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

Redshaw, Carl; Walton, Mark; Michiue, Kenji; Chao, Yimin; Walton, Alex; Elo, Pertti; Sumerin, Victor; Jiang, Chengying; Elsegood, Mark R. J.

Authors

Professor Carl Redshaw C.Redshaw@hull.ac.uk
Professor of Inorganic Materials Chemistry and REF Lead for Chemistry

Mark Walton

Kenji Michiue

Yimin Chao

Alex Walton

Pertti Elo

Victor Sumerin

Chengying Jiang

Mark R. J. Elsegood

Abstract

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.

Journal Article Type Article
Publication Date Jul 21, 2015
Journal Dalton transactions
Print ISSN 1477-9226
Electronic ISSN 1477-9234
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 44
Issue 27
Pages 12292-12303
Institution Citation Redshaw, C., Walton, M., Michiue, K., Chao, Y., Walton, A., Elo, P., …Elsegood, M. R. J. (2015). Vanadyl calix[6]arene complexes: Synthesis, structural studies and ethylene homo-(co-)polymerization capability. Dalton transactions : an international journal of inorganic chemistry / RSoC, 44(27), 12292-12303. doi:10.1039/c5dt00376h
DOI https://doi.org/10.1039/c5dt00376h
Keywords Vanadyl; Calix[6]arene; Ethylene polymerization; Ethylene/1-hexene co-polymerization; Ethylene/propylene co-polymerization; Homogenous; Heterogeneous
Publisher URL http://pubs.rsc.org/en/Content/ArticleLanding/2015/DT/C5DT00376H#!divAbstract
Copyright Statement ©2016 University of Hull
Additional Information Author's accepted manuscript of article which has been published in: Dalton transactions, 2015, v.44, issue 27.

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