Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design
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ArticleDate
2012-08-21Online Publication Date
2012-08-21Print Publication Date
2012-09-11Permanent link to this record
http://hdl.handle.net/10754/597791
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A series of cobalt(III) chloride porphyrin complexes of the general formula 5,10,15,20-tetra(p-alkoxy)phenylporphyrin cobalt chloride (4b-e) and the related 5,10,15,20-tetra(p-nitro)phenylporphyrin cobalt chloride (4f) are presented and their reactivity toward propylene oxide (PO)/CO 2 coupling/copolymerization is explored. While the nitro-substituted complex (4f), in conjunction with an onium salt, shows moderate activity toward cyclization, the 4b-e/onium systems show superior copolymerization activity in comparison to tetraphenylporphyrin Co(III) chloride (4a) with high selectivity and conversion to poly(propylene carbonate) (PPC). A comprehensive copolymerization behavior study of the alkoxy-substituted porphyrin complexes 4b-e in terms of reaction temperature and CO 2 pressure is presented. Complexes bearing longer alkoxy-substituents demonstrate the highest polymerization activity and molecular weights, however all substituted catalyst systems display a reduced tolerance to increased temperature with respect to PPC formation. Studies of the resulting polymer microstructures show excellent head-to-tail epoxide incorporation and near perfectly alternating poly(carbonate) character at lower polymerization temperatures. © 2012 American Chemical Society.Citation
Anderson CE, Vagin SI, Xia W, Jin H, Rieger B (2012) Cobaltoporphyrin-Catalyzed CO 2 /Epoxide Copolymerization: Selectivity Control by Molecular Design . Macromolecules 45: 6840–6849. Available: http://dx.doi.org/10.1021/ma301205g.Sponsors
We gratefully acknowledge the King Abdullah University of Science and Technology (KAUST), Award No. UK-C0020, KSA-C0069, for financial support. Ms. A. Jonovic is thanked for technical support with TGA and GPC measurements. Mr. V. Bretzler is acknowledged for helpful comments with the preparation of this manuscript.Publisher
American Chemical Society (ACS)Journal
Macromoleculesae974a485f413a2113503eed53cd6c53
10.1021/ma301205g