Living polymerization and block copolymerization of alpha-olefins by an amine bis(phenolate) titanium catalyst

Area of Science:

• Organometallic Chemistry
• Polymer Science
• Catalysis

Background:

• Alpha-olefin polymerization is crucial for producing various polymers.
• Achieving controlled molecular weight and architecture, such as living polymerization and block copolymers, remains a key challenge.
• Titanium-based catalysts are widely explored for olefin polymerization.

Purpose of the Study:

• To investigate the living polymerization behavior of a novel amine bis(phenolate) dibenzyl titanium complex.
• To explore the synthesis of high molecular weight poly(1-hexene) and block copolymers using this catalyst system.
• To evaluate the catalyst's performance under varying temperature conditions.

Main Methods:

• Synthesis of an amine bis(phenolate) dibenzyl titanium complex with a methoxy donor side arm.
• Activation of the titanium complex with tris(pentafluorophenyl)borane.
• Polymerization of alpha-olefins (1-hexene and 1-octene) under different temperature conditions.

Main Results:

• The activated titanium complex demonstrated unique living polymerization properties.
• Exceptionally high molecular weight poly(1-hexene) was synthesized in a living manner at room temperature.
• Living polymerization of 1-hexene was achieved above room temperature, and room-temperature block copolymerization of 1-hexene and 1-octene was successful.

Conclusions:

• The amine bis(phenolate) dibenzyl titanium complex, activated by tris(pentafluorophenyl)borane, is a highly effective catalyst for living alpha-olefin polymerization.
• This catalyst system offers precise control over polymer molecular weight and enables the synthesis of well-defined block copolymers.
• The findings open new avenues for designing advanced polyolefin materials with tailored properties.