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The prevalence, incidence and mortality rates of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease are gradually increasing. New approaches are being developed to manage the progression and treatment of neurodegenerative diseases. Catechins, polyphenolic compounds, are key compounds that demonstrate therapeutic effects with their properties such as antioxidant, anti-inflammatory, anti-apoptotic properties in the prevention and treatment of neurodegenerative diseases. The therapeutic effects of catechins have been exhaustively studied in human and animal models. Catechins can have anti-inflammatory effects by suppressing inflammatory pathways and cytokines, as well as antioxidant effects such as chelating metal ions and scavenging radicals. They might reduce phosphorylation of tau proteins, aggregation of amyloid-beta and apoptotic proteins release. They can also decrease alpha-synuclein accumulation and increase dopamine levels. With all these effects, they can have an effect on neurodegenerative diseases. This review points to the potential mechanisms of catechins in neurodegenerative diseases, based on their findings in the literature review. Catechins can reduce amyloid-β plaque aggregation and tau phosphorylation. Catechins can decrease alfa-synuclein levels. Catechins can protect neuronal cells with their anti-apoptotic effect. More comprehensive studies are needed to clarify this issue. [ABSTRACT FROM AUTHOR]

Radiation-induced processes in ionic liquid (IL) methyltributylammonium bis[(trifluoromethyl)sulfonyl] imide ([MeBu3N][NTf2]) solutions containing p-terphenyl (TP) and saturated with carbon dioxide (CO2) were studied using nanosecond pulse radiolysis technique with UV-vis detection. The transient absorption spectra generated in these solutions were assigned to TP radical anions (TP•−) and triplet excited states (3TP*). Saturation of [MeBu3N][NTf2] solutions with carbon dioxide efficiently takes out presolvated electrons (e presolv −) ({{\rm{e}}_{{\rm{presolv}}}^ - }) and solvated electrons (e solv −) ({{\rm{e}}_{{\rm{solv}}}^ - }). On the other hand CO2 is not a scavenger of excited states of TP (1TP*, 3TP*), which in the reaction with triethylamine (TEA) leads to the formation of TP•−. [ABSTRACT FROM AUTHOR]

A comparative study of the parameters of the plasma discharge and kinetics of heterogeneous processes (etching, polymerization) occurring on the silicon surface in CF4 and C2Br2F4 plasma is carried out. Plasma diagnostics using Langmuir probes and optical emission spectroscopy show that both systems are characterized by similar dependences of the concentrations of ions and fluorine atoms on the gas pressure. It is established that (a) the kinetics of polymerization corresponds to the radical ion mechanism of this process; and (b) the fundamental properties of C2Br2F4 plasma are a combination of the higher polymerization ability (stationary polymer film thickness) and etching rate. The latter fact does not agree with the differences in the flux densities of fluorine atoms from plasma, but may be due to the additional generation of active fluorine in a thick polymer layer under the action of ion bombardment. Assumptions are made about the mechanisms of the processes that cause a change in the effective probability of the interaction and yield of etching. [ABSTRACT FROM AUTHOR]

• Tetrathiafulvalene demonstrates versatility in molecular electronics. • Experimental and computational methods integrate for a redox-active hybrid. • Crystal structure analysis exposes a deformed pyramid in Copper (II) complex. • Noteworthy charge transfer in electronic properties hints at photoelectron conversion suitability. • Reactivity analysis pinpoints potential attack sites, highlighting sulfur atom reactivity. This paper presents a comprehensive study that combines experimental techniques and Density Functional Theory (DFT) to investigate a newly synthesized mixed-ligand complex, [Cu(hfac) 2 (Me 3 TTF-CH=CH-Pyr)] (where hfac is hexafluoroacetylacetonate), and a novel mixed-valence radical ion salt (Me 3 TTF-CH=CH-Pyr) 2 (PF 6) 3. Both are constructed using ligands derived from the tetrathiafulvalene (TTF) donor molecule. These materials are meticulously characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, specifically in the C2/c space group, with the following lattice parameters: a = 24.583(2) Å, b = 21.613(2) Å, c = 14.2066(13) Å, β = 99.789(5)°, and a volume of V = 7438.3(12) Å3. It exhibits five-coordinate behavior, forming a slightly distorted pyramid with a square base. The paper also provides a detailed account of the crystal structures and reports spectroscopic study results. Electrochemical behavior is explored through cyclic voltammetry in CH 2 Cl 2 as the solvent. Additionally, the reactivity of these compounds is predicted using various theoretical tools, such as Local and Global reactivity descriptors, Hirshfeld charge analyses, and Molecular Electrostatic Potential. To elucidate charge transfer processes, Time-Dependent Density Functional Theory is utilized. Various types of interactions are analyzed through the Quantum Theory of Atoms in Molecules and Non-Covalent Interaction analyses. Finally, conductivity is estimated using frontier molecular orbitals (FMO) and gap energies as crucial parameters. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Redox reactions in groundwater can help define earthquake chemical precursors. • H 2 O 2 and ∙OH radicals play key roles in generating the chemical precursors. • Advanced oxidation contributes greatly to the oxidation of organic compounds. • Behavioral changes in organisms before earthquake can help validate precursors. • Earthquake chemical precursors could be supportive to developing early warning system. To minimize the loss of life caused by earthquakes, it is crucial to have early warning tools that provide sufficient warning time. Although various methods are available, their accuracy is uncertain. This review explores alternative indicators related to hydrogeochemical anomalies that appear before earthquakes, which could potentially offer earlier warnings. It presents a theoretical basis for ionic and molecular changes initiated by the generation of hydroxyl radicals (•OH) and hydrogen peroxide (H 2 O 2) in groundwater before an earthquake. The review analyses 32 earthquake events by measuring ionic anomalies through standard reduction potential. The study also identifies significant pre-seismic erosional activity in minerals exposed to hydrogen peroxide. Additionally, the oxidation of organic compounds is shown to predict notable geochemical changes. The changes in the groundwater chemistry can also be validated by examining simultaneous microbial/ zooplankton responses. The findings suggest that the ionic, mineral, organic, and microbiological changes triggered by hydroxyl radicals and hydrogen peroxide could serve as a multi-parametric earthquake early-warning system. Implementation of such a system could improve the accuracy and timeliness of earthquake warning systems potentially reducing the associated risks and damages. [ABSTRACT FROM AUTHOR]

[Display omitted] • Peroxyoxalate chemiluminescence in aqueous medium is several orders of magnitude less efficient than in anhydrous aprotic organic solvents. • However, water addition of up to 0.7 mol/L to an aprotic organic medium results in a significant increase of singlet excitation quantum yields. • Contrarily, higher water concentrations result in a drastic quantum yield decrease, which is not only due to oxalic ester hydrolysis. • Photophysical studies with several chemiluminescence activators confirm the mechanism of the chemiexcitation step in partially aqueous media. Chemiluminescence transformations are widely utilized in analytical and bioanalytical applications. Specifically, the peroxyoxalate system can be employed for sensitive quantification of a wide variety of analytes. Under anhydrous conditions, the peroxyoxalate reaction shows extremely high emission quantum yields, comparable to highly efficient bioluminescence systems. However, in aqueous media, important for bioanalytical applications, the emission efficiency suffers a significant decrease of several orders of magnitudes, although the reason for this loss in efficiency is unknown up to now. In the present work, we show the results of a detailed photophysical study on the effect of water on the chemiexcitation efficiency of the peroxyoxalate reaction using bis(2,4-dinitrophenyl) oxalate as reagent and imidazole as base catalyst in the presence of different chemiluminescence activators. It is shown that in 1,2-dimethoxyethane/water mixtures (DME:H 2 O), singlet quantum yields increase with increasing the water concentrations up to 0.7 mol/L, followed by a steady decrease at higher water concentrations. The decrease in quantum yields is not predominantly due to concurrent ester hydrolysis, as quantum yields could be corrected for this side reaction. This indicates that the quantum yield decrease is due to the diminished chemiexcitation efficiency in the presence of water. Using different activators, it is shown that chemiexcitation occurs via electron transfer and electron back-transfer steps between a high-energy intermediate and the activator. Additionally, its efficiency is governed by the energetics of the electron back-transfer step, in agreement with the Chemically Initiated Electron Exchange Luminescence (CIEEL) mechanism, also in partially aqueous environment. Lower excitation efficiency in aqueous media may be due to formation of solvent-separated radical ion pairs, inhibiting chemiexcitation. [ABSTRACT FROM AUTHOR]

We present a comprehensive review of the photochemical and electrochemical methodologies employed in the α-C–H functionalization of tertiary amines. The discussion starts with an introduction to α-C–H functionalization strategies, emphasizing the generation of radical species. The iminium ion and α-aminoalkyl radical are identified as key intermediates interacting with various organic functional groups. The review is divided into two main sections: photocatalytic and electrocatalytic α-C–H functionalization. In the photocatalytic section, we classify the functionalization into photocatalyst-mediated and photocatalyst-free approaches. Photocatalyst-mediated functionalization is further categorized into four mechanisms: Nucleophilic substitution, Transition-metal complexing, Giese-type reaction, and Radical-radical cross-coupling. Photocatalyst-free functionalization focuses on the direct excitation of the substrate and the EDA complex pathways, with particular emphasis on the latter. The electrocatalytic section explores both direct and indirect electrolysis techniques, highlighting the role of redox mediators in the indirect approach. Each section critically analyzes recent research examples from the past five years. This review aims to elucidate the current state of α-C–H functionalization research and suggest promising directions for future investigations. [Display omitted] [ABSTRACT FROM AUTHOR]

• Uranium can be removed efficiently in air under natural solar with addition of benzyl alcohol without photocatalyst. • The residual concentration of U(VI) after photo-autocatalysis is lower than the emission standard in GB 23727-2020. • The intermediate [UO 2 +, Ph·CHOH] caused by U(VI) and benzyl alcohol can improve the photosynthesis of H 2 O 2. • The removal rate of simulated uranium-containing effluent could get to 99.08 %, suggesting great application potential. Photocatalysis, one of the environment-friendly and efficient technology, showed application prospects on uranium removal and recovery in spite of the expensive photocatalysts. Herein, we reported a novel strategy induced by benzyl alcohol for photo-autocatalytic removal and recovery of uranium, which achieved excellent removal rate and avoided the dependence on photocatalysts. The results showed that, in slightly acidic environments, the uranium removal rate could achieve over 99 % under air within an hour illumination via the redox reaction of radical ion pair [UO 2 +, Ph·CHOH], which can be produced by the photoactivation of benzyl alcohol for the active benzylic C(sp3) − H bonds. At the same time, benzyl alcohol was selectively oxidized to benzaldehyde, an important industrial feed stock of significance in fine and chemical industries. Moreover, uranium could be removed to 186 ppb within 4 h of illumination, which was up to the emission standard proposed in GB 23727–2020. This strategy exhibited excellent removal performance upon solar illumination and recovered uranium with 99.08 % removal rate in the existence of heteroions, which indicated that our strategy has important application potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Intense ECL from Ir(ppy) 3 was realized by using the radical anion of benzonitrile. • The ECL intensity of the mixed system was ∼ 250 times greater than that of the single system. • The ECL intensity increased by ∼ 90 times with the radical cation of thianthrene. • The mechanism of enhancing the ECL with several radical cations and anions is discussed. The electrogenerated chemiluminescence (ECL) of 0.2 mM tris(2-phenylpyridinato)iridium(III) (Ir(ppy) 3) in acetonitrile with a potential step method was dramatically enhanced by the electrochemically generated radical cation of 10-methylphenothiazine (MePT), thianthrene (TH), and dibenzo-1,4-dioxin (DD) or the radical anion of benzophenone (BP) and benzonitrile (BN). In the case of using the radical cation of phenothiazine (PT), no ECL was seen. Among the binary systems containing 0.2 mM Ir(ppy) 3 and 10 mM parent molecule of the radical ions, intense annihilation ECL of Ir(ppy) 3 was observed from a solution containing BN; the ECL intensity was about 250 times greater than that of the single system of 0.2 mM Ir(ppy) 3. Among the cases using the radical cations, the ECL intensity with TH was the largest (about 90 times higher than that of the single system). The mechanism for enhancing the ECL is discussed based on the redox potential, energy level of the lowest triplet excited (T 1) state, and electron-donating and −accepting characteristics. The electron transfer reaction between the reduced form of Ir(ppy) 3 (Ir(ppy) 3 •−) and the radical cations can produce the T 1 state of Ir(ppy) 3 (3Ir(ppy) 3 *) and that of MePT, TH, and DD, whereas the electron transfer reaction between the oxidized form of Ir(ppy) 3 (Ir(ppy) 3 •+) and the radical anions can produce 3Ir(ppy) 3 * but not the T 1 state of BN or BP. The lower ECL intensity using the radical cations relative to that of using BN suggests that the triplet energy transfer from the parent molecule of the radical cations to Ir(ppy) 3 is not efficient. It is also shown that the homogeneous electron transfer reaction between Ir(ppy) 3 and the electrochemically generated radical cation of TH and radical anion of BN to produce Ir(ppy) 3 •+ and Ir(ppy) 3 •−, respectively, which facilitates an ion annihilation reaction between Ir(ppy) 3 •− and Ir(ppy) 3 •+, is also responsible for the intense ECL. [ABSTRACT FROM AUTHOR]

Organic sulfur compounds (S-markers) such as benzothiophene (BT), dibenzothiophene (DBT), and benzonaphtothiophene (BNT) have been used for depositional paleoenvironment interpretations. In this study, the broader range of S-markers was semi-quantified by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) using atmospheric pressure photoionization in positive ion mode (APPI-P) for the interpretation of the depositional paleoenvironment and lithology in Amaral Machado's outcrop, Irati Formation, Paraná Basin for the first time. The variations in chemical composition, aromaticity as well as alkylation degree of the monosulfur compounds (S 1) and hydrocarbons (HC) classes (radical and protonated ions) analyzed in APPI-P were discussed in detail. The S-markers were semi-quantified using the internal standard DBT-d 8. The results from both S 1 and HC showed a clear distinction in the depositional paleoenvironment of the organic matter (OM) present in the evaluated samples. The S-markers interpretations were confirmed by classical biomarkers (regular steranes C 29 /C 27 , tetracyclic polyprenoids TPP/C 27 , diasteranes DIA 27 , steranes/17α-hopanes, gammacerane/C 30 , and pristane/phytane). The similarity in depth profiles using concentrations and peak intensities indicated that the ionization of major compound classes from extracts analyzed in APPI-P mode is not compromised by ion suppression. The double bond equivalent (DBE) distribution of S 1 and HC, together with the DBT/Phen ratio, provided valuable insights into the type and source of OM contributing to the reconstruction of the depositional paleoenvironment. S-markers semi-quantification was efficient in characterizing depositional paleoenvironment and allowed evaluation of different proxies of the outcrops. The base of the Amaral Machado outcrop presents an anoxic redox condition, typically hypersaline and abundant in S 1. The middle of the outcrop shows a strong marine influence with a contribution from terrestrial OM. Towards the top of the outcrop, belonging to the Serra Alta Formation, the environment is oxidizing with low concentrations of sulfur and typically terrigenous. • Evaluation from Paleoenvironment in Irati Formation, Amaral Machado outcrop by S-markers. • Semi-quantification of organic sulfur compounds and HC class by FTICR-MS. • Paleoenvironments are distinguished by molecular composition. • S-Marker C 40 proved to be a good paleoenvironment indicator. [ABSTRACT FROM AUTHOR]

The degradation of 8 structurally diverse pharmaceuticals and personal care products (PPCPs) by UV/chlorine and the effects of Cl- and SO 4 2- were systematically investigated. The 8 PPCPs are divided into 2 groups based on their stability under UV light. This is the first time the kinetic degradation of the 8 PPCPs in the presence of Cl- and SO 4 2- have been intensively evaluated. The results showed that the high degradation rate of the PPCPs is attributed to their second-order rate constants towards radicals (i.e., •OH, and reactive chlorine species (RCS)). 0–500 mM Cl- enhanced k PPCPs , while this range of SO 4 2- inhibited most of them (except in the case of ciprofloxacin (CIP)). An overview of the effect of 0–200 mM Cl-/SO 4 2- on the degradation of micropollutants by different UV-based advanced oxidation processes (UV-AOPs) in previous studies indicates that Cl-/SO 4 2- can cause varying effects on the degradation rate of pollutants (i.e., "increase", "decrease", or "no effect"), depending on the type of pollutant and the process. Cl-/SO 4 2- did not change the trend of pH influence on the PPCPs degradation rates by UV/chlorine. Acidic and neutral conditions were favorable to the degradation of the PPCPs in all cases. Under three operating conditions (i.e., the control process, 500 mM Cl- and SO 4 2-), [•OH]ss decreased considerably, but [Cl•]ss or ([Cl•]ss + [SO 4 •-]ss) slightly fluctuated when the pH was increased from 2.5 to 10.5. The synergistic effect of seawater and Cl-/SO 4 2- significantly improved some k PPCPs , thereby, decreasing energy consumption. [Display omitted] • Kinetic degradation of eight PPCPs were investigated in UV/chlorine. • The degradation of PPCPs can be divided into two groups based on UV and seawater effects. • 0–500 mM Cl- can enhance k PPCPs , while this range of SO 4 2- inhibited them. • pH from 2.5 to 10.5 reduced [•OH]ss but had negligible effect towards [Cl•]ss or ([Cl•]ss + [SO 4 •-]ss). • The synergy effect of seawater and Cl-/SO 4 2- can significantly improve some k PPCPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous nanofiber membrane gives gel electrolyte excellent liquid absorption rate and ultra-high ionic conductivity, • The dissociation and transport of lithium ions favored by NO 3 − anions, • Nanofiber membranes facilitate the interfacial stability and cycling efficiency. A nanofiber gel electrolytes with excellent physical properties, electrochemical properties, and cycle life based on poly(vinylidene fluoride)-hexafluoropropylene copolymer modified by magnesium–aluminum bilayered nanosheets (MgAl-LDs) intercalated with different acidic roots ions is prepared by electrostatic spinning. The electrolytes exhibit the best elongation at break of 166 % and tensile strength of 6.59 MPa, and the electrochemical windows are all higher than 5 V. Meanwhile, the ionic conductivity number of nano-GPE intercalated with CO 3 2–, ClO 4 −, and NO 3 – reach 5.55*10−3 S/cm, 5.04*10−3 S/cm, and 6.93*10−3 S/cm, respectively. The Li//Li symmetric battery can be stably cycled for more than 1000 h at 1 mA/cm2 with an overpotential of less than 50 mV. The LiFePO 4 // Li batteries assembled with nano-GPE modified by MgAl-LDs (s = NO 3 –) show better 0.1-2C multiplicity performance than CO 3 2– and ClO 4 −, accompanied by an optimal discharge capacity of up to 155 mAhg−1 at 0.1C as well as a high reversible capacity of 135 mAhg−1 and a capacity retention rate of 90 % after 100 cycles at 0.5C. In addition, the results of polarization, X-ray photoelectron spectroscopy (XPS), Computed Tomography (CT), and scanning electron microscope (SEM) tests show that a stable SEI film is formed between nano-GPE and Li anode. [ABSTRACT FROM AUTHOR]

• A strategy to enhance charge separated state lifetimes in compact dyads is reported. • Lifetime enhancement is nearly 1000 times. • Long lifetime is confirmed through secondary electron transfer experiments. • Long lifetime was attributed to low D-A electronic coupling. • The low electronic coupling is due to orthogonal orientation of D and A. Design of compact donor-acceptor dyads that can exhibit charge separated (CS) state lifetimes extending to the microsecond time domain remains a major challenge even today. A simple but effective design strategy that can lead to long CS state lifetimes, in at least a few compact dyads, is still elusive. Herein we propose that use of adamantane (AD) as bridge can enhance CS state lifetimes in small molecule donor-acceptor dyads. This paper reports AD-bridged dyads, AN-AD-NB and PY-AD-NB, wherein the anthracene (or pyrene) donor and nitrobenzene acceptor are attached to bridgehead positions of AD. The singlet CS states generated upon irradiation were long-lived (lifetimes >1 μs) and decayed to the ground and local triplet states, simultaneously. Electron transfer reactions of the CS state with secondary donor and acceptor established that the CS state is sufficiently long-lived to participate in intermolecular reactions. X-ray crystal structure of the AN-AD-NB dyad reveals that the donor and acceptor are orthogonally oriented, which reduces the donor-acceptor interaction, and thereby the charge recombination rate, significantly. By analysing the X-ray structure, we predict that all adamantane-bridged compact dyads will have orthogonal donor-acceptor orientation and exhibit long-lived CS states. We also report studies with bisadamantyl-substituted dyads and the results confirmed that the local triplets are formed from the CS state through hyperfine interaction. Based on our work we propose that the hyperfine interaction, which is not expected to occur in compact dyads because of the short donor-acceptor separation, can indeed occur if the CS state is sufficiently long-lived. [Display omitted] [ABSTRACT FROM AUTHOR]

In hydrothermal fluids, disulfur (S 2 •−) and trisulfur (S 3 •−) radical anions have been observed to coexist with the major hydrogen sulfide and sulfate species. These radical ions have potentially important effects on the solubility, transport and fractionation of metals and sulfur, with consequences for ore deposit formation and, more generally, for geochemical cycles of metals and volatiles. It is therefore essential to know the intrinsic isotopic properties of these important sulfur species in order to use sulfur isotopes for tracing different geological processes. Here, the theoretical equilibrium isotopic properties of the disulfur and trisulfur radical ions are computed and compared to the hydrogen sulfide (H 2 S) and sulfate ion (SO 4 2−), using, for the first time, a first-principles molecular dynamics (MD) approach. The isotopic properties are calculated directly from molecular dynamics trajectories using the vibrational density of states and the atomic kinetic energy, and then compared to the more established method based on sampling of several snapshots. This comparison allowed us to validate the new modelling method and to assess its advantages and limitations. The predicted equilibrium isotope fractionation in terms of 34S/32S between S 2 •− and S 3 •− is small, i.e. <1‰, with a slight enrichment in the heavier isotope for S 3 •−, over the temperature range 200–500 °C. Both radical ions are slightly depleted in the heavier isotope, by 1 to 2‰, relative to aqueous H 2 S. Our results help tuning sulfur isotope fractionation models used for tracing the origin and evolution of hydrothermal fluids. Our method opens large perspectives for using the rapidly growing body of MD simulation data in geosciences on structure and stability of aqueous complexes to assess in parallel element isotope fractionations from MD-generated trajectories. • S isotope fractionation among SO 4 2−, H 2 S, S 3 •− and S 2 •− in hydrothermal fluids. • Direct quantification of isotopic properties from molecular dynamics trajectories. • Assessing advantages and limitations of the novel molecular dynamics (MD) approach. • Perspectives opened by the MD method for predicting element isotope fractionations. [ABSTRACT FROM AUTHOR]

[Display omitted] • ED was coupled with AC for enhancing chlorine-resistant bacteria inactivation. • ED/AC had synergistic effects on chlorine-resistant/sensitive bacteria inactivation. • ED/AC had ∼ 2.5 times lower energy consumption for cell inactivation than AC alone. • EP/AC prompted the formation of neutral HClO molecules and free chlorine radicals. • ED/AC enabled oxidative damage of cell structures for bacterial inactivation. The widespread use of chlorination prompts the selection of chlorine-resistant bacteria in drinking water, posing a great threat to public health. Herein, according to sequential electrochemical oxidation/reduction (Ox/Red) processes with a flow-through mode, electrochemical devices (ED) with sequential Ox-Red, Red-Ox and Ox-Red-Ox processes were coupled with chlorination (AC) to evaluate their synergistic effects and mechanisms for inactivation of chlorine-resistant bacteria in drinking water. ED/AC enabled ∼ 3.0 log of synergistic effect and ∼ 2.5 times lower energy consumption for inactivation of various chlorine-sensitive/-resistant bacteria and gram-positive/-negative bacteria in DI and tap waters. Especially, ED/AC with Ox-Red-Ox device exhibited the best disinfection performance with achieving over 6.7 log inactivation of Bacillus cereus at 4.0 V and 0.5 mg/L-Cl 2 as compared with ED alone (∼1.25 log) and AC (∼2.67 log) disinfection. The electrochemical oxidation on Ti 4 O 7 -based anode promoted the generation of free chlorine radicals and H+ ions, which was accompanied with the formation of neutral HClO molecules. Characterizations of SEM and flow cytometer suggested that oxidative species of neutral HClO molecules and free chlorine radicals enhanced the bacterial inactivation via severe damages of cell structures. This work provided a promising strategy via coupling electrochemical oxidation and chlorination for eliminating chlorine-resistant bacteria in drinking water. [ABSTRACT FROM AUTHOR]

• The enhancement of CO 3 2− and Li+/K+ ions on Na 4 SiO 4 were stronger than other ions. • The cyclic capacity of Na 4 SiO 4 was enhanced about 40.0% after the Li 2 CO 3 doping. • CO 2 adsorbed on oxysalts modified Na 4 SiO 4 surfaces were studied by DFT method. • The theoretical calculation results accurately fitted with the experimental values. • The effects of water vapor on Na 4 SiO 4 and Na 4 SiO 4 -K 2 CO 3 were firstly simulated. Eutectic doping has been considered as one of the most efficient ways to modify the Na 4 SiO 4 -based CO 2 sorbent. Nevertheless, the effects of different acid radical ions and alkali metal cations of the oxysalts on the CO 2 capture performances of Na 4 SiO 4 have never been explored. In this study, Na 4 SiO 4 -based CO 2 sorbents were prepared using four kinds of oxysalts as the dopants. The effects of acid radical ions/alkali metal cations, doping ratios and sorption/desorption temperatures on the CO 2 capture performances of sorbents were investigated. The results showed that the promotion effects of CO 3 2− and Li+/K+ ions were stronger than others, the maximum CO 2 sorption capacity of Na 4 SiO 4 -30Li 2 CO 3 and Na 4 SiO 4 -30K 2 CO 3 at 700 °C reached 20.6 wt% and 19.5 wt%, respectively. The cyclic sorption capacity of Na 4 SiO 4 -30Li 2 CO 3 was 8.5 wt%, which was 40.0% higher than that of Na 4 SiO 4. Further, the oxysalt dopants could enhance the CO 2 adsorption energy on the Na 4 SiO 4 surfaces and reduce the energy level of the systems using density functional theory calculation, which were consistent with the experimental values. Finally, the effects of water vapor on the sorption of Na 4 SiO 4 and Na 4 SiO 4 -K 2 CO 3 were simulated, which could enhance the activity of O atoms on sorbent surfaces and promote rapid carbonization during the sorption progress. Thus, Na 4 SiO 4 doped with oxysalts exhibit promising potential for high-temperature CO 2 capture application. [ABSTRACT FROM AUTHOR]

Organic conjugated radicals are promising materials for organic magnets and spintronics; however, their solid-state properties are difficult to control and predict. We report the synthesis and magnetic properties of carboxylic acid-functionalized 1,2,4-benzotriazinyl radicals DAR, TAR and their corresponding coordination particles. These hydrogen bond containing compounds exhibit a typical antiferromagnetic behavior and good thermal stability up to 300 °C. Moreover, DAR and TAR possess stronger intermolecular spin–spin interactions than their ester counterparts as supported by their wider ESR line widths. Nanosize coordination particles are obtained upon sonication of these two radicals with metal ions at 0 °C. Diamagnetic Zn2+-based cubic UD-Zn and spherical UT-Zn show stronger spin–spin interactions than their corresponding ligands, along with the retained forbidden transition signal Δms = ±2. In sharp contrast, paramagnetic Cu2+-derived CPs display very weak magnetic signals due to the redox reaction between Cu2+ and radicals. This work is useful for the future design of conjugated radicals and radical ligand-based magnetic coordination particles. [ABSTRACT FROM AUTHOR]

This paper demonstrates the metal ion effects on the quercetin 2,4-dioxygenase (2,4-QD)-like reactivity. For this purpose, a series of five metal(II)–acetato complexes [MII(L)(OAc)] {M = Mn (1OAc), Co (2OAc), Ni (3OAc), Cu (4OAc), Zn (5OAc); OAc = acetate} supported with a newly designed N3O-donor carboxylato ligand L− {L− = 2-((benzyl((6′-methyl-[2,2′-bipyridin]-6-yl)methyl)amino)methyl)benzoate} has been synthesised as models for the active sites of MII-substituted 2,4-QDs. The enzyme–substrate (ES) model complexes [MII(L)(fla)] {M = Mn (1fla), Co (2fla), Ni (3fla), Cu (4fla), Zn (5fla); flaH = flavonol} have been synthesised by reacting flaH with their corresponding acetate-bound complexes in basic conditions. Detailed physicochemical properties of all the compounds are reported. Furthermore, single-crystal X-ray diffractions have been done to determine the structures of the compounds 2OAc·2H2O, 3OAc, 4OAc·CH2Cl2·2H2O, 5OAc·2H2O and 2fla·MeOH. The enzymatic reactivities of complexes 1OAc–5OAc towards the dioxygenation of flavonol have been explored in detail. All the complexes effectively catalyse the oxygenative degradation of flavonol in N,N-dimethylformamide (DMF) medium at 70 °C under multiple-turnover conditions and produce enzyme-type products. Kinetic investigations were performed to see the metal ions' effects on reactivity. The reaction rates vary with the metal ions, showing the order Co > Ni > Zn > Mn > Cu. The studies reveal that the reactivities of the [MII(L)(OAc)] complexes are governed primarily by three factors viz the ES adduct formation constant (Kf), the redox potential (Epa) of the bound fla−/fla˙ couple, and the degree of delocalisation of the fla˙ radical with the metal electrons, which are drastically influenced by the M2+ ions. In the mechanistic interpretation, a single-electron transfer (SET) from the bound-flavonolate to dioxygen has been proposed to generate the catalytically important "M(II)–fla˙" radical and superoxide ion, which react further to bring about the dioxygenation reaction. The identification of the metal(II)-bound flavonoxy radical intermediate for the case of cobalt using EPR spectroscopy and the detection of superoxide ion by NBT2+ test and EPR spin-trapping experiment (DMPO test) are remarkable in envisaging the reaction pathway. [ABSTRACT FROM AUTHOR]

The oxidation of Tb(III) by persulfate ions in solutions of unsaturated phosphotungstate K10P2W17O61 (L) was studied by spectrophotometry. The accumulation of Tb(IV) is observed at pH < 3. The yield of Tb(IV) depends on pH and [L]. The maximum yield is observed in solutions with pH 1.5–2.5 and [L] > 6×10–4 M. The accumulation of Tb(IV) proceeds as a zero-order reaction with respect to [Tb(III)] and a first-order reaction with respect to [S2O82–]. The reaction rate increases with the increase in pH from 0.91 to 1.5–1.9; an increase in pH to 2.44 decreases the rate. The activation energy (42–60°С) is estimated at 140 kJ/mol. The reaction mechanism includes the decomposition of S2O82– ions into SO4– radical ions, which are converted into OH˙ radicals, which oxidize Tb(III) bound in a complex with L (1 : 1). In parallel, the catalytic decomposition of S2O82– ions occurs, which leads to the formation of Caro's acid H2SO5. Its hydrolysis generates Н2О2, a reducing agent for Tb(IV). In addition, Tb(IV) is reduced by water. It was not possible to oxidize thulium(III) under the conditions of terbium(IV) formation. [ABSTRACT FROM AUTHOR]

Saccharomyces cerevisiae is an important microbial organization involved in ethanol synthesis. Mutant strains that can withstand multiple pressures during this process are critical to the industrial development of biofuels. In this study, a dual high-throughput screening method of Triphenyl-2H-tetrazoliumchloride (TTC)-based macroscopic observation and the reaction of ferric nitrate with pyruvate (or pyruvate radical ion) in fermentation broth was used. Using this, an S. cerevisiae mutant library that could tolerate 381 g/L sucrose was established by ARTP random mutation and adaptive evolution to select the best strain; its ethanol yield was increased by an additional 20.48%; and the sucrose utilization rate was 81.64%. This method is specific to the selection of strains with increased ethanol production. [ABSTRACT FROM AUTHOR]

The oxidation of Tb(III) by persulfate ions in solutions of unsaturated phosphotungstate K10P2W17O61 (L) was studied by spectrophotometry. The accumulation of Tb(IV) is observed at pH < 3. The yield of Tb(IV) depends on pH and [L]. The maximum yield is observed in solutions with pH 1.5–2.5 and [L] > 6×10–4 M. The accumulation of Tb(IV) proceeds as a zero-order reaction with respect to [Tb(III)] and a first-order reaction with respect to [S2O82–]. The reaction rate increases with the increase in pH from 0.91 to 1.5–1.9; an increase in pH to 2.44 decreases the rate. The activation energy (42–60°С) is estimated at 140 kJ/mol. The reaction mechanism includes the decomposition of S2O82– ions into SO4– radical ions, which are converted into OH˙ radicals, which oxidize Tb(III) bound in a complex with L (1 : 1). In parallel, the catalytic decomposition of S2O82– ions occurs, which leads to the formation of Caro's acid H2SO5. Its hydrolysis generates Н2О2, a reducing agent for Tb(IV). In addition, Tb(IV) is reduced by water. It was not possible to oxidize thulium(III) under the conditions of terbium(IV) formation. [ABSTRACT FROM AUTHOR]

Although radical ion chain pathways have long been recognized in the field of synthetic organic chemistry and are expected to be operative in various reactions, it is somewhat complicated to verify their involvement, since counting the number of electrons is not straightforward. Herein, a series of bis‐styrenes is designed and synthesized to investigate electron transfer events by using radical cation [4+2] cycloadditions as probes. It is demonstrated that the intramolecular single electron transfer seems to be ineffective, while the intermolecular variants are highly effective. Therefore, a truly catalytic amount of electricity is enough for full conversions, confirming that chain pathways were definitely involved. [ABSTRACT FROM AUTHOR]

The functionalization of nanomaterials with suitable capping ligands or bioactive agents is an interesting strategy in designing nanosystems with suitable applicability and biocompatibility; the physicochemical and biological properties of these nanomaterials can be highly improved for biomedical applications. In this context, numerous explorations have been conducted in the functionalization of silver (Ag) and gold (Au) nanomaterials using suitable functional groups or agents to design nanosystems with unique physicochemical properties such as excellent biosensing capabilities, biocompatibility, targeting features, and multifunctionality for biomedical purposes. Future studies should be undertaken for designing novel functionalization tactics to improve the properties of Au- and Ag-based nanosystems and reduce their toxicity. The possible release of cytotoxic radicals or ions, the internalization of nanomaterials, the alteration of cellular signaling pathways, the translocation of these nanomaterials across the cell membranes into mitochondria, DNA damages, and the damage of cell membranes are the main causes of their toxicity, which ought to be comprehensively explored. In this study, recent advancements in diagnostic and therapeutic applications of functionalized Au and Ag nanomaterials are deliberated, focusing on important challenges and future directions. [ABSTRACT FROM AUTHOR]

Laboratory data on the kinetics of the aqueous-phase oxidation of SO2 with dissolved oxygen in the presence of Mn/Fe ions are summarized as applied to modeling of the sulfate formation in the atmosphere. The empirical expressions available in the literature for the speed of this process have been found not to reproduce data of physical modeling. A mechanism of liquid-phase oxidation of SO2 with the participation of Mn/Fe ions satisfactorily describing experimental data is discussed. This chain–catalytic process involves free ion radicals and is characterized by chain branching. This framework allows synergism (the effect of the well-known nonadditive enhancement of the catalytic action of a pair of these ions) to be naturally interpreted. We present preliminary estimates for sulfate production in atmospheric droplet moisture, indicating a significant contribution of the catalytic (nonphotochemical) formation of sulfates even with a low acidity of droplet moisture and a relatively low concentrations of Mn/Fe ions. [ABSTRACT FROM AUTHOR]

During deep reactive ion etching (DRIE), microscale etch masks with small opening such as trenches or holes suffer from limited aspect ratio because diffusion of reactive ions and free radicals become progressively difficult as the number of DRIE cycle increases. For this reason, high aspect ratio structures of microscale trenches or holes are not readily available with standard DRIE recipes and microscale holes are more problematic than trenches due to omnidirectional confinement. In this letter, we propose an optimization for fabrication of high aspect ratio microscale hole arrays with an improved cross-sectional etch profile. Bias voltage and inductively coupled plasma power are considered as optimization parameters to promote the bottom etching of the high aspect ratio hole array. In addition, flow rates of octafluorocyclobutane (C 4 F 8 ) and sulfur hexafluoride (SF 6 ) for passivation and depassivation steps, respectively, are considered as optimization parameters to reduce the etch undercut. As a result of optimization, the aspect ratio of 20 is achieved for 1.3 μm-diameter hole array and etch area reduction at the bottom relative to the top is improved to 21%. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of isolable radicals of main-group elements have been a long-pursued quest. Although there has been considerable progress in this area, particularly in isolating carbon radicals, the isolation of radicals comprising heavier p-block elements is still scarce. Among heavier p-block elements, the radical chemistry involving silicon and phosphorus is explored considerably. This review focuses on isolable phosphorus-centered radicals. Most of the compounds described here have been characterized by single-crystal X-ray analysis and EPR spectroscopy. The cyclic voltammetry study revealed interesting redox chemistry for many of these compounds. Here, we described the synthesis and properties of the radicals and radical ions comprising the phosphorus center. [ABSTRACT FROM AUTHOR]

The first organic metals were obtained based on tetrathiafulvalene. The most significant advance in the field of organic metals was the discovery of superconductivity. The first organic superconductors were obtained based on tetramethyltetraselenafulvalene. These facts demonstrate great importance of tetraselenafulvalenes and their precursors, diselenafulvenes, for materials sciences. Derivatives of 1,4-diselenafulvene and 1,4,5,8-tetraselenafulvalene are useful building blocks for organic synthesis and donor units for the preparation of charge-transfer complexes and radical ion salts, the construction of organic metals, superconductors, organic Dirac materials, semiconductors, ferromagnets, and other conductive materials. This review covers the literature on the design, synthesis, and application of 1,4,5,8-tetraselenafulvalenes and 1,4-diselenafulvenes and their tellurium analogs over the past 15–20 years. These two classes of compounds are interconnected, since the main part of methods for the synthesis of tetraselenafulvalenes is based on the diselenafulvene derivatives as starting compounds. Special attention is paid to the development of novel efficient synthetic approaches to these classes of compounds. Conducting properties and distinguishing features of materials based on tetraselenafulvalenes and their tellurium analogs as well as examples of materials with high conductivity are discussed. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were performed to demonstrate nanometer-scale silicon (Si) trench etching with silicon dioxide ( SiO 2) hard masks by chlorine ( Cl +) ion beams possibly with low-energy chlorine (Cl) radicals. Although the sputtering yield of SiO 2 is typically much lower than that of Si , the etch rates of SiO 2 and Si can be comparable because of the lower Si atomic density of SiO 2. This implies that the erosion of the mask can significantly affect etched structures. This study has demonstrated that although the fluxes of incident ions and radicals are uniform in space and constant in time, the individuality of incident ions and radicals causes atomic-scale surface roughness, which cannot be neglected for nanometer-scale etched structures. Furthermore, some transient effects of surface etching, such as initial swelling of the Si surface due to incorporation of Cl atoms and preferential sputtering of oxygen, can affect the profiles of etched structures. The insufficiency of the local mechanical strengths of nanometer-scale materials also enhances their erosion, leading to the formation of nanometer-scale roughness on the sidewalls of masks and etched structures. [ABSTRACT FROM AUTHOR]

Pyromellitic acid diimides are not as chemically unreactive as conjecturable (and presupposed) from their numerous applications as electron acceptor units or electron carriers in molecular donor–acceptor dyads or triads. Similar to the corresponding phthalimides, electronically excited pyromellitic diimides oxidize alkyl carboxylates in aqueous solution via intermolecular electron transfer (PET) processes, which eventually results in radical–radical combination products, e.g., the benzylation product 6 from N,N′-dimethyl pyromellitic diimide 5. The analogous product 7 was formed with pivalic acid as tert-butyl radical source. One additional product 8 was isolated from alkylation/dearomatization and multiple radical additions, respectively, after prolonged irradiation. In intramolecular versions, from N-carboxyalkylated pyromellitic diimides 9a–e (C1 to C5-spaced), degradation processes were detected, e.g., the cyclization products 10 from the GABA substrate 9c. In sharp contrast to phthalimide photochemistry, the green pyromellitic diimide radical anion was detected here by UV-vis absorption (λabs = 720 nm), EPR (from 9d), and NMR spectroscopy for several intramolecular electron transfer examples. Only the yellow 1,4-quinodial structure is formed from intermolecular PET, which was deduced from the absorption spectra (λabs = 440 nm) and the subsequent chemistry. The pyromellitimide radical anion lives for hours at room temperature in the dark, but is further degraded under photochemical reaction conditions. [ABSTRACT FROM AUTHOR]

The incorporation of cationic groups onto electron-poor compounds is a viable strategy for achieving potent electron acceptors, as evidenced by reports of air-stable radical forms of large aromatic diimides such as naphthalene and perylene diimides. These ions have also been observed to exhibit anion-π interaction tendencies of interest in molecular recognition applications. The benefits of phosphonium incorporation, however, have not yet been extended to the smallest benzene diimides. Here, we report that dibrominated pyromellitic diimide and mellophanic diimide both readily undergo substitution reactions with phosphine sources to yield bisphosphonium compounds. In the single crystalline form, these dications display anion-π interactions and, in the case of mellophanic diimide, the stabilization of a bromide-water H-bonding ring pattern. The reaction of these dications with chemical reductants readily provides the singly and doubly reduced redox states, which were characterized by UV-vis spectroscopy and found to exhibit intense absorptions extending into the near-IR region. Taken together, this work demonstrates that phosphonium incorporation onto congested aromatic diimide scaffolds is synthetically viable and produces unusual electron-poor compounds., (© 2024 Wiley-VCH GmbH.)

The combination of continuous wave electron paramagnetic resonance (cw-EPR) with electrochemistry is highly attractive as it allows a clean in-situ generation and the subsequent spectroscopic characterisation of radical ions, which are important intermediates in many photocatalytic cycles as well as light-induced processes occurring in biological systems or optoelectronic devices. Although commercial setups for spectroelectrochemical EPR are available, they are often expensive and tailored to a particular spectroscopic setup. Here we present a design for a low-cost electrochemical EPR cell that can be used in combination with any commercial cw-EPR instrumentation. The cell design is compared to existing setups and the performance of the cell is evaluated by comparison of EPR spectra obtained by chemical and electrochemical oxidation of a graphene fragment., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

This document is a reminiscence on Frantisek Tureček, a renowned figure in the field of mass spectrometry. The author reflects on their personal relationship with Tureček, highlighting his influential work in the generation and chemistry of peptide radical ions. Tureček's contributions to mass spectrometry were celebrated in a workshop organized by various scientific societies and attended by researchers from around the world. The workshop resulted in a collaborative effort to develop a nomenclature system for peptide fragmentation. The document also mentions Tureček's visit to the University of Hong Kong, where he conducted investigations into radical-initiated fragmentation. Additionally, it acknowledges Tureček's expertise in exploring Hong Kong's natural spaces and his dedication to serving on editorial boards. The author expresses their admiration for Tureček as both a colleague and a friend. [Extracted from the article]

The industrial removal of organosulfur impurities from fossil fuels relies on transition‐metal‐based catalysts in harsh conditions (ca. 400 °C, up to 100 bar H2), yet desulfurization (DS) of refractory alkyl dibenzothiophenes (DBTs) remains challenging. Here, we report that carbon‐supported potassium hydride (KH/C) enables efficient DS of DBTs in mild conditions, viz. >97 % conversion of DBTs is achieved at 165 °C in 3–6 h while the yields of respective biphenyls are 84–95 % by using only 15 % excess of KH per a C−S bond. In addition, KH/C allows to lower the concentration of 4,6‐Me2DBT in the mesitylene solution from 1000 ppm to <3 ppm (165 °C, 20 h) and provides deoxygenation, denitrogenation and catalytic aromatic hydrogenation reactions. DS of various sulfur heterocycles by using KH/C, a transition‐metal‐free material based on earth abundant elements, is viable at low temperature and has prospects for the further development towards decentralized removal of organosulfur species from fossil fuels. [ABSTRACT FROM AUTHOR]

Thiyl radicals offer unique catalytic patterns for the direct covalent activation of alkenes. However, important limitations in terms of structural diversity and handling have hampered the routine use of thiyl radicals in covalent radical catalysis. Herein, we report a new class of cationic sulfur‐centered radicals to achieve covalent radical catalysis. Their generation from highly modular thioureas by photoredox catalysis make their utilization very simple and reliable. The synthetic potential and the versatility of the catalytic system were finally evaluated in a (3+2)‐radical cascade between vinylcyclopropanes and olefins. [ABSTRACT FROM AUTHOR]

The open‐shell iron pentacarbonyl cation [Fe(CO)5].+ was isolated by deelectronation, i.e. the single‐electron oxidation of the parent neutral Fe(CO)5 using [phenazineF].+ as the [Al(ORF)4]− and [F‐{Al(ORF)3}2]− salt (RF=C(CF3)3; phenazineF=perfluoro‐5,10‐bis(perfluorophenyl)‐5,10‐dihydrophenazine). [Fe(CO)5].+[Al(ORF)4]− was fully characterized (scXRD analysis, IR, NMR, EPR, 57Fe spectroscopy, CV and SQUID magnetization study) and, apart from being a compound of fundamental interest, may serve as a precursor for low‐valent iron coordination chemistry. [ABSTRACT FROM AUTHOR]

NH3 is mainly converted into NH4+ in air. The secondary aerosol generated by the reaction of NH4+ with acid radical ions such as SO42-, NO3- and Cl- are important components of PM2.5 in ambient air. In order to explore the pollution characteristics, sources and impacts of ammonia on PM2.5 emission in the ambient air of southwest region of Shanghai, this study selected urban residential station A and rural residential station B in this region to conduct NH3 monitoring for one year (March 2018-February 2019) using DOAS method ammonia monitor and simultaneous PM2.5 measurements at station A. The results showed that the daily average concentration of atmospheric NH3 in the southwest of Shanghai was 6.5 μg/m³, and the hourly average concentration ranged from 0.4 to 76.0 μg/m³; the concentration level of NH3 is summer > autumn > spring > winter; the daily average concentration of NH3 showed a single peak characteristic; there was a phenomenon of lower concentration of NH3 on weekends than on weekdays; the ratio of NH3/PM2.5 showed a seasonal pattern of summer>autumn>spring>winter, and the pollution level was excellent>good>light pollution> moderate pollution. [ABSTRACT FROM AUTHOR]

Bromodimethylsulfonium bromide (BDMS) is an expedient storage of molecular bromine or bromine radicals or bromonium ions and also of nucleophilic bromide ion. It is an easily available, inexpensive and versatile reagent. It is used as an effective brominating reagent as well as a valuable catalyst for several organic conversions. The prominent characteristics of this compound are the straight forwardness of the process, the ease of access of the compound, no requirement of chromatographic separation, no additional base, Lewis acid, or any other catalyst, better yields in comparatively less reaction times and assist to maintain the stoichiometric ratio during the reactions. The present article includes the catalytic applications as well as its brominating role in organic reactions. [ABSTRACT FROM AUTHOR]

Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub‐Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled. [ABSTRACT FROM AUTHOR]

Carbon dioxide is considered an inert gas that rarely participates in atmospheric chemical reactions. Nonetheless, we show here that CO 2 is involved in some important photo-oxidation reactions in the atmosphere through the formation of carbonate radicals (CO 3⚫-). This potentially active intermediate CO 3⚫- is routinely overlooked in atmospheric chemistry concerning its effect on sulfate formation. The present work demonstrates that the SO 2 uptake coefficient is enhanced by 17 times on mineral dust particles driven by CO 3⚫-. Importantly, upon irradiation, mineral dust particles are speculated to produce gas-phase carbonate radical ions when the atmospherically relevant concentration of CO 2 presents, thereby potentially promoting external sulfate aerosol formation and oxidative potential in the atmosphere. Employing a suite of laboratory investigations of sulfate formation in the presence of carbonate radicals on the model and authentic dust particles, ground-based field measurements of sulfate and (bi)carbonate ions within ambient PM, together with density functional theory (DFT) calculations for single electron transfer processes in terms of CO 3⚫- -initiated S(IV) oxidation, a novel role of carbonate radical in atmospheric chemistry is elucidated. [ABSTRACT FROM AUTHOR]

Stabilizing reactive radical ions promises outstanding performances in photocatalysis, organic optoelectronics and photothermal therapies, but it remains a challenge. In this contribution, we firstly report a persistent radical anion (PBI˙−-4Cz) derived from a propeller-shaped electron-deficient perylene bisimide-based pentad (PBI-4Cz). Detailed investigations confirm that PBI˙−-4Cz could intactly exist under inert conditions, and its lifetime is sufficiently prolonged up to more than one week under ambient atmosphere. Such exceptional stability is ascribed to the synergistic effect of the high electron-affinity and structural shielding originating from the compact spatial arrangement of PBI-4Cz. This work contributes to rational design and appropriate chemical construction of stable open-shell species. [ABSTRACT FROM AUTHOR]

In the context of the development of coordination energy-harvesting systems, the axial bonding of cobalt(II) octakis(3,5-di-tert-butylphenoxy)phthalocyanine (1) with gold(III) 2,3,7,8,12,18-hexamethyl,13,17-diethyl,5-(pyridin-4-yl)- and (2,3,7,8,12,18-hexamethyl,13,17-diethyl,5-(pyridin-3-yl)porphin (2 and 3), the structure, the spectral/electrochemical properties of the resulting donor–acceptor complexes and photoinduced electron transfer in them are studied. The process of the dyad formation passing as self-assembly in the donor–acceptor phthalocyanine–porphyrin systems was explored using UV-Visible, IR, and 1H NMR spectroscopy and mass spectrometry. The geometric and electronic structures of the dyads were identified using density functional theory (DFT) and time-dependent DFT calculations. The electron transfer in the coordination complexes studied was confirmed by recording the radical ion pairs namely 1˙+ : 2˙−/1˙+ : 3˙− and measuring the kinetics of the photoinduction and decay of these states by a femtosecond laser photolysis technique. The effect of the gold(III) porphyrin macrocycle nature in the lifetime of radical ion pairs was shown. The redox potential values for the coordination dyads and the photoelectrochemical parameters defining their perspective in design and understanding of PET systems were observed using the cyclic voltammetry/amperometry methods and the short-circuited electrochemical cell Ti‖a dyad film‖0.5 M Na2SO4‖Pt, respectively. [ABSTRACT FROM AUTHOR]

The incorporation of organic radicals into coordination polymers was considered as a promising strategy to promote metal‐ligand exchange interactions, but there are only a very limited number of stable organic radical‐based ligands that can serve well such a purpose. Herein, we report two new tris(2,4,6‐trichlorophenyl)methyl (TTM) radical‐based ligands L1 and L2 with two and three imidazole substituents, respectively. The imidazole unit serves as a coordination site and it can also stabilize the TTM radical by intramolecular donor–acceptor interaction. Coordination of L1 and L2 with cobalt(II) ions gave the corresponding one‐ (CoCP‐1) and two‐dimensional (CoCP‐2) coordination polymers, the structures of which were confirmed by X‐ray crystallographic analysis. Magnetic measurements and theoretical calculations suggest antiferromagnetic coupling between the paramagnetic cobalt(II) ions and the radical ligands. Our study provides a rational design for stable organic radical‐based ligands and further demonstrated the feasibility of a metal–radical approach toward magnetic materials. [ABSTRACT FROM AUTHOR]

Arimisia annua L. is an important anticancer herb used in traditional Chinese medicine. The molecular basis underpinning the anticancer activity is complex and not fully understood, but the herbal polysaccharides, broadly recognised as having immunomodulatory, antioxidant and anticancer activities, are potential key active agents. To examine the functions of polysaccharides from A. annua, their immunomodulatory and antioxidant potentials were evaluated, as well as their structural characterization. The water-soluble polysaccharides (AAPs) were fractionated using size-exclusion chromatography to obtain three dominant fractions, AAP-1, AAP-2 and AAP-3, having molecular masses centered around 1684, 455 and 5.8kDa, respectively. The antioxidant potentials of the isolated polysaccharides were evaluated by measuring radical scavenging activities against DPPH● (2,2-diphenyl-1-picrylhydrazyl radical), ABTS●+ (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid radical ion), and the OH● (hydroxyl radical). AAP-1 displayed high antioxidant activities against these radicals, which were 68%, 73% and 78%, respectively. AAP-2 displayed lower scavenging activities than the other two fractions. Immunostimulatory activities of AAPs were measured using mouse macrophages. The three polysaccharide fractions displayed significant antioxidant activities and stimulated the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). AAP-1 showed significant immunostimulatory activity (16-fold increase in the production of IL-6 compared to the control and 13-fold increase in the production of TNF-α) with low toxicity (>60% cell viability at 125 μg/mL concentration). Preliminary structural characterization of the AAPs was carried out using gas chromatography (GC) and FTIR techniques. The results indicate that AAP-1 and AAP-2 are pyranose-containing polysaccharides with β-linkages, and AAP-3 is a β-fructofuranoside. The results suggest that these polysaccharides are potential candidates for immunotherapy and cancer treatment. [ABSTRACT FROM AUTHOR]

Nine kinds of carbon dots (CDs) were synthesized by using fruits with different varieties as carbon sources; meanwhile, the fluorescence characteristics, quantum yield, and response ability to different metal ions and free radicals were systematically studied. These CDs showed similar excitation and emission spectral ranges (λex ≈ 345 nm, λem ≈ 435 nm), but very different fluorescence quantum yield (QY), in which orange and cantaloupe CDs have the highest QY around 0.25 and green plum CDs showed the lowest quantum yield around 0.1. Interestingly, the fluorescence of all of these CDs can be significantly quenched by hydroxyl radical (•OH) and iron ion (Fe3+); however, these CDs showed very different response characteristics to other metal ions (e.g., Co2+, Ni2+, Cu2+, Ce3+, Mn2+, Ag+, and Fe2+). Through in-depth analysis, we found some interesting patterns of the influence of carbon sources on the fluorescence characteristics of CDs. Finally, by using white pitaya CDs as fluorescence probe, we realized sensing of Fe3+ and •OH with limits of detection (LOD) of 19.4 μM and 0.7 μM, respectively. Moreover, the CDs were also capable for sensitive detection in immune cells and even in zebrafishes. Our work can provide valuable guidance for the rational design of functional CDs for biological applications. [ABSTRACT FROM AUTHOR]

Four ethers were compared as solvents of lithium naphthalenide (Li-NTL) solutions to pre-dope Li into Si electrodes. The solvents of the Li-NTL solutions affected the stability and equilibrium potential (Veq). X-ray diffraction, thermodynamic characterization and ultraviolet-visible (UV–vis) spectroscopy were used to clarify the effects of the solvation structure, the lowest unoccupied molecular orbital (LUMO) energy of the solvent molecule and the ion pair structure between Li+ ions and naphthalenide radical anions ([NTL]·−) on doping capacity. A Li-NTL solution having a low Veq and sufficient stability under potentials as low as that of Li metal was found to provide the highest pre-doping capacity. In particular, a 2-methyltetrahydrofuran (MeTHF) solution exhibiting the lowest Veq showed a pre-doping capacity as high as 3250 mAh g−1 after 24 h. UV–vis spectra and Walden plots indicated that a Li-NTL solution using MeTHF provided less dissociation than a tetrahydrofuran (THF) solution. The doping capacity is evidently determined by the Veq of the Li-NTL solution as a consequence of the dissociation equilibrium of the ion pair of the solvated Li+ ion and [NTL]·− radical ions. [ABSTRACT FROM AUTHOR]

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A systematic structural study on the intercalation of the radical cation 2-(4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (p-MPYNN) into a synthetic fluoromica clay named Somasif® ME 100, Na2xMg3.0−xSi4O10(FyOH1−y)2 (x = 0.33, y = 0.98), has been carried out. The guest–host interactions in these intercalation compounds have been characterized by X-ray powder diffraction and solid-state NMR of the constituent nuclei (23Na, 19F, 27Al and 29Si) of the Somasif lattice. The intercalation process can be quantitatively monitored using 23Na MAS-NMR. As a function of radical ion loading, different kinds of stacking arrangements can be realized, which modify the intermolecular interactions between the electron spins of the guest species, as probed by electron spin resonance (EPR) and 1H solid state nuclear magnetic resonance (NMR). The results are discussed in relation to previous literature data on similar systems. [ABSTRACT FROM AUTHOR]