TNP [OVAL]

A new barium(II)-based coordination polymer, poly[half[mu(7)-2,5-bis-(4-carboxy-phenylsulfanyl)-terephthalic acid-kappa O-7(1):O-2:O-3#3:O-4#1:O-4#4:O-5#2:O-5#4]barium(II)], [Ba(PSTP)(0.5)(H2O)](n) (1), was synthesized through a simple solvothermal method using Ba-II ions and 2,5-bis-(4-carboxy-phenylsulfanyl)-terephthalic acid (H4PSTP). The asymmetric unit includes one Ba-II center, half of PSTP4- ligand and one coordinated water molecule. Thermal stability, IR spectroscopy, el. emental analysis, powder X-ray diffraction, solid-state photoluminescence, and the ability to detect small organic molecules as a fluorescent probe were investigated. Experimental results indicate that 2,4,6-trinitrophenol (TNP) and p-nitroaniline (4-NA) have a strong quenching effect on the fluorescence of 1 (dispersed in DMF solution), and the quenching rate is as high as 99.7% and 99.2%, respectively. The quenching constant K-sv is 9.6 x 10(5) M-1 and 5.4 x 105 M-1, respectively. The calculated LOD (limit of detection) values are 0.56 ppm (for 4-NA) and 0.31 ppm (for TNP), respectively. It can be used as a good fluorescent probe to detect TNP and 4-NA effectively with high selectivity and high sensitivity.

A new Zn(II)-based coordination polymer (CP), [Zn(HL)center dot 1.5H(2)O] (1), has been synthesized using 4-(2,4,6-tricarboxylphenyl)-3,2,6,4-terpyridine (H3L). Single-crystal X-ray diffraction reveals that 1 possesses a 2D layer-like structure, which further connects through hydrogen bonding interactions to form a 3D supramolecular network. The luminescence measurements showed that 1 is capable of detecting nitro-aromatic compounds (NACs) in particular 2,4,6-trinitrophenol (TNP) as well as Fe3+ ions with high sensitivity and selectivity in aqueous medium. The limit of detections (LODs) for the recognition of TNP and Fe3+ are 1.23 and 0.94 ppm, respectively. The reason for decrease in intensity of emission of 1 on addition of NACs to it has been examined by theoretical calculations which suggested that charge transfer is taking place between 1 and NACs which may be the prime reason for the decrease in emission intensity. [GRAPHICS] .