Air-Initiated Radical Polymerization of Lithium Salts of omega-(Undecamethylcarba-closo-dodecaboran-1'-yl)alk-1-enes, CH2=CH(CH2)(n-2)C(BMe)11- Li+

Journal of the American Chemical Society
Kamesh VyakaranamJosef Michl

Abstract

We report an easy access to the salts of the LiC(BMe)11- anion, which greatly simplifies the synthesis of compounds carrying the -C(BMe)11- substituent, including the title anions. The previously recognized and puzzling spontaneous oligomerization of the solid lithium salts CH2=CH(CH2)(n-2)C(BMe)11- Li+ upon storage under ambient conditions is now shown to proceed by a radical mechanism, with the "naked" Li+ cation acting as a catalyst. The degree of polymerization is higher in solution, especially when azoisobutyronitrile (AIBN) is used as initiator (up to approximately 50). Initiation by the thermal decomposition of AIBN is also catalyzed by naked Li+, and this initiator is effective at room temperature. Di-tert-butyl peroxide and UV irradiation can also be used. The observation of Li+ catalysis agrees with a prior prediction from ab initio calculations, according to which Li+ complexation of ethylene strongly lowers the activation energy for methyl radical addition. The results bear on the current discussion of the possible sensitivity of radical clocks to their molecular environment and suggest that naked Li+ will catalyze the radical polymerization of simple terminal alkenes.

References

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Sep 24, 2004·Journal of the American Chemical Society·Ilya ZharovJosef Michl
Apr 28, 2006·Journal of the American Chemical Society·Kamesh VyakaranamJosef Michl
May 4, 2006·Journal of the American Chemical Society·Ilya ZharovJosef Michl
Oct 16, 1998·Angewandte Chemie·Philippe Renaud, Michèle Gerster

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Citations

Aug 16, 2013·Chemical Reviews·Christos Douvris, Josef Michl
Feb 25, 2010·Dalton Transactions : an International Journal of Inorganic Chemistry·Maik FinzeBernd Bastian Schaack
Feb 25, 2015·Dalton Transactions : an International Journal of Inorganic Chemistry·Russell N Grimes
May 26, 2017·Chemphyschem : a European Journal of Chemical Physics and Physical Chemistry·Timothy Clark
Jul 15, 2015·Dalton Transactions : an International Journal of Inorganic Chemistry·Szymon Z KonieczkaMaik Finze
Jan 22, 2009·Chemistry : a European Journal·Christof M JägerTimothy Clark
Nov 3, 2017·Dalton Transactions : an International Journal of Inorganic Chemistry·Dmitry S PerekalinFabrizia Fabrizi de Biani
May 15, 2019·Journal of the American Chemical Society·Benjamin WigmanHosea M Nelson
Oct 9, 2007·Journal of the American Chemical Society·Benjamin T KingJosef Michl
Dec 15, 2006·Chemical Reviews·Stefanie KörbeJosef Michl
Apr 28, 2006·Journal of the American Chemical Society·Kamesh VyakaranamJosef Michl
Aug 24, 2006·Journal of the American Chemical Society·Timothy Clark

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