Tetraphenylpyrazine-Based Manganese Metal-Organic Framework as a Multifunctional Sensor for Cu, Cr, MnO, and 2,4,6-Trinitrophenol and the Construction of a Molecular Logical Gate.

A tetraimidazole-decorating tetraphenylpyrazine has been designed and utilized for the fabrication of a novel metal-organic framework (MOF), denoted as {Mn(Tipp)(A)}·2HO (TippMn, where Tipp = 2,3,5,6-tetrakis[4-[(1-imidazol-1-yl)methyl]phenyl]pyrazine and A = deprotonation of 1,4-naphthalenedicarboxylic acid), through hydrothermal synthesis. Structural analysis reveals that TippMn possesses a 2-fold-interpenetrated 4,8-connected three-dimensional (3D) network with an unprecedented {4·6}{4·6} topology. Fluorescent spectral investigations indicate that TippMn shows discriminative fluorescence when treated by Cr and Cu, giving an INHIBIT logical gate performance. Meanwhile, TippMn can be further used as a sensor for MnO and 2,4,6-trinitrophenol (TNP) by fluorescence quenching. Notably, the sensing processes toward Cu, Cr, MnO, and TNP are labeled with high selectivity and sensitivity, quick response, and good recyclability. It is anticipated that this MOF-based versatile sensor could shed light on the exploration of MOFs for fluorescent sensors, optical switches, etc.