58097-69-1

Upstream product

• 7550-45-0 titanium tetrachloride 

Downstream Products

• 122597-80-2 dichloro{trimethylhydrazido^(1-)}-{tris(pyrazolyl)borato}titanium(IV) 
• 122597-81-3 dichloro{N-phenylhydrazido^(1-)-N}-{tris(pyrazolyl)borato}titanium(IV) 

Relevant academic research and scientific papers

Ethylene polymerization behavior of tris(pyrazolyl)borate titanium(IV) complexes

A set of Tp′TiCl3 and Tp′TiCl2(OR) complexes containing tris(pyrazolyl)borate ligands with diverse steric properties has been evaluated for ethylene polymerization under MAO activation conditions (Tp′ = HB(3-mesitylpyrazolyl)2(5-mesitylpyrazolyl)- TpMs*), HB(3-mesitylpyrazolyl)3- (TpMs), HB(3,5-Me2-pyrazolyl)3- (Tp*), HB(pyrazolyl)3- (Tp), BuB(pyrazolyl)3- (BuTp)). The activity of Tp′TiX3/MAO varies in the order TpMsTiCl3 (10c) > TpMsTiCl3 ? Tp*TiCl3, TpTiCl3, BuTpTiCl3, Tp*TiCl2(Ot), Tp*TiCl2(O-2-tBu-C6H4). The activity of 10c/ MAO is similar to that of Cp2ZrCl2/MAO. High MAO levels or addition of AlMe3 decrease the activity of 10c/MAO, probably due to coordination of AlMe3 to the active Ti species. The predominant chain transfer mechanism for 10c/MAO is chain transfer to AlMe3, which results in broad molecular weight distributions at low Al/Ti ratios (Al/Ti = 200-1000). At very high Al levels (10c/5000 MAO or 10c/1000 MAO/4000 AlMe3) bimodal molecular weight distributions comprising a major low molecular weight fraction (Mw/Mn ca. 3) and a minor high molecular weight fraction are observed, which suggests that several active species are present, only one of which undergoes efficient chain transfer to Al.

Photochemistry of tris(pyrazolyl)borate titanium(IV) complexes

The electronic features and photochemistry of TpTiCl3 (1) (Tp = hydrotris(pyrazol-1-yl)borate) and Tp*TiCl3 (2) (Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate) were studied in THF. Reactive decay of the excited states produced either HBpz3 (or HBpz3?*) and metal center Ti(III) radicals via homolytic cleavage of the Tp → Ti (Tp* → Ti) bond. Cleavage of the Tp → Ti and the Tp* → Ti bond as a primary photoprocess is shown to be consistent with LMCT Tp → Ti and Tp* → Ti excitation. TpTiCl2(THF) (3) and Tp*TiCl2(THF) (4) were also prepared by stoichiometric reduction of 1 and 2 with Li3N. The THF ligand in 3 and 4 was replaced by the stable nitroxyl radical TEMPO (2,2,6,6-tetramethyl-1- piperidinyloxy) to provide the new complexes TpTiCl2(TEMPO) (5) and Tp*TiCl2(TEMPO) (6) in which the TEMPO ligand is η1 coordinated to Ti(IV). Photolysis of 5 and 6 generate Ti(III) and the TEMPO radical in the primary photochemical step.