We report the synthesis of novel titanium and zirconium complexes ligated by bidentate �salicylaldimine-like� N-heterocyclic carbenes (NHC). Double addition of the NHC chelate to either TiCl4(thf)2 or ZrCl4 forms bis-ligated organometallic fragments 1  and 2 with a distorted octahedral geometry. These complexes are rare examples of group IV transition metal NHC adducts. Preliminary catalytic tests demonstrate that in the presence of methylaluminoxane (MAO). These complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene. It has been observed that the polyethylene produced is linear high density polyethylene. The Ti complexes were also employed to produce highly syndiotactic polystyrene. Figure 1.  Non-Metallocene Ti and Zr Precatalysts.

Titanium and zirconium complexes of chelating N-heterocyclic carbenes as polymerization catalysts

248th National Meeting (2014)

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