COA of Formula: C5H3Br2NIn 2020 ,《Regioselective, stereoselective, and living polymerization of divinyl pyridine monomers using rare earth catalysts》 appeared in Polymer Chemistry. The author of the article were Yan, Chao; Liu, Zhao-Xuan; Xu, Tie-Qi. The article conveys some information:
The first regioselective, stereoselective, and living polymerization of divinyl pyridine monomers, mediated by simple rare earth catalysts, is reported. The polymerization by Ln(CH2SiMe3)3(L)2 (Ln = Sc, Y, Lu, Dy; L = THF, Py) is perfectly regioselective for a 2,5-divinylpyridine (DVP) monomer, and the process only concerned the double bond at the 2-position of DVP and the C=C bond at the 5-position selectively remained unreacted. In contrast, the polymerization of DVP by La(CH2SiMe3)3(THF)2 is not regioselective, producing a crosslinking network. The polymerization by Lu(CH2SiMe3)3(Py)2/B(C6F5)3 is most stereoselective, yielding perfect isotactic PDVP with mmmm >99%. The isoselectivity (mm) of the polymers could be controlled in a range of 31% to 99% by adjusting the amount of THF added. The DVP polymerization is controlled by Lu[CH(C5H4N)CH2CH2SiMe3]3 (formed via in situ mixing of Lu(CH2SiMe3)3(THF)2 and 2-vinylpyridine), with the mol. weight (Mn) matching the theor. value of monomer conversion and a narrow dispersity. The stereoblock polymerization of DVP with 2-vinylpyridine was achieved by adding the monomer sequentially. The post-functionalization of stereoblock polymers containing vinyl groups has been achieved by the thiol-ene “”click”” reaction in which all the C=C double bonds are quant. converted to thioether bonds. The experimental process involved the reaction of 2,5-Dibromopyridine(cas: 624-28-2COA of Formula: C5H3Br2N)
2,5-Dibromopyridine(cas: 624-28-2) belongs to pyridine. Pyridine and pyridine-derived structures are privileged pharmacophores in medicinal chemistry and an essential functionality for organic chemists. As the prototypical π-deficient heterocycle, pyridine illustrates distinctive chemistry as both substrate and reagent. COA of Formula: C5H3Br2N