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Vanadyl calix[6]arene complexes: synthesis, structural studies and ethylene homo-(co-)polymerization capability

journal contribution
posted on 07.09.2015, 13:15 by Carl Redshaw, Mark J. Walton, Kenji Michiue, Yimin Chao, Alex Walton, Pertti Elo, Victor Sumerin, Chengying Jiang, Mark ElsegoodMark Elsegood
Treatment of p-tert-butylcalix[6]areneH6 (L6H6) with in situ [LiVO(Ot-Bu)4] afforded, after work-up, the dark green complex [Li(MeCN)4][V2(O)2Li(MeCN)(L6H2)2]·8MeCN (1·8MeCN). On one occasion, the reaction led to the formation of a mixture of products, the bulk of which differing from 1 only in the amount of solvate, viz. 2·9.67MeCN. The second minor yellow product has the formula {[(VO2)2(L6H2)-(Li(MeCN)2)2]·2MeCN}n (3·2MeCN), and comprises a 1D polymeric structure with links through the L6H2 ligand and Li2O2 units. When the reverse order of addition was employed such that lithium tert-butoxide (7.5 equivalents) was added to L6H6, and subsequently treated with VOCl3 (2 equiv.), the complex {[VO(THF)][VO(μ-O)]2Li(THF)(Et2O)][L6]}·2Et2O·0.5THF (4·2Et2O·0.5THF), which contains a trinuclear motif possessing a central octahedral vanadyl centre linked via oxo bridges to two tetrahedral (C3v) vanadyl centres, was isolated. The calix[6]arene in 4 is severely twisted and adopts a ‘down, down, down, down, out, out’ conformation. Use of excess lithium tert-butoxide led to a complex very similar to 4, differing only in the solvent of crystallization, namely 5·Et2O·2THF. The ability of 1 and 5 to act as pre-catalysts for ethylene polymerization in the presence of a variety of co-catalysts and under various conditions has been investigated. Co-polymerization of ethylene with propylene and with 1-hexene have also been conducted; results are compared versus VO(OEt)Cl2.

History

School

  • Science

Department

  • Chemistry

Published in

DALTON TRANSACTIONS

Volume

44

Issue

27

Pages

12292 - 12303 (12)

Citation

REDSHAW, C. ...et al., 2015. Vanadyl calix[6]arene complexes: synthesis, structural studies and ethylene homo-(co-)polymerization capability. Dalton Transactions, 44(27), pp.12292-12303.

Publisher

© The Royal Society of Chemistry

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2015

Notes

This paper is in closed access.

ISSN

1477-9226

Language

en

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