Department of Chemistry, University of California, Berkeley, California 94720, United States.
J Am Chem Soc. 2021 Mar 31;143(12):4531-4535. doi: 10.1021/jacs.1c00125. Epub 2021 Mar 18.
Polyolefins are important commodity plastics, yet their lack of functional groups limits their applications. The functionalization of C-H bonds holds promise for incorporating functionalities into polymers of ethylene and α-olefins. However, the selective functionalization of polyolefins derived from alkenes, even , 1,1-substituted alkenes, has not been achieved. These polymers are less reactive, due to steric effects, and they are prone to chain scission that degrades the polymer. We report the chemoselective and regioselective oxidation of a commercially important polymer of a branched olefin, polyisobutene. A polyfluorinated ruthenium-porphyrin catalyst incorporates ketone units into polyisobutene at methylene positions without chain cleavage. The oxidized polymer is thermally stable, yet it undergoes programmed reactions and possesses enhanced wetting properties.
聚烯烃是重要的大宗塑料，但由于缺乏官能团，其应用受到限制。C-H 键的功能化有望将官能团引入到乙烯和 α-烯烃聚合物中。然而，即使是 1,1-取代的烯烃衍生的聚烯烃的选择性官能化也尚未实现。由于空间位阻效应，这些聚合物的反应性较低，并且容易发生链断裂，从而降解聚合物。我们报告了一种商业上重要的支化烯烃聚合物聚异丁烯的化学选择性和区域选择性氧化。一种多氟化钌-卟啉催化剂将酮单元结合到聚异丁烯的亚甲基位置，而不会发生链断裂。氧化后的聚合物热稳定性好，但可进行程序反应，并具有增强的润湿性。
