Chiral Bis (Oxazoline) Metal Complexes:synthesis, Characterization And Catalysis On Olefins Polymerization

Chiral bis(oxazoline)(box) ligands have developed into one of the most useful ligand classes for asymmetric catalysis due to their easy preparation and modification, and their ability to generate C2-symmetric chiral catalysts by coordinating with a large number of metals. Metal-bis(oxazoline) complexes have been widely applied in asymmetric catalysis, but still rare in olefin polymerization.First, we synthesized several bis(oxazoline)phenyl ligands(Phebox) L1-L3 and bis(oxazolinylphenyl)amido ligands(BOPA) L4-L6 with different substituents. We try to synthesis rare earth metal complexes via one-pot acid-base reactions by use of the tris(trimethylsilylmethyl) rare earth metal complexes with the bis(oxazoline)phenyl ligands. At present, we successfully obtain bis(oxazoline)phenyl scandium complexes. Also, bis(oxazolinylphenyl)amido Mg(II) complexes have been synthesised via one-pot reaction of BOPA and PhMgBr。Secondly, we explored the use of catalysts bis(oxazoline)phenyl scandium complexes in 2-vinylpyridine polymerization. In the presence of [Ph3C][B(C6F5)4] and AliBu3, high efficent 2-vinylpyridine(2-VP) polymerization can be carried out, the activity can be up to 10.74 kg?mol-1?h-1. Meanwhile, they can polymerize isoprene(IP) and ocimene(OCI). We also attempt to apply bis(oxazolinylphenyl)amido Mg(II) complexes to polymerize 2-VP in the presence of MAO or [Ph3C][B(C6F5)4]/AliBu3 or EtONa,but there is no activity in the given experimental conditions. Suitable monomers and reaction conditions are still in further exploration.