Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization
The mixed-ligand complexes [Ti2(μ-OR)2(OR)2(κ3-tbop)2] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR)4 and H2tbop {H2tbop = 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti2(μ-OR)2(κ3-tbop)2(Me)2] (2a) for R = Me and (2b) for R = Et. Controlled hydrolysis of 2b causes the evolution of methane and the formation of the titanoxane compounds [{Ti2(μ-OEt)2(κ3-tbop)2}2(μ-O)2]·2CH2Cl2 (3). Structures of 1a, 1b, 2a, 2b, and 3 were confirmed by NMR spectroscopy; 1b and 3 were further investigated with X-ray crystallography. Compounds 1a…
2-Tetrahydrofurfuroxo-vanadium-(III) and -(IV) complexes. Synthesis, structures and reactivities of [V2Mg2(μ3,δ2-thffo)2(μ,δ2-thffo)4Cl4]· 2CH2Cl2 and [V2(μ,δ2-thffo)2Cl2O2] †
Vanadium complexes of 2-tetrahydrofurfuroxide (2-tetrahydrofurylmethoxide) (thffo) with the metal in oxidation state III and IV have been prepared and characterized. The reaction of [VCl3(thf)3] with 1.5 equivalents of [Mg(thffo)2] in tetrahydrofuran (thf) or CH2Cl2 led to the formation of [V2Mg2(µ3,η2-thffo)2(µ,η2-thffo)4Cl4]· 2CH2Cl21. Its structure consists of centrosymmetric tetranuclear molecules and CH2Cl2 of crystallization. Two Mg and two V atoms have distorted octahedral geometry and form a nearly regular Mg2V2 rhombus. The V · · · V distance is 3.266(2) A. The reaction of [VOCl2(thf)2] with Na(thffo) in thf yielded [V2(µ,η2-thffo)2Cl2O2] 2. Two VOCl units are linked by alkoxide ox…
Zirconium and hafnium complexes of the thio(bisphenolato) ligand: synthesis, structural characterization and testing as 1-hexenepolymerizationcatalysts
Thio(bisphenolato) complexes of the type [M2(mu-tbop-kappa3O,S,O)2Cl4] [M = Zr 1, Hf 2 and tbop = 2,2-thiobis{4-(1,1,3,3-tetramethyl-butyl)phenolate}] were prepared by HCl elimination from tbopH2 and MCl4. Substitution of the chlorides in 1 and 2 by 2,6-diisopropylphenolato groups (dipp) generates new compounds [M2(mu-tbop-kappa3O,S,O)2(dipp)4] (M = Zr 3, Hf 4). The structures of 1-4 were confirmed by NMR spectroscopy; complexes 3 and 4 were further investigated by X-ray crystallography. These studies showed 1-4 to be dimers either in the solid state or in solution and to have metal centers adopting distorted octahedral geometry. However treatment of MCl4 with [Al2(mu-OEt)2(tbop-kappa3O,S,O…
Synthesis, structural studies and reactivity of vanadium complexes with tridentate (OSO) ligand
The direct reaction between [VCl(3)(thf)3] or [VO(OEt)3] and 2,2'-thiobis{4-(1,1,3,3-tetramethyl-butyl)phenol (tbopH(2)) leads to the formation of [V(2)(micro-tbop-kappa(3)O,S,O)2Cl(2)(CH(3)CN)(2)] (1).4CH(3)CN or [V(2)(micro-OEt)2(O)2(tbop-kappa(3)O,S,O)2] (2), respectively, in high yield. Compounds 1 and 2 were characterized by chemical and physical techniques including X-ray crystallography and variable temperature magnetic susceptibility studies (J = -29.1 cm(-1)) for 1. Complexes 1 and 2 were supported on MgCl2 and when activated with aluminium alkyls, were found to effectively polymerize ethene to produce polyethylene with a narrow molecular weight distribution M(w)/M(n) approximately…
Homo- and Heterometallic Aluminum and Titanium Complexes of Tridentate (OSO) Ligand: Synthesis, Structure, and Catalytic Activity
The tridentate (OSO-functions) biphenol, 2,2‘-thiobis{4-(1,1,3,3-tetramethylbutyl)phenol} (tbopH2), reacts with AlMe3 to give [Al2(μ-tbop-κ3O,S,O)2Me2] (1). Alcoholysis of 1 results in the formation of [Al2(μ-OEt)2(tbop-κ3O,S,O)2] (2). The reaction of 2 with TiCl4 gives the trimeric complex [Ti3(μ-OEt)2(μ-tbop-κ3O,S,O)2Cl6] (3)·C6H14. Alkylation of 3·C6H14 with LiMe produces two dimeric complexes, [Ti2(μ-tbop-κ3O,S,O)2Me4] (4) and [Ti2(μ-OE)2(tbop-κ3O,S,O)2Me2] (5)·Et2O. Treatment of [Ti2(μ-OEt)2(tbop-κ3O,S,O)2(OEt)2] with AlMe3 and EtOH afforded the heterobimetallic species, [Ti2Al2(μ-OEt)6(μ-tbop-κ3O,S,O)2(OEt)4] (6). The structures of 1−6 were confirmed by NMR spectroscopy; complexes 1, …
Titanium Complexes of Chelating, Dianionic O,S,O‐Bisphenolato Ligands: Syntheses, Characterisation, and Catalytic Activity
Titanium complexes based on 2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenolato] (tbop) are prepared by reaction of TiCl 4 or Ti(NMe 2 ) 4 with the parent biphenol. Three new complexes are reported: [Ti 2 (μ-tbop-κ 3 O,S,O)(μ-tbop-κ 2 O,O)-(tbop-κ 3 O,S,O)Cl 2 ] (1).2CH 3 CN, [Ti 2 (μ-tbop-κ 3 O,S,O) 2 Cl 4 ] (2) and [Ti(tbop-κ 3 O,S,O) 2 ] (3). Substitution of the chlorides in 1 and 2 by 2,6-diisopropylphenolato and imido (NtBu) ligands generates the new compounds [Ti 2 (μ-tbop-κ 3 O,S,O) 2 -Cl 2 (dipp) 2 ] (4).Et 2 O and [Ti 2 (μ-tbop-κ 3 O,S,O) 2 (NtBu) 2 -(NH 2 tBu) 2 ] (5), respectively. Treatment of 5 with crude Me 3 -SiCl, containing Me 3 SiOH, produces [Ti(tbop-κ 3 O,S,O)Cl(O-SiMe 3 …