Phosphonylated polymers are attractive materials due to their applications in chemical sensors and their unique electronic properties. Because of its mild reaction conditions and simple protocol, anodic phosphonylation is a favorable strategy for introducing phosphonate into the main chains of π-conjugated polymers. However, the precursor polymer for the reaction remains limited to poly(3-hexylthiophene), and in addition, the degree of substitution is still low. Here, we demonstrated the anodic phosphonylation of thiophene–fluorene alternating copolymers (P(Fl-Th)) using triethyl phosphite as a phosphonate source. The reaction proceeded efficiently in the presence of 2,6-lutidine, and the phosphonate was selectively introduced into the electron-rich thiophene moiety. The optoelectronic properties of the phosphonylated polymer were gradually varied by tuning the degree of substitution. Interestingly, various trialkyl phosphites, such as P(OⁿBu)₃, P(OⁱPr)₃, and P(OC₂H₄Cl)₃, were suitable for the anodic phosphonylation. We also found that the phosphonate groups could be introduced into the fluorene moieties through the design of appropriate precursor polymers. Furthermore, constant-potential anodic phosphonylation instead of the constant-current method led to quantitative functionalization.

中文翻译：

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通过阳极 C-H 磷酸化对噻吩-芴交替共聚物进行电化学后官能化

膦酰化聚合物由于其在化学传感器中的应用及其独特的电子特性而成为有吸引力的材料。由于其温和的反应条件和简单的方案，阳极膦酰化是将膦酸酯引入π共轭聚合物主链的有利策略。然而，用于反应的前体聚合物仍然限于聚(3-己基噻吩)，此外，取代度仍然较低。在这里，我们演示了使用亚磷酸三乙酯作为膦酸源对噻吩-芴交替共聚物（P(Fl-Th)）进行阳极膦酰化。反应在2,6-二甲基吡啶存在下有效进行，并且膦酸酯被选择性地引入富电子噻吩部分。通过调节取代度逐渐改变膦酰化聚合物的光电性质。有趣的是，各种亚磷酸三烷基酯，例如P(O ⁿ Bu) ₃、P(O ⁱ Pr) ₃和P(OC ₂ H ₄ Cl) ₃，都适合阳极膦酰化。我们还发现，通过设计适当的前体聚合物，可以将膦酸酯基团引入芴部分。此外，恒电位阳极磷酸化代替恒电流方法导致了定量功能化。