Hydrogen-bonded organic frameworks (HOFs) have drawn unprecedented interest because of their high crystallinity as well as facile process for construction, deconstruction, and reassembly arising from reversible bond formation-dissociation. However, structural fragility and low stability frequently prevent formation of robust HOFs with permanent porosity. Here, we report that hexakis(4-carboxyphenyl)-hexaazatriphenylene (CPHAT) forms three dimensionally networked H-bonded framework CPHAT-1. Interestingly, the activated framework CPHAT-1 a retains not only permanent porosity but single-crystallinity, enabling precise structural characterization and property evaluation on a single crystal. Moreover, CPHAT-1 a retains its framework up to 339 °C or in hot water and in acidic aqueous solution. These results clearly show that even a simple H-bonding motif can be applied for the construction of robust HOFs, which creates a pathway to establish a new class of porous organic frameworks. We also characterize its uptake of gases and I2 , in addition to a detailed photophysical study (spectroscopy and dynamics of proton and charge transfers) of its unit in solution, and of its single crystal under fluorescence microscopy, in which we observed a marked strong anistropy and narrow distribution. The results bring new findings to the area of HOFs and their possible applications in science and technology.
Keywords: carboxylic acid; crystal engineering; fluorescence; hydrogen bonds; porous organic framework.
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