Department of Materials and Life Chemistry, Kanagawa University, Rokkakubashi, Kanagawa-ku, Yokohama, 221-8686, Japan.
Macromol Rapid Commun. 2018 Feb;39(3). doi: 10.1002/marc.201700586. Epub 2017 Nov 20.
Well-controlled synthesis of ethynyl-functionalized poly(3-hexylthiophene) (P3HT) is crucial for preparation of block copolymers containing the P3HT segment by means of click coupling reaction. A well-known chain end modification method, in which Kumada-Tamao catalyst-transfer polymerization is quenched with ethynylmagnesium chloride, under various conditions is re-examined, but in all cases not only P3HT with an ethynyl group at one end but also P3HT di-ethynylated at both ends is obtained. Accordingly, Sonogashira coupling reaction of P3HT having H/Br ends with trimethylsilylacetylene is tried, followed by removal of the trimethylsilyl group, and it is found that this protocol affords exclusively P3HT with an ethynyl group at one end. This post end-modification method is applied to the synthesis of an amphiphilic diblock copolymer of P3HT and poly(2-ethyl-2-oxazoline) (PEtOx) by means of click reaction between ethynylated P3HT and PEtOx with an azide group at one end, and the product is confirmed to be free from contamination with triblock copolymer. Micellization of this block copolymer is confirmed in tetrahydrofuran (THF)/water and THF/methanol mixtures.
炔基官能化聚（3-己基噻吩）（P3HT）的可控合成对于通过点击偶联反应制备含有 P3HT 段的嵌段共聚物至关重要。一种众所周知的链末端修饰方法，其中 Kumada-Tamao 催化剂转移聚合用炔基氯化镁猝灭，在各种条件下进行重新检查，但在所有情况下，不仅得到了一端带有炔基的 P3HT，而且还得到了两端都二炔基化的 P3HT。因此，尝试了具有 H/Br 端的 P3HT 与三甲基硅基乙炔的 Sonogashira 偶联反应，然后去除三甲基硅基，发现该方案仅得到一端带有炔基的 P3HT。该后端修饰方法应用于通过一端带有叠氮基的炔基化 P3HT 和聚（2-乙基-2-恶唑啉）（PEtOx）之间的点击反应合成两亲性 P3HT-PEtOx 嵌段共聚物，并且产物被确认不含三嵌段共聚物。该嵌段共聚物在四氢呋喃（THF）/水和 THF/甲醇混合物中的胶束化得到确认。
