Ab Initio Calculations of Propylene Addition to the Metal-Methyl Bond in Titanium and Aluminum Alkyl Complexes | Sciact - CRIS-system of Boreskov Institute of Catalysis

Ab Initio Calculations of Propylene Addition to the Metal-Methyl Bond in Titanium and Aluminum Alkyl Complexes Full article

Journal

Kinetics and Catalysis
ISSN: 0023-1584 , E-ISSN: 1608-3210

Output data

Year: 1997, Volume: 38, Number: 2, Pages: 231-235 Pages count : 5

Tags

OLEFIN POLYMERIZATION; ETHYLENE

Authors

Zakharov I.I. ¹ , Zakharov V.A. ¹ , Zhidomirov G.M. ¹

Affiliations

1	Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences, Novosibirsk, 630090 Russia

The reaction of propylene addition to the aluminum-methyl and titanium-methyl bonds in the H2AlCH3 and H2TiCH3 complexes has been examined by the ab initio SCF MO LCAO method in the valence-split Gaussian basis set. The structures of the transition state (TS) of the insertion reaction, the heats of the pi-complex formation, and the activation energies for the insertion of the coordinated propylene via the mechanisms of 1,2- and 2,1-cis-insertion were calculated. It is shown that a lower value of the free activation energy of the 1,2-addition in comparison with that of the 2,1-addition is determined by lower values of both the activation energy and entropy. It is suggested that the driving force for 1,2-insertion is the polarization of the C=C bond in propylene, due to which the electrostatic interaction in the four-center transition state stabilizes TS-1,2 more strongly than TS-2,1. The calculated results indicate that propylene is characterized by a decrease in reactivity (as compared to ethylene) in the reaction of addition to the M-R bond. This fact may be attributed to a higher position of the pi* orbital of propylene (the stronger pi bond) as compared to ethylene. It is shown that the energy of the antibonding pi* orbital of monomers (acetylene, ethylene, and propylene) can serve as a reactivity index for the reaction of addition to the metal-alkyl bond.

Zakharov I.I. , Zakharov V.A. , Zhidomirov G.M.
Ab Initio Calculations of Propylene Addition to the Metal-Methyl Bond in Titanium and Aluminum Alkyl Complexes
Kinetics and Catalysis. 1997. V.38. N2. P.231-235. WOS Scopus РИНЦ ANCAN

Захаров И.И. , Захаров В.А. , Жидомиров Г.М.
Неэмпирические расчеты реакции присоединения пропилена по связи металл-метил в алкильных комплексах титана и алюминия
Кинетика и катализ. 1997. Т.38. №2. С.254-258. РИНЦ

Submitted:

Nov 3, 1995

Web of science:	WOS:A1997WW73300011
Scopus:	2-s2.0-0642333142
Elibrary:	13263147
Chemical Abstracts:	1997:289236
Chemical Abstracts (print):	126:317705

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