Formation of a Titanium Complex with a TiCHAl₂ Structural Unit from LTiMe₃ and Trimethylaluminum

The reaction of LTiCl3 (1) (L = HC(CMeN(2,6-iPr2C6H3))2, nacnac) with MeLi·(Et2O)0.14 in toluene afforded the stable Ti(IV) alkyl complex LTiMe3 (1). Reaction of 1 with 2 equiv of AlMe3 in toluene resulted in the formation of LTi(Me)CH(Al2Me5) (2) in high yield. Compounds 1 and 2 were characterized by X-ray structural analysis, NMR, IR, mass spectrometry, and elemental analysis. The Ti−CH bond length (1.880(2) Å) of 2 is in the range of a short Ti−C bond. This was additionally supported by NMR and DFT calculations. Compound 2 polymerized ethylene without adding any cocatalyst, although activity is low; the best TOF value was 2.4 × 104 g(polymer)/mol catalyst·h·bar.