Bio-mineralized tin/bismuth oxide nanoparticles with silk fibroins for efficient electrochemical detection of 2-nitroaniline in river water samples.

In recent years, the usage of nitroaniline has played a vital role in pharmaceutical formulations as it is a crucial ingredient in the synthesis of pesticides and dyes. However, the level of nitroaniline existing in industrial waste keeps rising the environmental contamination. Thus, monitoring of active nitro-residuals becomes more significant in reducing the toxicity of the ecosystem. Therefore, we have taken an attempt to evaluate the hazardous pollutant 2-nitroaniline (2-NA) using the electrocatalyst viz., tin-doped bismuth oxide inserted on a biopolymer silk fibroin composite modified glassy carbon electrode (Sn-Bi2O3/SF@GCE). The Sn-Bi2O3/SF nanocomposite was synthesized through hydrothermal and co-precipitation methods. The physicochemical properties of the prepared Sn-Bi2O3/SF hybrid composite were examined by conventional microscopy and spectroscopic techniques like FE-SEM, HR-TEM, XRD, FTIR, Raman, and XPS. Furthermore, the bio-mineralized Sn-Bi2O3/SF@GCE displayed a wide linear range (0.009 µM-785.7 µM) and a lower detection limit (3.5 nM) with good sensitivity for 2-NA detection under the optimum conditions. The result shows that the Sn-Bi2O3/SF-modified GCE has good reproducibility, repeatability, and excellent selectivity for 2-NA detection in the presence of other co-interfering compounds. Moreover, the practical applicability of Sn-Bi2O3/SF@GCE sensors was investigated for the effective detection of 2-NA in real river water samples, revealing good recovery results.

Sustainable architecting of Co2SnO4/CE-BN-based electrochemical platform for highly selective and ultrasensitive detection of 2-nitroaniline in life samples.

A novel binary heterogeneous electrocatalyst, Co2SnO4, decorated on chemically exfoliated boron nitride sheets (CE-BN) with an exceptional capacity to detect electrochemical properties has been prepared by the simple hydrothermal method. The structural, surface morphology and electrochemical characteristics of Co2SnO4/CE-BN were characterized using a range of physicochemical and electrochemical techniques. Various voltammetric approaches were used to observe the analytical behaviour and applications of Co2SnO4/CE-BN/GCE for the determination of 2-nitroaniline (2-NA). The whole experiment is operated in the potential range from 0 to - 1.0 V vs Ag/AgCl (sat. KCl). The impact of operational factors on the peak current of 2-NA was investigated, including the pH, sample concentration, modifier amount and scan speed. With an estimated differential pulse voltammetry detection limit of 0.0371 µM and excellent sensitivity of 1,35 µA µM-1 cm-2, the produced sensor, Co2SnO4/CE-BN/GCE, revealed high electrocatalytic activity (DPV). The system is more practical and sustainable due to its repeatability, stability and reproducibility with respect to the results achieved for detection of 2-NA. The synthesized Co2SnO4/CE-BN-modified sensor may thus be a likely choice for the detection of 2-NA in actual water sample analysis.

Bismuth molybdate incorporated functionalized carbon nanofiber as an electrocatalytic tool for the pinpoint detection of organic pollutant in life samples.

Herein, we fabricated a feasible and accurate sensing platform for the quantification of toxic organic pollutant 2-nitroaniline (2-NA) in water samples through electrocatalyst made up of bismuth molybdate (Bi2MoO6, BMO) functionalized carbon nanofiber (f-CNF) modified electrode. The preparation of BMO/f-CNF composite is of two methods, such as co-precipitation (C-BMO/f-CNF) and ultrasonication method (U-BMO/f-CNF). The physicochemical properties of the composites were characterized by XRD, FTIR, Raman, BET, FE-SEM, and HR-TEM techniques. At U-BMO/f-CNF, the charge transfer resistance was low (Rct = 12.47 Ω) compared to C-BMO/f-CNF because nanosized U-BMO particles correctly aim at the defective sites of the f-CNF surface wall. Further, the electrocatalytic activity of C&U-BMO/f-CNF composites was examined by cyclic voltammetry (CV) and differential pulse voltammetry techniques (DPV) for the electrochemical detection of 2-nitroaniline (2-NA). The U-BMO/f-CNF/GCE shows a higher cathodic current, wide dynamic linear range of 0.01-168.01 µM, and superior electrocatalytic activity with a low detection limit (0.0437 µM) and good sensitivity (0.6857 µA µM-1 cm-2). The excellent selectivity nature of U-BMO/f-CNF/GCE was observed in the presence of various organic pollutants and a few toxic metal cations. The practical applicability such as stability, repeatability towards 2-NA outcomes with accepted results. Besides, the practical viability of as proposed U-BMO/f-CNF sensor was investigated in soil and lake water samples delivers good recovery results. Hence from these analyses, we conclude that U-BMO/f-CNF/GCE potential for the determination of hazardous environmental pollutant 2-NA.

Metal-Organic Frameworks of MIL-100(Fe, Cr) and MIL-101(Cr) for Aromatic Amines Adsorption from Aqueous Solutions.

MIL-100(Fe, Cr) and MIL-101(Cr) were synthesized by the hydrothermal method and applied to the adsorptions of five aromatic amines from aqueous solutions. These three metal-organic frameworks (MOFs) were well characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and surface area analysis. The adsorption mechanism of three MOFs and the effects of the structures of MOFs on the adsorption of aromatic amines were discussed. The results show that the cavity system and suitable hydrogen bond acceptor were important factors for the adsorption for five aromatic amines of aniline, 1-naphthalamine, o-toluidine, 2-amino-4-nitrotoluene and 2-nitroaniline: (a) the saturated adsorption capacity of aniline, 1-naphthylamine and o-toluidine on MIL-100(Fe) were 52.0, 53.4 and 49.6 mg/g, respectively, which can be attributed to the intermolecular hydrogen bond interaction and cavity system diffusion. (b) The adsorption capacity of 2-nitroaniline and 2-amino-4-nitrotoluene on MIL-101(Cr) were 54.3 and 25.0 mg/g, respectively, which can be attributed to the more suitable pore size of MIL-101(Cr) than that of MIL-100(Fe, Cr). The MOFs of MIL-100(Fe) and MIL-101(Cr) can be potential materials for removing aromatic amines from aqueous solutions.

Protonated N-Alkyl-2-nitroanilines Undergo Intramolecular Oxidation of the Alkyl Chain upon Collisional Activation.

The collisional activation of protonated N-propyl-2-nitroaniline obtained by electrospray ionization shows two major competitive dissociation pathways: the elimination of the elements of propionic acid, [M + H - C3H6O2]+ to give an m/z 107 ion, and of the elements of ethanol, [M + H - C2H6O]+ to give an m/z 135 ion. The mechanistic study reported here addresses these unusual fragmentations to reveal that both occur via a common intermediate formed by the transfer of an oxygen atom from the nitro group to the first carbon atom of the propyl group, allowing elimination of propionic acid and (H2O + ethene), respectively. The corresponding loss of CH4O does not occur when the propyl group is replaced by an ethyl group, but elimination of the elements of propanol does occur when propyl is replaced by a butyl group. Further, the product ions of m/z 107 and 135 are also formed when the propyl chain is replaced with a hexyl group.

2-Substituted Aniline as a Simple Scaffold for LuxR-Regulated QS Modulation.

The ability of the 2-substituted aniline motif to serve as a scaffold for designing potential LuxR-regulated quorum sensing (QS) modulators has been investigated, using docking experiments and biological evaluation of a series of 15 specially synthesized compounds. Aniline, 2-acetyl-aniline and 2-nitroaniline were considered, as well as their N-acylated derivatives. Docking experiments showed that the 2-substituted aniline motif fits within the LuxR binding site at the place of the lactone moiety of AHL, and the biological evaluation revealed QS antagonisitic activity for several compounds, validating the hypothesis that this scaffold acts on QS. Structure activity relationships are discussed regarding interactions with the key residues of the LuxR binding site, showing significant variations in the H-bonding pattern.

Ectopic expression of an Old Yellow Enzyme (OYE3) gene from Saccharomyces cerevisiae increases the tolerance and phytoremediation of 2-nitroaniline in rice.

2-nitroaniline (2-NA) is an environmental pollutant and has been extensively used as intermediates in organic synthesis. The presence of 2-NA in the environment is not only harmful for aquatic life but also mutagenic for human beings. In this study, we constructed transgenic rice expressing an Old Yellow Enzyme gene, ScOYE3, from Saccharomyces cerevisiae. The ScOYE3 transgenic plants were comprehensively investigated for their biochemical responses to 2-NA treatment and their 2-NA phytoremediation capabilities. Our results showed that the rice seedlings exposed to 2-NA stress, showed growth inhibition and biomass reduction. However, the transgenic plants exhibited strong tolerance to 2-NA stress compared to wild-type plants. Ectopic expression of ScOYE3 could effectively protect transgenic plants against 2-NA damage, which resulted in less reactive oxygen species accumulation in transgenic plants than that in wild-type plants. Our phytoremediation assay revealed that transgenic plants could eliminate more 2-NA from the medium than wild-type plants. Moreover, omics analysis was performed in order to get a deeper insight into the mechanism of ScOYE3-mediated 2-NA transformation in rice. Altogether, the function of ScOYE3 during 2-NA detoxification was characterized for the first time, which serves as strong theoretical support for the phytoremediation potential of 2-NA by Old Yellow Enzyme genes.

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity.

A halogenmethylsulfonyl moiety is incorporated in numerous active herbicides and fungicides. The synthesis of tribromomethyl phenyl sulfone derivatives as novel potential pesticides is reported. The title sulfone was obtained by following three different synthetic routes, starting from 4-chlorothiophenol or 4-halogenphenyl methyl sulfone. Products of its subsequent nitration were subjected to the S(N)Ar reactions with ammonia, amines, hydrazines and phenolates to give 2-nitroaniline, 2-nitrophenylhydrazine and diphenyl ether derivatives. Reduction of the nitro group of 4-tribromomethylsulfonyl-2-nitroaniline yielded the corresponding o-phenylenediamine substrate for preparation of structurally varied benzimidazoles.

Highly efficient and selective heterogeneous catalytic reduction of 2-nitroaniline by cerium oxide nanocatalyst under microwave irradiation.

Efficient nanocatalyst with incredible performance is highly demanding in a heterogeneous catalysis system. Herein, we report the facile fabrication of uniform and highly stable Cerium Oxide nanoparticles (CeO2 NPs), through chemical precipitation method using sodium hydroxide as reducing agent. The synthesized material is characterized through highly sophisticated techniques including UV-Visible, FT-IR, SEM, AFM, XRD, and Zeta Sizer- Potential to check the particle formation, surface morphology, topography, crystalline nature, size, and surface potential. The heterogeneous catalytic performance of CeO2 NPs has been accomplished for the reduction of 2-nitroaniline from the aqueous media. The CeO2 nanocatalyst displayed excellent reusability, while the reduction in several repetitive catalytic cycles against 2-nitroaniline under optimized conditions. The CeO2 nanocatalyst shows 99.12% efficiency within 60s reaction time under a greener source of microwave radiation.

Phase transition in polar 2-nitroanilinium nitrate. Graph-set approach of hydrogen bonding patterns and analysis of vibrational spectra.

A phase transition in new compound 2-nitroanilinium nitrate, (H2NA)NO3, was found. A symmetry lowering from orthorhombic, Pmn21, to monoclinic one, P21, at 249 K is observed. During the phase transition, the H2NA+ and nitrate ions displace from the mirror plane in high-temperature phase. As a result, hydrogen bonding network constructed by the ammonio group and NO3- anion is changed. Especially, a bifurcated hydrogen bond disappears. Mathematical operations using both elementary and hydrogen bond graph-set descriptors were used for the first time to describe a mechanism of phase transition. Changes in hydrogen bonding network were also studied by means of vibrational spectroscopy. Band shift associated with stretching and bending vibrations of the ammonio group indicates that the energy of intermolecular interactions rises along with temperature decrease. SHG response for the studied compound is higher than KDP, I(H2NA)NO3 = 1.1·IKDP, although a decay of the signal was observed due to instability of the sample.

Synthesis of tritium-labeled cyadox, a promising antimicrobial growth-promoting agent with high specific activity.

Cyadox is a new antimicrobial growth-promoting agent for food-producing animals. Studies on radiolabeled compounds enable the use of sensitive radiometric analytical methods and help in the elucidation of metabolic and elimination pathways. In the present study, 6-[3H]-cyadox with a high specific activity of 2.08 Ci/mmol was prepared by the catalytic bromine-tritium exchange of 4-bromo-2-nitroaniline followed by a three-step microscale synthesis, giving a high yield between 36.16% and 94.75%.

Catalytic reduction of 2-nitroaniline: a review.

2-nitroaniline (2-NA) is highly toxic and environmental contaminant. It is reduced to less toxic and environmental benign product o-phenylenediamine by using different reducing agents like sodium borohydride, potassium borohydride, or hydrazine hydrate in the presence of various catalytic systems. These catalytic systems have various advantages and drawbacks. Silica-supported gold nanoparticles are frequently reported catalyst for the reduction of 2-nitroaniline in aqueous medium. In this review article, different catalytic systems reported for reduction of o-nitroaniline under various reaction conditions have been discussed. The critical review of the recent research progress for development of novel catalysts used for the reduction of 2-nitroaniline has been provided here.

A new V-doped Bi2(O,S)3 oxysulfide catalyst for highly efficient catalytic reduction of 2-nitroaniline and organic dyes.

A new type of convenient, and environmentally friendly, Vanadium (V)-doped Bi2(O,S)3 oxysulfide catalyst with different V contents was successfully synthesized via a simple and facile method. The obtained V-doped Bi2(O,S)3 solid solution catalysts were fully characterized by conventional methods. The catalytic performance of the samples was tested by using the reduction of 2-nitroaniline (2-NA) in aqueous solution. The reduction/decolorization of methylene blue (MB) and rhodamine B (RhB) was also chosen to evaluate the universality of catalysts. It was observed that the introduction of V can improve the catalytic performance, and 20%V-Bi2(O,S)3 was found to be the optimal V doping concentration for the reduction of 2-NA, MB, and RhB dyes. For comparative purposes, a related V-free Bi2(O, S)3 oxysulfide material was synthesized and tested as the catalyst. The superior activity of V-doped Bi2(O,S)3 over pure Bi2(O,S)3 was ascribed mainly to an increase in active sites of the material and also due to the presence of synergistic effects. The presence of V5+ as found from XPS analysis may interact with Bi atoms and enhancing the catalytic activity of the sample. In the catalytic reduction of 2-NA, MB and RhB, the obtained V-doped Bi2(O,S)3 oxysulfide catalyst exhibited excellent catalytic activity as compared with other reported catalysts. Furthermore this highly efficient, low-cost and easily reusable V-doped Bi2(O,S)3 catalyst is anticipated to be of great potential in catalysis in the future.

Molecular structure, Mulliken charge, frontier molecular orbital and first hyperpolarizability analysis on 2-nitroaniline and 4-methoxy-2-nitroaniline using density functional theory.

In the present study, we made an attempt to calculate the energy gap, molecular dipole moment and first hyperpolarizability of 2-nitroaniline (2NA) and 4-methoxy-2-nitroaniline (4M2N) with a basis set 6-31G (d, p) function has been employed at density functional theory (DFT) methods. Geometry optimizations was carried out with DFT-B3LYP/6-31G (d, p), the results have revealed that intramolecular hydrogen bonding present in both the molecular system. We analyzed the energy gap, molecular dipole moment and hyperpolarizability changes due to substitution effect of the methoxy group in 2NA molecule. It is confirmed that strong electron acceptor and donor groups in a material yield higher NLO response.