A catalyst- and additive-free synthesis of 2-benzyl N-substituted anilines from (E)-2-arylidene-3-cyclohexenones and primary amines has been reported. The reaction proceeds smoothly through a sequential imine condensation-isoaromatization pathway, affording a series of synthetically useful aniline derivatives in acceptable to high yields. Mild reaction conditions, no requirement of metal catalysts, operational simplicity and the potential for scale-up production are some of the highlighted advantages of this transformation.

BACKGROUND: Nitroaromatic compounds are inherently hazardous and explosive, so convenient and rapid detection strategies are needed for the sake of human health and the environment. There is an urgent demand for chemical sensing materials that offer high sensitivity, operational simplicity, and recognizability to effectively monitor nitroaromatic residues in industrial wastewater. Despite its importance, the mechanisms underlying fluorescence quenching or enhancement in fluorescent sensing materials have not been extensively researched. The design and synthesis of multiresponsive fluorescent sensing materials have been a great challenge until now.
RESULTS: In this study, a one-dimensional Cd-based fluorescent porous coordination polymer (Cd-CIP-1) was synthesized using 5-(4-cyanobenzyl)isophthalic acid (5-H2CIP) and 4,4\'-bis(1-imidazolyl)biphenyl (4,4\'-bimp) and used for the selective detection of nitrobenzene in aqueous solution by fluorescence quenching, with a limit of detection of 1.38 × 10-8 mol L-1. The presence of aniline in the Cd-CIP-1 solution leads to the enhancement of fluorescence property. Density functional theory and time-dependent density functional theory calculations were carried out to elucidate the mechanisms of the fluorescence changes. This study revealed that the specific pore size of Cd-CIP-1 facilitates analyte screening and enhances host-guest electron coupling. Furthermore, π-π interactions and hydrogen bond between Cd-CIP-1 and the analytes result in intermolecular orbital overlap and thereby boosting electron transfer efficiency. The different electron flow directions in NB@Cd-CIP-1 and ANI@Cd-CIP-1 lead to fluorescence quenching and enhancement.
UNASSIGNED: The multiresponsive coordination polymer (Cd-CIP-1) can selectively detect nitrobenzene and recognize aniline in aqueous solutions. The mechanism of fluorescence quenching and enhancement has been thoroughly elucidated through a combination of density functional theory and experimental approaches. This study presents a promising strategy for the practical implementation of a multiresponsive fluorescent chemical sensor.

Radical ipso substitution offers an alternative to organometallic approaches for biaryl synthesis, but usually requires stoichiometric reagents such as tributyltin hydride. Here, we demonstrate that visible light photoredox catalysis can be used for ipso-biaryl synthesis, via a halogen atom transfer (XAT) regime. Using amide substrates that promote ipso over unwanted ortho addition, we demonstrate smooth biaryl formation with no constraint on the electronic character of the migrating arene ring. The photoreaction can be combined in one operation to achieve a formal arylation of the inert aniline C-N bond.

Extensive research has already provided reliable methods for the in silico prediction of pKa, while a trustworthy strategy for pKb determination is still being sought. Indeed, the approaches previously exploited for computing pKa have shown their weakness in predicting pKb. In the light of the exceptional reliability demonstrated in the pKa calculation of a wide panel of organic acids, in this work, we exploited our \"easy to use methodology\", based on the direct approach, to predict the pKb of primary amines. Herein, CAM-B3LYP was compared to WB97XD and B3PW91, exploring the solvation model based on density (SMD) and the polarizable continuum model (PCM), in the presence of two explicit water molecules. Noteworthy, CAM-B3LYP and WB97XD returned completely different solvent accessible surfaces (SAS) and electron potential maps (EPM) for the bases and the conjugated acids, independently from the nature of the substituents. Once again, CAM-B3LYP/SMD/2H2O method confirmed its remarkable reliability, leading to a minimum average error (MAE) lower than 0.3. This outstanding result strengthens the trustworthiness of our method, already successfully applied to predict the pKa of different substituted phenols and carboxylic acids. Thus, our \"easy-to-use\" process can predict also the pKb of primary ammines and anilines, always ensuring consistent outputs.

The selective electrocatalytic reduction of nitrobenzene (NB) to aniline demands a desirable cathodic catalyst to overcome the challenges of the competing hydrogen evolution reaction (HER), a higher overpotential, and a lower selectivity. Here, we deposit Co-doped 1T MoS2 on Ti mesh by the solvothermal method with different doping percentages of Co as x % Co-MoS2 (where x = 3, 5, 8, 10, and 12%). Because of the lowest overpotential, lower charge-transfer resistance, strong suppression of the competing HER, and higher electrochemical surface area, 8% Co-MoS2 achieves 94% selectivity of aniline with 54% faradaic efficiency. The reduction process follows first-order dynamics with a reaction coefficient of 0.5 h-1. Besides, 8% Co-MoS2 is highly stable and retains 81% selectivity even after 8 cycles. Mechanistic studies showed that the selective and exothermic adsorption of the nitro group at x % Co-MoS2 leads to a higher rate of NB reduction and higher selectivity of aniline. The aniline product is successfully removed from the solution by polymerization at FTO. This study signifies the impact of doping metal atoms in tuning the electronic arrangement of 1T-MoS2 for the facilitation of organic transformations.

Aniline (C6H5NH2) is one of the hazardous aromatic amine where an amino group -NH2) is connected to phenyl ring (C6H5). Based on the evaluation of the 96-hour LC50 of aniline, two sublethal concentrations (4.19 mg/l and 8.39 mg/l) were selected for acute exposure tests in freshwater fish Channa punctatus. The liver, gills and kidney of fish being the principal sites of xenobiotic material accumulation, respiration, biotransformation, and excretion are the focus of the present study. Throughout the exposure time, the comet assay revealed increased tail length and tail DNA percentage indicating maximum damage to liver, gills and kidney of treated group after 96 h. After acute exposure, there was a significant (p ≤ 0.05) increase in the enzymatic activity of glutathione-S-transferase (GST) and acetylcholinesterase (AChE), whereas decline in superoxide dismutase (SOD) and catalase (CAT) activity was observed. Meanwhile, levels of malondialdehyde (MDA) increased over the exposure period for both concentrations. After 96 h of exposure, degree of tissue change (DTC) was evaluated in liver, gill and kidney of aniline exposed fish. Additionally, light microscopy revealed multiple abnormalities in liver, gills and kidney of all the treated groups. Significant changes were observed in the levels of biochemical markers viz., glucose, triglyceride, cholesterol, aspartate transaminase, alanine transaminase and urea following a 96-hour exposure to aniline. Studies using ATR-FTIR and transmission electron microscopy (TEM) revealed changes in biomolecules and structural abnormalities in several tissues of the aniline-exposed groups in comparison to the control group respectively.

The sulfate radical-based advanced oxidation processes (SR-AOPs) is a promising method for the degradation of pollutants, with the development of highly efficient catalysts for persulfate activation has been widely concerned. The novel BiCoFe-LDH (BCF-x) was synthesized successfully by coprecipitation method, which can activate peroxydisulfate (PDS) efficiently to degrade aniline. Comparative analysis with pure CoFe-LDH revealed a remarkable increase in reaction rate constant by approximately 14.66 times; the degradation rate of aniline (10 mg/L) was 100% in 60 min with the condition of 0.5 g/L BCF-1.5 and 0.5 g/L PDS, due to BCF-1.5 which was characterized as a complex of CoFe-LDH and Bi2O2CO3, promoting electron transport to improve the efficiency of activated PDS. In the reaction system, SO4•-, ·OH, and 1O2 were responsible for the aniline degradation and ·OH was the primary one. Furthermore, this work proposes a reaction electron transfer catalytic mechanism, which provided a new insight and good application prospect for efficient activation of PDS for pollutant degradation.

Chloramination was commonly used as disinfectant for killing pathogens in water. However, in this process, nitrogen-containing disinfection by-products (N-DBPs) would accidently form and subsequently rise toxicity. Here, we investigated acute toxicity variation and by-products formation during chloramination treatment on UV filter 2-hydroxy-4-methoxy-5-sulfonic acid benzophenone (BP-4). Under alkaline conditions, the acute toxicity of this system had significant increase. A total of 17 transformation products were tentatively identified, and for them, plausible transformation pathways were proposed. Noticeably, numerous aniline and nitrosobenzene analogs were detected, and the dramatic increase of acute toxicity in this system might be primarily attributed to the formation of benzoquinone and aniline analogs. Besides, bromophenol, iodophenol and iodobenzoquinone analogs exhibiting high toxicity were generated in the presence of bromine and iodide ions. This study indicates that chloramination treatment may significantly increase potential health risk, further management on disinfection system is reasonable.

Aniline compounds, as a class of widely used but highly toxic chemical raw materials, are increasingly being released and accumulated in the environment, posing serious threats to environmental safety and human health. Therefore, developing detection methods for aniline compounds is of particular significance. Herein, we synthesized the fluorescent third monomer cyano-stilbene epoxide M and ternary copolymerized it with carbon dioxide (CO2) and propylene oxide (PO) to synthesize carbon dioxide-based polycarbonate (PPCM) with fluorescence recognition functions, as well as excellent performance, for the first time. The results revealed that the PPCM fluorescent probe exhibited typical aggregation-induced luminescence properties and could be quenched by aniline compounds. The probe presented anti-interference-specific selectivity for aniline compounds, and the detection limit was 1.69 × 10-4 M. Moreover, it was found to be a highly sensitive aniline detection probe. At the same time, the aniline biomarker p-aminophenol in urine could also be detected, which could expand the potential applications of polymers in the fluorescence-sensing field.

This study selected a contamination site associated with pesticide production to investigate the impact of soil settlement induced by pumping on the migration and transformation of the principal pollutant, aniline. The TMVOC model was enhanced by incorporating the settlement effect and validated through a soil-column experiment, which examined aniline distribution, phase transformation, and remediation efficiency under soil settlement. The results indicate that the optimized TMVOC model can accurately simulate the impact of pumping-induced soil settlement on aniline removal. The longitudinal migration of aniline was reduced, with the area of high concentrations drawing nearer to the surface. Furthermore, soil settlement negatively affected the removal of aniline in the Non-Aqueous Phase Liquid (NAPL) phase, resulting in a 10.59 % decline in the removal rate. In contrast, soil settlement positively influenced aniline removal in the gas and aqueous phases, increasing the removal rate by 12.55 % and 5.04 %, respectively, with the gas phase showing the most significant increase. Soil porosity decreased due to soil settlement, leading to a change in the proportion of each phase, with NAPL increasing after remediation. Additionally, soil settlement exhibited hysteresis, as evidenced by a noticeable decrease in the removal rate in the 10th month of the remediation process, and the final mass removal rate was reduced by 5.93 %.