Titanium Complexes Stabilized by a Sulfur‐Bridged Chelating Bis(aryloxo) Ligand as Active Catalysts for Olefin Polymerization

Abstract

The mixed-ligand complexes [Ti 2 (µ-OR) 2 (OR) 2 (κ 3 -tbop) 2 ] (1a) for R = Me and (1b) R = Et were prepared by the reaction of Ti(OR) 4 and H 2 tbop {H 2 tbop = 2,2Ј-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol]} in methanol. Treatment of 1a and 1b with AlMe 3 led to the substitution of terminal alkoxy groups to create the organometallic compounds [Ti 2 (µ-OR) 2 (κ 3 -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 [{Ti 2 (µ-OEt) 2 (κ 3 -

Di-μ-methanolato-bis[(2-tert-butyl-6-methylphenolato-κO)methyltitanium(IV)]

“…The angles associated with the C(24)-Ti-O system thus show that for the methoxy bridge the C 24 10and 121.77 (10) ° respectively which are similar to those found in other alkoxy bridged titanium dimers (Janas et al 2005(Janas et al , 2004 The separation between the phenolato ligands is shown by the O(1)-Ti-O(2) angle of 102.02 (5) ° which is much wider than the O 3 (Nielson et al 2006). Although these angles are essentially the same in (1), one phenyl ring is rotated so that its face points inwards towards the other but slightly down and the other ring is rotated so that it points away from and slightly down from the former.…”

“…For other alkoxy-bridged dialkyl or diphenyl bis-phenolate dititanium complexes, see: Janas et al (2004Janas et al ( , 2005; Zhang (2007a,b); Kobylka et al (2007). For other alkoxy-bridged bisphenolato dititanium complexes, see: Ejfler et al (2004).…”

“…Titanium complexes containing phenolato ligands (OAr) or alkoxo ligands (OR) as well as an alkyl ligand have been described (Janas et al 2005;Janas et al 2004;Zhang 2007a,b;Kobylka et al 2007) but complexes containing both oxygen ligand sets and an alkyl ligand are not known. The chemistry of phenolato and alkylato complexes has been known for many years (Bradley et al 1978) and in particular alkoxy bridged bis-phenolato dititanium complexes have been prepared (Ejfler et al 2004).…”

Titanium Complexes of Chelating, Dianionic O,S,O‐Bisphenolato Ligands: Syntheses, Characterisation, and Catalytic Activity

“…The third sulfur atom [S(2)] isnot bonded to any Ti atom. The average titanium–sulfur bond length of 2.735(2) Å is longer than those found in other complexes, for example[Ti 2 (μ‐O i Pr) 2 (O i Pr) 2 (tbmp‐κ 3 O,S,O) 2 ] [tbmp = 2,2′‐thiobis(6‐ tert ‐butyl‐4‐methylphenolato; 2.719(1) Å],[Ti(tbmp‐κ 3 O,S,O)(C 6 H 4 CH 2 NMe 2 ‐2‐κ 2 C,N)Cl] [2.704(1) Å]and [Ti(tbmp‐κ 3 O,S,O)Cl(O i Pr)(HO i Pr)] [2.693(1) Å],5,11 and shorter than those in [Ti 2 (μ‐OEt) 2 (OEt) 2 (tbop‐κ 3 O,S,O) 2 ] [2.800(1) Å] and [{Ti 2 (μ‐OEt) 2 (tbop‐κ 3 O,S,O) 2 } 2 ‐(μ‐O) 2 ] [2.762(2) Å] 13. The average Ti–O distances of 1.832(3) Å and 2.040(3) Å are in the expected range for Ti IV complexes with non‐bridging and bridging aryloxo ligands, respectively 4.…”

“…Recently we described the synthesis and structural char‐acterisation of the mixed‐ligand complexes [Ti 2 (μ‐OR) 2 (X) 2 ‐(tbop‐κ 3 O,S,O) 2 ] (R = Me, Et; X = OR or Me) 13. In these complexes the tbop ligand was found to coordinate to the titanium in a fac fashion.…”