Sensors For Nitroaromatic Compounds Research Articles

NEW PUSH–PULL SYSTEM BASED ON 4,5,6-TRI(HET)ARYLPYRIMIDINE CONTAINING CARBAZOLE SUBSTITUENTS: SYNTHESIS AND SENSITIVITY TOWARD NITROAROMATIC COMPOUNDS

A sequence of microwave-assisted Suzuki cross-coupling reaction and bromination with N-bromosuccinimide was used for the synthesis of 3,3'-(5,5'-{5-[5-(9-ethyl-9H-carbazol-3-yl)-3-hexylthiophen-2-yl]pyrimidine-4,6-diyl}bis(thiophene-5,2-diyl))bis(9-ethyl-9H-carbazole). The obtained compound was characterized with regard to its optical properties, as well as possible applications in sensors for nitroaromatic compounds in acetonitrile solutions and in vapor phase.

New push–pull system based on 4,5,6-tri(het)arylpyrimidine containing carbazole substituents: synthesis and sensitivity toward nitroaromatic compounds

A sequence of microwave-assisted Suzuki cross-coupling reaction and bromination with N-bromosuccinimide was used for the synthesis of 3,3'-(5,5'-{5-[5-(9-ethyl-9H-carbazol-3-yl)-3-hexylthiophen-2-yl]pyrimidine-4,6-diyl}bis(thiophene-5,2-diyl))bis(9-ethyl-9H-carbazole). The obtained compound was characterized with regard to its optical properties, as well as possible applications in sensors for nitroaromatic compounds in acetonitrile solutions and in vapor phase.

A microporous metal–organic framework with open metal sites for selective sensing Fe3+, CrO42- and nitrobenzene

A 3D network with the (42·6·83) topology of metal-organic framework possessing an open 1D channel was synthesized by rigid and planar tetracarboxylic acid 5,5’-(1H-2,3,5-triazole-1,4-diyl)diisophthalic acid (H4L). The luminescent properties of 1 shows highly sensitive response to nitrobenzene, Fe3+ and CrO42- through luminescence quenching effects, making it a promising luminescent sensor for nitro aromatic compounds, Fe3+ and CrO42-. KEY WORDS: Metal-organic framework, Luminescence quenching, Iron(III), Chromate, Nitrobenzene Bull. Chem. Soc. Ethiop. 2017, 31(2), 291-297. DOI: http://dx.doi.org/10.4314/bcse.v31i2.10

Metal-dependent ribbon and self-penetrated topologies in nitroaromatic-sensing zinc and cadmium coordination polymers with terephthalate and dipyridylamide ligands

Hydrothermal reaction of the requisite metal nitrate, potassium terephthalate (K2tere) and the dipyridylamide 3-pyridylisonicotinamide (3-pina) afforded a pair of crystalline coordination polymers whose dimensionality and topology depends critically on the metal coordination environment. The two new crystalline phases were structurally characterized via single-crystal X-ray diffraction. {[Zn(tere)(3-pina)2]·2H2O}n (1) manifests a 1-D zig-zag ribbon motif with monodentate 3-pina ligands. [Cd(tere)(3-pina)2]n (2) displays a self-penetrated 3-D network with 446108 mab topology. Thermal and luminescent properties of these two new materials are also presented. Both 1 and 2 show capability as sensors for nitroaromatic compounds via luminescence quenching, with better absorption for nitrobenzene than the more sterically bulky analyte m-nitrophenol.

MOF-177/graphene composite as a selective sensor for nitro aromatic compounds

ABSTRACTA zinc-based metal-organic framework, MOF-177, was synthesized on the surface of benzoic acid functionalized reduced graphene oxide (BFG). Large amount of BFG (30wt %) slightly improved the stability of the MOF on the graphene surface, decreased the porosity of the composite, and resulted in 1mm long and 50µm wide microrods of MOF-177/BFG composites which act as a selective sensor for trinitrophenol compared to trinitrotoluene.

A Rare L1D + R1D → 3D Luminescent Dense Polymer as Multifunctional Sensor to Nitro Aromatic Compounds, Cu2+, and Bases

A rarely reported L1D (left-handed helical 1D chain) + R1D (right-handed helical 1D chain) → 3D polycatenated network, [Cd(H2ttac)bpp]n (1), constructed from the vertical interpenetration of triple-stranded homochiral helices, has been synthesized under hydrothermal condition by H4ttac (1,1′,2′,1″-terphenyl-4,4′,4″,5′-tetracarboxylic acid), 1,3-bis(4-pyridyl)propane (bpp), and Cd(NO3)2·4H2O. The luminescent properties of 1 and the ones immersed in various kinds of organic compounds and nitrate@DMF solutions have been investigated. Importantly, 1 shows highly sensitive response to nitro aromatic compounds and Cu2+ through luminescence quenching effects, making it a promising luminescent sensor for nitro aromatic compounds and Cu2+. Besides, experiments upon deprotonation by NaOH, KOH, methylamine, and triethylamine are conducted, respectively. As base increases, the luminescence spectra exhibit gradual blue shifts. The mechanisms of the sensing properties have been studied in detail.

Modification of Extended Open Frameworks with Fluorescent Tags for Sensing Explosives: Competition between Size Selectivity and Electron Deficiency

Three new electron-rich metal-organic frameworks (MOF-1-MOF-3) have been synthesized by employing ligands bearing aromatic tags. The key role of the chosen aromatic tags is to enhance the π-electron density of the luminescent MOFs. Single-crystal X-ray structures have revealed that these MOFs form three-dimensional porous networks with the aromatic tags projecting inwardly into the pores. These highly luminescent electron-rich MOFs have been successfully utilized for the detection of explosive nitroaromatic compounds (NACs) on the basis of fluorescence quenching. Although all of the prepared MOFs can serve as sensors for NACs, MOF-1 and MOF-2 exhibit superior sensitivity towards 4-nitrotoluene (4-NT) and 2,4-dinitrotoluene (DNT) compared to 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB). MOF-3, on the other hand, shows an order of sensitivity in accordance with the electron deficiencies of the substrates. To understand such anomalous behavior, we have thoroughly analyzed both the steady-state and time-resolved fluorescence quenching associated with these interactions. Determination of static Stern-Volmer constants (KS) as well as collisional constants (KC) has revealed that MOF-1 and MOF-2 have higher KS values with 4-NT than with TNT, whereas for MOF-3 the reverse order is observed. This apparently anomalous phenomenon was well corroborated by theoretical calculations. Moreover, recyclability and sensitivity studies have revealed that these MOFs can be reused several times and that their sensitivities towards TNT solution are at the parts per billion (ppb) level.

Aggregation-Induced Emission Enhancement in Alkoxy-Bridged Binuclear Rhenium(I) Complexes: Application as Sensor for Explosives and Interaction with Microheterogeneous Media

The aggregation-induced emission enhancement (AIEE) characteristics of the two alkoxy-bridged binuclear Re(I) complexes [{Re(CO)3(1,4-NVP)}2(μ2-OR)2] (1, R = C4H9; 2, C10H21) bearing a long alkyl chain with 4-(1-naphthylvinyl)pyridine (1,4-NVP) ligand are illustrated. These complexes in CH2Cl2 (good solvent) are weakly luminescent, but their intensity increased enormously by almost 500 times by the addition of poor solvent (CH3CN) due to aggregation. By tracking this process via UV-vis absorption and emission spectral and TEM techniques, the enhanced emission is attributed to the formation of nanoaggregates. The nanoaggregate of complex 2 is used as a sensor for nitroaromatic compounds. Furthermore, the study of the photophysical properties of these binuclear Re(I) complexes in cationic, cetyltrimethylammonium bromide (CTAB), anionic, sodium dodecyl sulfate (SDS), and nonionic, p-tert-octylphenoxypolyoxyethanol (TritonX-100, TX-100), micelles as well as in CTAB-hexane-water and AOT-isooctane-water reverse micelles using steady-state and time-resolved spectroscopy and TEM analysis reveals that the nanoaggregates became small and compact size.

Fluorescent Sensors for Nitroaromatic Compounds Based on the Comb-Like Polysiloxane-Acrylate

A functional polysiloxane monomer, with a double bond and a fluorophore pyrene at each end of the polysiloxane chain, respectively, was synthesized. Copolymerize this functional monomer with other acrylates in emulsion, we got a comb-like polymer in which pyrene fluorophore is at the end of each polysiloxane side-chain. This polymer shows great advantage in sensing performance for 2,4-dinitrotoluene (DNT) over its analog that was prepared just by mixing pyrene with pure polyacrate emulsion.