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Inorganic Seminar Series: Adam Veige (University of Florida) – Via Zoom

October 8, 2020 | 3:00 pm - 4:00 pm

To attend the seminar, please email Elon Ison at eaison@ncsu.edu

Adam Veige
Adam S. Veige, Professor, Department of Chemistry, University of Florida

Transition Metal Catalysts for the Efficient, Large-scale and Stereoselective Synthesis of Cyclic Polymers

Employing a trianionic pincer ligand, we have discovered a highly active catalyst for the synthesis of cyclic polymers from alkynes. Though initiated with a trianionic pincer ligand supported tungsten catalyst, the active catalyst features a tetraanionic pincer ligand. Details of the catalyst design and a discussion of the polymerization mechanism and active catalyst elucidation will be provided. Access to these cyclic polymers enables the synthesis of commercially relevant polyolefins. Annually produced at a rate of 170 million tons per year, polyolefin manufacturing has changed human quality of life and planet Earth forever. Isotactic polypropylene comprises 25% of all polyolefins manufactured and is applied in countless products globally. Polypropylene and all industrially produced polyolefins are linear molecules containing chain-ends. Exploiting ring expansion polymerization of alkynes, atactic cyclic polypropylene can now be synthesized. Characterization and confirmation of a cyclic topology comes from size exclusion chromatography, dynamic light scattering, viscometry, and rheology. Importantly, the cyclic topology of polypropylene leads to dramatic differences in the physical properties of the polymer including a > 20 °C increase in its glass transition temperature (Tg) compared to the linear version. Additional polyolefins such as the bulk scale synthesis of cyclic poly-1-pentene, and the synthesis of a highly transparent cyclic version of the commodity polyolefin TPXTM, poly(4-methylpentene), will be discussed. Another challenge is to prepare stereoregular cyclic polymers. This seminar will discuss catalyst designs for the ring opening polymerization of norbornene to give cis and syndiotactic enriched cyclic polynorbornene. Featured in the catalyst designs are the concepts of an “Inorganic Enamine” and “Ynene Metathesis” and their relationship to accentuating the nucleophilicity of metal-carbon multiple bonds.

Education:

2002 – 2004 / Postdoctoral MIT, Cambridge, MA. Advisor: Professor Daniel G. Nocera
1998 – 2003 / Ph. D. Cornell University, Ithaca, NY. Advisor: Professor Peter T. Wolczanski
1993 – 1997 / Hons. B.Sc. University of Western Ontario. Advisor: Professor James F. King

Research:

The research group is primarily interested in the design, synthesis, isolation, and characterization of novel inorganic molecules. Efforts are concentrated towards building new complexes that either model or affect new small molecule transformations relevant to the industrial sector. Detailed mechanistic studies are undertaken in order to uncover subtle details of catalytic processes in hopes of building upon or challenging current models of molecular structure, periodic trends, reactivity, and bonding.

Check the Veige Research Group.

Details

Date:
October 8, 2020
Time:
3:00 pm - 4:00 pm
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Organizer

Elon Ison
Email
eaison@ncsu.edu
View Organizer Website