Mixed Bent Sandwich Titanium Complexes with the [2‐(Diisopropylamino)ethyl]cyclopentadienyl Ligand — Catalysts for the Polymerization of Ethylene and the Dehydrocoupling of Phenylsilane

Mixed bent sandwich titanium (IV) complexes containing the donor‐substituted [2‐(diisopropylamino)ethyl]cyclopentadienyl (C 5 H 4 CH 2 CH 2 N i Pr 2 Cp N ) ligand are described. The highly moisture‐sensitive metallocene dichloride (C 5 H 4 CH 2 CH 2 NN i Pr 2 )(C 5 H 4 SiMe 3 )TiCl 2 ( 1 ) was synthesized by reaction of Cp N Li with Cp S TiCl 3 (Cp S C 5 H 4 SiMe 3 ). Complex 1 reacts with one equivalent of HCl with protonation of the amino group to give the air‐ and water‐stable metallocene dichloride‐hydrochloride [(C 5 H 4 CH 2 CH 2 ‐N(H) i Pr 2 )(C 5 H 4 SiMe 3 )TiCl 2 ] + Cl − ( 2 ). The structure of 2 was determined by a single‐crystal X‐ray diffraction study. Compounds 1 and 2 are precursors for ethylene polymerization catalysts. The reaction of 2 with one equivalent of Na + B[3,5‐(CF 3 ) 2 C 6 H 3 ] 4 − afforded the borate [(C 5 H 4 CH 2 CH 2 N(H) i Pr 2 )‐(C 5 H 4 SiMe 3 )TiCl 2 ] + B[3,5‐(CF 3 ) 2 C 6 H 3 ] 4 − ( 3 ). The dimethyl compounds (C 5 H 4 CH 2 CH 2 N i Pr 2 )(C 5 H 4 SiMe 3 )Time 2 ( 4 ) was obtained by reaction of 1 with two equivalents of methyllithium. The diphenoxy complex (C 5 H 4 CH 2 CH 2 ‐N i Pr 2 )(C 5 H 4 SiMe 3 )Ti(OPh) 2 ( 5 ) was prepared analogously with a stoichiometric amount of lithium phenoxide. Compounds 4 and 5 show remarkable activity in the catalytic dehydrocoupling of phenylsilane.