In this study, we have investigated the concentration-dependent intermolecular dynamics of aqueous solutions of aniline hydrochloride, sodium phenoxide, and 4-methylpyridine using femtosecond Raman-induced Kerr effect spectroscopy at 298 K. The densities, viscosities, and surface tensions of the aqueous solutions were also measured at 298 K. Quantum chemistry calculations of the target aromatics and their clusters with water molecule(s) or a counterion were performed to obtain their optimized structures and cluster interaction energies. In the difference low-frequency Kerr spectra (<250 cm-1) of the aqueous aromatic solutions and neat water, the first moment (M1) of the intermolecular vibrational band, which mainly originated from the aromatic ring, showed that the librations of the anilinium cation and phenoxide anion were higher in frequency than that of 4-methylpydine. Furthermore, the libration of the phenoxide anion was also higher in frequency than that of the anilinium cation. Quantum chemistry calculations indicated that the strong hydrogen bonding and compact hydration structure resulting from the negatively charged aromatic ring led to higher-frequency libration of the phenoxide anion than the anilinium cation. In addition, the M1 increased with increasing concentration. The concentration sensitivities were stronger in aqueous solutions of aniline hydrochloride and sodium phenoxide than in aqueous solutions of 4-methylpyridine. Based on the quantum chemistry calculation results, we conclude that strong aromatic-water and aromatic-counterion interactions lead to a higher-frequency libration of aromatics with charged side groups. The collective orientational relaxation times of the aqueous aromatic solutions showed the fractional Stokes-Einstein-Debye behavior.

Unlocking dual-pathway peroxydisulfate activation mechanism in single atom Fe-based catalytic membranes for wastewater purification.

Electrochemical molecularly imprinted sensor for hippuric acid detection based on bifunctional monomers.

Aniline (ANI) was electropolymerized on ITO substrates with different surface resistivities. The process was performed by cyclic voltammetry from an aqueous, homogeneous solution containing sulfuric acid and the aniline monomer using various numbers of cycles and scan rates. The resulting polymer films (PANI) were characterized by ATR-IR spectroscopy, spectroscopic ellipsometry and atomic force microscopy. The influence of ITO surface resistivity on the electropolymerization process, the quality of the obtained PANI layers, and their optical properties was evaluated. Homogeneous PANI films were produced on ITO substrates with surface resistivities of 15–25 Ω/sq, encompassing both emeraldine salt and emeraldine base forms. Although the film’s growth was rapid, it also led to adhesion issues. In contrast, for ITO substrates with surface resistivities of 70–100 Ω/sq and 80–100 Ω/sq, the resulting films showed improved adhesion but were less homogeneous. Nevertheless, the conductive emeraldine salt form of polyaniline was successfully obtained. The conductive form of polyaniline was obtained without any additional modifications to the electropolymerization procedure. Notably, the literature provides no systematic analysis of electropolymerization on ITO substrates with different surface resistivities, which opens up new research opportunities and provides a basis for the rational design and optimization of PANI-based electro-optical coatings for advanced sensing applications.

The co-transport behavior of polyacrylonitrile microplastics and aniline compounds in porous media.

This study explores the mechanistic and kinetic details of aniline (AN) oxidation by hydroperoxyl radicals (HO2) using DFT (M06-2X/jun-cc-pVTZ) and high-level ab initio methods (CCSD(T), BD(T), CBS-QB3). Eight prereactive complexes were identified, with TD-DFT confirming their photolysis under atmospheric conditions. The most stable complex (CR2) exhibits the complexation energy of -11.06 to 4.29 kcal mol-1 across 300-3000 K. Among 12 reaction pathways (four H-abstractions, four additions, and four addition-eliminations), NH2 H-abstraction (P1) and ortho-addition (P6) are the most favorable. Rate constants increase with temperature and pressure, indicating thermally and pressure-activated kinetics. At 300 K, activation energies for H-abstraction (R1-R4) range from 5.47 to 29.31 kcal mol-1, while addition reactions (R5-R8) require 9.81-14.29 kcal mol-1, significantly lower than addition-elimination routes (R9-R12). Branching ratio analysis reveals dominant H-abstraction from the NH2 group (R1, 67-99% at <500 K) and ortho-addition (R6, up to 24%), with minor contributions from ipso/para-additions (R5/R8, 8-16% at 500-1000 K) and secondary H-abstractions (R3/R4, 20-33% at >2500 K). These findings highlight NH2 H-abstraction and ortho-addition as the primary low-temperature pathways for AN atmospheric degradation.

Advanced sensor technologies for niraparib detection: A comparative study of molecularly imprinted polymer and nanosensor systems.

The role of cellulose nanoparticles in enhancing human iPSC compatibility with composite conductive PANI/cellulose films.

Abstract Chemoselective allylic C(sp3)–H amination of alkenes is challenging in transition-metal catalyzed nitrene insertion reactions due to the competitive formation of aziridines. In this report, we introduce chiral paddle-wheel diruthenium catalysts for achieving chemoselective C(sp3)–H amination of allyl benzene derivatives and summarize the reactivity trend of the diruthenium catalysts toward C(sp3)–H amination and aziridination of mono-substituted alkenes. Computational studies support that both C(sp3)–H amination and aziridination with paddle-wheel diruthenium catalysts proceed through radical intermediates. Chemoselectivity in the diruthenium-catalyzed C(sp3)–H amination of allyl benzene is likely controlled by the stabilities of the radical intermediate and α-vinyl benzylic radical, and by non-covalent interactions between multiple phenyl rings in the ruthenium catalyst and substrates.

We report the first crystallization-induced diastereomer transformations (CIDTs) of donor-acceptor (D-A) cyclopropanes, providing access to important chiral nonracemic building blocks for stereospecific and stereoselective transformations. Lewis acids rapidly epimerize aniline-substituted D-A cyclopropanes through reversible C-C bond cleavage. Formation of the conjugate acid anilinium salt concurrently slows epimerization and enhances the crystallinity of the cyclopropanes. We present the first example of a temperature-dependent switchable stereoselective crystallization, which enables isolation of either diastereomer with high yield and diastereoenrichment. As a complement to the Lewis acid activation paradigm, solvent-promoted epimerization is demonstrated to enable a spontaneous CIDT of an aniline-substituted D-A cyclopropane in the absence of a Lewis acid. In both approaches, products can be isolated by direct filtration of the reaction mixture without the need for further purification. The latter approach was demonstrated on a multidecagram scale. Through manipulation of the aniline and ester functional handles, this method enables access to diastereo- and enantiopure cyclopropanes and derivatives thereof.

Cotton, a natural source of pure cellulose, is among the most eco-friendly materials, valued for its sustainability and biodegradability. Developing cotton fabrics (CF) with advanced functionalities, such as antibacterial activity and conductivity, while preserving both their stability and inherent characteristics, such as hydrophilicity, flexibility, and comfort, remains a significant challenge. In this study, we propose a straightforward approach to producing conductive cotton by grafting aniline (ANI) onto epoxy-modified CF utilizing epoxy–amine “click” chemistry. The addition of aniline and ammonium persulfate (APS) dissolved in hydrochloric acid (HCl) solution to aniline-coated cotton fabric enables the growth of polyaniline (PANI) on the fabric through polymerization. Various cotton fabrics were prepared by altering parameters such as the ANI-to-APS ratio, HCl concentration, and the polymerization temperature. The electrochemical performance of the CF/PANI electrodes was assessed via cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The PANI-modified fabric with enhanced electrochemical properties was subsequently functionalized with silver nanoparticles (AgNPs) and treated with amoxicillin (AMOX), exhibiting a promising antibacterial effect against both Gram-positive (G+) and Gram-negative bacteria (G−). Findings demonstrate that PANI-coated cotton fabrics, produced via the proposed method, represent promising candidates for applications in wearable electronics, biosensors, electrocatalysis, and supercapacitors.

Aniline analogues as synchronized Ca2+ oscillation modulators: structure-activity relationship and mechanism.

Dummy molecularly imprinted polymer nanochannel sensor for ultrasensitive detection of aniline compounds.

The existence of intermolecular hydrogen bonding between acetophenone (ACE) (H-Bond Acceptor) and four organic compounds, namely, phenol (PHE), aniline (ANI), cyclohexanol (CHL) and cyclohexylamine (CHA), (H-Bond Donors) was investigated in n-hexane medium at 303 K through the ultrasonic, UV-Visible and IR spectral and computational DFT and NCI methods. The formation and stability constants (K) of the four complexes were determined by experimental methods. The trend in the K values shows that the structure of HBD influences the strength of the H-bond. Theoretical analyses reveal that the strength and stability of the complexes follow the order ACE-PHE > ACE-ANI > ACE-CHL > ACE-CHA. The stability of the complex ACE-PHE is attributed to stronger hydrogen bonding interactions, significantly influenced by an adjacent aromatic ring. The theoretical findings agree well with experimental observations and show the critical role of molecular structure in governing the NCI strength.

The process of reduction of benzenediazonium tetrafluoroborate on a graphite electrode from acetonitrile solution was investigated by cyclic voltammetry. In the first cycle of the potential scan, reduction peaks are observed at potentials of about -0.07 and -0.30 V. The peak at a potential of -0.07 V corresponds to the process of reduction of diazo salt with the formation of a phenyl radical. In the subsequent cycles of potential scanning, a sharp decrease in reduction currents is observed. The results obtained indicate the possibility of modifying the graphite surface by electrochemical reduction of diazo salt. Electrochemical modification of the surface of graphite MPG-7 was carried out in an acetonitrile solution containing 0.1 M benzenediazonium tetrafluoroborate and 0.1 M lithium perchlorate. During the process, a gradual decrease in the reduction current is observed due to surface modification by reduction products. The modification leads to the formation of a coating characterized by significant electrical resistance. The wetting of a graphite surface modified by electrochemical reduction of benzenediazonium by solutions of aniline in hydrochloric acid was investigated. The contact angle of wetting of a solid graphite surface by solutions of aniline in hydrochloric acid was determined. The Dupre equation was used to calculate the work of cohesion, and the Dupre–Young equation was used to determine the equilibrium work of adhesion of the liquid. Electrochemical modification of the graphite surface significantly improves its wettability compared to the unmodified surface. Even in the case of pure water, the average value of cos θ = 0.44, which is somewhat higher compared to the unmodified surface (cos θ = 0.32). An increase in the concentration of acid and aniline leads to an increase in cos θ. The best wettability was achieved at aniline concentration of 1.0–2.0 N and acid – 3.0 N. The results obtained can be explained by the surface-inactive properties of hydrochloric acid and the surface-active properties of aniline hydrochloride. At high concentrations of aniline, the adsorption of the phenylammonium cation occurs on the graphite surface. In this case, it is obvious that the phenyl group will be oriented towards the surface, and the amine group towards the solution. The presence of phenyl groups grafted to the surface will facilitate this process. Based on the results of determining the contact angles of wetting, the values of the work of adhesion (Wа) and cohesion (Wс) were calculated. For water, the work of adhesion and cohesion are equal to 0.105 and 0.146 J/m2, respectively. An increase in the aniline concentration leads to a decrease in the work of cohesion, which is due to a decrease in the surface tension of solutions. The work of adhesion of solutions to the graphite surface shows a general tendency to increase with increasing aniline concentration, although in the case of 3.0 n HCl, the highest work value is observed at aniline concentration of 0.5 n. Electrochemical reduction of diazonium salts is a promising approach for modifying the graphite surface. This can be useful for creating specific materials that can be used in the development of current sources, supercapacitors, and sensors.

Sulfonated polyaniline (SPAN) has good water solubility and can be used as a proton reservoir to retain a high local H+ concentration on the polymer backbone, making it valuable for water-soluble zinc batteries. However, the mechanism of SPAN by electrochemical synthesis lacks experimental data support. Here, the roles of aniline (ANI) and acid in electropolymerization of SPAN were mainly investigated by electrochemical-mass spectrometry, which can directly and in real time detect the target substances in complicated mixtures containing species. Under acid-free conditions, the chain growth of SPAN was mainly driven by ANI and ANI dimer (i.e., N-phenyl-p-phenylenediamine). After addition of perchloric acid, a chain growth pathway dominated by o-aminobenzenesulfonic acid (oASA) emerged during the reaction, indicating that the reactivity ratio of ANI and oASA was altered. Furthermore, experimental evidence were provided regarding the influence of antioxidant capacity and intramolecular hydrogen bonding on the oASA homopolymerizaiton. These results offer theoretical guidance for optimizing the electropolymerization process of SPAN.

Abstract In this paper the Poly (aniline-co–o-methoxy aniline) (PAOMA) copolymer coatings, as well polyaniline (PANI) and poly (o-methoxy aniline) (POMA) individual polymer coatings, were synthesized on copper (Cu) substrates from an aqueous solution of sodium salicylate. A series of PAOMA copolymer coatings were deposited by electrochemical copolymerization of aniline (ANI) with o-methoxy aniline (OMA) using different monomer feed ratios under cyclic voltammetric conditions. A comparative analysis of the cyclic voltammograms (CVs) recorded during polymerization of aniline, o-methoxy aniline, and their copolymer clearly reveals the effect of the monomer ratio on the formation of the copolymer, polymer, and the quality of the coatings. All the resulting coatings were characterized by cyclic voltammetry, UV–visible absorption spectroscopy, scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The synthesis of the copolymer, using a mixture of monomers in the aqueous sodium salicylate solution, was confirmed through a comparative study of the results obtained from the polymerizations, as well with the characterizations of the individual monomers, aniline and o-methoxy aniline. Corrosion resistant characteristics of resulting coatings were evaluated by potentiodynamic polarization measurement in aqueous solution of 3% NaCl solution. It extracts the values of corrosion potential (Ecorr), corrosion rate (CR), porosity (P) and protection efficiency (%PE). The analysis of these results imply that the copolymer PAMOA-5 coating provides effective protection to Cu against corrosion in aqueous 3% NaCl as compared to that of the other copolymers and also than the corresponding homopolymers. For PAOMA-5 coated Cu it was found that the remarkable positive shift of 344 mV in Ecorr, substantial reduction in corrosion rate 875 times lower than that observed for bare Cu, lowest value of porosity (0.44 × 10–6) and highest protection efficiency of 99.9%.

New insights into the role of electron shuttles in enhancing permanganate oxidation for the removal of aniline compounds: Free radicals and intermediate manganese.

Accessible high-performance GC×GC: A DIY flow modulator with transient pulse sampling strategy.

It is still greatly desirable to activate peroxymonosulfate (PMS) forming nonradicals for the removal of electron-rich contaminants in complex water matrices. However, achieving this on heterogeneous metal-based catalysts with uniform electron distribution remains challenging due to the asymmetric structure of PMS molecules (H-O-O-SO3-). Here, inspired by the dipole effect, we design a Co-doped ZnO catalyst (ZOC) to break charge symmetry at active sites and enhance nonradicals generation. The high charge density at Co sites facilitates two-electron transfer, promoting O-O and O-H bond cleavage to form high-valent cobalt-oxo (CoIV=O), while positively polarized Zn sites drive PMS self-decomposition to generate singlet oxygen (1O2). As a result, the synergistic system of 1O2 and CoIV = O results in a k-value of 73.93 min⁻¹ M⁻¹ for aniline (AN) degradation, 189.6 times higher than ZnO/PMS (ZO/PMS), and also shows a high selectivity for electron-rich new pollutants. The practicality of this outstanding nonradicals system is confirmed by a significant increase in biochemical oxygen demand/chemical oxygen demand (BOD/COD) of the mixed wastewater to over 0.55 in the air-lifting internal circulating reactor. This study offers a structural regulation for controlling catalytic functionality and provides general guidelines for designing Fenton-like reactors to enhance wastewater biodegradability.