RESUMO
Porous molecular crystals are an emerging class of porous materials that is unique in being built from discrete molecules rather than being polymeric in nature. In this study, we examined the effects of molecular structure of the precursors on the formation of porous solid-state structures with a series of 16 rigid aromatics. The majority of these precursors possess pyrazole groups capable of hydrogen bonding, as well as electron-rich aromatics and electron-poor tetrafluorobenzene rings. These precursors were prepared using a combination of Pd- and Cu-catalyzed cross-couplings, careful manipulations of protecting groups on the nitrogen atoms, and solvothermal syntheses. Our study varied the geometry and dimensions of precursors, as well as the presence of groups capable of hydrogen bonding and [π···π] stacking. Thirteen derivatives were crystallographically characterized, and four of them were found to be porous with surface areas between 283 and 1821 m2 g-1. Common to these four porous structures were (a) rigid trigonal geometry, (b) [π···π] stacking of electron-poor tetrafluorobenzenes with electron-rich pyrazoles or tetrazoles, and
RESUMO
Dicarboxylic acids are important chemicals in human metabolism and various industries. Differentiation between the isomers and members of a homologous series is a challenge, due to their similar properties. We show that a triazine-based fluorinated AIEgen can recognize dicarboxylic acids with selectivity based on the relative position of the two -COOH groups.
RESUMO
Trigonal fluorinated pyrazoles assemble into porous molecular crystals and show solid-state fluorescence. However, in a DMF/H2O mixed solvent system, the triazine-centered compound displays aggregation-induced emission, while its benzene-based counterpart does not.