Paramagnetic Chloro‐, Alkoxo‐, or Azidovanadium(<scp>IV</scp>) Complexes Supported by an [ONNO]‐Type Amine Bis(phenolate) Ligand

Wolff, Fabien; Lorber, Christian; Choukroun, Robert; Donnadieu, Bruno

doi:10.1002/ejic.200300922

Cited by 32 publications

(30 citation statements)

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“…[15,16] Although vanadium complexes with oxidation numbers from +3 to +5 are known to catalyze ethylene polymerization, the active speEthylene Homo-and Copolymerization Activity of a Series of Vanadium(ii-iv) Catalysts FULL PAPER cies is probably a vanadium(iii) complex. Vanadium(ii) species are generally considered inactive.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, the phenolate groups of the [ONNO] ligand of 6 fold back away from the pendant (dimethylamino)ethyl sidearm; the angle δ between the two planes of the aromatic rings is now about +116°with a molecular structure that has two nonsymmetry-related phenolate rings. Such a helicoidal distortion of the tripodal amino nitrogen donor atom induces a lower symmetry in the ligand framework of 6, as already observed in the solid-state structure of two other [ONNO]-vanadium complexes, [15,16] and seems to arise from the presence of an O-ligated anionic ligand (alkoxo, oxo, acac) in a trans position to the (dimethylamino)ethyl sidearm nitrogen donor atom. Figure 6 presents a summary of the geometry of all the [ONNO]-vanadium compounds that we have prepared.…”

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confidence: 74%

“…[5b,5d-f, 15,16] Bonding distances between the metal center and the O and N donors of [ONNO] are in the range typically observed for such complexes: (i) V-O(phenoxide) distances are ca. 1.9-2.0 Å, which is slightly longer than those of higher oxidation state [ONNO]-vanadium(v/iv) analogues by about 0.1 Å, [14,15] (ii) the two vanadium-nitrogen bonds formed between the metal center and the tripodal amino-N atom and the dimethylamino sidearm N atom have distances that range from 2.…”

Section: X-ray Structure Determinationmentioning

confidence: 97%

“…Following this approach, we recently described the synthesis of a series of oxo-vanadium(v) [15] and vanadium(iv) [16] complexes with the ancillary amine bis(phenolate) (4), Cl (5)}, and we demonstrated interesting features in the solution and the solidstate structure of these unprecedented complexes. To complete our study on this new family of complexes, we wish to report here on the synthesis, and structural characterization, of new vanadium(iii) and vanadium(ii) complexes supported by [ONNO]-type bis(phenoxy)amine ligand, and to compare their ethylene homo-and copolymerization activity with other members of the vanadium(ii-v) complex family.…”

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Ethylene Homo‐ and Copolymerization Activity of a Series of [ONNO]‐Type Amine Bis(phenolate) Based Vanadium(II–V) Catalysts

et al. 2005

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The synthesis and structural characterization of new paramagnetic amine bis(phenolate) [ONNO]-vanadium(III) and -vanadium (II) complexes, V III (acac) [ONNO], V III (Cl) (THF) [ONNO], and V II (TMEDA)[ONNO], is described. These compounds complete the family of [ONNO]-vanadium(IV/V) complexes previously reported. The members of the [ONNO]-vanadium family at various oxidation states that range from vanadium(II) to vanadium(V), in association with IntroductionIn the past decade, a tremendous amount of effort has been devoted to the design of new "non-metallocene" group 4 transition metal complexes because of their importance as α-olefin polymerization catalysts.[1] Particularly, chelating diamide, [1a,2-4] dialkoxide, [1a,5-6] or phenoxyimine [7,8] ligands have been extensively studied as rigid supporting environments for titanium and zirconium complexes, which has resulted in the emergence of a great deal of novel and useful chemistry, including the discovery of highly active olefin polymerization precatalysts. Among these new ligands, chelating, dianionic [ONNO]-type amine bis(phenolate) ligands associated with group 4 metal complexes [5] have proven to be highly active 1-hexene polymerization catalysts, and in some cases, even isospecific living polymerization was possible.[5a] Recently yttrium-[ONNO] complexes have been reported for their catalytic activity in the ring-opening polymerization of ε-caprolactone. [9] Vanadium-based catalysts in homogeneous ZieglerNatta polymerization have been known for about half a century.[10] Although generally less active, their use presents a number of interesting advantages over group 4 metal catalysts: [11] (i) the synthesis of high molecular weight polymers with narrow polydispersity, (ii) the preparation of ethylene/ α-olefin copolymers with high α-olefin incorporation, and (iii) the preparation of syndiotactic polypropylene. The major reason for the low activity of these systems is their deactivation during the polymerization process, probably due to reduction of the catalytically active vanadium species [a] 2850EtAlCl 2 cocatalyst, were studied in the polymerization of ethylene and in the copolymerizations of ethylene-1-hexene and ethylene-norbornene. Poly(ethylene-co-1-hexene) and poly(-ethylene-co-norbornene) were produced with co-monomer content of up to 11 mol-% and 29 mol-% for 1-hexene and norbornene, respectively. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) to low-valent, less active or inactive species. Nevertheless, V(acac) 3 is currently employed in the synthesis of EP (ethylene-propylene) and EPDM (ethylene-propylene-diene monomer) elastomers.As part of an ongoing study of vanadium chemistry with various supporting ligands, [12] and in particular of vanadium complexes for olefin polymerization, we have recently used ancillary diamido ligands with sterically demanding protecting groups [13] or imido ligands [14] on vanadium(iv) complexes as a way to overcome the problem of catalyst deactivation by stabilization of the formal ...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 74%

Section: X-ray Structure Determinationmentioning

confidence: 97%

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confidence: 97%

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Ethylene Homo‐ and Copolymerization Activity of a Series of [ONNO]‐Type Amine Bis(phenolate) Based Vanadium(II–V) Catalysts

et al. 2005

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“…Their specific catalytic properties made them applicable in the production of poly(ethylene-co-propylene) and poly(ethyleneco-propylene-co-diene) elastomers [8,14,15]. Hence, much interest was attracted by postmetallocene complexes which had vanadium as the central metal, both for homoand copolymerization of olefins [5][6][7][15][16][17][18][19][20][21]. Nomura and Wang [7] used (arylimino)(aryloxo)vanadium(V) complexes in ethylene/1-hexene copolymerization.…”

Section: Introductionmentioning

confidence: 99%

Ethylene/1-olefin copolymerization behaviour of vanadium and titanium complexes bearing salen-type ligand

2013

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Ethylene/1-olefin copolymerization using vanadium and titanium complexes bearing tetradentate [O,N,N,O]-type ligand and EtAlCl 2 or MAO as a cocatalyst is carried out. In the presence of the vanadium complex activated with EtAlCl 2 is observed (a) negative ''comonomer effect'', (b) high comonomer incorporation and narrow chemical composition distribution (CCD), (c) unexpected copolymer microstructure, and (d) increased molecular weight of copolymers when compared with the homopolymer. In contrast, titanium catalyst gives copolymers with lower 1-olefin content and broad CCD. Supported complexes show higher activity, lower 1-olefins incorporation and give copolymers with ultra high molecular weights.

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Oxo‐ and Imidovanadium Complexes Incorporating Methylene‐ and Dimethyleneoxa‐Bridged Calix[3]‐ and ‐[4]arenes: Synthesis, Structures and Ethylene Polymerisation Catalysis

Redshaw

Rowan

Warford

et al. 2007

Chemistry A European J

133

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Reaction of [V(X)(OR)3] (X=O, Np-tolyl; R=Et, nPr or tBu) with p-tert-butylhexahomotrioxacalix[3]areneH3, LH3, affords the air-stable complexes [{V(X)L}n] (X=O, n=1 (1); X=Np-tolyl, n=2 (2)). Alternatively, 1 is readily available either from interaction of [V(mes)3THF] with LH3, and subsequent oxidation with O2 or upon reaction of LLi3 with [VOCl3]. Reaction of [V(Np-tolyl)(OtBu)3] with 1,3-dimethylether-p-tert-butylcalix[4]areneH2, Cax(OMe)2(OH)2, afforded [{VO(OtBu)}2(mu-O)Cax(OMe)2(O)2].2 MeCN (42 MeCN), in which two vanadium atoms are bound to just one calix[4]arene ligand; the n-propoxide analogue of 4, namely [{VO(OnPr)}2(mu-O)Cax(OMe)2(O)2].1.5 MeCN (51.5 MeCN), has also been isolated from a similar reaction using [V(O)(OnPr)3]. Reaction of [VOCl3], LiOtBu, (Me3Si)2O and Cax(OMe)2(OH)2 gave [{VO(OtBu)Cax(OMe)2(O)2}2Li4O2].8 MeCN (68 MeCN), in which an Li4O4 cube (two of the oxygen atoms are derived from the calixarene ligands) is sandwiched between two Cax(OMe)2(O)2. The reaction between [V(Np-tolyl)(OtBu)3] and Cax(OMe)2(OH)2, afforded [V(Np-tolyl)(OtBu)2Cax(OMe)2(O)(OH)]5 MeCN (75 MeCN), in which two tert-butoxide groups remain bound to the tetrahedral vanadium atom, which itself is bound to the calix[4]arene through only one phenolic oxygen atom. Reaction of p-tert-butylcalix[4]areneH4, Cax(OH)4 and [V(Np-tolyl)(OnPr)3] led to loss of the imido group and formation of the dimeric complex [{VCax(O)4(NCMe)}2].6 MeCN (86 MeCN). Monomeric vanadyl oxo- and imidocalix[4]arene complexes [V(X)Cax(O)3(OMe)(NCMe)] (X=O (11), Np-tolyl (12)) were obtained by the reaction of the methylether-p-tert-butylcalix[4]areneH3, Cax(OMe)(OH)3, and [V(X)(OR)3] (R=Et or nPr). Vanadyl calix[4]arene fragments can be linked by the reaction of 2,6-bis(bromomethyl)pyridine with Cax(OH)4 and subsequent treatment with [VOCl3] to afford the complex [{VOCax(O)4}2(mu-2,6-(CH2)2C5H3N)].4 MeCN (134 MeCN). The compounds 1-13 have been structurally characterised by single-crystal X-ray diffraction. Upon activation with methylaluminoxane, these complexes displayed poor activities, however, the use of dimethylaluminium chloride and the reactivator ethyltrichloroacetate generates highly active, thermally stable catalysts for the conversion of ethylene to, at 25 degrees C, ultra-high-molecular-weight (>5, 500,000), linear polyethylene, whilst at higher temperature (80 degrees C), the molecular weight of the polyethylene drops to about 450,000. Using 1 and 2 at 25 degrees C for ethylene/propylene co-polymerisation (50:50 feed) leads to ultra-high-molecular-weight (>2,900,000) polymer with about 14.5 mol% propylene incorporation. The catalytic systems employing the methyleneoxa-bridged complexes 1 and 2 are an order of magnitude more active than the bimetallic complexes 5 and 13, which, in turn, are an order of magnitude more active than pro-catalysts 8, 11 and 12. These differences in activity are discussed in terms of the structures of each class of complex.

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Paramagnetic Chloro‐, Alkoxo‐, or Azidovanadium(IV) Complexes Supported by an [ONNO]‐Type Amine Bis(phenolate) Ligand

Abstract: The reactions between V(N 3 ) 2 (NMe 2 ) 2 or V(OiPr) 4

Cited by 32 publications

References 59 publications

Ethylene Homo‐ and Copolymerization Activity of a Series of [ONNO]‐Type Amine Bis(phenolate) Based Vanadium(II–V) Catalysts

Ethylene Homo‐ and Copolymerization Activity of a Series of [ONNO]‐Type Amine Bis(phenolate) Based Vanadium(II–V) Catalysts

Ethylene/1-olefin copolymerization behaviour of vanadium and titanium complexes bearing salen-type ligand

Oxo‐ and Imidovanadium Complexes Incorporating Methylene‐ and Dimethyleneoxa‐Bridged Calix[3]‐ and ‐[4]arenes: Synthesis, Structures and Ethylene Polymerisation Catalysis

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