Two-State’ Living Coordination Polymerization for the Scalable Production of Precision Polyolefins

New paradigms are required that can dramatically change the range and pace at which specialty polyolefins can be discovered and commercialized.¹  In this regard, we have been pursuing, within a living coordination polymerization system, identification of dynamic fast and reversible bimolecular processes that are competitive with chain-growth propagation and the establishment of mechanistic control points that can provide external control over the relative rates of these processes.  In this way, a single catalyst can now be directed to produce, with a high degree of precision, a near continuum of different polyolefin grades that exists between two different limiting stereochemical microstructures, co-polymer compositions or polymer architectures.^2-7  When combined with living coordinative chain-transfer polymerization (LCCTP) that employs an excess of a main group metal alkyl as ‘surrogate’ chain-growth sites, practical, large-scale production of a broad range of specialty ‘precision’ polyolefin materials can now be brought closer to realization.  This talk will focus on our most recent investigations involving the identification, development, and exploitation of several different classes of two-state LCCTP systems for considerably expanding the range of structure and function of polyolefins.

Relevant References:

(1) Sita, L. R. Angew. Chem. Int. Ed. 2009, 48, 2464. (2) Zhang, W.; Sita, L.R. J. Am. Chem. Soc. 2008, 130, 442. (3) Zhang, W.; Wei, J.; Sita, L.R. Macromolecules 2008, 41, 7829-7833.  (4) Wei, J.; Zhang, W.; Sita, L. R. Angew. Chem. Int. Ed. 2010, 49, 1768. (5) Wei, J.; Zhang, W.; Wickham, R.; Sita, L. R. Angew. Chem. Int. Ed. 2010, 49, 9140. (6) Wei, J.; Whang, W.; Zhang, W.; Sita, L. R. J. Am. Chem. Soc. 2013, 135, 2132. (7) Crawford, K.; Sita, L. R. J. Am. Chem. Soc. 2013, 135, 8778.