Stereo-electronic effect of the perfluoropropyl group on the solid-state molecular packing of isomeric dibenzo[ a , c ]phenazine derivatives
Stereo-electronic effect of the perfluoropropyl group on the solid-state molecular packing of isomeric dibenzo[ a , c ]phenazine derivatives
复制标题
全氟丙基对异构二苯并[a,c]吩嗪衍生物固态分子堆积的立体电子效应
DOI：
10.1039/d2ce00019a
复制
发表时间：
2022
期刊：
影响因子：
3.1
通讯作者：
Sun, Haoran
中科院分区：
文献类型：
--
作者：
Putta, Anjaneyulu;Gairhe, Shankar;Feng, Yao;Sun, Haoran
本文报道了三种全氟丙基化二苯并[a，c]吩嗪结构异构体的合成、表征和晶体结构，它们之间唯一的区别是全氟丙基取代基的位置。这些全氟丙基化二苯并[a，c]吩嗪异构体的晶体结构表明，全氟丙基对二苯并[a，c]吩嗪分子的立体电子效应在决定固态晶体堆积基序中起着至关重要的作用。我们的结果从X射线晶体学和计算方法表明，全氟丙基基团的位置上的二苯并[a，c]吩嗪环显着影响静电势分布沿着的芳环表面，导致在固态下的分子包装的急剧变化，从人字形到层状晶体包装，在这三个宪法异构体。简单的拓扑考虑在固态的分子包装是巧合的合作与静电势分布的变化，局部的部分正电荷和部分负电荷可能占主导地位的芳香环之间的分子间相互作用。总之，二苯并[a，c]吩嗪环上的全氟丙基化为我们提供了一个幸运的场景，其中分子拓扑结构和静电势共同作用，以促进形成所需的层状π-π堆叠晶体堆积。同时，电化学、紫外-可见吸收光谱和发射光谱以及计算化学的结果表明，改变二苯并[a，c]吩嗪核上全氟烷基化基团的位置，分子的电子性质只发生轻微到中等程度的变化.虽然通过设计控制芳烃的固态结构还有很长的路要走，但我们希望我们的工作将点燃一个火花，可能会蔓延到有机固态材料的设计领域。
We report here the synthesis, characterization, and crystal structures of three perfluoropropylated dibenzo[a,c]phenazine constitutional isomers, in which the only difference among them was the positions of the perfluoropropyl substituents. The crystal structures of these perfluropropylated dibenzo[a,c]phenazine isomers indicated that the stereo-electronic effect of the perfluoropropyl group on the dibenzo[a,c]phenazine molecule plays a crucial role in determining the crystal-packing motif in the solid state. Our results from both X-ray crystallography and computational approaches revealed that the positions of the perfluoropropyl groups on the dibenzo[a,c]phenazine ring significantly affected the electrostatic potential distribution along the aromatic ring surface, resulting in drastic changes in the molecular packing in the solid state, from herringbone to lamellar crystal packing, among these three constitutional isomers. Simple topological consideration of the molecular packing in the solid state was coincidently cooperative with the changes in the electrostatic potential distributions, where localized partial positive and partial negative charges perhaps dominated the intermolecular interactions between the aromatic rings. Together, the perfluoropropylation on the dibenzo[a,c]phenazine ring provided us with a fortunate scenario, wherein the molecular topological structure and electrostatic potential worked together to facilitate the formation of the desired lamellar π–π stacked crystal packing. Meanwhile, electrochemistry, UV-visible absorption and emission spectra, and the computational chemistry results pointed out that there were only minor to moderate changes in the electronic properties of the molecules upon changing the position of the perfluoroalkylation on the dibenzo[a,c]phenazine core. While controlling the solid-state structure of aromatics by design still has a long way to go, we hope that our work will ignite a spark that can potentially spread into the field of the design of organic solid-state materials.