Structures of MAO: Experimental Data and Molecular Models According to DFT Quantum Chemical Simulations | Sciact - CRIS-system of Boreskov Institute of Catalysis

Structures of MAO: Experimental Data and Molecular Models According to DFT Quantum Chemical Simulations Full article

Conference

Organometallic Catalysts and Olefin Polymerization
18-22 Jun 2000 , Oslo

Source

Organometallic Catalysts and Olefin Polymerization: Catalysts for a New Millennium
Compilation, Springer Berlin, Heidelberg. 2001. 443 c. ISBN 9783642639876.

Output data

Year: 2001, Pages: 63-71 Pages count : 9 DOI: 10.1007/978-3-642-59465-6_6

Tags

Cage Structure; Oligomerization Degree; Density Functional Theory Quantum Chemical; Catalyst Active Center

Authors

Zakharov Vladimir A. ¹ , Zakharov Ivan I. ¹ , Panchenko Valentina N. ¹

Affiliations

1	Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Prospect Akademika Lavrentieva, 5, Novosibirsk 630090, Russia

A DFT quantum chemical calculations have been performed in order to optimize the geometric and electronic cage structure of polymethylalumoxane (MAO) with oligomerization degree n =12 and find such structures that fit most closely the existing experimental data on the MAO composition and structure. The following peculiarities of the MAO structure were found: i) In “classic” MAO (ratio A1:CH3:O = 1:1:1), which has triple-layer cage structure, the inner layer contains highly reactive bonds Al-O. ii) Reaction between “classic MAO” and trimethylaluminium (TMA) proceeds by the concerted mechanism with the insertion of A1-CH3 groups into these Al-O bonds. The reaction produces “true” MAO showing ratio A1:CH3:O = 1:1.5:0.75. Calculated geometry and electronic structures of “true” MAO with n= 12 are presented. iii) “True” MAO and “classic” MAO exist in equilibrium. Driving force for the formation of “true” MAO is the decrease of enthalpy, and of “classic” MAO is the increase of entropy in the equilibrium reaction between “classic” MAO and A1(CH3)3

Zakharov V.A. , Zakharov I.I. , Panchenko V.N.
Structures of MAO: Experimental Data and Molecular Models According to DFT Quantum Chemical Simulations
In compilation Organometallic Catalysts and Olefin Polymerization: Catalysts for a New Millennium. – Springer Berlin, Heidelberg., 2001. – C.63-71. – ISBN 9783642639876. DOI: 10.1007/978-3-642-59465-6_6ANCAN OpenAlex

Chemical Abstracts:	2001:325829
Chemical Abstracts (print):	135:318733
OpenAlex:	W122828311

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