Titanium dinuclear complexes with two different procatalytic centres.

Abstract:
Dinuclear titanium complexes will be synthesized which after activation by a cocatalyst will supply two active centers with different reactivity toward ethylene. It is proposed that the first active site will trimerize ethylene to 1-hexene and the second site copolymerize the in situ formed 1-hexene with ethylene. The polyethylene with isolated C4 branches will be produced. The dinuclear complexes will be prepared by synproportionation reaction of ansa titanocene dichlorides bearing hemi-labile ligand bonded to the ansa-bridge with TiCl4 or ArOTiCl3 (ArO denotes 2,6-disubstituted phenolates). The prepared complexes will be converted to methylderivatives, which by the reaction with B(C6F5)3 will provide cationic complexes. These will be tested in the ethylene polymerization for production of LLDPE type polymers. A fluxional behavior of the hemi-labile ligand in the selected cationic complexes will be investigated by Dynamic NMR spectroscopy.