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Angucyclines and angucyclinones represent a class of natural compounds that belong to the group of aromatic polyketides. They exhibit a wide array of biological properties, such as antimicrobial, antiviral, and cytotoxic. Their considerable therapeutic potential and diverse scaffolds have attracted many synthetic chemists to devise novel strategies to construct their intricate molecular architecture. Over 300 class members have been isolated from natural sources, mainly from bacterial strains of Streptomyces species. This review highlights recent advancements in their synthesis, such as oxidative cyclization, photooxidation, and metal‐catalyzed [4+2]‐cycloaddition, which has facilitated the efficient and practical total syntheses of various angucycline and angucyclinone natural products. [ABSTRACT FROM AUTHOR]

The photooxidation of 3,3′-diethyl-9-methylthiacarbocyanine and 3,3′-diethylthiacarbocyanine by viologens (methyl viologen, p-chlorophenyl viologen, p-cyanophenyl viologen) in acetonitrile and their dimeric complexes with cucurbit[8]uril by monomeric complexes of viologens with cucurbit[8]uril in water has been studied. The photooxidation products of dye monomers in acetonitrile are radical dications of the dyes and radical cations of viologens. The photooxidation of dimeric complexes produces radical trications of the dimeric complexes and radical cations of the monomeric complexes of viologens. The photooxidation reaction of the dyes occurs most efficiently in acetonitrile. [ABSTRACT FROM AUTHOR]

Polymerization of primary amine‐containing monomers is challenging because the amine inhibits polymerization catalyst activity. An alternative approach to access primary amine functionalized polymers is postpolymerization modification. To this end, the hydroaminoalkylation of vinyl‐terminated polyolefins with N‐(trimethylsilyl)benzylamine is used to prepare primary amine‐terminated polyolefins, with the free primary amine substituent being revealed upon hydrolytic work up. These materials are spectroscopically characterized, and an investigation of thermal properties by differential scanning calorimetry and thermogravimetric analysis is completed. These results show that the primary amine substituent increases the glass transition temperature and improves thermal stability. The reactive primary amine functionality is used in the photo‐oxidative dimerization of polyolefins to demonstrate how this elusive functionality can be applied in oligomer valorization. [ABSTRACT FROM AUTHOR]

Gas–liquid oxidation processes, despite their wide application in the chemical industry, still pose considerable safety concerns. Microchemical technology has received high recognition for its intrinsic safety performance and process-intensification capability in hazardous reactions. This Short Review offers a comprehensive summary on how microchemical technology can be employed to achieve gas–liquid oxidation processes for continuous synthesis of chemicals in a safe, efficient, and controlled manner. Herein, we discuss the key aspects of gas–liquid dispersion and hydrodynamics, as well as mass transfer characteristics on microscale, and present representative gas–liquid oxidation cases in microflow reactors. Finally, the current challenges in industrial applications and potential academic research directions are presented. 1 Introduction 2 Microbubble Generation Technology for Gas–Liquid Oxidation Reactions 3 Hydrodynamic and Mass-Transfer Characteristics of Gas–Liquid Oxidation Microreactors 4 Gas–Liquid Oxidation Reactions in Microreactors 5 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

[Display omitted] The challenge of mitigating pollution stemming from industrial exhaust emissions is a pressing issue in both academia and industry. This study presents the successful synthesis of nitrogen-defect-enriched graphite carbon nitride (g-C 3 N 4) using a two-step calcination technique. Furthermore, a g-C 3 N 4 -Au heterostructure was fabricated through the photo-deposited Au quantum dots (QDs). When subjected to visible light irradiation, this heterostructure exhibited robust nitric oxide (NO) photooxidation activity and stability. With its fluffy, porous structure and large surface area, the nitrogen-defect-enriched g-C 3 N 4 provides more active sites for photooxidation processes. The ability of g-C 3 N 4 to absorb visible light is enhanced by the local surface plasmon resonance (LSPR) effect of Au QDs. Additionally, the lifetime of photogenerated charge carriers is extended by the presence of N defects and Au, which effectively prevent photogenerated electron-hole pairs from recombining during the photooxidation process. Moreover, the oxidation pathway of NO was analyzed through In-situ Fourier transform infrared (FT-IR) spectroscopy and Density Functional Theory (DFT) calculation. Computational findings revealed that the introduction of Au QDs decreases the activation energy of the oxidation reaction, thereby facilitating its occurrence while diminishing the formation of intermediate products. As a result, NO is predominantly converted to nitrate (NO 3 −). This work unveils a novel approach to constructing semiconductor-cocatalyst heterostructures and elucidates their role in NO photooxidation. [ABSTRACT FROM AUTHOR]

The European Food Safety Authority (EFSA) has approved the use of a 1045 J/L UV-C dose as an adjunct to pasteurization to increase the shelf life and vitamin D3 content of milk. However, there are no verification methods analogous to the alkaline phosphatase test for pasteurized milk to ensure that the desired UV-C dose has been correctly applied. The aim is to develop a real-time in-line detector based on fluorescence spectroscopy. In this study, 22 different UV-C doses (ranging from 0 to 2000 J/L) were applied to milk to assess the impact of photooxidation on intrinsic photosensitive chromophores. Fluorescence spectroscopy (90°-angle) was employed as the method of analysis for monitoring the changes in the fluorescence spectra of chromophores in milk without sample pretreatment. Three important chromophore areas (CAs) were identified: CA 1 (riboflavin), CA 3 (vitamin A and dityrosine) and CA 4 (tryptophan), with statistically significant changes at around 1045 J/L and 1500 J/L. The findings of our preliminary study support our hypothesis that the fluorescence of intrinsic chromophores can be used as verification of the applied UV-C dose. [ABSTRACT FROM AUTHOR]

This study addresses the global issue of recycling vehicle rubbish tires by a vacuum pyrolysis process, exploring a novel environmentally responsive approach for thermal decomposition and recovery of the carbon black particles contained in tires (25–30 wt%). Carbon black is typically used for its UV protection in plastics and abrasion resistance in composites and rubbers. This research aims at providing an eco‐responsible alternative to commercial carbon black of fossil origin by recycling the carbon black (rCB) from end‐of‐life tires. A particle reinforced composite material was developed containing rCB and high‐density polyethylene. For comparison purposes, an identical composite was manufactured using commercial carbon black (CB). Accelerated aging studies have been carried out on the materials. Topographic evolution of the samples with aging and oxidation kinetic of the surface and through the thickness were studied. Multiscale mechanical properties have been evaluated for a more comprehensive understanding of the mechanisms involved in the degradation. A comparison of the different materials properties was carried out in order to highlight the various elements linked to the degradation and UV protection of materials. This work helps demonstrating the feasibility of using recycled carbon black particles from waste tires as a high‐performance filler for plastics and composites. Highlights: Recycled carbon black (rCB) is an eco approach of revalorizing tire waste.Vacuum pyrolysis successfully allows recovery of reusable rCB.The rCB acts as a photon absorber, limiting degradation of HDPE.The rCB limits the cross‐linking responsible of embrittlement of HDPE.A critical carbonyl index of 20 marks the occurrence of cracks and degradation. [ABSTRACT FROM AUTHOR]

Although carnosine (β-Ala-L-His) is one of physiological protectants against in vivo damages caused by reactive oxygen species (ROS), its reactivity against singlet oxygen (1O2), an ROS, is still unclear at the molecular level. Theoretically, the reaction consists of two steps: i) oxygenation of the His side chain to form an electrophilic endoperoxide and ii) nucleophilic addition to the endoperoxide. In this study, the end product of 1O2-mediated carnosine oxidation was evaluated using 2D-NMR and other analytical methods both in the presence and absence of external nucleophiles. Interestingly, as the end product without external nucleophile, a cyclic homodimer was confirmed under our particular conditions. The reaction was also replicated in pork specimens. [ABSTRACT FROM AUTHOR]

A photooxidation approach to the conversion of phosphines into the corresponding phosphine oxides is reported. By taking advantage of O2 in the air as an oxidant and oxygen source, phosphine oxides were obtained efficiently in moderate to excellent yields. A four-coordinated organoboron compound was used as the photocatalyst to activate O2 to its singlet state. This photooxidation method features mild reaction conditions, broad functional-group tolerance, and a wide substrate scope. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Covalent organic frameworks (COFs) driven photocatalytic organic transformations especially photooxidation reactions have become a fertile topic and attracted numerous research attentions. Boosting the charge generation and transport process is the key factor for achieving high catalytic efficiencies. As one of the most effective strategies, the introduction of "heavy atoms" into the long‐range ordered conjugated backbones can effectively facilitate the intersystem crossing (ISC) process and hence improve the generation of active oxygens, which is beneficial for the oxidation. In this work, we designed and synthesized a benzoselenadiazole based covalent organic framework (COF) material, BSe‐COF with heavy atom of selenium (Se), and a benzothiadiazole based BT‐COF with isomorphic backbone for comparison. Compared to BT‐COF, BSe‐COF exhibits broader absorption range, stronger photocurrent response and enhanced intersystem crossing (ISC) with higher singlet oxygen (1O2) generation efficiency. When applied in photocatalytic organic transformation, BSe‐COF presents remarkably higher photocatalytic activity in the oxidation of sulfides than BT‐COF under the irradiation of blue LED lamp. Furthermore, BSe‐COF can be used as efficient photocatalyst for the window ledge reaction with high yields (over 84%) of various sulfoxides from a wide range of thioether substrates scope. [ABSTRACT FROM AUTHOR]

Methionine is an essential amino acid for mammals and it is limiting for monogastric animals. It can be oxidized easily by UV light. This could influence the bioaccessibility and bioavailability of methionine. In this work, the photosensitized degradation of peptide-bound methionine in the presence of riboflavin was investigated in a model system. Capillary electrophoresis was employed to analyze the time course of the degradation. The products were identified by liquid chromatography coupled to mass spectrometry (LC–MS/MS). Benzoyl methionine was degraded by 50% during UV irradiation in the presence of riboflavin after 5.0 min with 10 mol% riboflavin and 6.4 min with 3 mol% riboflavin. Homocysteine (16–20 mol%) and β-aspartic semialdehyde (ca. 30 mol%) were found as major degradation products next to methionine sulfoxide (ca. 25 mol%). A smaller molar ratio of riboflavin led to a higher formation of aspartic semialdehyde. The formation of homocysteine was paralleled by the formation of formaldehyde. Furthermore, the experiment was transferred to small peptides, which showed the analogous degradation products of peptide-bound methionine. [ABSTRACT FROM AUTHOR]

Photosynthesis is initiated when the sun's light induces electron transfer from chlorophyll to plastoquinone, a para-quinone. While photosynthesis occurs in the intact chloroplasts of living plants, similar photochemical reactions between dietary chlorophyll metabolites and quinones are likely and may affect health outcomes. Herein, we continue our studies of the direct photoreduction of para-quinones and ortho-quinones that were generated by the photo-oxidation of catechols. Chlorophyll metabolites, including pheophorbide A, chlorin e6, and pyropheophorbide A, as well as methylene blue were employed as photosensitizers. We detected hydrogen peroxide using horseradish peroxidase following the photo-oxidation of the catechol dopamine, even in the presence of EDTA, a tertiary amine electron donor. Under ambient oxygen, hydrogen peroxide was also detected after the photoreduction of several para-quinones, including 2,3-dimethoxy-5-methyl-p-benzoquinone (CoQ0), methoxy-benzoquinone, and methyl-benzoquinone. The combinations of methylene blue and EDTA or pheophorbide A and triethanolamine as the electron donor in 20% dimethylformamide were optimized for photoreduction of the para-quinones. Chlorin e6 and pyropheophorbide A were less effective for the photoreduction of CoQ0 but were equivalent to pheophorbide A for generating hydrogen peroxide in photo-oxidation reactions with photosensitizers, oxygen, and triethanolamine. We employed dinitrophenylhydrazine to generate intensely colored adducts of methoxy-benzoquinone, methyl-benzoquinone, and 1,4-benzoquinone. [ABSTRACT FROM AUTHOR]

A supramolecular naphthalenediimide radical anion was developed through host--guest interactions between NDI and cucurbit[7]uril (CB[7]), which can be greatly promoted in the presence of chloride ions to obtain Cl• and NDI-2CB[7]•-. Under the synergistic action of Cl• as a hydrogen atom transfer (HAT) agent and NDI-2CB[7]•- transferring electrons to O2 to produce O2•, the photocatalytic oxidation reactions of alkylarenes to carbonyls can be realized with universal applicability. [ABSTRACT FROM AUTHOR]

Two biodegradable polyesters, poly(butylene succinate) (PBS) and poly(butylene succinate‐co‐adipate) (PBSA), were artificially aged in a UV irradiation test chamber, and their photodegradation behaviors investigated. The attenuated total reflection (ATR) infrared (IR) spectra of the initial and UV‐aged samples revealed conformational changes in the tetramethylene sequences of the photoaged PBS and PBSA. The one‐dimensional wide‐angle X‐ray scattering (WAXS) profiles showed that the (110) d‐spacing of the α‐form crystal progressively decreased during UV aging, suggesting that the crystalline polymer chains became arranged more closely along the fiber axis. Accordingly, we conclude that PBS and PBSA transform from their TGTGT to nearly TTTTT conformations upon photoaging. The observed WAXS, small‐angle X‐ray scattering, and IR spectral data suggest that photodegradation preferentially occurs in the amorphous phase of each polymer. The less crystallizable butylene adipate co‐unit enhances the degradability of PBSA, with prolonged photooxidation leading to partial degradation of the crystalline region of the copolymer. This finding is consistent with and may be linked to the higher biodegradability of PBSA compared to PBS. [ABSTRACT FROM AUTHOR]

The bonding effects between 3d transition‐metal single sites and supports originate from crystal field stabilization energy (CFSE). The 3d transition‐metal atoms of the spontaneous geometrical distortions, that is the Jahn–Teller effect, can alter CFSE, thereby leading to the Irving–Williams series. However, engineering single‐atom sites (SASs) using the Irving–Williams series as an ideal guideline has not been reported to date. Herein, alkynyl‐linked covalent phenanthroline frameworks (CPFs) with phenanthroline units are developed to anchor the desired 3d single metal ions from d5 to d10 (Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+). The Irving–Williams series was employed to accurately predict the bonding effects between 3d transition‐metal atoms and phenanthroline units. To verify this, theoretical calculations and experimental results reveal that Cu‐SASs/CPFs exhibits higher stability and faster charge‐transfer efficiency, far surpassing other metal‐SASs/CPFs. As expected, Cu‐SASs/CPFs demonstrates a high photoreduction of CO2‐to‐CO activity (~30.3 μmol ⋅ g−1 ⋅ h−1) and an exceptional photooxidation of CH3CHO‐to‐CH3COOH activity (~24.7 μmol ⋅ g−1 ⋅ h−1). Interestingly, the generated *O2− is derived from the process of CO2 reduction, thereby triggering a CH3CHO oxidation reaction. This work provides a novel design concept for designing SASs by the Irving–Williams to regulate the catalytic performances. [ABSTRACT FROM AUTHOR]

In this study, diiodo boron dipyrromethene (BODIPY) is employed as the energy donor and 3,4,9,10-perylene tetracarboxylic dianhydride (PDA) as the energy acceptor, enabling the synthesis of two new compounds: a BODIPY-perylene dyad named Pl, and a triad named P2. To investigate the impact of the energy donor on the photophysical processes of the system, P1 comprises one diiodo-BODIPY unit and one PDA unit, whereas P2 contains two dhodo-BODIPY moieties and one PDA unit. Due to the good spectral complementarity between diiodo-BODIPY and PDA, these two compounds exhibit excellent light-harvesting capabilities in the 400–620 nm range. Steady-state fluorescence spectra demonstrate that when preferentially exciting the diiodo-BODIPY moiety, it can effectively transfer energy to PDA; when selectively exciting the PDA moiety, quenching of PDA fluorescence is observed in both P1 and P2. Nanosecond transient absorption results show that both compounds can efficiently generate triplet excited states, which are located on the PDA part. The lifetimes of the triplet states for these two compounds are 103 and 89 μs, respectively, significantly longer than that of diiodo-BODIPY. The results from the photooxidation experiments reveal that both P1 and P2 demonstrate good photostability and photooxidation capabilities, with P2 showing superior photooxidative efficiency. The photooxidation rate constant for P2 is 1.3 times that of P1, and its singlet oxygen quantum yield is 1.6 times that of P1. The results obtained here offer valuable insights for designing new photosensitizers. [ABSTRACT FROM AUTHOR]

To promote adsorption capacity of biochar as engineering material, pinewood biochar (PC) and bamboo biochar (BC) were prepared by slow pyrolysis (700 °C) and then directly irradiated with UV light at room temperature. The elemental analysis, SEM, FTIR, XPS, and Boehm titration measurements showed that UV irradiation significantly increased the BET surface area, porosity, and surface oxygen functional groups of the biochar. After UV treatment, the BET surface areas of PC and BC were increased by 63.0% and 217%, while the amount of total (acidic) groups increased by 62.0% (155%) and 24.9% (28.2%), respectively. FTIR and XPS measurements suggested that photochemical reactions, including photodegradation and photooxidation processes, may play primary roles in altering biochar the pore structure and surface functional groups of biochar. The Langmuir model capacities (qmax) of modified PC and BC were increased by 94.5% and 50.5% for Pb (II), 18.5% and 13.7% for Cd (II), respectively, compared to their unmodified counterparts. This study examined the effects of UV irradiation on the surface properties of biochar and demonstrate its potential as an effective, simple, and green method for functionalizing biomass material.

With the rapid industrial development, air pollution and global climate change have become pressing issues. Addressing the effective removal of nitrogen oxides (NOx), a major contributor to these problems, is crucial. Photo-oxidation technology emerges as a promising solution, offering a new, green method of NOx removal. This technology stands out for its safety, cost-effectiveness, cleanliness, and cycle stability, making it an efficient approach to tackling NOx emissions. In this study, we explore a novel strategy that involves the in-situ growth of ZnO nanodot arrays on surfaces of graphite-phase carbon nitride (g-C3N4) to construct column-supported structure composites. These composites are designed for the photo-oxidation removal of NO under visible light. By employing an ion adsorption reaction, ZnO NP/g-C3N4 column-supported structure composite photo-oxidizers were successfully synthesized with varying ZnO particle mass fractions of 1%, 2.5%, and 5%, respectively. The investigation revealed that introducing ZnO NP significantly increases the specific surface area of the ZnO NP/g-C3N4 composites compared to pure g-C3N4 samples, which have a specific surface area of 31.092 m2·g‒1. Specifically, the 2.5% ZnO NP/g-C3N4 composites exhibited a substantial increase to 58.063 m2·g‒1, while the 1% and 5% ZnO NP/g-C3N4 composites reached 37.141 m2·g‒1 and 42.563 m2·g‒1, respectively. This enhancement in the specific surface area, attributed to the columnar support structure, addresses the stacking issue of the g-C3N4 lamellae in the composites. The resulting structure is stretchier and fluffier, exposing a greater number of reactive sites. Furthermore, the construction of a heterostructure improves the energy band structure of the composites, facilitating the migration and separation of photogenerated carriers, which significantly enhances the photo-oxidation performance. During the NO photo-oxidation removal experiments, the ZnO NP/g-C3N4 composites demonstrated a marked improvement in photo-oxidation efficiency compared to pure g-C3N4. Notably, the 2.5% ZnO NP/g-C3N4 composites achieved a 100% photo-oxidation removal rate of NO, maintaining an effective removal performance across different NO concentrations and exhibiting robust performance in five cycles of stability tests. This study provides an effective strategy for designing and constructing high-performance photo-oxidizers and provides a technical reference for eliminating industrial NO pollutants. In addition, our study introduces a method for the photo-oxidation removal of NO and inspires new approaches in the design and synthesis of composite photocatalysts. By modulating the composition and structure of these composites, their photo-oxidation performance can be further optimized to achieve more efficient and stable pollutant removal. This advancement holds significant implications for environmental protection and sustainable development.

[Display omitted] Semiconductor/redox-based dual light-induced color switching systems (LCSs) with a visible light response at different wavelengths are highly sought after for efficient redox reactions. In this work, Sn2+ self-doped SnO 2 has been designed as nanophotocatalysts for preparing visible light-responsive inks/fabrics with single/multi-color abilities. The self-doping of SnO 2 nanoparticles results in the formation of oxygen vacancies due to charge compensation effects leading to electron-driven photoreduction and photooxidation of LSC inks. By mixing SnO 2-x nanoparticles dispersions with specific redox-sensitive dyes can lead to the creation of well-designed sets of visible light-responsive semiconductor-driven LCS systems with both single-color (RGB) and multi-color (violet and green) changes. The exposure of LCS inks to green (550 nm) light culminates in the rapid photoreduction of the inks to decolorized state, while red (660 nm) light initiates the photooxidation in air. The combination of the LCS inks with –OH-rich polymers can be coated on the hydrophobic surface of the layered fabric to produce photo-responsive fabrics with single/multi-color response. The interaction of green light with the semiconductor-driven LCS systems allows the remote photo-printing of different images/letters on the LCS fabrics. Spontaneous erasure can be achieved by red light with high stability and repeatability (>35 cycles). The research in this paper provides new perspectives and insights for the development of new color-changing materials with potential applications as light-activated sensors and display units. [ABSTRACT FROM AUTHOR]

Abstract Robust solid-core silica particles with submicrometer size and anthracene-containing mesoporous shell were obtained and studied as model water-dispersable photoreactors. An anthracene derivative containing a triethoxysilyl group was synthesized and co-condensed with tetraethoxysilane in various ratios to form a photoactive mesoporous shell with a thickness up to approximately 80 nm on previously prepared solid silica particles. Mesopores of as-synthesized particles, without a commonly applied removal of the micellar templates, offered a confined space for solubilization of hydrophobic molecules. Efficient excitation energy transfer from anthracene chromophores to both hydrophobic (perylene) and hydrophilic (fluoresceine) encapsulated acceptors was observed in an aqueous dispersion of the particles. Photosensitized oxidation of encapsulated perylene was shown to proceed efficiently in such systems serving as water-dispersable photoreactors. Importantly, the designed core–shell systems were found to be stable for a long time (at least 24 months) and robust enough, thanks to the presence of solid cores, to be handled by centrifugation in aqueous dispersions. All these features make them promising candidates for reusable systems for the photosensitized degradation of water pollutants, especially hydrophobic pollutants.

Background: Dispensed drugs stored by patients are often in single-dose packages (SDPs) or are crushed and mixed after being removed from a press-through package (PTP) sheet. Information on their stability is extremely limited. To address this, we explored using chemiluminescence (CL) measurements to detect oxidative degradation. Methods: Eight amlodipine, 14 telmisartan, and two warfarin preparations were used as specimens. These preparations were stored at room temperature under various conditions, after which CL was measured. Cellopoly packaging paper was used for SDP. Three light conditions were used (Condition A: darkness, Condition B: indoor diffused light (approximately 400 lx), and Condition C: exposure to 4,000 lx). CL cumulative light output was measured every minute under nitrogen gas conduction and with a sample chamber temperature of 150 °C, for a maximum of 10 min. Luminescence images were obtained simultaneously with the CL measurements. Results: CL was observed on light-exposed tablet surfaces. For each preparation, an increase in the CL value was observed with the duration of light exposure. In the same preparation with the same exposure time, CL tended to be higher in the order of Condition A < B < C. Moreover, CL increased even when no changes in color were observed by the naked eye. A comparison between preparations with the same main ingredients showed differences in the rate of increase in CL with exposure, and each was found to show a different reactivity to light. Conclusions: To the best of our knowledge, this is the first study to visually capture the surface oxidation of tablets exposed to light using the CL method. The CL values, thought to be derived from photooxidation, increased with exposure of tablets and powders to light after SDP. This method can sensitively assess drug degradation due to photooxidation. Further research is needed to establish a CL method for assessing the stability of preparations in clinical settings. [ABSTRACT FROM AUTHOR]

Polyoxometalate‐based frameworks, as a kind of material constructed by polyoxometalates (POMs), metal ions or clusters, organic ligands, are combined both the advantages of oxygen‐rich POMs and porous metal‐organic frameworks (MOFs) within one single system. This integration greatly expands their potential applications compared to the individual POMs or MOFs. Particularly for photocatalysis, the narrow light absorption range of the typical POMs units in the ultraviolet region hinders their extensive uses as visible‐light‐driven photocatalysts. However, the incorporation of photoactive units into POMs‐based frameworks can be considered as an effective approach to overcome this limitation. In this paper, we review selected examples of recent progress based on the POM‐based frameworks along with their construction strategies and applications in various areas of photocatalysis, mainly including water splitting, CO2 reduction, organic synthesis and also the selective coupling reactions. [ABSTRACT FROM AUTHOR]

The oxidation of benzylic alcohols is an important transformation in modern organic synthesis. A plethora of photoredox protocols have been developed to achieve the aerobic oxidation of alcohols into carbonyls. Recently, several groups described that ultraviolet (UV) or purple light can initiate the aerobic oxidation of benzylic alcohols in the absence of an external catalyst, and depicted different mechanisms involving the photoinduction of •O2− as a critical reactive oxygen species (ROS). However, based on comprehensive mechanistic investigations, including control experiments, radical quenching experiments, EPR studies, UV–vis spectroscopy, kinetics studies, and density functional theory calculations (DFT), we elucidate here that HOO•, which is released via the H2O2 elimination of α-hydroxyl peroxyl radicals [ArCR(OH)OO•], serves as the real chain carrier for the autocatalytic photooxidation of benzylic alcohols. The mechanistic ambiguities depicted in the precedent literature are clarified, in terms of the crucial ROS and its evolution, the rate-limiting step, and the primary radical cascade. This work highlights the necessity of stricter mechanistic analyses on UV-driven oxidative reactions that involve aldehydes' (or ketones) generation. [ABSTRACT FROM AUTHOR]

The photooxidation of volatile organic compounds (VOCs) in the troposphere has important implications for air quality, weather, and climate. A deeper understanding of the underlying mechanisms can be achieved by studying these reactions under controlled conditions and analysing the emerging photooxidation products. This requires dedicated laboratory infrastructure as well as sensitive and selective analytical techniques. Here, we constructed a new 300 L indoor Teflon atmospheric simulation chamber as part of the Bayreuth ATmospheric simulation CHambers (BATCH) infrastructure. The chamber was irradiated by a bandpass-filtered solar simulator that enabled experiments with realistic photon fluxes and OH radical concentrations. It was coupled to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) and a solid-phase microextraction–gas chromatography–mass spectrometry (SPME-GC-MS) system for the on-line analysis of the precursor VOC and its oxidation products in the gas phase. As part of the SPME-GC-MS method, multifunctional oxygenated compounds (carbonyls, alcohols, carboxylic acids) were derivatized with O -(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and N -trimethylsilyl- N -methyltrifluoroacetamide (MSTFA). We designed a permeation source for the on-line addition of internal standards to improve method reproducibility. The joint setup was tested and validated by studying the OH-radical-induced photooxidation of toluene, one of the most abundant aromatic hydrocarbons in the atmosphere. For chamber characterization, we first derived the photolysis rates for several typical toluene products in the irradiated BATCH Teflon chamber (1.77 × 10 -8 –3.02 × 10 -4 s -1). Additionally, wall loss rates were determined empirically (4.54 × 10 -6 –8.53 × 10 -5 s -1) and then parameterized according to fundamental molecular properties. For the cresols, we compiled a weighted calibration factor for the PTR-ToF-MS, taking into account isomer-specific sensitivities as well as the relative distribution as determined by the SPME-GC-MS. The weighted calibration improved the instrumental agreement to 14 %, whereas the PTR-ToF-MS overestimated the sum of the isomers by 31 % compared to the SPME-GC-MS concentrations when using the averaged calibration factor. Thus, the combined data set offered insight into both temporal trends and the isomeric composition. Finally, we conducted six toluene photooxidation experiments to evaluate the ring-retaining first-generation products. Based on the loss-corrected concentrations, we derived formation yields for o -cresol (8.0 ± 1.8 %), m -cresol (0.4 ± 0.1 %), p -cresol (2.4 ± 0.6 %), benzyl alcohol (0.5 ± 0.1 %), and benzaldehyde (4.6 ± 1.7 %) under NO x -free conditions at T = 298 ± 1 K. These yields are consistent with previous studies and therefore serve as proof of concept for our applied methods. [ABSTRACT FROM AUTHOR]

Many industrial processes such transesterification of fatty acid for biodiesel production, soap manufacturing and biosynthesis of ethanol generate glycerol as a major by‐product that can be used to produce commodity chemicals. Photocatalytic transformation of glycerol is an enticing approach that can exclude the need of harsh oxidants and extraneous thermal energy. However, the product yield and selectivity remain poor due to low absorption and unsymmetrical site distribution on the catalyst surface. Herein, tellurium (Te) nanorods/nanosheets (TeNRs/NSs) wrapped potassium‐doped carbon nitride (KCN) van der Waal (vdW) heterojunction (TeKCN) is designed to enhance charge separation and visible‐NIR absorption. The iridium (Ir) single atom sites decoration on the TeKCN core‐shell structure (TeKCNIr) promotes selective oxidation of glycerol to glyceraldehyde with a conversion of 45.6% and selectivity of 61.6% under AM1.5G irradiation. The catalytic selectivity can reach up to 88% under 450 nm monochromatic light. X‐ray absorption spectroscopy (XAS) demonstrates the presence of undercoordinated IrN2O2 sites which improved catalytic selectivity for glycol oxidation. Band energies and computational calculations reveal faile charge transfer in the TeKCNIr heterostructure. EPR and scavenger tests discern that superoxide (O2•−) and hydroxyl (•OH) radicals are prime components driving glycerol oxidation. [ABSTRACT FROM AUTHOR]

We here describe a visible-light photooxidation of sulfinate salts with common alkenes to yield β-hydroxy sulfones on DNA. This process demonstrates a broad substrate compatibility and achieves conversion rates ranging from moderate to excellent. Most importantly, it presents a straightforward, efficient, and metal-free approach for synthesizing Csp3-rich DNA-encoded libraries. [ABSTRACT FROM AUTHOR]

Tandem processes are valuable tools that allow to build molecular complexity while reducing waste production and the number of steps of synthetic routes. In this work, the in situ photooxidation of benzyl alcohols to the corresponding benzaldehydes is coupled with a Knoevenagel condensation for the preparation of benzylidenemalononitrile derivatives. In this rapid one‐pot tandem process, sodium anthraquinone‐1,5‐disulfonate (SAS) and β‐alanine are employed as safe and inexpensive catalysts, while air is used as a terminal oxidant. Moreover, using water as reaction medium results in most cases in the precipitation of the target products, thus facilitating their isolation. [ABSTRACT FROM AUTHOR]

The reuse of waste and the use of renewable materials are of great environmental and economic interest. With that in mind, the synthesis of mesoporous silica can be performed using rice husk ash, which is an industrial waste generated in large quantities. This mesoporous material can be functionalized with photoactive molecules, enabling application in photocatalysis. In this work, we used mesoporous silica nanoparticles functionalized with rose bengal dye (RB) for photooxidation reactions of organic molecules, such as the antibiotic cefuroxime 1‐acetoxyethyl ester (cefuroxime axetil). The characterization results showed the formation of one‐dimensional channels with uniform size and two‐dimensional hexagonal arrangement, with surface area and pore diameter of 230 m2 g−1 and 5 nm, respectively. The infrared and UV‐Vis spectroscopy indicated the functionalization of silica with photoactive molecules. Finally, SBA‐15/RB was applied for the photooxidation of ascorbic acid and antibiotic cefuroxime axetil under irradiation with green light, proving to be efficient for the degradation of cefuroxime axetil. Investigation of the reactive oxygen species involved in photodegradation showed that the photooxidation mechanism mainly involves singlet oxygen. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel AIE-TADF photosensitizer was constructed based on triphenylamine and pyrazine. • The control of singlet oxygen and superoxide radical can be realized by using AIE-TADF molecule as photosensitizers. • The AIE-TADF can be used as photocatalysts for photocatalytic oxidation of phosphine and hydroazobenzenes in water. Recently, there has been a great interest in the study of photocatalysts (PCs) and photosensitizers (PSs) in the field of organic photocatalysis. In the present study, a pure organic thermally activated delayed fluorescence (TADF) molecule 4,4′-(12-(pyridin-4-yl)dibenzo[ f , h ]pyrido[2,3-b]quinoxaline-3,6-diyl)bis(N, N -diphenylaniline) (DPQ-TPA) was designed and synthesized, which not only have excellent TADF property and small energy splitting (Δ E ST), but also can self-assembly in water to form cross-linked nanoparticles with exceptional aggregation-induced emission (AIE) characteristics. DPQ-TPA exhibits excellent remarkable selectivity and notably enhances the production capacity of reactive oxygen species (ROS), particularly 1O 2 , which was employed as a highly effective photocatalyst in the photooxidation reaction of phosphine and hydroazobenzenes under blue light irradiation with high yields up to 94% and 91%, respectively. This work expands the potential application of (donor-acceptor) D-A type AIE-TADF molecules in photocatalytic organic transformations through supramolecular self-assembly. [ABSTRACT FROM AUTHOR]

The Red Sea is a hotspot of biodiversity susceptible to oil pollution. Besides, it is one of the warmest seas on the Earth with highly transparent waters. In this study, we estimated the oil dissolution rates under natural sunlight spectra and temperature conditions using coastal oil slicks collected after the 2019 Sabiti oil spill in the Red Sea. Optical analyses revealed the significant interactive effect of sunlight and temperature in enhancing the dissolution of oil into dissolved organic matter (DOM). The highest oil dissolution rate (38.68 g C m−3 d−1) was observed in full-spectrum sunlight. Oil dissolution significantly enhanced total organic carbon (TOC) and polycyclic aromatic hydrocarbons (PAHs) in seawater. High nucleic acid (HNA) bacteria, likely the oil degraders, proliferated from 30 to 70 – 90% after 4 days. The heavier stable carbon isotopic composition of methane (δ13C-CH4) and lighter stable carbon isotopic composition of carbon dioxide (δ13C-CO2) indicate the putative role of bacterial processes in the natural degradation of crude oil. The results indicated that the combined effect of temperature and solar radiation enhanced the biological and photochemical dissolution of oil on the Red Sea surface. [ABSTRACT FROM AUTHOR]

Aminomethanol is released into the atmosphere through various sources, including biomass burning. In this study, we have expounded the chemical kinetics of aminomethanol in the reaction pathways initiated by the hydroxyl radical (OH) with the aid of ab /n/t/o//density functional theory (DFT) i.e., coupled-cluster theory (CCSD(T))//hybrid-DFT (M06-2X/6-311++G (3df, 3pd). We have explored various possible directions of the OH radical on aminomethanol, as well as the formation of distinct pre-reactive complexes. Our computational findings reveal that the H transfer necessitates activation energies ranging from 4.1 to 6.5 kcal/mol from the -CH2 group, 3.5-6.5 kcal/mol from the -NH2 group and 7-9.3 kcal/mol from the -OH group of three rotational conformers. The H transfer from -CH2, -NH2 and -OH exhibits an estimated total rate constant (kOH) of approximately 1.97 x 10-11cm3 molecule-1 s-1 at 300 K. The branching fraction analysis indicates a pronounced dominance of C-centered NH2CHOH radicals with a favorability of 77%, surpassing the N-centered N HCH2OH (20%) and O-centered NH2CH2O (3%) radicals. Moreover, our investigation delves into the oxidation of the prominently favored carbon-centered NH2CHOH radical through its interaction with atmospheric oxygen molecules. Intriguingly, our findings reveal that formamide (NH2CHO) emerges as the predominant product in the NH2CHOH + 3O2 reaction, eclipsing alternative outcomes such as amino formic acid (NH2COOH) and formimidic acid (HN = C(H)-OH). At atmospheric conditions pertinent to the troposphere, the branching fraction value for the formation of formamide is about 99%, coupled with a rate constant of 5.5 x 10-12 cm3 molecule-1 s-1. Finally, we have scrutinized the detrimental impact of formamide on the atmosphere. Interaction of formamide with atmospheric hydroxyl radicals could give rise to the production of potentially perilous compounds such as HNCO. Further, unreacted NHCH2OH radicals may initiate the formation of carcinogenic nitrosamines when reacting with trace N-oxides (namely, NO and NO2). This, in turn, escalates the environmental risk factors. [ABSTRACT FROM AUTHOR]

The electronic structure and photophysical properties of several acrylaldehyde‐bridged deazaflavin derivatives (cFLs) were investigated theoretically. The impact of acrylaldehyde bridging on photophysical properties of deazaflavin (cFL) is strongly site‐dependent. Specifically, the change of adiabatic energy of electronic transitions(ΔEad) and vibronic coupling promote fluorescent emission to be comparable to internal conversion of cFL and cFL4 (both C5−C6 and C9−N10 bridged, but C9−N10 bridged by propene), turning them eligible as fluorescent sensors. As El‐Sayed's rule is satisfied in cFL1(C5−C6 bridged), cFL2(C9−N10 bridged) and cFL3(both C5−C6 and C9−N10 bridged), intersystem crossing from first singlet excited state to triplet excited states (Tn) become dominant and the evolution of excited cFLs from T1 appears vital. The rate constants of photophysical processes indicate these cFLs are of dominantly high steady state T1 concentration and are potential triplet sensitizers. We expect the findings would pave the way for rational design of novel cFLs with extraordinary photophysical properties. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Stability against oxygen is an important factor affecting the performance of organic semiconductor devices. Improving photooxidation stability can prolong the service life of the device and maintain the mechanical and photoelectric properties of the device. Generally, various encapsulation methods from molecular structure to macroscopic device level are used to improve photooxidation stability. Here, we adopted a crystallization strategy to allow 14H‐spiro[dibenzo[c,h]acridine‐7,9′‐fluorene] (SFDBA) to pack tightly to resist fluorescence decay caused by oxidation. In this case, the inert group of SFDBA acts as a "steric armor", protecting the photosensitive group from being attacked by oxygen. Therefore, compared with the fluorescence quenching of SFDBA powder under 2 h of sunlight, SFDBA crystal can maintain its fluorescence emission for more than 8 h under the same conditions. Furthermore, the photoluminescence quantum yields (PLQYs) of the crystalline film is 327% higher than that of the amorphous film. It shows that the crystallization strategy is an effective method to resist oxidation. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) blocking films are an emerging technology currently being utilized in food packaging applications. UV radiation can cause photochemical reactions in food products, resulting in color, texture, flavor, and nutritional quality degradation. These active films protect the food from photooxidation, maintain the quality attributes, and enhance the food product's shelf life. Incorporating various UV-blocking agents is the current trend in active food packaging applications. These agents absorb, reflect, or scatter the incident UV light, reducing the transmittance of UV radiation through packaging film. Here, we review the possible cause of food spoilage by photooxidation reactions. The different types of UV absorbers were used in food packaging with the benefits and effectiveness achieved. Furthermore, the mechanism and incorporation techniques of UV-shielding agents in food packaging applications have been reviewed. Finally, the challenges and future perspectives of UV-blocking films have been discussed. This article provides a comprehensive explication on the significance of utilizing UV-blocking films for food packaging applications to enhance the shelf life of food products. UV-blocking films are next-generation packaging technology enhancing the shelf life of food products. [ABSTRACT FROM AUTHOR]

In the quest to combat global warming, traditional thermal chemistry processes are giving way to selective photocatalysis, an eco-friendly approach that operates under milder conditions, using benign solvents like water. Benzaldehyde, a versatile compound with applications spanning agroindustry, pharmaceuticals, and cosmetics, serves as a fundamental building block for various fine chemicals. This study aims at enhancing benzaldehyde production sustainability by utilizing photooxidation of benzyl alcohol. Gold nanoparticle-based catalysts are renowned for their exceptional efficiency in oxidizing bio-based molecules. In this research, Au nanoparticles were anchored onto three distinct supports:  T i O 2 ,  Z r O 2 , and graphitic carbon nitride (g- C 3 N 4 ). The objective was to investigate the influence of the support material on the selective photocatalysis of benzyl alcohol. In the preparation of g- C 3 N 4 , three different precursors—melamine, urea, and a 50:50 mixture of both—were chosen to analyze their impact on catalyst performance. After 4 h of irradiation at 365 nm, operating under acidic conditions (pH = 2), the Au photocatalyst on graphitic carbon nitride support synthesized using urea precursor (Au@g- C 3 N 4 (u r e a) ) displayed the optimal balance between conversion (75%) and selectivity (85%). This formulation outperformed the benchmark Au@TiO2, which achieved a similar conversion rate (80%) but exhibited lower selectivity (55%). [ABSTRACT FROM AUTHOR]

The removal of pesticides and other organic pollutants from water through advanced oxidation processes (AOPs) holds great promise. The main advantage of these technologies is that they remove, or at least reduce, pesticide levels by mineralization rather than transfer, as in conventional processes. This study first evaluated the effectiveness of UV/S2O8= compared to heterogeneous photocatalysis using UV/TiO2 processes on the degradation of two commonly used herbicides (terbuthylazine and isoproturon) in aqueous solutions using a laboratory photoreactor. In addition, the effect of the UV wavelength on the degradation efficiency of both herbicides was investigated. Although the degradation rate was greater under UV(254)/S2O8= nm than under UV(365)/S2O8= nm, complete degradation of the herbicides (0.2 mg L−1) was achieved within 30 min under UV-366 nm using a Na2S2O8 dose of 250 mg L−1 in the absence of inorganic anions. To assess the impact of the water matrix, the individual and combined effects of sulfate (SO4=), bicarbonate (HCO3−), and chloride (Cl−) were evaluated. These can react with hydroxyl (HO•) and sulfate (SO4•−) radicals generated during AOPs to form new radicals with a lower redox potential. The results showed negligible effects of SO4=, while the combination of HCO3− and Cl− seemed to be the key to the decrease in herbicide removal efficiency found when working with complex matrices. Finally, the main intermediates detected during the photodegradation process are identified, and the likely pathways involving dealkylation, dechlorination, and hydroxylation are proposed and discussed. [ABSTRACT FROM AUTHOR]

This study evaluated a novel municipal solid waste leachate (MSWL) treatment system called the Batch flow leachate treatment system (BFLTS). This process uses a combination of coagulation/flocculation (C-F), advanced oxidation (sulfate-hydroxyl radical), and extended aeration of activated sludge (EAAS) to treat MSWL. The results indicated that the primary treatment phase using coagulation/flocculation with 0.8 g L-1 FeCl3 at pH 6 achieved 67% turbidity and 63% chemical oxygen demand (COD) reduction. The secondary treatment phase with the presence of both K2S2O8 and H2O2 peroxides was more efficient than single peroxide processes. While PS-based or H2O2-based single peroxide processes are less effective (UV-PS 65.7%, UV-H2O2 43.2%, Heat-PS 58.6%, Heat-H2O2 34.5%, and Heat-PS/H2O2 74.8%). The UV-PS/H2O2 system achieved the highest COD removal rate of 89.4%. In the third treatment phase, the efficient removal of COD and Biochemical oxygen demand (BOD) under optimal operating conditions was 87.3% and 94.7% respectively. Overall, the BFLTS treatment system has demonstrated high efficiency in removing COD, BOD, TSS, Turbidity, TKN, and Heavy metals by 99%, 98%, 97%, 89%, 86%, and 98%, respectively. This hybrid process has potential for reducing organic load in MSWL and can be used for various leachates. [ABSTRACT FROM AUTHOR]

This paper review presents a comparison between conventional leaching and advanced photochemical leaching processes and their potential for use in chalcopyrite leaching. Likewise, it presents an analysis of the differences between the advanced leaching processes, photoleaching and radical-leaching, indicating that the photochemical mechanisms (photooxidation/photoreduction and generation of radical oxygen species (ROS) and radical sulfur species (RSS)) would improve the oxidative dissolution of chalcopyrite, taking advantage of the high oxidizing power of free radicals. Initial experimental results of solar-assisted radical-leaching on chalcopyrite are presented, demonstrating that sulfate radicals (SO4−) allow copper to be leached at a rate 4.7 times higher than in the absence of radicals and sunlight. With these results, a radical-leaching process is presented for the first time, with a perspective toward the future development of a new hydrometallurgical route: solar-assisted radical-leaching. [ABSTRACT FROM AUTHOR]

Heterojunction composites with intimate interfaces can shorten the diffusion distance, which leads to a shorter path for photogenerated carriers, thereby increasing photocatalytic activity. Herein, we report the fabrication of Ti3C2-Bi2WO6 (TC-BW) heterojunctions hinged by Bi2Ti2O7 joints via an in situ hydrothermal reaction of Ti3C2 in the presence of Na2WO4 and Bi(NO3)3. The TC-BW was characterized using X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), and Raman spectroscopy. TC-BW showed superior photocatalytic activity (productivity over 15TC-WB reaches up to 5.0 mmolreacted BA·gcat.−1·h−1) in the oxidation of benzyl alcohol using light-emitting diode (LED) light, arising from the surface defects and intimate heterojunction interface between the Ti3C2 MXene and Bi2WO6 nanosheets. TC-BW heterojunctions provide an enhanced separation efficiency of photogenerated charges, which in turn yields superior photocatalytic activity. Furthermore, it is well substantiated by density functional theory (DFT) calculations. In summary, this study elucidates the preparation of heterojunction composites with intimate interfaces for highly efficient photooxidation. [ABSTRACT FROM AUTHOR]

The most effective approach to develop new photocatalysts involves solar activation and prevention of the recombination of photogenerated hole–electron pairs. To achieve these goals, in this work, a series of bismuth oxyiodide and graphene oxide (BiOI/GO) composites were synthesized by a simple ex situ method. The structural, morphological, optical, and electrical properties of the synthesized compounds were thoroughly investigated. The photooxidation reaction of NO in the gas phase under visible light irradiation was used to assess the photocatalytic activity of BiOI/GO composites. The results showed that a small amount of GO significantly improved the photocatalytic activity. The BiOI/GO-0.5% sample prepared with 0.5 wt% GO showed the highest NO conversion (∼100%), indicating excellent photocatalytic stability after four continuous irradiation cycles and a high selectivity of 97% for nitrate ion formation. The increase in photocatalytic activity was mainly related to increased light absorption, high specific surface area, and better separation of light-generated charges. The use of chemical scavengers contributed to clarifying certain aspects of the possible photooxidation process of NO, which demonstrated that superoxide radicals (˙O2−) could be the main factor responsible for the photodegradation of NO by BiOI/GO-0.5%. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides. Triphenylamine and its derivatives (TPAs) are promising for the above reaction, but suffer from the easy polymerization and difficult separation. To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates, herein, we constructed one TPA‐based metal‐organic framework (MOF), (Me2NH2)[Sr(TCBPA)]·DMA·3H2O (1), by direct self‐assembly of tris(4′‐carboxybiphenyl)amine (H3TCBPA) and photoredox inert strontium ion (Sr2+). DFT calculations revealed that the valence band maximum (VBM) and the conduction band minimum (CBM) are mainly located on TCBPA3–, successfully inhibiting the undesirable electron migration to metal nodes. Experimental results indicated that 1 displays superior performance than homogeneous H3TCBPA, which may result from the abundant π···π and C—H···π interactions between the well‐arranged TCBPA3– and the build‐in electric field between the anionic framework and the Me2NH2+. This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols. [ABSTRACT FROM AUTHOR]

Robust solid-core silica particles with submicrometer size and anthracene-containing mesoporous shell were obtained and studied as model water-dispersable photoreactors. An anthracene derivative containing a triethoxysilyl group was synthesized and co-condensed with tetraethoxysilane in various ratios to form a photoactive mesoporous shell with a thickness up to approximately 80 nm on previously prepared solid silica particles. Mesopores of as-synthesized particles, without a commonly applied removal of the micellar templates, offered a confined space for solubilization of hydrophobic molecules. Efficient excitation energy transfer from anthracene chromophores to both hydrophobic (perylene) and hydrophilic (fluoresceine) encapsulated acceptors was observed in an aqueous dispersion of the particles. Photosensitized oxidation of encapsulated perylene was shown to proceed efficiently in such systems serving as water-dispersable photoreactors. Importantly, the designed core–shell systems were found to be stable for a long time (at least 24 months) and robust enough, thanks to the presence of solid cores, to be handled by centrifugation in aqueous dispersions. All these features make them promising candidates for reusable systems for the photosensitized degradation of water pollutants, especially hydrophobic pollutants. [ABSTRACT FROM AUTHOR]

The photooxidation process of aromatic hydrocarbons isolated from crude petroleum from the Zagly field by liquid chromatography was studied using modern spectroscopic methods (UV spectroscopy, IR spectroscopy, NMR spectroscopy, and luminescence) and changes in the chemical composition, spectral parameters, and spectral luminescent properties. [ABSTRACT FROM AUTHOR]

Limiting postharvest losses of fruit from fungal attack is a major priority. While synthetic chemical fungicides are efficacious, the development of chemical resistance and consumer concerns are driving reinvestigation of natural antimicrobial agents. This review emphasizes the control of postharvest decay in citrus fruits with the use of some most common essential oils (EO), the efficacy of EOs in combating fungal infection in both in vitro and in vivo models, and the mode of action of EOs along with the potency of photochemical by-products that have also been investigated as antifungal agents. [ABSTRACT FROM AUTHOR]

This paper investigated the cross‐linking network structure of epoxy asphalt (EA) with the different ratio of composite curing agents, and further determined the effect of photooxidation aging on the tensile and interfacial adhesion behavior of EA with different cross‐linking network structures through molecular simulation. Based on the molecular models of EA and the interface model between EA and aggregate, the crosslinking network structural characteristics and tensile mechanical behavior were determined. The interfacial adhesion behavior and the mechanization were further studied. The results indicate that 20‐EA and 6‐EA have an epoxy resin cross‐linked network with uniform pore structure and phase distribution. 2‐EA showed a denser cross‐linking network and uneven aggregation phenomenon. Photooxidative aging alleviated the aggregation phenomenon. A dense cross‐linking network improved the tensile strength and the ability of tensile performance to resist photooxidation aging. The interface of EA‐quartz exhibited higher adhesion strength than EA‐calcite due to the closer distance and stronger nonbonding interactions between EA and quartz. The low anhydride content and photooxidation aging made EA approach to the aggregate interface, increasing nonbonding interaction and interfacial adhesion strength. In addition, quartz aggregates were more suitable for application in EA mixtures due to the higher interfacial adhesion strength and lower water sensitivity. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) are widely investigated as an enhancing photocatalytic component of various nanocomposites. With this aim hetero-structures containing CQDs associated to metal oxides were prepared following a hydrothermal approach in which commercial ZnO and TiO2 P-25 Degussa were used as carriers. CQDs were synthesized in advance by a low-temperature hydrothermal (LHT) treatment of useless humins wastes produced by the glucose dehydration in an acidic medium. Their photocatalytic behavior was investigated in the HMF selective oxidation. The obtained results revealed electronic interactions between CQDs and MOx (i.e., ZnO and TiO2) which have as effect the enhancement of the charge separation and diminution of the charge recombination. The influence of CQDs and buffer addition on the products distribution was evaluated. The highest photocatalytic efficiency corresponded to the TiO2/CQD180-12 heterostructure: under UV irradiation FDCA was produced in 360 min with a selectivity of 35.5% for a conversion of 93.4% of HMF. [ABSTRACT FROM AUTHOR]

Although carnosine (β-Ala-L-His) is one of physiological protectants against in vivo damages caused by reactive oxygen species (ROS), its reactivity against singlet oxygen (1O2), an ROS, is still unclear at the molecular level. Theoretically, the reaction consists of two steps: i) oxygenation of the His side chain to form an electrophilic endoperoxide and ii) nucleophilic addition to the endoperoxide. In this study, the end product of 1O2-mediated carnosine oxidation was evaluated using 2D-NMR and other analytical methods both in the presence and absence of external nucleophiles. Interestingly, as the end product without external nucleophile, a cyclic homodimer was confirmed under our particular conditions. The reaction was also replicated in pork specimens.

Amidst the ongoing LED technology-driven energy revolution, it’s crucial to re-examine how certain processes work. For this purpose, the present study dives into a new way of depositing platinum nanoparticles onto titania via photodeposition using LED light, carefully controlling the process by irradiating with different wavelengths. This novel approach has helped us to understand how the chosen wavelength may affect the properties of the synthesized materials, especially in relation to the shape of photodeposited nanoparticles. Moreover, the photodeposition method herein presented was proven to allow the nucleation and growth of Pt over amorphous titania, effectively expanding the application range of photodeposition. Importantly, the prepared samples were found to be highly effective at photocatalytically breaking down recalcitrant pharmaceutical drugs such as naproxen. This work significantly contributes to our understanding on how these materials can be used for technological applications such as photocatalysis, making it a noteworthy addition to the research field.

This study effectively addresses the challenge of nitrogen adsorption and activation in photocatalytic nitrogen fixation by introducing an oxidizing co-catalyst, NiFeB hydroxides. The NiFeB hydroxides could provide reactive active sites and significantly enhance the nitrogen oxidation activity, offering a novel pathway for co-catalysts in nitrogen fixation reactions. [ABSTRACT FROM AUTHOR]