Novel bi- and hexanuclear titanium (IV) complexes: Synthesis, structure and catalytic activities in oligo- and polymerization of 1-hexene

•Novel bi- and hexanuclear Ti complexes bearing [O,O,O,O]4− ligand were synthesized.•In the presence of Et2AlCl or Et3Al2Cl3 these complexes were active in 1-hexene oligomerization.•The addition of Bu2Mg switched the activity to 1-hexene polymerization.

Novel bi- and hexanuclear titanium (IV) complexes with 2,2′-bis-(hydroxymethyl)-1,1′-biphenole derivative were synthesized. Structure of complexes 4–5 were established by X-ray diffraction. Resulting catalytic systems obtained by pre-catalysts activation by diethylaluminum chloride or ethyl aluminum sesquichloride were active in the 1-hexene oligomerization. Replacement of alkylaluminumchlorides by a {3Et2AlCl + Bu2Mg} binary system results in formation of predominantly isotactic, high molecular weight poly-1-hexene (content of isotactic pentad mmmm 70%). Systems treated with “traditional” activators – MAO and AlR3 were not active.

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