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 ) · 2 CH 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 (N t Bu) 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 (N t Bu) 2 ‐(NH 2 t Bu) 2 ] ( 5 ), respectively. Treatment of 5 with crude Me 3 ‐SiCl, containing Me 3 SiOH, produces [Ti(tbop‐κ 3 O,S,O)Cl(OSiMe 3 )(NH 2 t Bu)] ( 6 ). Reaction of 2 with an excess of NH i Pr 2 provides a mixture of compounds: ionic [NH 2 i Pr 2 ][Ti(tbop‐κ 3 O,S,O)Cl 3 ] ( 7 ) · CH 2 Cl 2 and molecular [Ti 2 (μ‐tbop‐κ 3 O,S,O) 2 ‐Cl 2 (N i Pr 2 ) 2 ] ( 8 ). The structures of 1 – 8 were confirmed by NMR spectroscopy; complexes 1 , 5 , 6 and 7 were further investigated by X‐ray crystallography. Compounds 1 , 2 , 4 and 5 , when supported on MgCl 2 and activated with alkylaluminiums, effectively polymerise ethene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)