Functional Two-Dimensional Coordination Polymer Exhibiting Luminescence Detection of Nitroaromatics

A polyfluorinated-aromatic carboxylic acid has been designed and synthesized by the acylation reaction, tetrafluoro-bis(3,5-dicarboxyphenyl)terephthalamide (H 4 bdtfa), which assembled with Zn 2+ ions in the mixed solvents of DMF, py, and H 2 O under solvothermal conditions to produce a two-dimensional (2D) coordination polymer (CP), {[Zn 2 (bdtfa)(py) 3 (H 2 O)]·2DMF} n ( 1 ), (py = pyridine, DMF = N, N′ -dimethylmethanamide). The final structure has been carefully characterized by various methods including single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), infrared (IR) spectroscopy, and thermogravimetric analysis. Two types of four-coordinated Zn 2+ centers present a 2D “ sql ”-type layer through bdtfa 4– ligands, and the adjacent layers are connected through hydrogen bonds and π···π stacking interactions to produce a three-dimensional supramolecular framework. Luminescent results reveal that CP 1 can be regarded as a highly sensitive sensor for detecting nitroaromatics based on the fluorescence quenching effect. Moreover, the reason for the luminescent response of CP 1 toward nitroaromatics has been investigated by theoretical calculations, which indicates that the reason for the quenching can be primarily due to the energy- and electron-transfer as well as the electrostatic interaction between nitroaromatics and CP 1 .