Chloride ions accelerated the removal of naproxen in Cu(II)/peracetic acid system: Promotion of copper cycling through the formation of copper-chloride complexes.

This study investigates the structural, optical, and magnetic properties of Ni²⁺-doped TiO₂ nanostructures (1.0–10.0 wt%) synthesized via an acidic sol–gel route. Dopant-induced lattice modifications are primarily expressed through microstructural strain, lattice parameter distortion, and phonon softening rather than macroscopic lattice defects visible by TEM. X-ray diffraction and Rietveld refinement reveal systematic shifts of the anatase (101) peak, lattice contraction, and increasing compressive strain with Ni incorporation, as confirmed by Williamson–Hall analysis. Raman and electron paramagnetic resonance (EPR) spectra indicate oxygen vacancy formation and localized electronic states. Optical absorption and Tauc analysis show progressive bandgap narrowing, while crystal field theory (CFT) confirms Ni²⁺ ions occupying both octahedral and tetrahedral coordination environments. EPR signals further evidence Ni²⁺ magnetic centers and Ti³ ⁺/oxygen vacancy-related species. These results demonstrate that defect-mediated lattice distortion governs the optoelectronic and magnetic tuning of Ni-doped TiO₂, offering insights for advanced photocatalytic and spintronic material design.

From persistence to reactivity: halogen-regulated photosensitization of xanthene chromophores for sustainable water purification.

Revealing the activation mechanism of periodate by groundwater treatment plant waste iron-containing sludge for sulfadiazine removal: the key activation role of transition metal Mn.

Tuning the interface of graphite felt-supported NiCo composites for superior electrocatalytic degradation of pharmaceutical pollutants.

Microwave-assisted synthesis of Cu-doped UiO-66 activated persulfate for tetracycline degradation.

The preparation of different green-bluish copper pigments via synthetic routes is reported in several treatises, from antiquity to the beginning of 19th century. The most famous preparation is the one for the production of verdigris, a bright green pigment resulting from the corrosion of pure copper plate by vinegar. The recipes are numerous, and many differences in terms of ingredients and procedures emerge from a comparative study. Such a variety of preparations corresponds to a chemical variety. Many works have already investigated such systems with the most common spectroscopic techniques (e.g., ATR-IR, Raman, etc.). However, recently the Electron Paramagnetic Resonance (EPR) spectroscopy has emerged as a new tool for the investigation of these pigments, since new and more complete information on the chemistry of such systems can be gained. In this work, three different recipes have been selected as more representative, reproduced, and characterized with EPR, micro-ATR-IR and micro-Raman spectroscopies. Our experiments highlight the advantages in the use of EPR, with respect to simple Raman and IR investigations. In particular, the EPR spectroscopy evidenced the presence of different bimetallic and monometallic species in the samples, allowing us to differentiate and characterize the Cu(II)-complexes among the studied samples. • The ingredients included in ancient recipes for green/bluish pigment preparations actually impacts on the pigment chemistry. • The ATR-IR and Raman are not always the most suitable tools. • CW-EPR spectroscopy is a very informative, non-damaging technique that can unveil the coordination of Cu(II) cations. • CW-EPR can overcome some ATR-IR and Raman spectroscopies drawbacks and limitations. • EPR spectroscopy must be included into a multispectroscopic protocol to study ancient copper-based pigments.

Myricetin-loaded ethyl cellulose/carboxymethyl cellulose nanoparticles to inhibit the formation of parent and oxygenated polycyclic aromatic hydrocarbons in baking systems.

Carbon-carbon bonds are the most frequently encountered bonds in drugs, natural products, agrichemicals, and perfumes. This makes reactions that can access C-C bonds, particularly those that access sterically complex architectures, of high impact to multiple industries and applications. Common C-C bond-forming reactions such as the Suzuki coupling or Diels-Alder cycloaddition have revolutionized synthesis, yet the building blocks required to perform these reactions, such as boronic acids or dienes, are only available in modest diversity from commercial suppliers compared to other common building blocks. A reaction that makes densely functionalized C-C bonds from broadly available starting materials would facilitate deeper access into chemical space. Here, we demonstrate an sp3-sp3 C-C coupling method that uses amines and carboxylic acids, which are among the most broadly available building blocks in vendor catalogs. Our method achieves the coupling of tertiary carbon centers to access dense carbon architectures including from complex pharmaceutical and natural product substrates. Preactivation of both the amine and acid functional groups enables an iron catalyst to unite the carbon-based building blocks under reducing conditions, which were identified using high-throughput experimentation. Extensive electron paramagnetic resonance measurements highlight the intermediacy of radicals and the spin state transformation of iron during the reaction. Our amine-acid coupling establishes a method for navigating chemical space that complements the current toolbox of carbon-carbon bond-forming reactions.

Molecular doping is an effective strategy for optimizing electroluminescent device performance. Herein, we developed a solution-processable triarylamine-fluorene copolymer (YM3) as a high-efficiency p-dopable host for inverted organic light-emitting diodes (i-OLEDs). Blending YM3 with 5-10 wt.% F4TCNQ induces quantitative integer charge transfer, evidenced by complete bleaching of neutral F4TCNQ absorption, emergence of F4TCNQ- and polymer polaron bands in ultraviolet-visible-near infrared spectroscopy, CN-stretch downshift ‌from Fourier transform infrared spectroscopy, strong polymer radical electron paramagnetic resonance signal, and results from UV photoelectron spectroscopy, X-ray photoelectron spectroscopy, and liquid and solid-state nuclear magnetic resonance characterizations. The doped YM3:F4TCNQ composite forms ultra-smooth, homogeneous hole-injection layers, elevating the electrode's effective work function to 4.83eV and ensuring excellent solvent orthogonality with the underlying emissive layer. Fully solution-processed blue i-OLEDs with 20-nm YM3:F4TCNQ hole-injection layer exhibit low turn-on voltage (∼3.00V), deep-blue emission (CIE: 0.14, 0.12), maximum external quantum efficiency of 5.72%, current efficiency of 6.30cd A- 1, reduced roll-off, and improved operational stability. These results demonstrate that the YM3:F4TCNQ system, with superior solubility, suppressed dopant aggregation, and efficient work-function tuning, provides an acid-free, neutral, and industrially feasible hole-injection solution for high-performance fully solution-processed printable i-OLEDs.

Copper homeostasis in bacteria requires tightly regulated import systems to balance copper's essential redox functions with its inherent cytotoxicity; yet, the mechanisms of cytoplasmic copper uptake remain poorly understood. In particular, the widespread CopD family of transmembrane proteins has been linked genetically to cytoplasmic copper import, but has not been mechanistically characterized. Here, using in vivo uptake assays, proteoliposome-based, real-time copper translocation kinetic measurements, and spectroscopic and electrochemical analyses, we demonstrate that CopD from the methanotroph Methylosinus trichosporium OB3b functions as a Cu+/H+ symporter and a Cu2+ reductase. Real-time transport measurements reveal transporter-mediated saturable transport with micromolar Cu+ affinity and rapid translocation rates consistent with facilitated diffusion or potential secondary active transport, and pH-sensitive fluorescence assays establish obligatory proton cotransport coupled to Cu+ translocation. Three conserved residues, two histidines and a tryptophan, predicted to reside in the periplasmic and transmembrane regions, respectively, were identified as critical determinants of copper uptake, with likely roles in substrate coordination and gating. Notably, CopD contains a C-terminal periplasmic cytochrome c domain with a complex electron paramagnetic resonance spectrum dominated by a low-spin, six-coordinate heme with a midpoint potential of 138 ± 5 mV. Spectroscopic and electrochemical data show that this heme can reduce Cu2+ to Cu+, both in solution and when copper is bound to the cognate M. trichosporium OB3b periplasmic chaperone CopC. These findings support a model in which CopD couples periplasmic Cu2+ reduction to Cu+/H+ symport across the inner membrane, establishing a new paradigm for bacterial copper import and metal transporter function.

Chronological assessments of Quina Neanderthals at De Nadale cave (Italy) using combined uranium-series/electron spin resonance dating of fossil teeth.

ABSTRACT The microstructural evolution of highly metamorphosed coal during low-temperature heating remains poorly understood. This study investigates two coal samples from 30°C to 300°C using in situ electron paramagnetic resonance (EPR), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). EPR results show that the concentration of free radicals increases from 2.0 × 1018 to 3.3 × 1018 spins·g−1 with increasing temperature, accompanied by linewidth narrowing, indicating enhanced radical mobility and aromatic conjugation. FTIR reveals distinct evolution patterns of four functional groups, which are coupled with changes in radical parameters (N g, g‑factor, ΔH). XRD shows reduced aromatic layer spacing and increased layer diameter and stacking thickness, suggesting a transition toward higher aromatic ordering. Based on these observations, we propose a microstructural evolution mechanism involving functional group elimination, aliphatic chain cleavage, radical reactions, and aromatic carbon aggregation, driving the coal structure from disorder to order. This work provides mechanistic insights and a theoretical foundation for optimizing clean and efficient coal utilization technologies.

Antimicrobial photodynamic therapy (aPDT) is a promising non-pharmacological approach for managing biofilm-associated fungal infections. In this study, we investigated the antifungal efficacy of a double-agent aPDT system combining bisdemethoxycurcumin (BDMC) as a photosensitizer and potassium iodide (KI) as a photodynamic enhancer against Candida albicans biofilms, with particular emphasis on the underlying reactive oxygen species (ROS)-mediated mechanisms. Mature C. albicans biofilms were treated with BDMC alone (20, 40, and 80 µM), KI alone (100 mM), or their combination, followed by dental blue LED irradiation (430 ± 10nm LED, 200 mW/cm², 0-100J/cm²). Biofilm viability was assessed, and ROS generation quantified using fluorescence-based assays and electron paramagnetic resonance spectroscopy. The contribution of specific ROS to antifungal activity was evaluated through Spearman correlation analyses. The combined BDMC-KI aPDT system produced significantly greater biofilm inactivation than single-agent treatments. Enhanced antifungal activity was strongly associated with increased singlet oxygen (1O₂) generation, while hydroxyl radicals contributed to a lesser extent. These findings support a double-mode photodynamic mechanism in which BDMC-derived ROS are chemically amplified by iodide, yielding longer-lived reactive iodine species and oxidative intermediates that enhance biofilm disruption. Overall, this study demonstrates that KI functions as an effective photodynamic potentiator rather than a photosensitizer, significantly augmenting BDMC-mediated aPDT against C. albicans biofilms. The mechanistic insights gained here support the further development of double-agent photodynamic strategies for the management of drug-resistant fungal biofilm infections. Clinical relevance: Bisdemethoxycurcumin+potassium iodide act as a photosensitizer in PDT to inhibit Candida albicans biofilms.

Structural and Mechanical Alterations in Polyoxymethylene: Insights from Advanced Irradiation Technologies.

Endogenous Fe-Al self-doped biochar derived from rubber sludge for effective peroxymonosulfate activation: Dominant role of 1O2 and electron transfer.

Electric-field (E) modulation of magnetic order in hybrid materials remains of significant interest for multiferroic metal-organic frameworks. Here, we investigated the spin-resonance response of single-crystal [(CH3)2NH2]Fe(HCOO)3 (Fe-MOF) via X-band electron spin resonance (ESR) under four cooling conditions, including zero-field cooling (ZFC), magnetic-field cooling (HFC), electric-field cooling (EFC), and combined electric- and magnetic-field cooling (EHFC). These measurements revealed protocol-dependent variations in the resonance field (Hr) and double-integral intensity (I) within the magnetically ordered phase below ∼18.5 K (TN). After EFC, E variation from 0 to 2.2 MV/m and back produced small but reproducible Hr shifts (ΔHr ≈ 0.3 mT) and systematic I(E) variations. While under EHFC, E variation from +2.2 to -2.2 MV/m and back produced a larger symmetric modulation (ΔHr ≈ 1.2 mT) and reversible I(E) changes. The electric-field response decreased progressively with increasing temperature, and it became negligible at TN, indicating that the effect was confined to the magnetically ordered phase. These results demonstrated electric-field sensitivity of the resonance response, consistent with dipole-coupled spin interactions in the framework.

The hidden power of microalgal extracellular polymeric substances: A natural source of persistent free radicals for aquatic environmental remediation.

In this work, we report a photoinduced, halogen-bond-assisted, catalyst-free strategy for the synthesis of a broad range of biaryl compounds. The halogen-bonding interaction facilitates the generation of an aryl radical from N-aryl-2-iodobenzamides and N-sulfonyl-2-iodobenzamides, which subsequently undergoes a 1,4-aryl migration through a Truce-Smiles-type rearrangement, ultimately affording structurally diverse and valuable functionalized biaryls. Preliminary mechanistic investigations using TEMPO trapping and EPR spectroscopy support the involvement of radical intermediates, while additional studies (UV-vis and NMR) confirm the presence of a halogen-bonding interaction between the amine and the aryl iodide. Moreover, DFT calculations elucidate the preference for ipso substitution over ortho addition and provide insight into the overall reaction pathway.

While alkylborane oxidation constitutes one of the most widely utilized strategies to construct C-O bonds, asymmetric versions of this transformation remain elusive. Establishing such an asymmetric approach would unlock a strategically distinct disconnection to oxygen-bearing stereogenic centers, which are ubiquitous across biologically active scaffolds. Herein, we employ a Cu-catalyzed single-electron mechanism to achieve enantioconvergent alkylborane oxidation for the first time. The central challenge─suppressing the unselective carbocation pathway from alkyl radical oxidation by the Cu(II)-carboxylate─is addressed by (1) lowering the reaction temperature to attenuate the undesired radical-polar crossover while (2) leveraging photochemical activation to preserve the single-electron radical functionalization manifold. The reaction exhibits broad functional-group compatibility, engaging benzyl- and allylboronic esters; diverse carboxylic acids, including complex pharmaceutical substructures and heterocycle-containing substrates, are also well tolerated. The reported protocol is scalable to gram quantities and was utilized for the asymmetric synthesis of an immunosuppressant drug candidate. Mechanistic studies, including stoichiometric interrogation of elementary steps, rate law determination, radical trapping experiments, and density functional theory (DFT) computations, indicate that the reaction operates by balancing two light-driven processes: (1) rate-determining N-H bond homolysis followed by N-radical-mediated C-B bond activation and (2) enantioselective Cu-mediated radical functionalization via an inner-sphere pathway. The reactive Cu(II)-carboxylate intermediate was isolated and structurally characterized, permitting direct examination of its spectroscopic features and radical-trapping reactivity. Electron paramagnetic resonance (EPR) studies identified the Cu(II)-carboxylate species as the catalyst resting state, and stoichiometric reaction of the Cu(II)-carboxylate with a persistent trityl radical demonstrated its competency for C-O bond formation. Hammett analysis further revealed that the efficiency of C-O bond formation is governed by the electrophilicity of the Cu(II)-carboxylate intermediate.