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Titanium "constrained geometry" complexes with pendant arene groups.

Meghan A Dureen¹, Christopher C Brown, Jason G M Morton

¹Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, Canada, M5S 3H6.

Dalton Transactions (Cambridge, England : 2003)

|February 8, 2011

Summary

This summary is machine-generated.

New titanium complexes featuring silyl-amide ligands were synthesized and tested as catalysts for olefin polymerization. Complex 9 demonstrated significantly higher activity in styrene and ethylene polymerization compared to complex 10 and a related catalyst.

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Area of Science:

Organometallic Chemistry
Polymerization Catalysis

Background:

Titanium complexes with cyclopentadienyl and amide ligands are known catalysts for olefin polymerization.
The influence of ligand structure on catalyst activity and selectivity is a key area of research.

Purpose of the Study:

To synthesize novel titanium complexes bearing silyl-amide ligands with varying substituents.
To evaluate the catalytic performance of these new complexes in the polymerization of styrene and ethylene.

Main Methods:

Synthesis of proligands C(5)Me(4)HSiMe(2)N(H)R) via salt metathesis.
Preparation of titanium complexes including C(5)Me(4)(SiMe(2)NR)Ti(NMe(2))(2) and C(5)Me(4)(SiMe(2)NR)TiMe(2) through reactions with titanium precursors.
Catalytic testing of titanium complexes 9 and 10 with [Ph(3)C][B(C(6)F(5))(4)] activator for styrene and ethylene polymerization.

Main Results:

Novel titanium complexes 4-10 were synthesized, with complexes 4 and 5 obtained in good yields.
Complexes 9 and 10 effectively catalyzed styrene and ethylene polymerization when activated.
Complex 9 exhibited significantly higher catalytic activity than complex 10 and a benchmark catalyst [C(5)Me(4))SiMe(2)(NtBu)]TiMe(2).

Conclusions:

The steric and electronic properties of the silyl-amide ligand significantly impact catalytic performance.
Complex 9 represents a promising catalyst for olefin polymerization, showing enhanced activity.
Further investigation into the structure-activity relationship of these titanium catalysts is warranted.