o-Phenylene-bridged Cp/amido titanium and zirconium complexes and their polymerization reactivity

o-Phenylene-bridged trimethylcyclopentadienyl/amido titanium complexes [(η5-2,3,5-Me3C5H)C6H4NR-κN]TiCl2 (18, R = CH3; 19, R = CH2CH3; 20, R = CH2C(CH3)3; 21, R = CH2(C6H11)) and zirconium complexes {[(η5-2,3,5-Me3C5H)C6H4NR-κN]ZrCl-μCl}2 (22, R = CH3; 23, R = CH2CH3; 24, R = CH2C(CH3)3; 25, R = CH2(C6H11); 26, R = C6H11; 27, R = CH(CH2CH3)2) are prepared via a key step of the Suzuki-coupling reaction between 2-dihydroxyboryl-3-methyl-2-cyclopenten-1-one (2) and the corresponding bromoaniline compounds. The molecular structures of titanium complexes 18 and 19 and dinuclear zirconium complexes 24 and 26 were confirmed by X-ray crystallography. The Cp(centroid)–Ti–N and Cp(centroid)–Zr–N angles are smaller, respectively, than those observed for the Me2Si-bridged complex [Me2Si(η5-Me4C5)(NtBu)]TiCl2 and its Zr-analogue, indicating that the o-phenylene-bridged complexes are more constrained than the Me2Si-bridged complex. Titanium complex 19 exhibits comparable activity and comonomer incorporation to the CGC ([Me2Si(η5-Me4C5)(NtBu)]TiCl2) in ethylene/1-octene copolymerization. Complex 19 produces a higher molecular-weight polymer than CGC.