[en] Solutions of methyl α-lithioisobutyrate (MIBLi) in THF added with various amounts of lithium chloride (LiCl) have been analyzed by Li-7 NMR spectroscopy in a wide range of temperatures. Although below ca. 205 K tetramers of MIBLi have been reported to be in equilibrium with dimers, 1/1 and 2/1 LiCl/MIBLi mixed complexes instantaneously form upon the addition of 1 and 2 mol equiv of LiCl, respectively. Further addition of LiCl more likely promotes the formation of a less stable 3/1 complex. Both 1/1 and 2/1 adducts are stable between -80-degrees-C and at least +12-degrees-C. From C-13 NMR spectroscopy, it appears that the addition of an equimolar amount of LiCl to the MIBLi solution in THF is at the origin of a ca. 7.0 ppm upfield shift of the metalated α-carbon compared to the tetrameric MIBLi species and a ca. 1.0 ppm downfield shift with respect to the dimeric MIBLi. However, the charge distribution over the carbanion does not change anymore when the amount of LiCl exceeds 1 mol equiv. In contrast to nonligated MEBLi, the OR group has a considerable rotational freedom in LiCl-modified MIBLi. A comparison of the structure and dynamics of the LiCl-modified MIBLi species in THF at 197 K with the characteristic features of the anionic polymerization of MMA under the same conditions suggests that the formation of one type of LiCl-complexed species has a decisive effect on the control of the living polymerization of MMA. This conclusion is in agreement with a kinetic study carried out by Muller for the same system.
Research center :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Chemistry Materials science & engineering
Author, co-author :
Wang, Jin-Shan; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Warin, R.; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Jérôme, Robert ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Teyssié, Philippe ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Language :
English
Title :
Anionic polymerization of acrylic monomers. 11 NMR investigation of the mixed complexation of methyl α-lithioisobutyrate and lithium chloride
Publication date :
06 December 1993
Journal title :
Macromolecules
ISSN :
0024-9297
eISSN :
1520-5835
Publisher :
American Chemical Society, Washington, United States - District of Columbia
La chimie des Acryliques; Techno-Nathan Nouvelle Librairie S.A.: Paris, 1987; p 14.
Wiles, D. M. In Structure and Mechanism in Vinyl Polymerization; Tsuruta, T., O'Driscoll, K. F., Eds.; Marcel Dekker: New York, 1969; p 233.
Famham, W. B.; Sogah, D. Y. U.S. Patent 4,414,372, Nov 8, 1983.
Webster, O. W.; Hertler, W. R.; Sogah, D. Y.; Farnham, W. B.; Rajan Babu, T. V. J. Am. Chem. Soc. 1983, 105, 5706.
Lochmann, L.; Trekoval, J. U.S. Patent 4,056,580, Nov 1977
J. Polym. Sci., Polym. Chem. Ed. 1979, 17, 1727.
Huynh-Ba, G.; McGrath, J. E. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 1986, 27 (1), 179.
Kitayama, T.; Shinozaki, T.; Sakamoto, T.; Yamamoto, M.; Hatada, K. Makromol. Chem., Suppl. 1989, 15, 167.
Ballard, D. G. H.; Bowles, R. J.; Haddleton, D. M.; Richards, S. N.; Sellens, R.; Twose, D. L. Macromolecules 1992, 25, 5907.
Jérôme, R.; Forte, R.; Varshney, S. K.; Fayt, R.; Teyssié, Ph. In Recent Advances in Mechanistic and Synthetic Aspects of Polymerization; Fontanille, M., Guyot, A., Eds.; NATO Advanced Study Institute Series C 215; Plenum: New York, 1987; p 101.
Teyssié, Ph.; Fayt, R.; Hautekeer, J. P.; Jacobs, C.; Jérôme, R.; Leemans, L.; Varshney, S. K. Makromol. Chem., Macromol. Symp. 1990, 32, 61.
Teyssié, Ph.; Varshney, S. K.; Jérôme, R.; Fayt, R. Eur. Pat. 87402893.9, 1987
U.S. Patent 4,826,941, May 2, 1989.
Fayt, R.; Fort, R.; Jacobs, C.; Jérôme, R.; Ouhadi, T.; Teyssié, Ph.; Varshney, S. K. Macromolecules 1987, 20, 1442.
Varshney, S. K.; Hautekeer, J. P.; Fayt, R.; Jérôme, R.; Teyssié, Ph. Macromolecules 1990, 23, 2618.
Varshney, S. K.; Bayard, Ph.; Jacobs, Ch.; Jérôme, R.; Fayt, R.; Teyssié, Ph. Macromolecules, in press.
Hautekeer, J. P.; Jacobs, C.; Fayt, R.; Jérôme, R.; Teyssié, Ph.; Warin, R., unpublished results
Lochmann, L.; Lim, D. J. Organomet. Chem. 1973, 50, 9.
Novak, D. P.; Brown, T. L. J. Am. Chem. Soc 1972, 94, 3793.
Hall, P. L.; Gilchrist, J. H.; Collum, D. B. J. Am. Chem. Soc. 1991, 113, 9571.
Jackman, L. M.; Szeverenyi, N. M. J. Am. Chem. Soc. 1977, 99, 4954.
Jackman, L. M.; Rakiewicz, E. F. J. Am. Chem. Soc. 1991, 113, 1201, 4101.
Seebach, D. Angew. Chem., Int. Ed. Engl. 1988, 27, 1624.
Kunkel, D.; Müller, A. H. E.; Janata, M.; Lochmann, L. Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 1991, 32 (1), 301.
Kunkel, D.; Müller, A. H. E.; Janata, M.; Lochmann, L. Makromol. Chem., Macromol. Symp. 1992, 60, 315.
Wong, M. K.; Popov, A. I. J. Inorg. Nucl. Chem. 1972, 34, 3615.
Long, T. E.; Allen, R. D.; McGrath, J. E. In Recent Advances in Mechanistic and Synthetic Aspects of Polymerization; Fontanille, M., Guyot, A., Eds.; NATO Advanced Study Institute Series 215; Plenum: New York, 1987; p 79.
Szwarc, M. Carbanion, living polymer and electron transfer processes; Wiley-Interscience: New York, 1968.