Houck Matthew B, Brown Loren C, Lambeth Robert H, Iacono Scott T
Department of Chemistry and Chemistry Research Center, Laboratories for Advanced Materials, United States Air Force Academy, Colorado Springs, Colorado 80840, United States.
Composites and Hybrid Materials Branch, Army Research Laboratory, Aberdeen Proving Grounds, Maryland 21005, United States.
ACS Macro Lett. 2020 Jul 21;9(7):964-968. doi: 10.1021/acsmacrolett.0c00298. Epub 2020 Jun 16.
Fluorinated molecules containing reactive functionalities are of great interest to the materials community as these compounds can be used to prepare fluorinated polymers with desirable physical and electronic properties. Despite their potential, many of these compounds are limited by their synthesis which generally requires transition-metal-catalyzed coupling reactions or harsh fluorinating conditions. Perfluoroheteroaromatic compounds provide a unique solution to this problem as compounds such as perfluoropyridine can undergo SAr reactions with a wide range of simple nucleophiles in a controlled and regioselective manner. Herein we report the transition-metal-free synthesis of a pool of highly soluble high aromatic content (HAC) perfluoropyridine-based thermosetting precursors and compounds of interest which can be easily obtained from readily available chemical precursors using simple nucleophilic chemistries. These thermally active monomers cure readily, in 350-400 °C temperature ranges, into highly densified polyaryelene networks and demonstrate decomposition temperatures well above 400 °C and high char yields at 900 °C, making these promising materials for high-temperature applications as well as templates for carbon-based nanomaterials.
含有反应性功能团的氟化分子引起了材料界的极大兴趣,因为这些化合物可用于制备具有理想物理和电子性能的氟化聚合物。尽管它们具有潜力,但许多此类化合物的合成受到限制,其合成通常需要过渡金属催化的偶联反应或苛刻的氟化条件。全氟杂芳族化合物为这个问题提供了独特的解决方案,因为诸如全氟吡啶之类的化合物可以与多种简单亲核试剂以可控的区域选择性方式进行亲核芳香取代(SAr)反应。在此,我们报告了一系列高溶解性、高芳香含量(HAC)的基于全氟吡啶的热固性前体及相关化合物的无过渡金属合成方法,这些化合物可以使用简单的亲核化学方法,从容易获得的化学前体轻松制备。这些热活性单体在350-400°C的温度范围内易于固化,形成高度致密的聚亚芳基网络,并显示出远高于400°C的分解温度以及在900°C时的高残炭率,这使得这些材料有望用于高温应用以及作为碳基纳米材料的模板。