Group 4 Metal Complexes That Contain a Thioether‐Functionalized Phenolato Ligand: Synthesis, Structure, and 1‐Hexene Polymerization

Reaction of group 4 metal tetrabenzyl complexes [M(CH 2 Ph) 4 ] (M = Ti, Zr, Hf) with 1 or 2 equiv. of a thioether‐functionalized phenol 2,4‐ t Bu 2 ‐6‐(PhSCH 2 )C 6 H 2 OH afforded dibenzyl complexes [M(L) 2 (CH 2 Ph) 2 ] (M = Ti, 1 ; M = Zr, 2 ; M = Hf, 3 ) and the tribenzyl zirconium complex [Zr(L)(CH 2 Ph) 3 ] ( 4 ). Benzyl abstraction with a Lewis acid gave the zirconium monobenzyl cation [Zr(L) 2 CH 2 Ph] + [PhCH 2 B(C 6 F 5 ) 3 ] – ( 5 ) and the dibenzyl cation [Zr(L)(CH 2 Ph) 2 ] + [PhCH 2 B(C 6 F 5 ) 3 ] – ( 6 ). The monobenzyl cation 5 oligomerized 1‐hexene to low molecular‐weight atactic oligo(1‐hexene) ( M n = 560–820), while the dibenzyl cation 6 polymerized 1‐hexene isospecifically ([ mmmm ] > 90 %). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)