Pressure-Induced Polymerization of Polycyclic Arene-Perfluoroarene Cocrystals: Single Crystal X-ray Diffraction Studies, Reaction Kinetics, and Design of Columnar Hydrofluorocarbons
Pressure-Induced Polymerization of Polycyclic Arene-Perfluoroarene Cocrystals: Single Crystal X-ray Diffraction Studies, Reaction Kinetics, and Design of Columnar Hydrofluorocarbons
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多环芳烃 - 全氟芳烃共晶的压力诱导聚合：单晶X射线衍射研究、反应动力学及柱状氢氟烃的设计
DOI：
10.1021/jacs.0c09021
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发表时间：
2020-11-04
影响因子：
15
通讯作者：
Marder, Todd B.
中科院分区：
文献类型：
--
作者：
Friedrich, Alexandra;Collings, Ines E.;Marder, Todd B.
芳香族化合物的压力诱导聚合导致含有sp（3）碳键网络的新型材料。通过分子间相互作用（如芳烃-全氟芳烃相互作用）选择分子种类并控制它们在晶体结构中的排列，可以实现目标聚合物的设计。我们已经研究了两个多环1：1芳烃-全氟芳烃共晶，萘/八氟萘（NOFN）和蒽/八氟萘（AOFN）的晶体结构压缩和压力诱导聚合反应动力学，分别高达25和30 GPa，使用单晶同步辐射X射线衍射，红外光谱和基于密度泛函理论的理论计算。我们的研究表明，芳烃-全氟芳烃平行π堆积排列具有显著的压力稳定性，并且通过ca. 19-22%，达到临界反应距离。在20 GPa下NOFN（18.8%）和25 GPa下AOFN（8.7%）沿着堆叠方向的进一步强的、不连续的和不可逆的减少表明通过形成α-键合聚合物的压力诱导的π堆叠的破裂。的结构变形与发生的化学反应的关联被确认通过使用红外光谱的高压动力学研究，表明一维聚合物生长。完全聚合的高压相组成的氢氟烃的高度有序的棒的结构预测的基础上提出的理论计算，这是非常符合实验确定的晶胞参数。我们表明，聚合发生沿着芳烃-全氟芳烃π-堆积方向和列的横向延伸取决于芳烃和全氟芳烃分子的延伸。
Pressure-induced polymerization of aromatic compounds leads to novel materials containing sp(3) carbon-bonded networks. The choice of the molecular species and the control of their arrangement in the crystal structures via intermolecular interactions, such as the arene-perfluoroarene interaction, can enable the design of target polymers. We have investigated the crystal structure compression and pressure-induced polymerization reaction kinetics of two polycyclic 1:1 arene-perfluoroarene cocrystals, naphthalene/octafluoronaphthalene (NOFN) and anthracene/octafluoronaphthalene (AOFN), up to 25 and 30 GPa, respectively, using single-crystal synchrotron X-ray diffraction, infrared spectroscopy, and theoretical computations based on density-functional theory. Our study shows the remarkable pressure stability of the parallel arene-perfluoroarene pi-stacking arrangement and a reduction of the interplanar pi-stacking separations by ca. 19-22% before the critical reaction distance is reached. A further strong, discontinuous, and irreversible reduction along the stacking direction at 20 GPa in NOFN (18.8%) and 25 GPa in AOFN (8.7%) indicates the pressure-induced breakdown of pi-stacking by formation of a-bonded polymers. The association of the structural distortion with the occurrence of a chemical reaction is confirmed by a high-pressure kinetic study using infrared spectroscopy, indicating one-dimensional polymer growth. Structural predictions for the fully polymerized high-pressure phases consisting of highly ordered rods of hydrofluorocarbons are presented based on theoretical computations, which are in excellent agreement with the experimentally determined unit-cell parameters. We show that the polymerization takes place along the arene-perfluoroarene pi-stacking direction and that the lateral extension of the columns depends on the extension of the arene and perfluoroarene molecules.