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Although cold preservation remains the gold standard in organ transplantation, cold stress-induced cellular injury is a significant problem in clinical orthotopic liver transplantation (OLT). Because a recent study showed that cold stress activates ferroptosis, a form of regulated cell death, we investigated whether and how ferroptosis determines OLT outcomes in mice and humans. Treatment with ferroptosis inhibitor (ferrostatin-1) during cold preservation reduced lipid peroxidation (malondialdehyde; MDA), primarily in liver sinusoidal endothelial cells (LSECs), and alleviated ischemia/reperfusion injury in mouse OLT. Similarly, ferrostatin-1 reduced cell death in cold-stressed LSEC cultures. LSECs deficient in nuclear factor erythroid 2-related factor 2 (NRF2), a critical regulator of ferroptosis, were susceptible to cold stress-induced cell death, concomitant with enhanced endoplasmic reticulum (ER) stress and expression of mitochondrial Ca2+ uptake regulator (MICU1). Indeed, supplementing MICU1 inhibitor reduced ER stress, MDA expression, and cell death in NRF2-deficient but not WT LSECs, suggesting NRF2 is a critical regulator of MICU1-mediated ferroptosis. Consistent with murine data, enhanced liver NRF2 expression reduced MDA levels, hepatocellular damage, and incidence of early allograft dysfunction in human OLT recipients. This translational study provides a clinically applicable strategy in which inhibition of ferroptosis during liver cold preservation mitigates OLT injury by protecting LSECs from peritransplant stress via an NRF2-regulatory mechanism.

π‐Conjugated polyfluorenes (PPs) comprising 2,3‐diaminobenzene‐1,4‐diyl (unit A) and 9,9‐dihexylfluorene‐2,7‐diyl (polymer‐1) or 9,9‐bis(6‐N,N,N,‐trimethylammoniumhexyl)fluorene‐2,7‐diyl (unit B) (polymer‐2) units were synthesized using Suzuki‐Miyaura coupling polycondensation. To compare the chemical properties and functionality of polymer‐2, a water‐soluble PP comprising benzene‐1,4‐diyl and unit B (polymer‐3) was synthesized. Polymer‐1 exhibited solvatochromism: the photoluminescence (PL) peak of the polymer in solutions shifted to a longer wavelength with an increase in the dielectric constants of solvents. Polymer‐1 formed charge transfer (CT) complexes with organic electron acceptors. The CT complexation behavior was systematically elucidated by the PL measurements using Stern–Volmer and Benesi–Hildebrand methods. Water‐soluble polymer‐2 could be used as a sensor for the chain length of telomere DNA by monitoring the changes in its PL intensity upon the addition of the analyte. The DNA sensing performance of polymer‐2 surpassed that of polymer‐3, attributed to the presence of unit A in polymer‐2. This unit brought polymer‐2 closer to DNA through hydrogen bonding between the amino group of polymer‐2 and nucleic acids in DNA. This interaction facilitated the occurrence of CT from the polymer backbone to DNA. [ABSTRACT FROM AUTHOR]

An efficient synthesis of new (methylsulfonyl)benzopyranophenazin-3-amines via the condensation of 2-hydroxynaphthoquinone, 1,2-phenylenediamine, methylsulfonylacetonitrile, and arylaldehydes derivatives catalyzed by ionic liquid [(EtO)3Si–CH2–CH2–CH2–NH3+][HCOO−] immobilized on magnetic Fe3O4@SiO2, as a novel heterogeneous nanocatalyst, was described. The novel nanocatalyst was characterized by FE-SEM, XRD, FT-IR, TGA‐DTG, and VSM techniques. The environmentally friendly protocol presented some advantages, such as a simple work-up and excellent yields. This nanocatalyst can be easily reused several times and recovered by an external magnet. The activity of the recoverable nanocatalyst remains intact even after five repeated runs. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) phosphors in white laser diodes (WLD) have the advantages of sufficient surface functionalization sites and low cost. Specially, their color rendering index (CRI) in WLD is unsatisfactory due to the uncontrollable synthesis process and low thermal stability. Herein, surface nitrogen‐containing groups of CDs are synthesized from phenylenediamine isomers and trimeric acid, and the optical and thermal properties of CDs are modulated by introducing amide bonds (–CONH). By varying the phenylenediamine isomers, CDs synthesized from o‐phenylenediamine, m‐phenylenediamine, and p‐phenylenediamine emit different fluorescence peaks at 534, 498, and 434 nm, respectively. Further investigation shows that the increase of –CONH and adjacent –NH2 favors the reduction of bandgap, which in turn induces redshifted emission. The green‐emitting CDs are also found to be thermally stable at high –CONH contents up to 10.35%. Finally, by assembling the fluorescent film with 450 nm laser diode, WLD with color coordinates of (0.3767, 0.3540), correlated color temperature of 3924 K, and CRI of 87 is realized, and its CRI reaches the advancing value for single phosphors‐based WLD devices. This work will lay the theoretical and experimental foundation for the realization of the low‐cost, high photothermal stability, high‐color‐rendering‐index CDs‐based laser lighting devices. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and catalytic application of a new N,N′-dineopentyl-1,2-phenylenediamine-based bismuthenium cation (3). 3 has been synthesized via the treatment of chlorobismuthane LBiCl [L = 1,2-C6H4{N(CH2tBu)}2] (2) with AgSbF6, and was further used as a robust catalyst for the cyanosilylation of ketones under mild reaction conditions. Experimental studies and DFT calculations were performed to understand the mechanistic pathway. [ABSTRACT FROM AUTHOR]

Ratiometric fluorescence and colorimetric strategies for detecting activity of butyrylcholinesterase (BChE) in human serum were developed by using g-C3N4 nanosheets, silver ion (Ag+) and o-phenylenediamine (OPD) as chromogenic agents. The oxidation-reduction reaction of OPD and Ag+ generates 2,3-diaminophenazine (oxOPD). Under exciation at 370 nm, g-C3N4 nanosheets and oxOPD emit fluorescence at 440 nm (F440) and 560 nm (F560), respectively. Additionally, oxOPD exhibits quenching ability towards g-C3N4 nanosheets via photoinduced electron transfer (PET) process. Thiocholine (TCh), as a product of BChE-catalyzed hydrolysis reaction of butylthiocholine iodide (BTCh), can coordinate with Ag+ intensively, and consequently diminish the amount of free Ag+ in the testing system. Less amount of free Ag+ leads to less production of oxOPD, resulting in less fluorescence quenching towards g-C3N4 nanosheets as well as less fluorescence emission of oxOPD. Therefore, by using g-C3N4 nanosheets and oxOPD as fluorescence indicators, the intensity ratio of their fluorescence (F440/F560) was calculated and employed to evaluate the activity of BChE. Similarly, the color variation of oxOPD indicated by the absorbance at 420 nm (ΔA420) was monitored for the same purpose. These strategies were validated to be sensitive and selective for detecting BChE activity in human serum, with limits of detection (LODs) of 0.1 U L−1 for ratiometric fluorescence mode and 0.7 U L−1 for colorimetric mode. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescence sensing strategy has been developed for the determination of Cu2+ and glyphosate with high sensitivity and specificity based on OPD (o-phenylenediamine) and glutathione-stabilized gold nanoclusters (GSH-AuNCs). Water-soluble 1.75-nm size GSH-AuNCs with strong red fluorescence and maximum emission wavelength at 682 nm were synthesized using GSH as the template. OPD was oxidized by Cu2+, which produced the bright yellow fluorescence oxidation product 2,3-diaminophenazine (DAP) with a maximum fluorescence emission peak at 570 nm. When glyphosate existed in the system, the chelation between glyphosate and Cu2+ hindered the formation of DAP and reduced the fluorescence intensity of the system at the wavelength of 570 nm. Meanwhile, the fluorescence intensity at the wavelength of 682 nm remained basically stable. It exhibited a good linear relationship towards Cu2+ and glyphosate in water in the range 1.0–10 µM and 0.050–3.0 µg/mL with a detection limit of 0.547 µM and 0.0028 µg/mL, respectively. The method was also used for the semi-quantitative determination of Cu2+ and glyphosate in water by fluorescence color changes visually detected by the naked eyes in the range 1.0–10 µM and 0.30–3.0 µg/mL, respectively. The sensing strategy showed higher sensitivity, more obvious color changes, and better disturbance performance, satisfying with the detection demands of Cu2+ and glyphosate in environmental water samples. The study provides a reliable detection strategy in the environment safety fields. [ABSTRACT FROM AUTHOR]

[Display omitted] The cancer therapeutic efficacy of the peroxidase (POD)-mimicking nanozyme-based monotherapy is significantly hindered due to insufficient intratumoral hydrogen peroxide (H 2 O 2) and glutathione (GSH) consumption effect on reactive oxygen species (ROS). In this study, we present the development of poly (o -phenylenediamine)@gold nanoparticles (AuNPs) (PoPD@Au) nanocomposites for multifunctional catalytic-photothermal therapy. These nanocomposites exhibit triple distinct nanozymatic activities, i.e. , POD-like activity that catalyzes H 2 O 2 to ROS, glucose oxidase (GOx)-like activity that supplements endogenous H 2 O 2 , and GSH depleting activity that decreases the ROS consumption efficiency. This open source and reduce expenditure strategy for ROS generation allows for the amplification of tumor oxidative stress, thereby enhancing anti-tumor efficiency. Additionally, the PoPD@Au nanocomposites demonstrate outstanding photothermal conversion efficiency, contributing to the synergistic effect between PoPD and AuNPs. Moreover, we reveal the improved photothermal performance of PoPD@Au triggered by the tumor microenvironment pH, which provides additional benefits for targeted catalytic-photothermal therapy. This "four-in-one" design of PoPD@Au enables efficient anti-tumor effects both in vitro and in vivo , making it a universal strategy for engineering catalytic-photothermal therapeutic nanoagents. [ABSTRACT FROM AUTHOR]

A simple, convenient, efficient and environmentally benign method has been developed for the synthesis of benzo[3,4-a]phenazin-5-ol as well as benzo[f]pyrido[2,3-b]quinoxalin-5-ol derivatives via the condensation of lawsoneand o-phenylenediamines or pyridine-2,3-diamines respectively by using a catalytic amount of trisodium citrate as an efficient, commercially available and low cost organo-catalyst in aqueous ethanol at room temperature. Mild reaction conditions, use of metal-free organocatalyst, nontoxic solvent, energy efficiency, no column chromatographic separation, gram scale production and reusability of the catalyst containing solvent media are some of the notable advantages of our developed protocol. [ABSTRACT FROM AUTHOR]

The photochemical degradation pathways of 6PPD-quinone (6PPDQ, 6PPD-Q), a toxic transformation product of the tire antiozonant 6PPD, were determined under simulated sunlight conditions typical of high-latitude surface waters. Direct photochemical degradation resulted in 6PPDQ half-lives ranging from 17.5 h at 20 °C to no observable degradation over 48 h at 4 °C. Sensitization of excited triplet-state pathways using Cs+ and Ar purging demonstrated that 6PPDQ does not decompose significantly from a triplet state relative to a singlet state. However, assessment of processes involving reactive oxygen species (ROS) quenchers and sensitizers indicated that singlet oxygen and hydroxyl radical do significantly contribute to the degradation of 6PPDQ. Investigation of these processes in natural lake waters indicated no difference in attenuation rates for direct photochemical processes at 20 °C. This suggests that direct photochemical degradation will dominate in warm waters, while indirect photochemical pathways will dominate in cold waters, involving ROS mediated by chromophoric dissolved organic matter (CDOM). Overall, the aquatic photodegradation rate of 6PPDQ will be strongly influenced by the compounding effects of environmental factors such as light screening and temperature on both direct and indirect photochemical processes. Transformation products were identified via UHPLC-Orbitrap mass spectrometry, revealing four major processes: (1) oxidation and cleavage of the quinone ring in the presence of ROS, (2) dealkylation, (3) rearrangement, and (4) deamination. These data indicate that 6PPDQ can photodegrade in cool, sunlit waters under the appropriate conditions: t1/2 = 17.4 h tono observable decrease (direct); t1/2 = 5.2-11.2 h (indirect, CDOM).

Bis-silylenes do not only act as strong chelating σ-donor ligands, but also exhibit cooperative behaviour in the activation of small molecules. Three different P–Si containing molecules were prepared from the reaction between tBuC≡P and different bis-silylenes, which are bridged by ferrocenediyl, diaminobenzene, or o-carborane. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescence sensor has been established based on dual-excitation carbon dots (D-CDs) for the detection of flavonoids (morin is chosen as the typical detecting model for flavonoids). D-CDs were prepared using microwave radiation with o-phenylenediamine and melamine and exhibit controllable dual-excitation behavior through the regulation of their concentration. Remarkably, the short-wavelength excitation of D-CDs can be quenched by morin owing to the inner filter effect, while the long-wavelength excitation remains insensitive, serving as the reference signal. This contributes to the successful design of an excitation-based ratiometric sensor. Based on the distinct and differentiated variation of excitation intensity, morin can be determined from 0.156 to 110 µM with a low detection limit of 0.156 µM. In addition, an intelligent and visually lateral flow sensing device is developed for the determination of morin content in real samples with satisfying recoveries, which indicates the potential application for human health monitoring. [ABSTRACT FROM AUTHOR]

A post-modified covalent organic skeleton (JLNU-305-Fe) for degradation of 2,4-DCP was prepared. This study provides a broad prospect for the practical application of COF materials in the degradation of organic pollutants. [Display omitted] Herein, a novel two-dimensional double-pore covalent organic framework (JLNU-305) was synthesized using N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TAPD) and 2,2′-bipyridine-5,5′-dicarboxaldehyde (BPDA). The extended π-π conjugated structure and nitrogen-riched pyridine in JLNU-305 (JLNU = Jilin Normal University) provide abundant binding sites for Fe doping. The obtained JLNU-305-Fe exhibited high and recycled catalytic efficiency for peroxydisulfate (PDS) activation to completely degrade 10 mg/L 2,4-dichlorophenol (2,4-DCP) within 8 min. The JLNU-305-Fe/PDS system showed excellent catalytic activity and cyclic stability. The capture experiments and electron paramagnetic resonance (ESR) analysis indicated that the catalytic behavior of JLNU-305-Fe/PDS is contributed to the synergistic effect between free radicals and non-free radicals. It is the first time to activate PDS for covalent organic frameworks (COFs) being used to degrade 2,4-DCP, which has a great potential for development and practical application in related water environment remediation. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA)-based biopolymer hydrogels are promising therapeutic dressings for various wounds but still underperform in treating diabetic wounds. These wounds are extremely difficult to heal and undergo a prolonged and severe inflammatory process due to bacterial infection, overexpression of reactive oxygen species (ROS), and insufficient synthesis of NO. In this study, a dynamic crosslinked hyaluronic acid (HA) hydrogel dressing (Gel-HAB) loaded with allomelanin (AMNP)-N, N′-dis-sec-butyl-N, N′-dinitroso-1, 4-phenylenediamine (BNN6) nanoparticles (AMNP-BNN6) was developed for healing diabetic wounds. The dynamic acylhydrazone bond formed between hydrazide-modified HA (HA-ADH) and oxidized HA (OHA) makes the hydrogel injectable, self-healing, and biocompatible. The hydrogel, loaded with AMNP-BNN6 nanoparticles, exhibits promising ROS scavenging ability and on-demand release of nitric oxide (NO) under near-infrared (NIR) laser irradiation to achieve mild photothermal antibacterial therapy (PTAT) (∼ 48 °C). Notably, the Gel-HAB hydrogel effectively reduced the oxidative stress level, controlled infections, accelerated vascular regeneration, and promoted angiogenesis, thereby achieving rapid healing of diabetic wounds. The injectable self-healing nanocomposite hydrogel could serve as a mild photothermal-enhanced antibacterial, antioxidant, and nitric oxide release platform for the treatment of diabetic wounds. [Display omitted] • A hyaluronic acid hydrogel with excellent synergistic antimicrobial properties via mild photothermal effect and NO release. • Hydrogel effectively reduces the inflammatory microenvironment and promotes the growth of M2 macrophages. • Hydrogel effectively manages diabetic wound infections, reduces inflammation levels, promotes angiogenesis and collagen deposition, and accelerates rapid wound healing. [ABSTRACT FROM AUTHOR]

As an antioxidant and antiozonant, N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) is predominantly used in the rubber industry to prevent degradation. However, 6PPD can be ozonated to generate a highly toxic transformation product called N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone (6PPD-quinone), which is toxic to aquatic and terrestrial organisms. Thus, 6PPD and 6PPD-quinone, two emerging contaminants, have attracted extensive attention recently. This review discussed the levels and distribution of 6PPD and 6PPD-quinone in the environment and investigated their toxic effects on a series of organisms. 6PPD and 6PPD-quinone have been widely found in air, water, and dust, while data on soil, sediment, and biota are scarce. 6PPD-quinone can cause teratogenic, developmental, reproductive, neuronal, and genetic toxicity for organisms, at environmentally relevant concentrations. Future research should pay more attention to the bioaccumulation, biomagnification, transformation, and toxic mechanisms of 6PPD and 6PPD-quinone. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) possess a considerable number of beneficial features for latent applications in biotargeted drugs, electronic transistors, and encrypted information. The synthesis of fluorescent carbon dots has become a trend in contemporary research, especially in the field of controllable multicolor fluorescent carbon dots. In this study, an elementary one-step hydrothermal method was employed to synthesize the multicolor fluorescent carbon dots by co-doping unique phenylenediamine isomers (o-PD, m-PD, and p-PD) with B and P elements, which under 365 nm UV light exhibited signs of lavender-color, grass-color, and tangerine-color fluorescence, respectively. Further investigations reveal the distinctness in the polymerization, surface-specific functional groups, and graphite N content of the multicolor CDs, which may be the chief factor regarding the different optical behaviors of the multicolor CDs. This new work offers a route for the exploration of multicolor CDs using B/P co-doping and suggests great potential in the field of optical materials, important information encryption, and commercial anticounterfeiting labels. [ABSTRACT FROM AUTHOR]

Nitrogen, boron co-doped carbon quantum dots (gCQDs), and a coloration probe (PPD-NPs) with response to cobalt ions (Co2+) were prepared by using 4-hydroxyphenylboric acid as the common precursor, with ethylenediamine and p-phenylenediamine (PPD) adopted as nitrogen-doped reagents, respectively. A noticeable brown-to-purple color change can be observed with the addition of Co2+, and a broad absorption band emerges at 535 nm. At the same time, gCQDs, which is introduced as the fluorescence signal source, will be significantly quenched due to the enhanced inner filtration effect, induced by the overlap between the emission spectrum of gCQDs and the emerging absorption band. Therefore, a colorimetric/fluorescent dual-mode sensing probe for Co2+ is constructed by combining the recognition unit PPD-NPs and the fluorescent gCQDs into PPD-NP/gCQD. Under the optimized experimental conditions, the calculated limits of detection are 1.51 × 10−7 M and 3.75 × 10−7 M for the colorimetric mode and the fluorescence mode, respectively, well qualified for the determination of Co2+ maximum permitted level in drinking water. The feasibility of the proposed method has been verified in tap water, lake water, and black tea samples. [ABSTRACT FROM AUTHOR]

Aromatic amines, crucial organic entities, exist in drugs, natural products, organic materials, and catalysts. The introduction of amines to aromatics without using metal catalysts and chemical oxidants poses a formidable challenge. Recent years have witnessed extensive developments in the oxidative aromatization of aniline. In this context, we present the electrochemical cross-dehydrogenation aromatization (ECDA) reaction involving cyclohex-2-enone and amines, culminating in the synthesis of 1,4-phenylenediamine, devoid of supplementary metal catalysts and chemical oxidants. The broad applicability of the reaction substrate is underscored, demonstrating its compatibility with select natural and pharmaceutical molecules, thus showing considerable potential for the synthesis of bioactive compounds. The mechanistic underpinnings of the reaction were probed using online electrochemical mass spectrometry. [ABSTRACT FROM AUTHOR]

An effective, green and eco-friendly method was developed to synthesize 1H-benzimidazole under microwave irradiation. The reactions of substituted o-phenylenediamine with DMF were efficiently promoted by butanoic acid, and the desired product 1H-benzimidazole derivatives were obtained in good to excellent yields. Compared with the conventional heating method, microwave irradiation significantly reduced the reaction time and improved the yields of the target products. [ABSTRACT FROM AUTHOR]

Human exposure to p-phenylenediamine derivatives (PPDs) may induce hepatotoxicity and altered glycolipid metabolism. Recent studies have demonstrated the wide presence of PPDs in environmental matrixes. However, until now, the occurrence of PPDs in tap water has not been well known. This study analyzed nine PPDs in tap water collected from Hangzhou and Taizhou, China. The results showed that seven PPDs were detected in tap water samples from Hangzhou (n = 131), with the concentration of total detected PPDs ranging from 0.29 to 7.9 ng/L (mean: 1.6 ng/L). N-(1, 3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD; mean: 0.79 ng/L,

A panel of 1,1-(phenylene)bis[3-chloro-4-(substituted phenyl)azetidin-2-ones] (4a-m) and 3,3′-(1,4-phenylene)bis[2-(substituted phenyl)thiazolidin-4-ones] (5a-m) were synthesized from Schiff base intermediates 3a-m, that were in turn prepared from reaction between p-phenylenediamine and substituted benzaldehydes. The structures of title compounds and intermediates were confirmed by IR, 1H NMR, 13C NMR and mass spectral data. The compounds were screened for antibacterial, DPPH radical scavenging and antidiabetic activities. Compounds 4f and 4a exhibited good antibacterial activity against Gram-positive bacteria, but none showed appreciable activity against Gram-negative bacteria. In DPPH scavenging assay, compounds 5f, 5e and 5a exhibited good activity. Compound 5a displayed highly significant antidiabetic activity in fructose-induced diabetes in rats. The molecular docking studies of bis-thiazolidinones with PPAR-ã revealed the fit with high binding affinity and good interactions. Docking of compound 5a was comparable to the standard drug pioglitazone. The in silico physicochemical, drug-likeness and ADME properties of title compounds were also performed and the majority of them displayed satisfactory results. [ABSTRACT FROM AUTHOR]

The rates of substitution of the chloride ligand in dinuclear complexes, [Pt2(N,N'-bis(2-pyridylcarboxamide)-1,3-phenylenediamine)Cl4] (1), [Pt2(N,N'-bis(2-pyridylcarboxamide)-1,4-phenylenediamine)Cl4] (2), [Pt2(N,N'-bis(3-isoquinolylcarboxamide)-1,3-phenylenediamine)Cl4] (3) and [Pt2(N,N'-bis(3-isoquinolylcarboxamide)-1,4-phenylenediamine)Cl4] (4), by three bio-relevant nucleophiles, thiourea (TU), N,N-dimethylthiourea (DMTU) and N,N,N',N'-tetramethylthiourea (TMTU), were investigated. The mononuclear analogue [Pt(N-phenylpyridine-2-carboxamide)Cl2] (5) was included to compare the results. The kinetics of the reactions were studied under pseudo first-order conditions in a methanol solution (I = 0.1 M LiCl) as a function of concentration and temperature using the stopped-flow spectrophotometer. The observed pseudo first-order rate constants for the substitution reactions of all the complexes were calculated from two well-separated steps and obey the rate law kobs (1st/2nd) = k2 (1st/2nd)[Nu]. The reactivity of the complexes decreases in the order 2 > 1 > 4 > 3 > 5. The conformational symmetry of the complexes as controlled by the phenylenediamine bridges, steric hindrance due to the bridges as well as the σ-donor capacity of the coordinated groups around the metal centers influence the reactivity of the dinuclear complexes. The low enthalpy (ΔH#) and negative intrinsic entropy (ΔS#) values support an associative mechanism of substitution. The kinetic data are supported by DFT calculations. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) tin halide perovskite shows impressive stability by introducing diamine organic spacer. However, due to the dielectric confinement and uncontrollable crystallization process, 2D DJ perovskite usually exhibits large exciton binding energy and poor film quality, resulting in unfavorable charge dissociation, carrier transport and device performance. Here, the ortho‐, meta‐, and para‐isomers of phenylenediamine (PDA) are designed for 2D DJ tin halide perovskites. Theoretical simulation and experimental characterizations demonstrate that compared with p‐PDA and m‐PDA, o‐PDA shows larger dipole moment, which further reduces the exciton binding energy for the 2D perovskites. Besides, there is a strong hydrogen bond interaction between o‐PDA cation and inorganic octahedron, which not only improves the structural stability, but also induces larger aggregates in the precursor to form dense and uniform high‐quality films, and strengthens the antioxidant barrier. More interestingly, femtosecond transient absorption further proves that o‐PDA organic spacers can reduce unfavorable small n‐phases, resulting in sufficient and effective charge transfer between different n‐value. As a result, the 2D DJ (o‐PDA)FA3Sn4I13 solar cells achieve a record power conversion efficiency of 7.18%. The study furnishes an effective method to optimize the carrier transport and device performance by tailoring the chemical structure of organic spacers. [ABSTRACT FROM AUTHOR]

[Display omitted] N -(1,3-dimethylbutyl)- N ′-phenyl- p -phenylenediamine quinone (6PPDQ) has attracted significant attention due to its highly acute lethality to sensitive salmonids. However, studies investigating the mechanisms underlying its acute toxicity have been lacking. In this work, we demonstrated the sensitivity of rainbow trout to 6PPDQ-induced mortality. Moribund trout exhibited significantly higher brain concentrations of 6PPDQ compared to surviving trout. In an in vitro model using human brain microvascular endothelial cells, 6PPDQ can penetrate the blood–brain barrier and enhance blood–brain barrier permeability without compromising cell viability. The time spent in the top of the tank increased with rising 6PPDQ concentrations, as indicated by locomotion behavior tests. Furthermore, 6PPDQ influenced neurotransmitter levels and mRNA expression of neurotransmission-related genes in the brain and exhibited strong binding affinity to target neurotransmission-related proteins using computational simulations. The integrated biomarker response value associated with neurotoxicity showed a positive linear correlation with trout mortality. These findings significantly contribute to filling the knowledge gap between neurological impairments and apical outcomes, including behavioral effects and mortality, induced by 6PPDQ. [ABSTRACT FROM AUTHOR]

Redox non-innocent ligands react with metal precursors to form complexes where the oxidation states of the ligand and thus the metal atom cannot be easily defined. A well-known example of such ligands is bis(o-aminophenol) N,N′-bis(3,5-di-tertbutyl-2-hydroxy-phenyl)-1,2-phenylenediamine, previously developed by the Wieghardt group, which has a potentially tetradentate coordination mode and four distinct protonation states, whereas its electrochemical behavior allows for five distinct oxidation states. This rich redox chemistry, as well as the ability to coordinate to various transition metals, has been utilized in the syntheses of metal complexes with M2L, ML and ML2 stoichiometries, sometimes supported with other ligands. Different oxidation states of the ligand can adopt different coordination modes. For example, in the fully oxidized form, two N donors are sp2-hybridized, which makes the ligand planar, whereas in the fully reduced form, the sp3-hybridized N donors allow the formation of more flexible chelate structures. In general, the metal can be reduced during complexation, but redox processes of the isolated complexes typically occur on the ligand. Combination of this non-innocent ligand with redox-active transition metals may lead to complexes with interesting magnetic, electrochemical, photonic and catalytic properties. [ABSTRACT FROM AUTHOR]

Schiff bases have advanced physical, chemical, and medicinal properties, making them strong biological agents. Comparable FTIR, UV-VIS, 1HNMR, 13CNMR spectra confirmed the successful formation of N-N-(1,2-Phenylene)bis(1-(4-bromophenyl)methanimine) (CS3) compound. Geometry was optimized using DFT with B3LYP/cc-pVDZ basis set. Obtained energy gap of the compound was 2.07 eV. Carbon and oxygen atoms were electrophilic, according to molecular electrostatic potential analysis. Mulliken charge analysis found that C atoms have + ve and -ve charges, H atoms have only positive charges, while Br, O, and N atoms have only -ve charges. The ELF analyzed the molecule and found that the atoms of C, N, and Br all had delocalized electron density. The wave function LOL identified localized orbital positions in the hydrogen atoms. RDG maps provided various non-covalent interactions. Synthesized compound was docked using PDB: 2ZM5 protein, with the lowest binding attractions obtained, are −5.44 (7BYE) kcal/mol. [ABSTRACT FROM AUTHOR]

A.Z. El-Sonbati et al., in their article "Synthesis, characterization of Schiff base metal complexes and their biological investigation" (Appl. Organometal. Chem. 2019, 33, e5048) reported on the synthesis of a new Schiff base named (E)-2-(((3-aminophenyl)imino)methyl)phenol (also known as N-salicylidene-m-phenylenediamine, HL), which was obtained through condensation reaction of m-phenylenediamine and salicylaldehyde in a 1:1 molar ratio. The reported Schiff base HL was involved in the complexation reaction with a series of metal cations named Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). Although no crystal structures of either the parent ligand HL or its complexes with the mentioned metal cations were reported, the newly synthesized compounds were characterized by means of elemental analysis, IR-, UV-vis- and 1H NMR spectroscopy, mass-spectrometry, magnetic susceptibility, conductivity and thermal analyses. The antimicrobial activity of the discussed compounds, together with the molecular docking results, were also reported. Additionally, both the Schiff base HL and its metallocomplexes were thoroughly examined by quantum chemical calculations. Despite a plethora of different methods being applied to characterize the obtained compounds, herein, I argue that discussion of the results is doubtful. Furthermore, the results of quantum chemical calculations are dubious and must be reconsidered. Although numerous synthetic attempts failed in this work, the hypothetically possible Schiff base HL was revisited using quantum chemical calculations. A.Z. El-Sonbati et al., in their article "Synthesis, characterization of Schiff base metal complexes and their biological investigation" (Appl. Organometal. Chem. 2019, 33, e5048) reported on a new Schiff base (E)-2-(((3-aminophenyl)imino)methyl)phenol (also known as N-salicylidene-m-phenylenediamine, HL) and its metallocomplexes. Herein, I argue that the discussion of the results is doubtful. [ABSTRACT FROM AUTHOR]

In this study, bilirubin (BR) is detected by using a novel molecularly imprinted electrochemical sensor based on a Ti3C2TxMXene‐modified ITO electrode. First, Ti3C2TxMXene is synthesized by chemical etching and deposited at the ITO electrode surface by drop casting. After that, ortho‐phenylenediamine (o‐PD) as monomer is electropolymerized in the presence of a sodium acetate buffer solution containing the BR template to prepare BR‐imprinted electrode. Field emission scanning electron microscopy (FESEM), x‐ray diffraction and UV–visible absorption spectroscopy confirms the MXene synthesis. The molecular imprinted polymer (MIP) formation at the electrode is confirmed by electrochemical methods such as differential pulse voltammetry, electrochemical impedance spectroscopy, and cyclic voltammetry, and FESEM. The linearity range, limit of detection and the limit of quantification are calculated as 0.1 mg/dL to 20 mg/dL, 0.002 mg/dL, and 6.6 mg/dL respectively. Stability and reproducibility are also reported for the prepared MIP sensor. [ABSTRACT FROM AUTHOR]

The effective and accurate determination of heavy metals and significant biomolecules is crucial for environmental protection and human health. A novel carbon dot (Si-CDs)-based multivariate sensing method was established for monitoring Cu2+, Mn2+, Co2+ and dopamine (DA) concomitantly. The Si-doped CDs were favorably synthesized using p-phenylenediamine (PPD) and (3-aminopropyl) trimethoxysilane (APTMS) as precursors with a quantum yield of 23.3% and a lifetime of 23.4 μs. The optimal emission of Si-CDs was determined at 500 nm with an excitation at 390 nm with an excellent aqueous dispersibility and environmental tolerance. Moreover, the proposed Si-CDs exhibited sensitive FL quenching toward Cu2+, Mn2+ and DA, and a colorimetric response towards Co2+, thus a multiple dual-mode sensing platform was constructed. The similar FL responses for Cu2+, Mn2+ and DA could be distinguished by different colorimetric variations, which enabled the multivariate detection of these three analytes via dual-mode FL and colorimetric integration. Also, the colorimetric mode that solely recognized Co2+ also realized an excellent linearity correlation between absorption and concentration. Furthermore, the heavy metals in real water samples and DA in serum could be quickly and directly analyzed by visual detection with reliable accuracy. To the best of our knowledge, this is the first report based on CDs for the simultaneous detection of three heavy metal ions and DA by a dual-mode method, opening a new avenue for the ultrasensitive sensing of multiple metal ions and biomolecules in environment protection and biomedical fields. [ABSTRACT FROM AUTHOR]

Conjugated polymers (CPs) having a backbone of alternating single and multiple bonds are well known for their technological applications. Herein, we report the successful synthesis of CPs; poly(o-chloroaniline) (POCA), poly(o-phenylenediamine) (POPD), and for the first time their copolymer poly(OPD-co-OCA) along with the evaluation of corrosion inhibition efficiency. The obtained materials were characterized by UV–Visible spectroscopy, FTIR, SEM, XRD, TGA, and cyclic voltammetry measurements. The comparative analysis confirmed the satisfactory formation of homopolymers POCA, POPD and its copolymer poly(OPD-co-OCA). The homopolymer POPD and copolymer poly(OPD-co-OCA) are soluble in common organic solvents (acetone, methanol, N-methyl-2-pyrrolidone (NMP), Dimethyl sulfoxide (DMSO), and chloroform) while homopolymer POCA is insoluble. The novel copolymer poly(OPD-co-OCA) reveals good thermal stability than homopolymers POPD and POCA. The cyclic voltammetry studies show that copolymer poly(OPD-co-OCA) acquired redox behavior having an anodic peak at about 0.4 V, nevertheless corresponding homopolymer POPD act as an insulator with no obvious redox peak. The corrosion inhibition efficiency on a mild steel for copolymer poly(OPD-co-OCA) is found 70 to 80% which is reasonably higher than homopolymer POPD (68%), probably is due to donor–acceptor substituents involved in copolymer. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescence platform was developed based on the cobalt oxyhydroxide (CoOOH) nanosheet–modulated fluorescence response of blue emissive copper nanoclusters (Cu NCs) and yellow emissive o-phenylenediamine (OPD). CoOOH nanosheets showed dual function of strong absorption and oxidation ability, which can effectively quench the blue fluorescence of Cu NCs, with an excitation and emission peak maximum at 390 and 450 nm, respectively , and transfer the OPD into yellow fluorescence products, with an excitation and emission peak maximum at 390 and 560 nm, respectively. Upon introducing butyrylcholinesterase (BChE) and its substrates, CoOOH nanosheets were decomposed into Co2+, and malachite green (MG) showed strong inhibition ability to this process. This resulted in the obvious difference on the ratio of blue and yellow fluorescence recorded on the system in the presence and absence of MG, which was utilized for the quantitative detection of MG, with a limit of detection of 0.140 μM and a coefficient of variation of 3.5%. The fluorescence ratiometric assay showed excellent detection performances in practical sample analysis. [ABSTRACT FROM AUTHOR]

Nanomaterials are desirable for sensing applications. Therefore, MnO2 nanosheets and nitrogen-doped carbon dots (NCDs) were used to construct a ratiometric biosensor for quantification of 2,4-dichlorophenoxyacetic acid. The MnO2 nanosheets drove the oxidation of colorless o-phenylenediamine to OPDox, which exhibits fluorescence emission peaks at 556 nm. The fluorescence of OPDox was efficiently quenched and the NCDs were recovered as the ascorbic acid produced by the hydrolyzed alkaline phosphatase (ALP) substrate increased. Owing to the selective inhibition of ALP activity by 2,4-D and the inner filter effect, the fluorescence intensity of the NCDs at 430 nm was suppressed, whereas that at 556 nm was maintained. The fluorescence intensity ratio was used for quantitative detection. The linear equation was F = 0.138 + 3.863·C 2,4-D (correlation coefficient R2 = 0.9904), whereas the limits of detection (LOD) and quantification (LOQ) were 0.013 and 0.040 μg/mL. The method was successfully employed for the determination of 2,4-D in different vegetables with recoveries of 79%~105%. The fluorescent color change in the 2,4-D sensing system can also be captured by a smartphone to achieve colorimetric detection by homemade portable test kit. [ABSTRACT FROM AUTHOR]

A film is developed on the surface of the carbon paste electrode by electro-ionic depositing of thiosemicarbazide (TSC) chemical substance and electropolymerized with paraphenylenediamine (PPD) and the modified carbon paste electrode (MCPE) was constructed at physiological pH 7.5 in PBS buffer solution. The bioactive molecules of dopamine (DP) and uric acid (UA) electro-chemical distinctiveness were studied by cyclic voltammetry method. TSC/poly(paraphenylenediamine) MCPE was used to examine DP and UA by cyclic voltammetric (CV), and differential pulse voltammetric (DPV) techniques. The addition of research constraints distressing the electrocatalytic action on MCPE such as the effect of pH, scan rate, and concentration differentiations are studied. The limit of detection of DP and UA were premeditated by CV as 1.34 µM and 4.19 µM, respectively. The modified electrode illustrated advanced sensitivity and selectivity for the synchronized determination of DP and UA, and the unclean consequence is also eradicated by this MCPE. [ABSTRACT FROM AUTHOR]

Twelve novel compounds (Phenylenediamine side chain modified 4‐Aminoquinoline Mannich Bases) were synthesized and characterized by using a variety of analytical and spectroscopic methods. All the synthesized compounds were screened for in‐vitro antimalarial activity on 3D7 strain of Plasmodium falciparum. Synthesized compounds showed MIC values between 1.9 and 125 μg/ml in antimalarial screening (in‐vitro). Two compounds (MIC=1.9 μg/ml or 1.953± ${\pm }$ 0.10 μM and 7.8 μg/ml or 2.200± ${\pm }$ 0.08 μM) were found most potent against chloroquine sensitive 3D7 strain of Plasmodium falciparum which is comparable to standard drug chloroquine (MIC=0.4 μg/ml or 0.106± ${\pm }$ 0.01 μM). [ABSTRACT FROM AUTHOR]

Traditional techniques for adding chelating agents to solids take time, energy, and materials. This study focuses on the preparation of a quick and easy solid-phase extraction approach using microwave-enforced green synthesis. CuFe2O4 magnetic nanoparticles (CFO-NPs) were modified chemically by bis(salicylaldehyde) phenylenediamine (BSAPhD) investigated for Cu(II) removal from aqueous solutions. The modification conditions (power and time) of the process are optimized. The performance of the resulting magnetic composite nanoparticles (BSAPhD@CFO-NPs) was compared with that of those prepared using a conventional reflux method (BSAPhD/reflux@CFO). BSAPhD@CFO-NPs was characterized using Fourier-transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). All the data confirmed the success of the preparation of BSAPhD and modification for CFO with BSAPhD via microwave synthesis. The experimental adsorption conditions including pH, contact time, and adsorbent mass were also optimized. BSAPhD@CFO-NPs has an adsorption capacity of 429.8 mg-Cu(II) g-1, which is more than that of BSAPhD/reflux@CFO (287 mg g-1) at pH 8 with 15 min contact time. The Freundlich, Langmuir, and Temkin isotherm models were used to describe adsorption equilibrium. It was found that the Langmuir model (R2 = 0.9988) best fits Cu(II) adsorption on the BSAPhD@CFO-NPs adsorbent surface. The application of the BSAPhD@CFO-NPs adsorbent for the removal of Cu(II) from various water samples was performed. The results showed good recovery with high sensitivity. [ABSTRACT FROM AUTHOR]

To reach a deeper understanding of the charge storage mechanisms of electrode materials is one of the challenges toward improving their energy storage performance. Herein, we investigate the interfacial ion exchange of a composite electrode made of carbon nanotube/poly(ortho-phenylenediamine) (CNT/PoPD) in a 1M NaCl aqueous electrolyte via advanced electrogravimetric analyses based on electrochemical quartz crystal microbalance (EQCM). Classical EQCM at different scan rates of the potential revealed the complex electrogravimetric behavior likely due to multi-species participation at different temporal scales. Thereafter, in order to better understand the behavior of each species (ions, counter ions, and co-ions) in the charge compensation mechanism, the electrogravimetric impedance spectroscopy analysis (also called ac-electrogravimetry) was pursued. Ac-electrogravimetry revealed the role of each species where Na+ cations and Cl− anions as well as protons participate in the charge compensation mechanism of the CNT/PoPD composite with different kinetics and proportions. The water molecules with opposite flux direction with the cations are also detected, suggesting their exclusion during cationic species transfer. Having analyzed ac-electrogravimetry responses in depth, the synergistic interaction between the CNT and PoPD is highlighted, revealing the improved accessibility of species to new sites in the composite. [ABSTRACT FROM AUTHOR]

Polyfluorene-based copolymers such as poly(9,9-dioctylfluorene)-alt-5% [bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine] (F8-5% BSP) are efficient blue-emitting polymers with various electronic phases: F8 blue-emitting glassy phase, F8 ordered more red-emitting β-phase, and F8/BSP charge transfer (CT) state. Polymer light-emitting device performance and color purity can be significantly improved by forming β-phase segments. However, the role of the β-phase on energy transfer (ET) among glassy F8, β-phase, and F8/BSP CT state is unclear. Herein, we identify dynamic molecular conformation-controlled ET from locally excited states to either the CT state or β-phase in light-emitting copolymers. By conducting single-molecule spectroscopy for single F8-5% BSP chains, we find inefficient intra-chain ET from glassy segments to the CT state, while efficient ET from the glassy to the β-phase. Spontaneous and reversible CT on–off emission is observed both in the presence and absence of the β-phase. The density functional theory calculations reveal the origin of the on-chain CT state and indicate this CT emission on–off switching behavior could be related to molecule torsional motion between BSP and F8 units. The population of the CT state by ET can be increased via through-space interaction between the F8 block and the BSP unit on a self-folded chain. Temperature-dependent single-molecule spectroscopy confirms such interaction showing a gradual increase in intensity of the CT emission with the temperature. Based on these observations, we propose the dynamic molecular motion-induced conformation change as the origin of the glassy-to-CT ET, and thermal energy may provide the activation for such a change to enhance the ET from glassy or β-phases to the CT state. [ABSTRACT FROM AUTHOR]

The environmental issues and health problems of waste plastics have attracted remarkable attention. It is quite important to convert waste plastics into high value-added electrochemical materials. Herein, four kinds of Co-based metal–organic frameworks (CoMOFs) were synthesized from poly(ethylene terephthalate) plastic, and their electrochemical applications were examined. A mixture of N,N-dimethylformamide (DMF) and H2O was used as the solvent, and hydrothermal reaction was employed. It is found that the surface area and porous structure of CoMOFs are closely related to the volume ratio of DMF/H2O. As a result, the prepared CoMOFs exhibit different catalytic enhancement activities toward the oxidation of p-phenylenediamine (PPD). Based on the solvent-controlled sensing performance of CoMOFs, a highly sensitive and rapid detection method has been developed for PPD, with a linear range from 0.05 to 8.0 μM. The detection limit was 45 nM, and the practical application in hair dye samples was successfully demonstrated. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) are attracting significant research attention due to their low toxicity and highly favorable photochemical properties. This study reports the synthesis of nitrogen‐doped CDs (N‐CDs) using 3‐aminophenol and o‐phenylenediamine as carbon precursors and their application to nontoxic, biocompatible polychromatic agents for biological imaging studies. The prepared N‐CDs exhibit multicolored fluorescence (blue, green, yellow, orange) with excellent optical stability and biocompatibility. As a result of Fourier‐transform infrared spectroscopy and X‐ray photoelectron spectroscopy, N‐CD is found to have similar –OH and C–H in the surface functional group, showing a graphene structure with good hydrophilicity. The size of the synthesized N‐CDs is confirmed by transmission electron microscopy images to be less than 10 nm. The 3‐4,5‐dimethylthiazol‐2,5‐diphenyl tetrazolium bromide analysis is performed using HeLa cells, and cell survival is very high in all N‐CDs. Among N‐CDs, G‐CDs exhibit the highest fluorescence intensity and provide excellent fluorescence microscopic images for cells in blue, green, and red channels. [ABSTRACT FROM AUTHOR]

As potential intravesical exfoliants for the treatment of bladder cancer, four new imdiazolium salts have been prepared. These compounds are modified on the nitrogen positions of the 4,5‐diphenyl‐1H‐imidazole or benzimidazole rings with naphthalen‐2‐ylmethyl groups, and the 2 positions on the azolium cations are occupied by arene rings. The 4,5‐diphenyl‐1H‐imidazole and benzimidazole precursors are produced from 1,2‐phenylenediamine and benzil respectively, and the imidazolium cations are generated from sequential alkylation of the nitrogen positions using 2‐bromomethyl naphthalene. The four imidazolium salts were screened for their chemotherapuetic activity using the NCI‐60 Human Tumour Cell Line Screen, and we observed that the cytotoxicity was more dependent on the identity of the imidazolium group (benzimidazolium versus diphenylimidazolium) rather than on the 2‐aryl position structure. [ABSTRACT FROM AUTHOR]

Modern biocatalysis requires fast, sensitive, and efficient high-throughput screening methods to screen enzyme libraries in order to seek out novel biocatalysts or enhanced variants for the production of chemicals. For instance, the synthesis of bio-based furan compounds like 2,5-diformylfuran (DFF) from 5-hydroxymethylfurfural (HMF) via aerobic oxidation is a crucial process in industrial chemistry. Laccases, known for their mild operating conditions, independence from cofactors, and versatility with various substrates, thanks to the use of chemical mediators, are appealing candidates for catalyzing HMF oxidation. Herein, Schiff-based polymers based on the coupling of DFF and 1,4-phenylenediamine (PPD) have been used in the set-up of a novel colorimetric assay for detecting the presence of DFF in different reaction mixtures. This method may be employed for the fast screening of enzymes (Z' values ranging from 0.68 to 0.72). The sensitivity of the method has been proved, and detection (8.4 μM) and quantification (25.5 μM) limits have been calculated. Notably, the assay displayed selectivity for DFF and enabled the measurement of kinetics in DFF production from HMF using three distinct laccase–mediator systems. [ABSTRACT FROM AUTHOR]

A dual-mode pH sensor based on nitrogen-doped carbon dots (N-CDs) with the source of o-phenylenediamine and tryptophan has been constructed. Under the stimulation of pH, the N-CDs exhibited prominent both color and fluorescence changes, leading to the rarely discovered colorimetric and fluorescent dual-readouts for the evaluation of pH. The mathematic relationship was established between pH and fluorescence intensity of N-CDs, and between pH and the UV–Vis absorbance ratio at 630 nm and 488 nm of N-CDs, respectively, over a quite broad pH range of 2.2 to 12.0. Multiple techniques are used to explore the dual-mode pH-responsive mechanism, and the preliminary explanation is put forward. The experimental results show that the N-CDs have visualized pH sensing applicability for actual samples, including various water samples and HeLa cell. Furthermore, the N-CD ink is developed for successful information encryption and anti-counterfeiting. This work might provide valuable insights into the sensing mechanism of CDs, and the application potential of CDs in broader fields. [ABSTRACT FROM AUTHOR]

A novel o-phenyl­enedi­amine (opda)-based cadmium complex, bis­(benzene-1,2-di­amine-κ²N,N′)bis­(benzene-1,2-di­amine-κN)cadmium(II) naphthalene-1,5-di­sulfonate, [Cd(C6H8N2)4](C10H6O6S2), was synthesized. The complex salt crystallizes in the monoclinic space group C2/c. The Cd atom occupies a special position and coordinates six nitro­gen atoms from four o-phenyl­enedi­amine mol­ecules, two as chelating ligands and two as monodentate ligands. The amino H atoms of opda inter­act with two O atoms of the naphthalene-1,5-di­sulfonate anions. The anions act as bridges between [Cd(opda)4]2+ cations, forming a two-dimensional network in the [010] and [001] directions. The Hirshfeld surface analysis shows that the primary factors contributing to the supramolecular inter­actions are short contacts, particularly van der Waals forces of the type HH, OH and CH. [ABSTRACT FROM AUTHOR]

This work was aimed at the development of a sensitive electrochemical detection method for oxycodone in water. Molecularly imprinted electrodes were formed by electro-polymerization process using o-phenylenediamine as a monomer. The electro-polymerization was performed on glassy carbon electrodes in the presence of oxycodone before the extraction of entrapped oxycodone molecules. Various electrochemical techniques were employed to monitor the polymerization and response of the fabricated electrodes toward oxycodone. These techniques included cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The oxycodone concentration was determined using SWV by measuring the change in the oxidation peak current of [Fe(CN)6]3−/4− in a 0.1 mM acetate buffer solution. At the optimal electro-polymerization conditions, a calibration curve of the current versus the concentration of oxycodone indicated a linear response at a region from 0.4 nM to 5.0 nM with a detection limit of 1.8 ± 0.239 nM. The MIP-modified electrode's binding isotherm was fitted using a Langmuir model and showed an association constant, KA, of 1.12 × 106, indicating a high affinity of oxycodone molecules to binding sites. This sensor has the potential to act as an alternative method suitable for the on-site analysis of oxycodone. [ABSTRACT FROM AUTHOR]

Herein, a new and simple strategy based on electrochemical cascade reactions was used to prepare copper/poly(para‐phenylenediamine). The catalysts were prepared by a facile one‐pot synthesis via an electrochemical method in a solution containing monomer and copper in a suitable concentration using potentiostatic or galvanostatic mode. Using galvanostatic mode leads to the formation of nanodendritic shape of copper hydroxide‐copper oxide in contrast with potentiostatic mode which leads to a spherical form. The response toward ethanol oxidation was greatly affected by the morphology of the obtained nanocomposite. Indeed, the current density obtained when using potentiostatic mode is about 26.55 mA cm−2 at 1.05 V vs Ag/AgCl. This performance is about 2.4 times higher than of the electrocatalyst prepared by galvanostatic mode (11.09 mA cm−2 at 0.85 V). The durability and long‐term stability of the obtained electrocatalysts were investigated using chronoamperometry and cyclic voltammetry. The decrease in current density is about 19 % and 49 % for electrocatalysts prepared by galvanostatic and potentiostatic mode respectively, after 700 scans. Finally, ex–situ FTIR spectroscopy was conducted in order to understand the reaction mechanism of ethanol oxidation in alkaline medium. It demonstrates that Cu(OH)2−Cu2O@PpPD can perform the complete oxidation of ethanol molecules, leading to the formation of CO2 molecule as the final product. This study highlighted a new simple and facile approach for synthesizing electrocatalysts based on Cu(OH)2−Cu2O@PpPD for alcohol oxidation applications. [ABSTRACT FROM AUTHOR]

This study investigates the incorporation of active secondary amine moieties into the polymer backbone by co‐polymerizing 2,4,6‐tris(chloromethyl)‐mesitylene with three diamines, namely 1,4‐diaminobutane, m‐phenylenediamine, and p‐phenylenediamine. This process results in the stabilization of the amine moieties and the subsequently introduced nitroso groups. Charging bioactive nitric oxide (NO) into the polymers is accomplished by converting the amine moieties into N‐nitroso groups. The ability of the polymers to store and release NO depends on their structures, particularly the amount of incorporated active secondary amines. With grafting photosensitive N‐nitroso groups into the polymers, the derived NO@polymers exhibit photoresponsivity. NO release is completely regulated by adjusting UV light irradiation. These resulting polymeric NO donors demonstrate remarkable bactericidal and bacteriostatic activity, effectively eradicating E. coli bacteria and inhibiting their growth. The findings from this study hold promising implications for combining NO delivery with phototherapy in various medical applications. [ABSTRACT FROM AUTHOR]

A series of new fluorinated 2,3-diaminophenazines were obtained by the oxidation of fluorinated o-phenylenediamines with iron trichloride in water acidified with HCl. Isomeric 2,3-diaminophenazines with F atoms in both benzene fragments were obtained when o-phenylenediamines contained an F atom at the ortho-position with respect to the amino group. The ratio of isomers depends on the number and position of F atoms in o-phenylenediamines. DFT calculations for the formation of fluorinated 2,3-diaminophenazines in question were consistent with the experimentally observed ratio of the isomers. The formation of the predominant isomer was attributed to the action of the amino group with the highest N-charge of protonated o-phenylenediamines at the most electron-depleted position of the most stable protonated diimine. New compounds were characterized using various spectroscopy techniques (IR, UV, 1H, 19F, 13C NMR, and mass). Fluorinated 2,3-diaminophenazines are heat-resistant and fluoresce from green to red depending on the number of F atoms in the ring bearing amino groups. The presence of F atoms decreases the emission intensity but at the same time bathochromically shifts the fluorescence maximum. In the absence of the F atom in the ring bearing amino groups, fluorinated 2,3-diaminophenazines exhibited fluorescence intensities comparable to those of a non-fluorinated analog. [ABSTRACT FROM AUTHOR]

p -Phenylenediamine reacts with Sanger's reagent in hot ethanol to give the expected mono- and di-substitution products, but in ethanol at room temperature, it gave exclusively 2-nitro-5-fluorophenyl- p -phenylenediamine, where a hydrogen atom is displaced by attack at an activated, unsubstituted position. The reactions of p -phenylenediamine and aniline with Sanger's reagent were compared in the cheap, 'green' solvent ethanol. An unexpected product forms from reacting Sanger's reagent with p -phenylenediamine [ABSTRACT FROM AUTHOR]

V-MOF after being calcined at 700°C under N 2 atmosphere, has good cholesterol oxidase-like and peroxidase-like activities. Based on the tandem enzyme reaction between V-MOF-700 and cholesterol, we designed an enzyme-free fluorescence detection platform to achieve cholesterol detection in the presence of o-phenylenediamine (OPD). Especially, it can be applied to the rough quantification of membrane cholesterol in living tumor cells. [Display omitted] It remains a great challenge to properly design and synthesize single-component artificial tandem enzymes for specific substrates with high selectivity. Herein, V-MOF is synthesized by solvothermal method and its derivatives are constructed via pyrolyzing V-MOF in nitrogen atmosphere at different temperatures, which are denoted as V-MOF-y (y = 300, 400, 500, 700 and 800). V-MOF and V-MOF-y possess tandem enzyme-like activity, i.e. cholesterol oxidase-like and peroxidase-like activity. Among them, V-MOF-700 shows the strongest tandem enzyme activity for V-N bonds. Based on the cascade enzyme activity of V-MOF-700, the nonenzymatic detection platform for cholesterol by fluorescent assay can be established in the presence of o-phenylenediamine (OPD) for the first time. The detection mechanism is that V-MOF-700 catalyzes cholesterol to generate hydrogen peroxide and further form hydroxyl radical (•OH), which can oxidize OPD to obtain oxidized OPD (oxOPD) with yellow fluorescence. The linear detection of cholesterol ranges of 2–70 μM and 70–160 μM with a lower detection limit of 0.38 μM (S/N = 3) are obtained. This method is used to detect cholesterol in human serum successfully. Especially, it can be applied to the rough quantification of membrane cholesterol in living tumor cells, indicating that it has the potential for clinical application. [ABSTRACT FROM AUTHOR]

The reaction mechanism for the synthesis of quinoline-fused benzo/dia/oxa/thia/zepins is investigated using the DFT/B3LYP/6-31G(d) method. DFT conceptual reactivity indices analysis allows classification of o-aminophenol (2, X = O), o-aminothiophenol (2, X = S) and o-phenylenediamine (2, X = N) and R-substituted 2-chloroquinoline-3-carbaldehydes (1 ac) as strong electrophiles, suggesting a polar process. Besides, Parr functions and Fukui indices predict the most reactive sites for observed experimentally product formation, in agreement with the dual descriptor analysis. In the energy aspect, there is no effect of the R (R = CH3, OCH3) substituent on the thermodynamic quantities, whereas the substitution of the X has a remarkable effect. The products (4a–c, X = N) are the most stable, and their cyclizations are the easiest. An extended analysis was performed using the activation strain model/energy decomposition analysis ASM/EDA model. The obtained results indicate that the orbital interaction and electrostatic stabilizations are the principal factors favoring the reaction with X = N. Topological analysis of the electron localization function (ELF) of the bending point structures along the reaction path indicates that the reaction occurs via a non-concerted two-step mechanism. [ABSTRACT FROM AUTHOR]