Iodido{4-phenyl-1-[1-(1,3-thia­zol-2-yl-κN)ethyl­idene]thio­semicarbazidato-κ2 N′,S}{4-phenyl-1-[1-(1,3-thia­zol-2-yl)ethyl­idene]thio­semicarbazide-κS}mercury(II)

In the title compound, [Hg(C12H11N4S2)I(C12H12N4S2)], the Hg atom is in a distorted square-pyramidal coordination, defined by the iodide ligand, by the S atom of the neutral ligand in the apical position, and by the N atom of the thia­zole ring, the thio­ureido N and the S atom of the deprotonated ligand. The deprotonated ligand intra­molecularly hydrogen bonds to the thia­zole ring N atom, while the deprotonated ligand forms an inter­molecular hydrogen bond to the thiol­ate S atom. The deprotonation of the tridentate ligand and its coordination to Hg via the S atom strikingly affects the C—S bond lengths. In the free ligand, the C—S bond distance is 1.685 (7) Å, whereas it is 1.749 (7) Å in the deprotonated ligand. Similarly, the Hg—S bond distance is slightly longer to the neutral ligand [2.6682 (18) Å] than to the deprotonated ligand [2.5202 (19) Å]. The Hg—I distance is 2.7505 (8) Å

Chloridodiphen­yl{[1-(1,3-thia­zol-2-yl-κN)ethyl­idene]-4-phenyl­thio­semicarbazidato-κ2 N 1,S}tin(IV) methanol monosolvate

The title compound, [Sn(C6H5)2(C12H11N4S2)Cl]·CH4O, is formed during the reaction between 2-acetyl­thia­zole 4-phenyl­thio­semicarbazone (Hacthptsc) and diphenyl­tin(IV) dichloride in methanol. In the crystal structure, the Sn atom exhibits an octa­hedral geometry with the [N2S] anionic tridentate thio­semicarbazone ligand having chloride trans to the central N and the two phenyl groups trans to each other. The Sn—Cl distance is 2.5929 (6), Sn—S is 2.4896 (6) and Sn—N to the central N is 2.3220 (16) Å. The MeOH mol­ecules link the Sn complexes into one-dimensional chains via N—H⋯O and O—H⋯Cl hydrogen bonds

Two-step fabrication of nanoporous copper films with tunable morphology for SERS application

peer-reviewedIt is important to design and fabricate nanoporous metals (NPMs) with optimized microstructures for specific applications. In this contribution, nanoporous coppers (NPCs) with controllable thicknesses and pore sizes were fabricated via the combination of a co-sputtering of Cu/Ti with a subsequent dealloying process. The effect of dealloying time on porous morphology and the corresponding surface enhanced Raman scattering (SERS) behaviors were systematically investigated. Transmission electron microscopy (TEM) identified the presences of the gaps formed between ligaments and also the nanobumps on the nanoparticle-aggregated ligament surface, which were likely to contribute as the “hot spots” for electromagnetic enhancement. The optimal NPC film exhibited excellent SERS performance towards Rhodamine 6G (R6G) with a low limiting detection (10−9 M), along with good uniformity and reproducibility. The calculated enhancement factor of ca. 4.71 × 107 was over Au substrates and comparable to Ag systems, promising the proposed NPC as a cheap candidate for high-performance SERS substrate

Photodegradation of Selected PCBs in the Presence of Nano-TiO2 as Catalyst and H2O2 as an Oxidant

Photodegradation of five strategically selected PCBs was carried out in acetonitrile/water 80:20. Quantum chemical calculations reveal that PCBs without any chlorine on ortho-positions are closer to be planar, while PCBs with at least one chlorine atoms at the ortho-positions causes the two benzene rings to be nearly perpendicular. Light-induced degradation of planar PCBs is much slower than the perpendicular ones. The use of nano-TiO2 speeds up the degradation of the planar PCBs, but slows down the degradation of the non-planar ones. The use of H2O2 speeds up the degradation of planar PCBs greatly (by >20 times), but has little effect on non-planar ones except 2,3,5,6-TCB. The relative photodegradation rate is: 2,2′,4,4′-TCB > 2,3,5,6-TCB > 2,6-DCB ≈ 3,3′,4,4′-TCB > 3,4′,5-TCB. The use of H2O2 in combination with sunlight irradiation could be an efficient and “green” technology for PCB remediation

Optical chemosensors and reagents to detect explosives

[EN] This critical review is focused on examples reported from 1947 to 2010 related to the design of chromo-fluorogenic chemosensors and reagents for explosives (141 references). © 2012 The Royal Society of Chemistry.Financial support from the Spanish Government (project MAT2009-14564-C04) and the Generalitat Valencia (project PROMETEO/2009/016) is gratefully acknowledged. Y.S. is grateful to the Spanish Ministry of Science and Innovation for her grant.Salinas Soler, Y.; Martínez Mañez, R.; Marcos Martínez, MD.; Sancenón Galarza, F.; Costero Nieto, AM.; Parra Álvarez, M.; Gil Grau, S. (2012). Optical chemosensors and reagents to detect explosives. Chemical Society Reviews. 41(3):1261-1296. https://doi.org/10.1039/c1cs15173hS12611296413Furton, K. (2001). The scientific foundation and efficacy of the use of canines as chemical detectors for explosives. Talanta, 54(3), 487-500. doi:10.1016/s0039-9140(00)00546-4H�kansson, K., Coorey, R. V., Zubarev, R. A., Talrose, V. L., & H�kansson, P. (2000). Low-mass ions observed in plasma desorption mass spectrometry of high explosives. Journal of Mass Spectrometry, 35(3), 337-346. doi:10.1002/(sici)1096-9888(200003)35:33.0.co;2-7Walsh, M. (2001). Determination of nitroaromatic, nitramine, and nitrate ester explosives in soil by gas chromatography and an electron capture detector. Talanta, 54(3), 427-438. doi:10.1016/s0039-9140(00)00541-5Sylvia, J. M., Janni, J. A., Klein, J. D., & Spencer, K. M. (2000). Surface-Enhanced Raman Detection of 2,4-Dinitrotoluene Impurity Vapor as a Marker To Locate Landmines. Analytical Chemistry, 72(23), 5834-5840. doi:10.1021/ac0006573Yinon, J. (1982). Mass spectrometry of explosives: Nitro compounds, nitrate esters, and nitramines. Mass Spectrometry Reviews, 1(3), 257-307. doi:10.1002/mas.1280010304Mathurin, J. C., Faye, T., Brunot, A., Tabet, J. C., Wells, G., & Fuché, C. (2000). High-Pressure Ion Source Combined with an In-Axis Ion Trap Mass Spectrometer. 1. Instrumentation and Applications. Analytical Chemistry, 72(20), 5055-5062. doi:10.1021/ac000171mHallowell, S. (2001). Screening people for illicit substances: a survey of current portal technology. Talanta, 54(3), 447-458. doi:10.1016/s0039-9140(00)00543-9Vourvopoulos, G. (2001). Pulsed fast/thermal neutron analysis: a technique for explosives detection. Talanta, 54(3), 459-468. doi:10.1016/s0039-9140(00)00544-0Krausa, M., & Schorb, K. (1999). Trace detection of 2,4,6-trinitrotoluene in the gaseous phase by cyclic voltammetry. Journal of Electroanalytical Chemistry, 461(1-2), 10-13. doi:10.1016/s0022-0728(98)00162-4Steinfeld, J. I., & Wormhoudt, J. (1998). EXPLOSIVES DETECTION: A Challenge for Physical Chemistry. Annual Review of Physical Chemistry, 49(1), 203-232. doi:10.1146/annurev.physchem.49.1.203Moore, D. S. (2004). Instrumentation for trace detection of high explosives. Review of Scientific Instruments, 75(8), 2499-2512. doi:10.1063/1.1771493Martínez-Máñez, R., Sancenón, F., Hecht, M., Biyikal, M., & Rurack, K. (2010). Nanoscopic optical sensors based on functional supramolecular hybrid materials. Analytical and Bioanalytical Chemistry, 399(1), 55-74. doi:10.1007/s00216-010-4198-2Moragues, M. E., Martínez-Máñez, R., & Sancenón, F. (2011). Chromogenic and fluorogenic chemosensors and reagents for anions. A comprehensive review of the year 2009. Chemical Society Reviews, 40(5), 2593. doi:10.1039/c0cs00015aMartínez-Máñez, R., & Sancenón, F. (2005). New Advances in Fluorogenic Anion Chemosensors. Journal of Fluorescence, 15(3), 267-285. doi:10.1007/s10895-005-2626-zXu, Z., Chen, X., Kim, H. N., & Yoon, J. (2010). Sensors for the optical detection ofcyanide ion. Chem. Soc. Rev., 39(1), 127-137. doi:10.1039/b907368jNolan, E. M., & Lippard, S. J. (2008). Tools and Tactics for the Optical Detection of Mercuric Ion. Chemical Reviews, 108(9), 3443-3480. doi:10.1021/cr068000qPallavicini, P., Diaz-Fernandez, Y. A., & Pasotti, L. (2009). Micelles as nanosized containers for the self-assembly of multicomponent fluorescent sensors. Coordination Chemistry Reviews, 253(17-18), 2226-2240. doi:10.1016/j.ccr.2008.11.010Que, E. L., & Chang, C. J. (2010). Responsive magnetic resonance imaging contrast agents as chemical sensors for metals in biology and medicine. Chem. Soc. Rev., 39(1), 51-60. doi:10.1039/b914348nMohr, G. J. (2004). Tailoring the sensitivity and spectral properties of a chromoreactand for the detection of amines and alcohols. Analytica Chimica Acta, 508(2), 233-237. doi:10.1016/j.aca.2003.12.005Martínez-Máñez, R., & Sancenón, F. (2003). Fluorogenic and Chromogenic Chemosensors and Reagents for Anions. Chemical Reviews, 103(11), 4419-4476. doi:10.1021/cr010421eJ. P. Agrawal and R. D.Hodgson, Organic Chemistry of Explosives, John Wiley & Sons, Chichester, 2007, ISBN-13, 978, 0-470-02967-1, HBCumming, C. J., Aker, C., Fisher, M., Fok, M., la Grone, M. J., Reust, D., … Williams, V. (2001). Using novel fluorescent polymers as sensory materials for above-ground sensing of chemical signature compounds emanating from buried landmines. IEEE Transactions on Geoscience and Remote Sensing, 39(6), 1119-1128. doi:10.1109/36.927423Toal, S. J., & Trogler, W. C. (2006). Polymer sensors for nitroaromatic explosives detection. Journal of Materials Chemistry, 16(28), 2871. doi:10.1039/b517953jMcQuade, D. T., Pullen, A. E., & Swager, T. M. (2000). Conjugated Polymer-Based Chemical Sensors. Chemical Reviews, 100(7), 2537-2574. doi:10.1021/cr9801014Zhou, Q., & Swager, T. M. (1995). Method for enhancing the sensitivity of fluorescent chemosensors: energy migration in conjugated polymers. Journal of the American Chemical Society, 117(26), 7017-7018. doi:10.1021/ja00131a031Yang, J.-S., & Swager, T. M. (1998). Porous Shape Persistent Fluorescent Polymer Films:  An Approach to TNT Sensory Materials. Journal of the American Chemical Society, 120(21), 5321-5322. doi:10.1021/ja9742996Yang, J.-S., & Swager, T. M. (1998). Fluorescent Porous Polymer Films as TNT Chemosensors:  Electronic and Structural Effects. Journal of the American Chemical Society, 120(46), 11864-11873. doi:10.1021/ja982293qYamaguchi, S., & Swager, T. M. (2001). Oxidative Cyclization of Bis(biaryl)acetylenes:  Synthesis and Photophysics of Dibenzo[g,p]chrysene-Based Fluorescent Polymers. Journal of the American Chemical Society, 123(48), 12087-12088. doi:10.1021/ja016692oZahn, S., & Swager, T. M. (2002). Three-Dimensional Electronic Delocalization in Chiral Conjugated Polymers. Angewandte Chemie International Edition, 41(22), 4225-4230. doi:10.1002/1521-3773(20021115)41:223.0.co;2-3Amara, J. P., & Swager, T. M. (2005). Synthesis and Properties of Poly(phenylene ethynylene)s with Pendant Hexafluoro-2-propanol Groups. Macromolecules, 38(22), 9091-9094. doi:10.1021/ma051562bZhao, D., & Swager, T. M. (2005). Sensory Responses in Solution vs Solid State:  A Fluorescence Quenching Study of Poly(iptycenebutadiynylene)s. Macromolecules, 38(22), 9377-9384. doi:10.1021/ma051584yThomas III, S. W., Amara, J. P., Bjork, R. E., & Swager, T. M. (2005). Amplifying fluorescent polymer sensors for the explosives taggant 2,3-dimethyl-2,3-dinitrobutane (DMNB). Chemical Communications, (36), 4572. doi:10.1039/b508408cNarayanan, A., Varnavski, O. P., Swager, T. M., & Goodson, T. (2008). Multiphoton Fluorescence Quenching of Conjugated Polymers for TNT Detection. The Journal of Physical Chemistry C, 112(4), 881-884. doi:10.1021/jp709662wChen, S., Zhang, Q., Zhang, J., Gu, J., & Zhang, L. (2010). Synthesis of two conjugated polymers as TNT chemosensor materials. Sensors and Actuators B: Chemical, 149(1), 155-160. doi:10.1016/j.snb.2010.06.007Long, Y., Chen, H., Yang, Y., Wang, H., Yang, Y., Li, N., … Liu, F. (2009). Electrospun Nanofibrous Film Doped with a Conjugated Polymer for DNT Fluorescence Sensor. Macromolecules, 42(17), 6501-6509. doi:10.1021/ma900756wChang, C.-P., Chao, C.-Y., Huang, J. H., Li, A.-K., Hsu, C.-S., Lin, M.-S., … Su, A.-C. (2004). Fluorescent conjugated polymer films as TNT chemosensors. Synthetic Metals, 144(3), 297-301. doi:10.1016/j.synthmet.2004.04.003Levitsky, I. A., Euler, W. B., Tokranova, N., & Rose, A. (2007). Fluorescent polymer-porous silicon microcavity devices for explosive detection. Applied Physics Letters, 90(4), 041904. doi:10.1063/1.2432247Chen, L., McBranch, D., Wang, R., & Whitten, D. (2000). Surfactant-induced modification of quenching of conjugated polymer fluorescence by electron acceptors: applications for chemical sensing. Chemical Physics Letters, 330(1-2), 27-33. doi:10.1016/s0009-2614(00)00970-2Rose, A., Zhu, Z., Madigan, C. F., Swager, T. M., & Bulović, V. (2005). Sensitivity gains in chemosensing by lasing action in organic polymers. Nature, 434(7035), 876-879. doi:10.1038/nature03438Tamao, K., Uchida, M., Izumizawa, T., Furukawa, K., & Yamaguchi, S. (1996). Silole Derivatives as Efficient Electron Transporting Materials. Journal of the American Chemical Society, 118(47), 11974-11975. doi:10.1021/ja962829cSohn, H., Huddleston, R. R., Powell, D. R., West, R., Oka, K., & Yonghua, X. (1999). An Electroluminescent Polysilole and Some Dichlorooligosiloles. Journal of the American Chemical Society, 121(12), 2935-2936. doi:10.1021/ja983350iOhshita, J., & Kunai, A. (1998). Polymers with alternating organosilicon and π-conjugated units. Acta Polymerica, 49(8), 379-403. doi:10.1002/(sici)1521-4044(199808)49:83.0.co;2-zToal, S. J., Magde, D., & Trogler, W. C. (2005). Luminescent oligo(tetraphenyl)silole nanoparticles as chemical sensors for aqueous TNT. Chemical Communications, (43), 5465. doi:10.1039/b509404fSohn, H., Sailor, M. J., Magde, D., & Trogler, W. C. (2003). Detection of Nitroaromatic Explosives Based on Photoluminescent Polymers Containing Metalloles. Journal of the American Chemical Society, 125(13), 3821-3830. doi:10.1021/ja021214eSanchez, J. C., DiPasquale, A. G., Rheingold, A. L., & Trogler, W. C. (2007). Synthesis, Luminescence Properties, and Explosives Sensing with 1,1-Tetraphenylsilole- and 1,1-Silafluorene-vinylene Polymers. Chemistry of Materials, 19(26), 6459-6470. doi:10.1021/cm702299gSanchez, J. C., Urbas, S. A., Toal, S. J., DiPasquale, A. G., Rheingold, A. L., & Trogler, W. C. (2008). Catalytic Hydrosilylation Routes to Divinylbenzene Bridged Silole and Silafluorene Polymers. Applications to Surface Imaging of Explosive Particulates. Macromolecules, 41(4), 1237-1245. doi:10.1021/ma702274cSanchez, J. C., & Trogler, W. C. (2008). Efficient blue-emitting silafluorene–fluorene-conjugated copolymers: selective turn-off/turn-on detection of explosives. Journal of Materials Chemistry, 18(26), 3143. doi:10.1039/b802623hLiu, J., Zhong, Y., Lam, J. W. Y., Lu, P., Hong, Y., Yu, Y., … Tang, B. Z. (2010). Hyperbranched Conjugated Polysiloles: Synthesis, Structure, Aggregation-Enhanced Emission, Multicolor Fluorescent Photopatterning, and Superamplified Detection of Explosives. Macromolecules, 43(11), 4921-4936. doi:10.1021/ma902432mLu, P., Lam, J. W. Y., Liu, J., Jim, C. K. W., Yuan, W., Xie, N., … Tang, B. Z. (2010). Aggregation-Induced Emission in a Hyperbranched Poly(silylenevinylene) and Superamplification in Its Emission Quenching by Explosives. Macromolecular Rapid Communications, 31(9-10), 834-839. doi:10.1002/marc.200900794Liu, Y., Mills, R. C., Boncella, J. M., & Schanze, K. S. (2001). Fluorescent Polyacetylene Thin Film Sensor for Nitroaromatics. Langmuir, 17(24), 7452-7455. doi:10.1021/la010696pToy, L. G., Nagai, K., Freeman, B. D., Pinnau, I., He, Z., Masuda, T., … Yampolskii, Y. P. (2000). Pure-Gas and Vapor Permeation and Sorption Properties of Poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] (PTMSDPA). Macromolecules, 33(7), 2516-2524. doi:10.1021/ma991566eSaxena, A., Fujiki, M., Rai, R., & Kwak, G. (2005). Fluoroalkylated Polysilane Film as a Chemosensor for Explosive Nitroaromatic Compounds. Chemistry of Materials, 17(8), 2181-2185. doi:10.1021/cm048319wSaxena, A., Rai, R., Kim, S.-Y., Fujiki, M., Naito, M., Okoshi, K., & Kwak, G. (2006). Weak noncovalent Si···FC interactions stabilized fluoroalkylated rod-like polysilanes as ultrasensitive chemosensors. Journal of Polymer Science Part A: Polymer Chemistry, 44(17), 5060-5075. doi:10.1002/pola.21607Toal, S. J., Sanchez, J. C., Dugan, R. E., & Trogler, W. C. (2007). Visual Detection of Trace Nitroaromatic Explosive Residue Using Photoluminescent Metallole-Containing Polymers. Journal of Forensic Sciences, 52(1), 79-83. doi:10.1111/j.1556-4029.2006.00332.xStringer, R. C., Gangopadhyay, S., & Grant, S. A. (2010). Detection of Nitroaromatic Explosives Using a Fluorescent-Labeled Imprinted Polymer. Analytical Chemistry, 82(10), 4015-4019. doi:10.1021/ac902838cLi, J., Kendig, C. E., & Nesterov, E. E. (2007). Chemosensory Performance of Molecularly Imprinted Fluorescent Conjugated Polymer Materials. Journal of the American Chemical Society, 129(51), 15911-15918. doi:10.1021/ja0748027Bunte, G., Hürttlen, J., Pontius, H., Hartlieb, K., & Krause, H. (2007). Gas phase detection of explosives such as 2,4,6-trinitrotoluene by molecularly imprinted polymers. Analytica Chimica Acta, 591(1), 49-56. doi:10.1016/j.aca.2007.02.014Zhang, X., & Jenekhe, S. A. (2000). Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions. Macromolecules, 33(6), 2069-2082. doi:10.1021/ma991913kHou, S., Ding, M., & Gao, L. (2003). Synthesis and Properties of Polyquinolines and Polyanthrazolines Containing Pyrrole Units in the Main Chain. Macromolecules, 36(11), 3826-3832. doi:10.1021/ma025768dKim, T. H., Kim, H. J., Kwak, C. G., Park, W. H., & Lee, T. S. (2006). Aromatic oxadiazole-based conjugated polymers with excited-state intramolecular proton transfer: Their synthesis and sensing ability for explosive nitroaromatic compounds. Journal of Polymer Science Part A: Polymer Chemistry, 44(6), 2059-2068. doi:10.1002/pola.21319Nie, H., Zhao, Y., Zhang, M., Ma, Y., Baumgarten, M., & Müllen, K. (2011). Detection of TNT explosives with a new fluorescent conjugated polycarbazole polymer. Chem. Commun., 47(4), 1234-1236. doi:10.1039/c0cc03659eQin, A., Lam, J. W. Y., Tang, L., Jim, C. K. W., Zhao, H., Sun, J., & Tang, B. Z. (2009). Polytriazoles with Aggregation-Induced Emission Characteristics: Synthesis by Click Polymerization and Application as Explosive Chemosensors. Macromolecules, 42(5), 1421-1424. doi:10.1021/ma8024706Kumar, A., Pandey, M. K., Anandakathir, R., Mosurkal, R., Parmar, V. S., Watterson, A. C., & Kumar, J. (2010). Sensory response of pegylated and siloxanated 4,8-dimethylcoumarins: A fluorescence quenching study by nitro aromatics. Sensors and Actuators B: Chemical, 147(1), 105-110. doi:10.1016/j.snb.2010.02.004Nguyen, H. H., Li, X., Wang, N., Wang, Z. Y., Ma, J., Bock, W. J., & Ma, D. (2009). Fiber-Optic Detection of Explosives Using Readily Available Fluorescent Polymers. Macromolecules, 42(4), 921-926. doi:10.1021/ma802460qAlbert, K. J., & Walt, D. R. (2000). High-Speed Fluorescence Detection of Explosives-like Vapors. Analytical Chemistry, 72(9), 1947-1955. doi:10.1021/ac991397wGao, D., Wang, Z., Liu, B., Ni, L., Wu, M., & Zhang, Z. (2008). Resonance Energy Transfer-Amplifying Fluorescence Quenching at the Surface of Silica Nanoparticles toward Ultrasensitive Detection of TNT. Analytical Chemistry, 80(22), 8545-8553. doi:10.1021/ac8014356Fang, Q., Geng, J., Liu, B., Gao, D., Li, F., Wang, Z., … Zhang, Z. (2009). Inverted Opal Fluorescent Film Chemosensor for the Detection of Explosive Nitroaromatic Vapors through Fluorescence Resonance Energy Transfer. Chemistry - A European Journal, 15(43), 11507-11514. doi:10.1002/chem.200901488Geng, J., Liu, P., Liu, B., Guan, G., Zhang, Z., & Han, M.-Y. (2010). A Reversible Dual-Response Fluorescence Switch for the Detection of Multiple Analytes. Chemistry - A European Journal, 16(12), 3720-3727. doi:10.1002/chem.200902721Yang, J., Aschemeyer, S., Martinez, H. P., & Trogler, W. C. (2010). Hollow silica nanospheres containing a silafluorene–fluorene conjugated polymer for aqueous TNT and RDX detection. Chemical Communications, 46(36), 6804. doi:10.1039/c0cc01906bFeng, J., Li, Y., & Yang, M. (2010). Conjugated polymer-grafted silica nanoparticles for the sensitive detection of TNT. Sensors and Actuators B: Chemical, 145(1), 438-443. doi:10.1016/j.snb.2009.12.056Tao, S., Shi, Z., Li, G., & Li, P. (2006). Hierarchically Structured Nanocomposite Films as Highly Sensitive Chemosensory Materials for TNT Detection. ChemPhysChem, 7(9), 1902-1905. doi:10.1002/cphc.200600185Tao, S., Yin, J., & Li, G. (2008). High-performance TNT chemosensory materials based on nanocomposites with bimodal porous structures. Journal of Materials Chemistry, 18(40), 4872. doi:10.1039/b802486cTao, S., Li, G., & Zhu, H. (2006). Metalloporphyrins as sensing elements for the rapid detection of trace TNT vapor. Journal of Materials Chemistry, 16(46), 4521. doi:10.1039/b606061gTao, S., & Li, G. (2007). Porphyrin-doped mesoporous silica films for rapid TNT detection. Colloid and Polymer Science, 285(7), 721-728. doi:10.1007/s00396-007-1643-7Yildirim, A., Budunoglu, H., Deniz, H., O. Guler, M., & Bayindir, M. (2010). Template-Free Synthesis of Organically Modified Silica Mesoporous Thin Films for TNT Sensing. ACS Applied Materials & Interfaces, 2(10), 2892-2897. doi:10.1021/am100568cLi, H., Wang, J., Pan, Z., Cui, L., Xu, L., Wang, R., … Jiang, L. (2011). Amplifying fluorescence sensing based on inverse opal photonic crystal toward trace TNT detection. J. Mater. Chem., 21(6), 1730-1735. doi:10.1039/c0jm02554bTao, S., Li, G., & Yin, J. (2007). Fluorescent nanofibrous membranes for trace detection of TNT vapor. Journal of Materials Chemistry, 17(26), 2730. doi:10.1039/b618122hNaddo, T., Che, Y., Zhang, W., Balakrishnan, K., Yang, X., Yen, M., … Zang, L. (2007). Detection of Explosives with a Fluorescent Nanofibril Film. Journal of the American Chemical Society, 129(22), 6978-6979. doi:10.1021/ja070747qContent, S., Trogler, W. C., & Sailor, M. J. (2000). Detection of Nitrobenzene, DNT, and TNT Vapors by Quenching of Porous Silicon Photoluminescence. Chemistry - A European Journal, 6(12), 2205-2213. doi:10.1002/1521-3765(20000616)6:123.0.co;2-aKang, J., Ding, L., Lü, F., Zhang, S., & Fang, Y. (2006). Dansyl-based fluorescent film sensor for nitroaromatics in aqueous solution. Journal of Physics D: Applied Physics, 39(23), 5097-5102. doi:10.1088/0022-3727/39/23/030Zhang, S., Lü, F., Gao, L., Ding, L., & Fang, Y. (2007). Fluorescent Sensors for Nitroaromatic Compounds Based on Monolayer Assembly of Polycyclic Aromatics. Langmuir, 23(3), 1584-1590. doi:10.1021/la062773sHe, G., Zhang, G., Lü, F., & Fang, Y. (2009). Fluorescent Film Sensor for Vapor-Phase Nitroaromatic Explosives via Monolayer Assembly of Oligo(diphenylsilane) on Glass Plate Surfaces. Chemistry of Materials, 21(8), 1494-1499. doi:10.1021/cm900013fGoodpaster, J. V., & McGuffin, V. L. (2001). Fluorescence Quenching as an Indirect Detection Method for Nitrated Explosives. Analytical Chemistry, 73(9), 2004-2011. doi:10.1021/ac001347nHughes, A. D., Glenn, I. C., Patrick, A. D., Ellington, A., & Anslyn, E. V. (2008). A Pattern Recognition Based Fluorescence Quenching Assay for the Detection and Identification of Nitrated Explosive Analytes. Chemistry - A European Journal, 14(6), 1822-1827. doi:10.1002/chem.200701546Malashikhin, S., & Finney, N. S. (2008). Fluorescent Signaling Based on Sulfoxide Profluorophores: Application to the Visual Detection of the Explosive TATP. Journal of the American Chemical Society, 130(39), 12846-12847. doi:10.1021/ja802989vFocsaneanu, K.-S., & Scaiano, J. C. (2005). Potential analytical applications of differential fluorescence quenching: pyrene monomer and excimer emissions as sensors for electron deficient molecules. Photochemical & Photobiological Sciences, 4(10), 817. doi:10.1039/b505249aLee, Y. H., Liu, H., Lee, J. Y., Kim, S. H., Kim, S. K., Sessler, J. L., … Kim, J. S. (2010). Dipyrenylcalix[4]arene-A Fluorescence-Based Chemosensor for Trinitroaromatic Explosives. Chemistry - A European Journal, 16(20), 5895-5901. doi:10.1002/chem.200903439Jian, C., & Seitz, W. R. (1990). Membrane for in situ optical detection of organic nitro compounds based on fluorescence quenching. Analytica Chimica Acta, 237, 265-271. doi:10.1016/s0003-2670(00)83928-8Vijayakumar, C., Tobin, G., Schmitt, W., Kim, M.-J., & Takeuchi, M. (2010). Detection of explosive vapors with a charge transfer molecule: self-assembly assisted morphology tuning and enhancement in sensing efficiency. Chemical Communications, 46(6), 874. doi:10.1039/b921520dZyryanov, G. V., Palacios, M. A., & Anzenbacher, P. (2008). Simple Molecule-Based Fluorescent Sensors for Vapor Detection of TNT. Organic Letters, 10(17), 3681-3684. doi:10.1021/ol801030uCavaye, H., Shaw, P. E., Wang, X., Burn, P. L., Lo, S.-C., & Meredith, P. (2010). Effect of Dimensionality in Dendrimeric and Polymeric Fluorescent Materials for Detecting Explosives. Macromolecules, 43(24), 10253-10261. doi:10.1021/ma102369qPonnu, A., & Anslyn, E. V. (2010). A fluorescence-based cyclodextrin sensor to detect nitroaromatic explosives. Supramolecular Chemistry, 22(1), 65-71. doi:10.1080/10610270903378032Zhang, C., Che, Y., Yang, X., Bunes, B. R., & Zang, L. (2010). Organic nanofibrils based on linear carbazole trimer for explosive sensing. Chemical Communications, 46(30), 5560. doi:10.1039/c0cc01258kLi, Z., Dong, Y. Q., Lam, J. W. Y., Sun, J., Qin, A., Häußler, M., … Tang, B. Z. (2009). Functionalized Siloles: Versatile Synthesis, Aggregation-Induced Emission, and Sensory and Device Applications. Advanced Functional Materials, 19(6), 905-917. doi:10.1002/adfm.20

Electrospun fluorescent nanofibers for explosive detection

Development of an instant on-site visual detection method for 2,4,6 trinitrotoluene (TNT) has become a significant requirement of the hour towards a secured society and a greener environment. Despite momentous advances in the respective field, a portable and reliable method for quick and selective detection of TNT still poses a challenge to many reasons attributing to inappropriate usage in subordinate areas and untrained personnel. The recent effort on the fluorescent based detection represents as one of easy method in terms of fast response time and simple on/off detection. Therefore, this chapter provides a consolidation of information relating to recent advances in fluorescence based TNT detection.Further, the main focus will be towards advances in the nanofibers based TNT detection and their reason to improving thesensitivity. © Springer International Publishing Switzerland 2015

Photodegradation of Selected PCBs in the Presence of Nano-TiO2 as Catalyst and H2O2 as an Oxidant

Photodegradation of five strategically selected PCBs was carried out in acetonitrile/water 80:20. Quantum chemical calculations reveal that PCBs without any chlorine on ortho-positions are closer to be planar, while PCBs with at least one chlorine atoms at the ortho-positions causes the two benzene rings to be nearly perpendicular. Light-induced degradation of planar PCBs is much slower than the perpendicular ones. The use of nano-TiO2 speeds up the degradation of the planar PCBs, but slows down the degradation of the non-planar ones. The use of H2O2 speeds up the degradation of planar PCBs greatly (by >20 times), but has little effect on non-planar ones except 2,3,5,6-TCB. The relative photodegradation rate is: 2,2’,4,4’-TCB > 2,3,5,6-TCB > 2,6-DCB ≈ 3,3’,4,4’-TCB > 3,4’,5-TCB. The use of H2O2 in combination with sunlight irradiation could be an efficient and “green” technology for PCB remediation

Short-term oxidation response of Nb–15Re–15Si–10Cr–20Mo alloy

The Nb–15Re–15Si–10Cr–20Mo alloy was subjected to 24 h of air exposure in a temperature range from 700 to 1400 °C. Re addition to the Nb–Si–Cr–Mo alloy has been found to control the pesting at lower temperatures and spalling at higher temperatures. The curve in a graph of weight gain per unit area as a function of temperature was used to determine the oxidation resistance. Re2Si formation around a solid solution phase reduces the infusion of oxygen into the metal, controlling the kinetics of the alloy system. Oxidation characterization was carried out using XRD and back scattered imaging, EDS, and X-ray mapping modes on the SEM. Mo addition promotes the formation of oxidation resistance Nb5Si3

Meisenheimer complex between 2,4,6-trinitrotoluene and 3-aminopropyltriethoxysilane and its use for a paper-based sensor

2,4,6-Trinitrotoluene (TNT) forms a red-colored Meisenheimer complex with 3-aminopropyltrienthoxysilane (APTES) both in solution and on solid phase. The TNT–APTES complex is unique since it forms yellow-colored complexes with 2,4,6-trinitrophenol and 4-nitrophenol, and no complex with 2,4-dinitrotoluene. The absorption spectrum of TNT–APTES has two absorption bands at 530 and 650 nm, while APTES complexes with 2,4,6-trinitrophenol and 4-nitrophenol have absorption maxima at around 420 nm, and no absorption change for 2,4-dinitrotoluene. The TNT–APTES complex facilitates the exchange of the TNT-CH3 proton/deuteron with solvent molecules. The red color of TNT–APTES is immediately visible at 1 μM of TNT. Keywords: TNT detection, Nitroaromatics, Meisenheimer comple