Department of Chemistry, University of California-Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory , Kavli Energy NanoSciences Institute at Berkeley and Berkeley Global Science Institute , Berkeley , California 94720 , United States.
Department of Chemical and Biomolecular Engineering, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory , University of California-Berkeley , Berkeley , California 94720 , United States.
J Am Chem Soc. 2019 Jul 17;141(28):11253-11258. doi: 10.1021/jacs.9b04731. Epub 2019 Jul 2.
Herein, we demonstrate the first example of a multistep solid-state organic synthesis, in which a new imine-linked two-dimensional covalent organic framework (COF-170, ) was transformed through three consecutive postsynthetic modifications into porous, crystalline cyclic carbamate and thiocarbamate-linked frameworks. These linkages are previously unreported and inaccessible through synthesis. While not altering the overall connectivity of the framework, these chemical transformations induce significant conformational and structural changes at each step, highlighting the key importance of noncovalent interactions and conformational flexibility to COF crystallinity and porosity. These transformations were assessed using N multiCP-MAS NMR spectroscopy, providing the first quantitation of yields in COF postsynthetic modification reactions, as well as of amine defect sites in imine-linked COFs. This multistep COF linkage postsynthetic modification represents a significant step toward bringing the precision of organic solution-phase synthesis to extended solid-state compounds.
在此，我们展示了第一个多步固态有机合成的实例，其中通过三个连续的后合成修饰，将新型亚胺键二维共价有机骨架（COF-170， ）转化为多孔、结晶的环状碳酸酯和硫代碳酸酯键合的骨架。这些键合以前是无法通过合成得到的。虽然没有改变骨架的整体连接性，但这些化学转化在每个步骤中都引起了显著的构象和结构变化，突出了非共价相互作用和构象灵活性对 COF 结晶度和孔隙率的关键重要性。这些转化使用 N 多 CP-MAS NMR 光谱进行了评估，首次对 COF 后合成修饰反应的产率以及亚胺键合 COF 中的胺缺陷位点进行了定量。这种多步 COF 键合后合成修饰代表了朝着将有机溶液相合成的精度引入扩展的固态化合物迈出的重要一步。
