Two New Luminescent Metal-Organic Frameworks as Fluorescent Sensors of Nitrobenzene, Fe3+, and Cr2O72-

Two new luminescent metal-organic frameworks (MOFs), namely, [Zn-2(H<bold>L</bold>)(2)](n)<bold>(1)</bold> and {[Cd-2(H<bold>L</bold>)(2)(H2O)(2)]& sdot;(H2O)(0.5)}(n) (<bold>2</bold>) [H-3<bold>L</bold> = 5-((4-(1H-1,2,4-triazol-1-yl)benzyl)amino)isophthalic acid ligand], have been solvothermally synthesized and characterized. Single-crystal x-ray diffraction shows that <bold>1</bold> exhibits a 3D framework, whereas <bold>2</bold> features 2D network. Furthermore, the fluorescence studies demonstrated that <bold>1</bold> and <bold>2</bold> exhibited luminescent sensing activity for nitrobenzene (NB), Fe3+ ions, and Cr2O72- anions with high selectivity, high sensitivity, and low detection limit, the corresponding detection limits of <bold>1</bold> were 6.40 x 10(-7), 1.26 x 10(-7), and 1.44 x 10(-7) M, respectively, and that of <bold>2</bold> were 2.42 x 10(-6), 3.41 x 10(-7), and 2.90 x 10(-7) M, respectively. <bold>1</bold> and <bold>2</bold> exhibited excellent solvent, pH, and thermal stabilities. The results suggested that both <bold>1</bold> and <bold>2</bold> can be considered as potential fluorescent sensors of NB, Fe3+ ions, and Cr2O72- anions.