The Williams Research Group, Imperial College London

Polymers From Carbon Dioxide

We have reported a series of new bimetallic complexes as catalysts for the copolymerisation of carbon dioxide and cyclohexene oxide. These new catalysts are active at just 1 atmosphere pressure of carbon dioxide and show excellent turn-over-numbers and turn-over-frequencies. Indeed, some of the new catalysts have activities matching, and even exceeding, the best previously known catalysts but operate at a fraction of the carbon dioxide pressure (1/10 or 1/60 of the pressure). We have reported the first examples of homogeneous Fe(III) and Mg(II) catalysts for this polymerization. The di-magnesium catalysts are particularly notable as they are highly active, yet the metal is abundant, inexpensive and colourless. We have investigated, in significant detail, the polymerisation kinetics and have uncovered a rate law and proposed a mechanism, which has been supported experimentally, spectroscopically and using DFT theory. The catalysts are tolerant of excesses of chain transfer agents, including water; we have utilized this to prepare polymers where the end-groups can be controlled with very high selectivity.

Publications

Kember, M. R.; Williams, C. K., J. Am. Chem. Soc. 2012, 134 , 15676
Kember, M. R.; Jutz, F.; Buchard, A.; White, A. J. P.; Williams, C. K., Chem. Sci. 2012, 3 , 1245
Kember, M. R.; Copley, J.; Buchard, A.; Williams, C. K., Polym. Chem. 2012, 3 , 1196
Buchard, A.; Jutz, F.; Kember, M. R.; White, A. J. P.; Rzepa, H. S.; Williams, C. K., Macromolecules 2012, 45, 6781
Kember, M. R.; Buchard, A.; Williams, C. K., Chem. Commun. 2011, 47 , 141
Jutz, F.; Buchard, A.; Kember, M. R.; Fredrickson, S. B.; Williams, C. K., J. Am. Chem. Soc. 2011, 133, 17395
Buchard, A.; Kember, M. R.; Sandeman, K. G.; Williams, C. K., Chem. Commun. 2011, 47, 212
Kember, M. R.; White, A. J. P.; Williams, C. K. Macromolecules 2010, 43, 2291.
Kember, M. R.; White, A. J. P.; Williams, C. K. Inorg. Chem. 2009, 48, 9535.
Kember, M. R.; Knight, P. D.; Reung, P. T. R.; Williams, C. K. Angew. Chem. Int. Ed. 2009, 931.
Williams, C. K.; Kember, M. R.; Knight, P. D., 20.10.2009, WO 2009/130470 A1

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Polymers From Carbon Dioxide

We have reported a series of new bimetallic complexes as catalysts for the copolymerisation of carbon dioxide and cyclohexene oxide. These new catalysts are active at just 1 atmosphere pressure of carbon dioxide and show excellent turn-over-numbers and turn-over-frequencies. Indeed, some of the new catalysts have activities matching, and even exceeding, the best previously known catalysts but operate at a fraction of the carbon dioxide pressure (1/10 or 1/60 of the pressure). We have reported the first examples of homogeneous Fe(III) and Mg(II) catalysts for this polymerization. The di-magnesium catalysts are particularly notable as they are highly active, yet the metal is abundant, inexpensive and colourless. We have investigated, in significant detail, the polymerisation kinetics and have uncovered a rate law and proposed a mechanism, which has been supported experimentally, spectroscopically and using DFT theory. The catalysts are tolerant of excesses of chain transfer agents, including water; we have utilized this to prepare polymers where the end-groups can be controlled with very high selectivity.

Publications

Kember, M. R.; Williams, C. K., J. Am. Chem. Soc. 2012, 134 , 15676 Kember, M. R.; Jutz, F.; Buchard, A.; White, A. J. P.; Williams, C. K., Chem. Sci. 2012, 3 , 1245 Kember, M. R.; Copley, J.; Buchard, A.; Williams, C. K., Polym. Chem. 2012, 3 , 1196 Buchard, A.; Jutz, F.; Kember, M. R.; White, A. J. P.; Rzepa, H. S.; Williams, C. K., Macromolecules 2012, 45, 6781 Kember, M. R.; Buchard, A.; Williams, C. K., Chem. Commun. 2011, 47 , 141 Jutz, F.; Buchard, A.; Kember, M. R.; Fredrickson, S. B.; Williams, C. K., J. Am. Chem. Soc. 2011, 133, 17395 Buchard, A.; Kember, M. R.; Sandeman, K. G.; Williams, C. K., Chem. Commun. 2011, 47, 212 Kember, M. R.; White, A. J. P.; Williams, C. K. Macromolecules 2010, 43, 2291. Kember, M. R.; White, A. J. P.; Williams, C. K. Inorg. Chem. 2009, 48, 9535. Kember, M. R.; Knight, P. D.; Reung, P. T. R.; Williams, C. K. Angew. Chem. Int. Ed. 2009, 931. Williams, C. K.; Kember, M. R.; Knight, P. D., 20.10.2009, WO 2009/130470 A1

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