ICS84

Synthesis and catalytic activity of zirconium imidazolin-2-iminato complexes

Alexandra Liobine 1 Matthias Tamm 2 Moris Eisen 1
1Schulich Faculty of Chemistry, Technion – Israel Institute of Technology, Haifa, Israel
2Institute for Inorganic and Analytical Chemistry, Technical University of Braunschweig, Braunschweig, Germany

Some of the major achievements of metallocenes in the polymerization of olefins are their high activity, the ability to produce narrow molecular weight distribution polymers, and their good stereochemical control1. Early transition metals complexes containing the imidazoline-2-iminato ligands can be considered as monodentate analogs of the well-known Cp ligand. This is attributed to the fact that the ligand can donate 2s, and 4𝛑- electrons to the corresponding metal center via resonance structures were the imidazolium ring stabilize a positive charge. Hence, in various group four complexes, large C-N-M angle (160°-180°) and short N-M triple bonds have been reported. Some of these complexes have been used in some homogeneous catalysis processes, particularly in the polymerization of olefin and alkyne metathesis2.

Following the excellent polymerization results with Ti-centered complexes, that contained the imidazoline-2-iminato ligand3,4,5, the aim of this research was to expand the scope by preparing new Zr-based complexes containing various imidazoline-2-iminato ligands and to examine their catalytic activity in the polymerization of olefins. The poster presents the synthesis, X-ray solid-state characterization of various complexes and their performance in the polymerization of ethylene. The optimization of the polymerization conditions included the screening of time, volume of solvent, ratio of catalyst to cocatalyst, different types of cocatalyst, pressure, and amount of catalyst.

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References

  1. 1. Reddy, S. S.; S. Prog. Polym. Sci. 1995, 20, 309-367.
  2. Wu, X.; Tamm, M., Coord. Chem. Rev. 2014, 260, 116-138.
  3. Sharma, M.; Yameen, H. S.; Tumanskii, B.; Filimon, S. A.; Tamm, M.; Eisen, M. S., J. Am. Chem. Soc. 2012, 134 (41), 17234-17244.
  4. 4. Shoken, D.; Sharma, M.; Botoshansky, M.; Tamm, M.; Eisen, M. S., Am. Chem. Soc. 2013, 135 (34), 12592-12595.
  5. Shoken, D.; Shimon, L. J. W.; Tamm, M.; Eisen, M. S., Organometallics. 2016, 35 (8), 1125-1131









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