Early transition metal complexes bearing a C-capped tris(phenolate) ligand incorporating a pendant imine arm: Synthesis, structure, and ethylene polymerization behavior

Wright, Joseph A.; Hughes, David L.; Elsegood, Mark R.J.; Redshaw, Carl; Homden, Damien

Abstract

The ligand 3-[2,2′-methylenebis(4,6-di-tert-butylphenol)-5-tert- butylsalicylidene-(2,6-diisopropyl)phenylimine] (L 1 H 3 ) was reacted with MCl 4 (M = Ti, Zr) or MCl 5 (M = Nb, Ta) to give complexes of the type [MCl 2 (L 1 H 2 ) 2 ] (M = Ti (1); Zr (2)), [NbCl 3 (L 1 H)] (3), or [TaCl 4 (L 1 H 2 )] (4), respectively. Single crystal X-ray diffraction of 1-4 revealed common "iminium" species resulting in zwitterionic complexes. Reaction of [V(Np-tol)(On-Pr) 3 ] with L 1 H 3 afforded [{(VNp-tol)(L 1 H)} 2 (μ-On-Pr) 2 ] (5), and a second complex [(VO) 2 (μ-O)(L 3 H) 2 ] (6) (L 3 H being derived from 3-[2,2′-methylenebis(4,6-di-tert-butylphenol)-5-tert- butylsalicylidene-p-tolylimine]). The condensation reaction between 3-[2,2′-methylenebis(4,6-di-tert-butylphenol)-5-tert-butyl-2- hydroxybenzaldehyde] (L 0 H 3 ) and o-phenylenediamine (1, 2-diaminobenzene) afforded two products: a pseudo-16-membered hydrogen bonded macrocyclic structure {1,2-bis-3-[2,2′-methylenebis(4,6-di-tert- butylphenol)-5-tert-butylsalicylidene-benzyldiimine]} (L 5 H 6 ), or the benzimidazolyl bearing ligand (L 6 H 3 ). The reaction of L 5 H 6 or L 6 H 3 with [VO(On-Pr) 3 ] under varying conditions produced the complexes [(VO)(L 5 H 4 )] (7), [(VO) 2 (L 5 H)] (8), or [VO(L 6 H 2 ) 2 ] (9). L 0 H 3 was reacted with a number of anilines to give the proligands {3-[2,2′-methylenebis(4,6-di-tert-butylphenol)-5-tert- butylsalicylidene-R-imine]}, where R = NC 6 H 5 (L 2 H 3 ), NC 6 H 4 -Me (L 3 H 3 ), and NC 6 H 2 -Me 3 (L 4 H 3 ). Reactions of these ligands with [VO(On-Pr) 3 ] formed bischelating complexes of the form [(VO)(L 2-4 H 2 ) 2 ] (10, 11, and 12, respectively). The reaction of L 1 H 3 with trimethylaluminum led to a bis-aluminum complex {(AlMe 2 )[AlMe(NCMe)]L 1 } (13). The ability of complexes 1-12 to polymerize ethylene in the presence of an organoaluminum cocatalyst was investigated. Procatalysts 1 and 2 were found to produce negligible activities in the presence of dimethylaluminum chloride (DMAC) and the reactivator ethyltrichloroacetate (ETA), whereas 3 and 4 were found to be completely inactive for polymerization using a variety of different organoaluminum cocatalysts. Using the combination of DMAC and ETA, complexes 5-12 were found to be highly active catalysts; in all cases, the polymer formed was of high molecular weight linear polyethylene. © 2008 American Chemical Society.

Citation

Wright, J. A., Hughes, D. L., Elsegood, M. R., Redshaw, C., & Homden, D. (2008). Early transition metal complexes bearing a C-capped tris(phenolate) ligand incorporating a pendant imine arm: Synthesis, structure, and ethylene polymerization behavior. Inorganic chemistry, 47(13), 5799-5814. https://doi.org/10.1021/ic702506w

• Journal Article Type: Article
• Acceptance Date: Dec 28, 2007
• Online Publication Date: Jun 5, 2008
• Publication Date: Jul 7, 2008
• Deposit Date: Nov 13, 2014
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Electronic ISSN: 1520-510X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 47
• Issue: 13
• Pages: 5799-5814
• DOI: https://doi.org/10.1021/ic702506w
• Keywords: Physical and Theoretical Chemistry; Inorganic Chemistry
• Public URL: https://hull-repository.worktribe.com/output/468216