Abstract: The mechanism of ethylene polymerization on phenoxy-imine (FI) titanium catalysts was studied theoretically to identify the major factors affecting the catalytic activity. Geometry optimizations of FI ligands, octahedral titanium dichloride complexes, active cationic species, and their pi-complexes with ethylene as well as calculations of the energy profile of chain propagation were performed at the BP86-D3 level. We found that the calculated energy gaps between frontier orbitals (HOMO and LUMO) in the active cations of the catalysts correlate with the experimental activity values. High activities of FI catalysts with a-Cumyl groups were attributed to smaller HOMO-LUMO gaps due to hyperconjugation between pi-systems of a-Cumyl and (N-aryl)salicylaldimine moieties in the active cations. The correlation provides a qualitative estimate of the catalytic activity for further design of new FI titanium complexes. (C) 2016 Elsevier B.V. All rights reserved.

Cite: Nikitin S.V. , Nikitin V.V. , Oleynik I.I. , Oleynik I.V. , Bagryanskaya E.G.
Activity of phenoxy-imine titanium catalysts in ethylene polymerization: A quantum chemical approach
Journal of Molecular Catalysis A: Chemical. 2016. V.423. P.285-292. DOI: 10.1016/j.molcata.2016.07.010 WOS Scopus РИНЦ

Dates:

Published print:

Nov 1, 2016

Identifiers:

Web of science	WOS:000383827600033
Scopus	2-s2.0-84978419529
Elibrary	27036118
OpenAlex	W2467627143

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