEt⁺ cation is hindered because of equilibrium between the CpTi(C₂H₄)Et⁺ primary complex and the pri-
mary product of CpTiBu⁺ insertion. At the same time, the polymerization of ethylene on CpTiEt⁺A ion pairs
(A = CH₃B(C₆F₅ or B(C₆F₅) is thermodynamically allowed (E from –26.2 to –25.6 kcal/mol and G₂₉₈
from –10.9 to –10.4 kcal/mol) and is not related to overcoming substantial energy barriers (E^# = 8.2–
12.3kcal/mol and = 7.8–13.3 kcal/mol). The degree of polymerization can be low because of the effec-
tive occurrence of polymer chain termination by hydrogen transfer from the polymer chain to the monomer.

DOI: 10.1134/S0036024408110162

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