Solvo-thermal Preparation and Characterization of Two CdII Coordination Polymers Constructed From 2,6-(1,2,4-Triazole-4-yl)pyridine and 5-R-Isophthalic Acid (R = Nitro, Sulfo)

Under the solvo-thermal conditions, two novel Cd-II mixed-ligand coordination materials with 2,6-(1,2,4-triazole-4-yl)pyridine(L-1) and aromatic poly-carboxylic acid co-ligands such as 5-R-isophthalic acid (R = nitro, sulfo), namely [Cd(L-1)(NO2-BDC)(H2O)(2)]center dot 2H(2)O (1) and [Cd(L-1)(HSIP)(H2O)]center dot 4H(2)O (2) (NO2-H2BDC = 5-nitroisophthalic acid, H3SIP = 5-sulfobenzene -isophthalic acid) were successfully prepared. These Cd-II mixed-ligand coordination polymers 1-2 have been measured by crystal X-ray analysis, FT-IR spectra and powder X-ray diffraction analyses. In 1, these seven-coordinate Cd-II atoms (Cd1) are inter-linked by didentate 5-nitroisophthalic acid ligands forming 1D chain structures. In 2, these L-1 and partially de-pronated HSIP2- are inter-linked by central Cd-II centers and are arranged into the unique 2D micro-porous metal-organic framework of 2. Side view of 2, it is noted that numerous oxygen atoms of un-coordinated carboxylate groups and coordinated SO3 groups protrude out and decorate the 2D framework of 2. PXRD patterns of 1 and 2 sample is tested, which is consistent with the simulated PXRD diffraction pattern. Photoluminescence studies show that 2 is highly selective and sensitive to trace elements of Eu3+ with excellent K-sv value (7.86 x 10(4) m(-)(1)) and low detection limit (5.56 x 10(-2) mM), which also provides a convenient method and platform for real-time detection of Eu3+.