Highly Sensitive Fluorescent Sensing for Nitrobenzene of Cd Complexes Based on Three Isomers and a Bis-Imidazole Ligand.

Detection of nitro pollutants is an important topic in environmental protection. A total of 3 Cd (II) complexes (-) based on 3 soft organic isomers, n-(3,5-dicarboxylato benzyloxy) benzoic acid ( = 2, 3 or 4-HDBB), and a linear N-donor ligand, 3-bis(imidazole-l-ylmethyl) benzene (3-bibz), have been synthesized hydrothermally. Structural diversity of Complexes - displays the architectural 2D or 3D change: Complex exhibits a 2D network featuring tri-nuclear metal units, Complex is a 3D framework based on similar tri-nuclear metal units, and Complex shows a 3D network with binuclear units. Fluorescent sensing properties exhibited in all these complexes have been discovered to detect nitrobenzene (NB) selectively and sensitively. In particular, Complex possesses high sensitivity for NB with the lowest detection limit of 1.15 × 10 M. The results of the theoretical calculation verified the fluorescence detection mechanism of NB by these Cd-based complexes. Therefore, these Cd-based complexes might be used as excellent luminescent sensors for NB.