Substituent Effects in the Structural Chemistry of Lithium Amidinates and in the Catalytic Polymerization of Propylene Promoted by Titanium Amidinate Complexes
Written by Sinai Aharonovich
Sinai Aharonovich, Moshe Kapon, Mark Botoshanski, and Moris S. Eisen
Schulich Faculty of Chemistry and Institute of Catalysis Science and Technology, Kyriat Hatechnion, Haifa, 32000, Israel
The N, N'-bis(trimethylsilyl) amidinate ligand, [RC(NSiMe3)2]-, is an important member of the non-metallocene ancillary ligands used in olefin polymerization catalysis. Since the steric and electronic properties of the ancillary ligands are known to affect key catalytic parameters such as the catalytic activity, molecular weight and the microstructure of the polymers, we were interested in examining the amidinate carbon substituent effects. The synthesis of the Ti(IV) amidinates complexes was accomplished by the salt metathesis of TiCl4 and the corresponding Li amidinate complexes.
In the first half of this presentation we will review the diverse structural chemistry of the Li amidinates, (mononmers, dimers, tetramers, cages, and polymers) and characterize several structural motifs such as dipole-dipole interactions and Li slippage. In the second half of the talk we will describe the catalytic behavior of the titanium amidinates in propylene polymerization, and focus on the electronic and steric substituent effects of the carbon substituent in the catalysis.
Aharonovich, S.; Volkis, V.; Eisen, M. S. Macromol. Symp. 2007, 260, 165.Aharonovich, S.; Kapon, M.; Botoshanski, M.; Eisen, M. S. Organometallics 2008, 27, 1869.