Poly(iminoborane)s: An Elusive Class of Main Group Polymers

聚（亚氨基硼烷）：一类难以捉摸的主族聚合物

• 批准号: 373192637
• 负责人: Professor Dr. Holger Helten
• 金额: --
• 依托单位: Institut für Anorganische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/373192637?language=en
• 关键词: Poly; iminoborane; Elusive; Class; Main

Polymers with a backbone comprised of inorganic elements often show useful properties and functions that complement those of state-of-the-art organic macromolecular materials. Prominent examples are the well-known silicones, which are nowadays regarded as commodity products. Poly(iminoborane)s (PIBs) constitute a class of inorganic main group polymers with a linear chain of alternating boron and nitrogen atoms. Considerable theoretical interest has been devoted to these species, as they are formally BN analogs of the important semiconducting organic polymer polyacetylene. However, despite extensive experimental effort, poly(iminoborane)s have never been prepared and convincingly characterized thus far.The aim of this research project is to develop novel synthetic routes that enable the synthesis of poly(iminoborane)s with well-defined microstructure for the first time. The failure of previous attempts to obtain linear PIBs was generally due to the susceptibility of potential BN monomers to form cyclic iminoborane trimers (i.e., borazines, BN analogs of benzene) instead. This project focuses on two strategies to prevent ring formation during the polymerization process. The idea of the first approach is to link two boron or two nitrogen atoms of the backbone via a hydrocarbon bridge. This provides a geometrical constraint that makes the unwanted cyclization with formation of borazines impossible. Poly(iminoborane)s composed of various types of heterocyclic systems are targeted that may be aromatic, non-aromatic, or anti-aromatic.The idea of the second approach is to develop novel chain growth polycondensation processes to access poly(iminoborane)s. The growing polymer chain generated should have functional groups of the same kind on both chain ends. Consequently, the competing formation of cyclic species, which would require the presence of two complementary end groups, should be prevented at any stage of the polymerization process. Novel, possibly catalytic B-N bond formation methods will be developed and their applicability in polymerization procedures will be explored.Besides interesting electronic features anticipated to be associated with this novel class of macromolecules, solution-processable poly(iminoborane)s may be valuable polymeric precursors for the fabrication of shaped ceramics such as hexagonal boron nitride, a desirable insulator and thermal conductor that is isoelectronic with graphite/graphene. Boron-rich materials are also of interest for use in boron neutron capture therapy (BNCT) for cancer. Moreover, the synthesis of PIB block copolymers will be pursued with this project. Self-assembly of the resulting materials will be investigated for applications in nanoscience.

主链由无机元素组成的聚合物通常显示出有用的特性和功能，与最先进的有机高分子材料互补。最突出的例子是众所周知的有机硅，它们如今被视为商品。聚(亚胺硼烷)S(PIB)是一类由硼、氮原子链交替排列的无机主族聚合物。由于这些物种在形式上是重要的半导体有机聚合物聚乙炔的BN类似物，所以在理论上对它们很感兴趣。然而，尽管进行了大量的实验研究，但到目前为止，还没有合成出具有令人信服的表征的聚亚胺硼烷S。本研究项目的目的是开发新的合成路线，使之能够合成具有明确微观结构的聚亚胺硼烷S。先前获得线性PIB的尝试的失败通常是由于潜在的BN单体易形成环亚胺硼烷三聚体(即，硼氮杂环苯的BN类似物)。本项目的重点是防止聚合过程中环形成的两种策略。第一种方法的想法是通过碳氢桥将主干上的两个硼或两个氮原子连接起来。这提供了几何约束，使得不需要的与形成硼氮杂环化的环化是不可能的。聚亚胺硼烷S由各种类型的杂环体系组成，目标可能是芳香的、非芳香的或反芳香的。第二种方法的思想是开发新的链长缩聚工艺来获得聚亚胺硼烷S。生成的成长聚合物链的两端应该具有相同类型的官能团。因此，在聚合过程的任何阶段都应防止环状物种的竞争形成，这将需要两个互补的端基的存在。除了有望与这种新型大分子相关的有趣的电子特征外，可溶液处理的聚亚胺硼烷S可能是制备成形陶瓷的有价值的聚合物前体，如六方氮化硼、理想的绝缘体和与石墨/石墨烯等电子的热导体。富含硼的材料也被用于癌症的硼中子俘获疗法(BNCT)。此外，该项目还将致力于聚异丁二烯嵌段共聚物的合成。这种材料的自组装将被研究在纳米科学中的应用。