AIE-Active Tetrazolyl Tetraphenylethylene-Based Metal–Organic Framework as Highly Selective Chemosensor for Nitro Explosives

The development of fast and sensitive fluorescence sensors for nitro-explosive detection in aqueous environments remains a critical challenge for security and environmental monitoring. This work presents two novel metal–organic frameworks (MOFs) constructed from tetrakistetrazole-functionalized tetraphenylethylene (H 4 tazope), an aggregation-induced emission (AIE)-active ligand. Assembled with Cd(II) and Co(II) ions, the multidentate molecule based on the TPE core can afford neutral and anionic coordination polymers 1 and 2 with rare nona- and octa-coordinating bridging modes for each tetrakistetrazole ligand, in which the framework structures show the unprecedented 2D 3-nodal with the point symbol of {3 2 .4 6 .3.4 2 .3.5 2 .4.6 2 .5 2 .4 2 }{3}{4 6 .3 2 .5 2 } and 2-fold interpenetrated (4,12)-connected topological networks, respectively. Detailed research on the use of the luminescent MOF with TPE chromophore attached with four tetrazolyl substituents for highly selective fluorescence-based aqueous-phase explosive detection was also conducted. An unprecedented 2D 3-nodal topological network with AIE-active tetrazolyl-tetraphenylethene ligand exhibits promising application prospects in nitro-explosive detection.