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The document from the journal "Analyst" published by The Royal Society of Chemistry in 2024 provides a comprehensive list of research papers and articles on various topics related to chemistry. The papers cover a wide range of subjects, including electrochemical approaches for biomarker detection, detection of volatile organic compounds, catalytic kinetics, and sensor development for various applications. The journal aims to connect the global chemistry community through impactful research and publications, reinvesting profits back into the field. [Extracted from the article]

The document titled "Green Chemistry" published by the Royal Society of Chemistry in 2024 showcases cutting-edge research in the field of green chemistry for a sustainable future. The contents include editorial pieces, critical reviews, tutorial reviews, communications, and papers covering various topics such as biomass-derived molecules, clean production, and chemical recycling. The journal aims to advance scientific knowledge and promote environmentally friendly practices in the chemical sciences. [Extracted from the article]

The most common methodology for performing multiple chemical and biological reactions in parallel is to use microtitre plates with either manual or robotic dispensing of reactants and wash solutions. We envision a paradigm shift where acoustically levitated droplets serve as wells of microtitre plates and are acoustically manipulated to perform chemical and biological reactions in a non-contact fashion. This in turn requires that lines of droplets can be levitated and manipulated simultaneously so that the same operations (merge, mix, and detect) can be performed on them in parallel. However, this has not been demonstrated until this work. Because of the nature of acoustic standing waves, a single focus has more than one trap, and can allow levitation of columns of droplets at the focal point and at half a wavelength above and below that point. Using this approach, we increased the number of acoustically levitated and merged droplets to 6 compared to 2 in the state-of-the-art. We showed that droplets in a column can be moved and merged with droplets in another column simultaneously and in a controlled manner to perform repeats and/or parallelisation of chemical and biological reactions. To demonstrate our approach experimentally, we built an acoustic levitator with top and bottom surfaces made of a 16 × 16 grid of 40 kHz phased array transducers and integrated optical detection system, studied two acoustic trap generation and movement algorithms, and performed an exemplar enzyme assay. This work has made significant steps towards acoustic levitation and manipulation of large numbers of droplets to eventually significantly reduce the use of the current state-of-the-art tools, microtitre plates and robots, for performing parallelised chemical and biological reactions. [ABSTRACT FROM AUTHOR]

The spin–flip or intersystem crossing (ISC) process plays a main role in photophysics and photochemistry. ISC is the radiationless electronic transition between singlet and triplet states. ISC is responsible for phosphorescence and the chemical reaction which happens only in the electronic state with the specific spin. One specific and challenging case is the formation of accretion products in peroxy radical cross-reactions, recently demonstrated to be important in atmospheric chemistry. Here, the ISC or spin–flip occurs between triplet and singlet states of a complex of two alkoxy radicals (RO˙⋯R′O˙). The complex is initially formed in a triplet state, while the formation of the ROOR′ accretion product can only happen on the singlet surface. Therefore, the ISC rate dictates the rate of this reaction. We developed a fast algorithm to calculate ISC rate constants (kISC) between the lowest electronic states of alkoxy radical pairs. The kISC calculation requires the spin-orbital coupled interaction matrix elements (SOCME) and the excitation energies (E) of the involved electronic states. The E and SOCME are calculated quickly using the CASSCF level of theory, and a novel analytical expression, respectively. Finally, the kISC calculation is performed efficiently; within 5–60 seconds even for radical pairs with the large substituents such as CH3(CO)CH2O˙ and HOCH2CH(O˙)CH2CH3. This algorithm is applied to a large number of radical pairs with different substituents, and the kISC is calculated for 95 875 radical pair conformers using this algorithm. It provides an opportunity to generate large amounts of data (input and output values, e.g. geometries and associated ISC rates) quickly. Therefore, we believe that the fast algorithm can be useful not only for photophysical calculations, but also for Big Data creation to implement machine learning methods. [ABSTRACT FROM AUTHOR]

The effects of void defect sizes on the hotspot formation and pyrolysis mechanism of the high-energy cocrystal 4,40,5,50-tetranitro-2,20-bi-1H-imidazole/2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (TNBI/TANPDO) were quantitatively assessed by ReaxFF-lg molecular dynamics simulations. Nanosized defects can boost the enhancement of temperature in the surrounding localized regions, generating hotspots in the defective areas and triggering pyrolysis reactions. The formation of larger voids results in the generation of more intense hotspots, which in turn leads to the occurrence of more violent chemical reactions and the production of a greater number of reaction products in a shorter period of time. The decomposition rates of the components TNBI and TANPD vary with the temperature and defect size. The activation energies of defective crystals are lower, reflecting their higher sensitivity. These discoveries may offer a valuable reference for the development of new cocrystal explosives. [ABSTRACT FROM AUTHOR]

Materials performance is primarily influenced by chemical composition, making compositional analysis (CA) essential in materials science. Traditional quantitative mass spectrometry, which deconvolutes analyte spectra into reference spectra, struggles with reactive systems where spectral variations occur, such as peak shifts and new peak emergences. Additionally, obtaining reference spectra for all pure constituents is often impractical. To address these challenges, I propose nonlinear reference-free quantitative mass spectrometry (NL-RQMS). This method simultaneously determines composition, reference spectra, and nonlinear interaction effects directly from a spectral dataset of mixtures, eliminating the need for prior reference spectra. In a benchmark test on ternary reactive polymers of epoxy and amines, NL-RQMS inferred compositions with an error margin of just 3 wt%, significantly outperforming the 6 wt% error margin of linear RQMS. The inferred interaction terms clearly indicate in situ reactions between epoxy and amine moieties. This framework enables accurate compositional analysis without prior knowledge of the constituents, even in systems with interactive components, and holds significant potential for applications such as grading recycled plastics, where pristine materials, degradation compounds, and stabilizers interact complexly, causing nonlinear spectral distortions. [ABSTRACT FROM AUTHOR]

Low-valent palladium nanoparticles are efficient species promoting catalytic activity and selectivity in a number of chemical reactions. Recently, an atom-centered cuboctahedral Pd13 motif has been characterized as a ligand-protected [Pd13(Tr)6]2+ cluster featuring a 1s2 superatomic shell structure. In this report, we describe the ligand-cluster of and endohedral-cage interaction in [Pd13(Tr)6]2+, which accounts for a favorable situation in the overall cluster. In addition, the spherical aromatic properties of the cluster were evaluated to understand the behavior of the ligand-protected Pd13 cluster core. Our results indicate a sizable interaction towards carbon-based ligands in an overall spherical aromatic cluster featuring a long-range shielding cone. Thus, [Pd13(Tr)6]2+ is rationalized as the first ligand-protected palladium cluster to date exhibiting spherical aromatic properties, serving as a stable building block for molecule-based materials or as a dopant in porous carbon materials. [ABSTRACT FROM AUTHOR]

Recently, we investigated the interaction mechanism of 1H-tetrazole (1H-TZ) and nitrocellulose (NC). Next, we tried to introduce an amino group at the C and N atoms of 1H-tetrazole, so as to explore the influence of amino group modification on the pyrolysis process of NC. The focus of this study was on investigating the interaction mechanism of aminotetrazole (5-ATZ or DATZ) and NC through kinetics methods and TG-DSC-FTIR analysis. The quenching and reheating experiments revealed that the imino form of 5-ATZ or DATZ played an important role in this process. The addition of aminotetrazole (5-ATZ and DATZ) mainly affected the autocatalytic reaction at the initial stage of the pyrolysis process of NC. TG-DSC-FTIR experiments revealed that there was a chemical reaction between NO2 and decomposition products of 5-ATZ or DATZ. In this reaction, R–N＝C＝NH or N≡C–NH–R (R = H and NH2) reacted with NO2 to form N2O and CO2. [ABSTRACT FROM AUTHOR]

TiO2(rutile–anatase, R–A)/Ti3C2Tx heterophase junction (HPJ)–Schottky junction (SHJ) composites oxidized in situ by Ti3C2Tx MXenes were synthesized via a one-step hydrothermal method using Ti3C2Tx MXenes as the Ti source and water as the solvent. There was no need for the induction and oxidation of other chemical reagents in the reaction, the reaction conditions were green and non-toxic, and the experimental operation was simple. The number of TiO2(R–A) HPJs and Ti3C2Tx SHJs can be regulated by changing the reaction temperature and time. The optimized photocatalyst exhibited a large number of TiO2(R–A) HPJs attached to the surface of Ti3C2Tx. TiO2(R–A)/Ti3C2Tx-200 °C-15 h showed a photocatalytic N2 reduction efficiency of 59.35 μmol L−1 h−1. The photoelectrochemical properties of the photocatalyst indicated that TiO2(R–A) HPJs and Ti3C2Tx SHJs have synergistic effects on the separation of photogenerated charges. Under the condition of photoexcitation, the photogenerated charge generated by TiO2 was separated at the rutile/anatase interface and transferred in the form of type II heterojunctions. Owing to the effect of Ti3C2Tx SHJs, it can quickly transfer and store holes on TiO2. Thus, the photocatalyst had remarkable photogenerated charge separation efficiency; TiO2(R–A)/Ti3C2Tx-200 °C-15 h had the strongest photocatalytic performance. This provides a new way to rationally design homogeneous heterojunctions for photocatalytic applications. [ABSTRACT FROM AUTHOR]

Responsiveness to stimuli is important in daily life: natural biological activity is governed by continuous stimulus responsiveness. The design of stimuli-responsive materials is required for the development of advanced sensing systems. Although fully controlled stimuli-responsive systems have been constructed in nature, artificial systems remain a challenge. Conventional stimuli-responsive materials show direct responsiveness to an applied stimulus (Stimulus 1), with structural changes in their molecules and organized states. This feature article focuses on cascading responses as a new concept for integrating stimuli-responsive material design. In cascading responses, an original stimulus (Stimulus 1) is converted into other stimuli (Stimulus 2, 3, ..., N) through successive conversions. Stimulus N provides the eventual output response. Integration of multiple stimuli-responsive materials is required to achieve cascading responses. Although cascade, domino, and tandem chemical reactions have been reported at the molecular level, they are not used for materials with higher organized structures. In this article, we introduce functional carriers and sensors based on cascading responses as model cases. The concept of cascading responses enables the achievement of transscale responsivity and sensitivity, which are not directly induced by the original stimulus or its responsive material, for the development of advanced dynamic functional materials. [ABSTRACT FROM AUTHOR]

The 1D homochiral coordination polymer (CP-1) {[Co(dTMP)(bpe)2(H2O)3]·9H2O}n was constructed by using 2′-deoxy thymidine 5′-monophosphate disodium salt (dTMP·2Na), and auxiliary ligand bpe (1,2-bis(4-pyridyl)ethene) and characterized by single-crystal XRD, PXRD, IR, UV-visible, CD and TGA analyses. Molecular simulations revealed the selective chiral behaviour of CP-1 towards phenylalanine and histidine, as indicated by their higher binding free energies compared to other amino acids. Theoretical parameters were also compared with experimental UV-visible verdicts. Notably, the D -enantiomers of phenylalanine and histidine demonstrated strong bonding abilities and optimal configurations for probing and distinguishing them from their L -counterparts. These findings led to propositions suggesting that the dissimilarities between these D and L amino acid forms and their binding orientations with CP-1 may contribute to alterations in the CD signal. CP-1 exhibited a robust inherent circular dichroism (CD) signal in aqueous solutions, modulated by the presence of specific amino acids, namely D / L phenylalanine and D / L histidine. Leveraging the measurement of CD signal intensity, a sensor capable of detecting unmodified amino acids has been developed. Unlike previously reported approaches that relied on complex chemical reactions between initially CD-silent molecules and probed amino acids, this new method offers a more straightforward means of amplifying the CD signal. Consequently, this change facilitates a more accurate differentiation between the enantiomers of these specific amino acids compared to others. [ABSTRACT FROM AUTHOR]

Biological assays involve the lysis of biological particles, enzyme reactions, and gene amplification, and require a certain amount of time for completion. Microfluidic chips are regarded as powerful devices for biological assays and in vitro diagnostics; however, they cannot achieve a high mixing efficiency, particularly in some time-consuming biological reactions. Herein, we introduce a microfluidic reverse-Tesla (reTesla) valve structure in which the fluid is affected by vortices and branch flow convergence, resulting in flow retardation and a high degree of mixing. The reTesla is passively operated by a microfluidic capillary force without any pumping facility. Compared with our previously developed micromixers, this innovative pumpless microfluidic chip exhibited high performance, with a mixing efficiency of more than 93%. The versatility of our reTesla chip will play a pivotal role in the study of various biological and chemical reactions. [ABSTRACT FROM AUTHOR]

The control over fluid flow achievable in microfluidic devices creates opportunities for applications in many fields. In simple microchannels, flow is purely laminar when one solvent is used, and hence, achieving reliable mixing is an important design consideration. Integration of structures, such as grooves, into the channels to act as static mixers is a commonly used approach. The mixing induced by these structures can be validated by determining concentration profiles in microfluidic channels following convergence of solvent streams from separate inlets. Spatially resolved characterisation is therefore necessary and requires in-line analysis methods. Here we report a line-focused illumination approach to provide operando, spatially resolved Raman spectra across the width of channels in the analysis of single- and multi-phase liquid systems and chemical reactions. A scientific complementary metal oxide semiconductor (sCMOS) sensor is used to overcome smearing encountered during spectral readout of images with CCD sensors. Isotopically labelled probes, in otherwise identical flow streams, show that z-confocality limits the spatial resolution and certainty as to the extent of mixing that can be achieved. These limitations are overcome using fast chemical reactions between reagents entering a microchannel in separate solvent streams. We show here that the progression of a chemical reaction, for which only the product is observable, is a powerful approach to determine the extent of mixing in a microchannel. Specifically resonance enhancement of Raman scattering from a product formed allows for determination of the true efficiency of mixing over the length and width of microchannels. Raman spectral images obtained by line-focused illumination show onset of mixing by observing the product of reagents entering from the separate inlets. Mixing is initially off-centre and immediately before the apex of the first groove of the static mixer, and then evolves along the entire width of the channel after a full cycle of grooves. [ABSTRACT FROM AUTHOR]

Nitrogen oxides, including nitrous oxide (N2O), are undoubtedly classified as greenhouse gases. In this research, we conducted a theoretical investigation into the N2O capturing reactions using frustrated Lewis pair (FLP)-assisted molecules based on the intramolecular dimethylxanthene backbone G13/P (G13 = B, Al, Ga, In, and Tl) and B/G15 (G15 = N, P, As, Sb, and Bi). Density functional theory (DFT) along with frontier molecular orbital (FMO) theory, activation strain model (ASM), and energy decomposition analysis–the natural orbitals for the chemical valence (EDA–NOCV) were employed to analyze the molecular reaction barriers and chemical reactivity. From the DFT calculations, it is evident that only B/P-Rea, among the FLP-type molecules utilizing G13/P and B/G15 as Lewis base/Lewis acid sites, exhibits the ability to capture N2O in a reversible reaction. The EDA examinations suggest that the bonding nature between the G13/G15-FLP and N2O in the G13/G15-TS structure can be elucidated by the donor–acceptor interaction (singlet–singlet bonding) model, instead of the electron-sharing interaction (triplet–triplet bonding) model. FMO and NOCV analyses reveal that the reaction between N2O and the G13/G15-based FLP exhibits two distinct bonding properties: one is the forward bonding, the lone pair of G15 → the p–π* orbital of the N-terminus of N2O, which is a significantly strong FLP-to-N2O interaction. The other is the back-bonding, the empty orbital of G13 ← the filled p–π orbital of the O atom of N2O, which is a relatively weak N2O-to-FLP interaction. In basic terms, Lewis base interacting with N2O is more pivotal than the interaction of Lewis acid with N2O. The ASM analytical findings indicate that the deformation energy of the small N2O molecule significantly influences the reaction barrier of the N2O capture reaction by the intramolecular dimethylxanthene-linked G13/G15-FLPs. The theoretical evidence for N2O capture by intramolecular dimethylxanthene-linked G13/G15-based FLPs shows that the relationships between geometrical structures and energetic values are in accordance with the Hammond postulate. [ABSTRACT FROM AUTHOR]

Fungi are a diverse group of organisms that play an essential role in the biosphere. They have a unique ability to produce a vast array of secondary metabolites, including enzymes that have important applications in various industries. Fungal enzymes have been utilized in many fields, such as food processing, textile, paper, and pulp industries, to name a few. In recent years, there has been growing interest in the use of fungal enzymes in the synthesis of pharmaceutical compounds due to their scalability, high catalytic activity, relatively low cost, and ability to catalyze a wide range of chemical reactions under mild reaction conditions making the overall process greener and sustainable. Fungi produce a variety of enzymes such as oxidoreductases, transferases, and hydrolases which can be used in the synthesis of specific compounds with required chemo-, regio-, and stereoselectivity. This paper discusses the role of fungal enzymes in the synthesis of various drugs, active pharmaceutical ingredients (API), and drug intermediates and their applications in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

The present paper reviews 47 Life Cycle Assessments (LCA) applied to chemical reactions. The selection of the evaluated articles was conducted with a systematic literature review methodology. The review arises from the need to define the best methods for developing LCAs of chemical processes at industrial scale. The authors go through the stages defined in ISO 14040 and 14044, identifying both the gaps and the best techniques used in all the reviewed papers. The main difficulty observed when developing LCAs of chemical reactions is the lack of data due to confidentiality issues in chemical companies. In addition, this data is commonly only available at the laboratory scale. Laboratory data is sometimes directly upscaled without further consideration. Even though, simulation software, advanced calculations benchmarks, pinch analysis and retrosynthetic analysis are the best methods to estimate and scale up the mass and energy balances in the Life Cycle Inventory (LCI) stage. The article discusses these upscale procedures, makes a deep analysis of each single LCA stage, and assesses how chemical process information is managed, which is a novelty regarding previous reviews of chemical reaction LCA. From the Life Cycle Impact Assessment (LCIA) methodologies, they should be standardized to enable the comparability between LCAs of the same product. Both the European Commission and the Life Cycle Initiative are making progress in this regard. Eventually, the ReCiPe is the most used methodology among the reviewed papers. Finally, the article proposes different analyses to be performed in the interpretation phase: i.e., projecting the energy mix foreseen for the years 2030 and 2050 in energy-intensive processes or including other sustainability vectors (economic and social) in cross-cutting projects. [ABSTRACT FROM AUTHOR]

The +5 state is an unusual oxidation state of uranium due to its instability in the aqueous phase. As a result, gaining information about its aqueous speciation is extremely difficult. The present work is an attempt in that direction and it provides insight into the existence of a new pentavalent species in the presence of hetero-bifunctional phosphonocarboxylate (PC) chelators, other than the carbonate ion, in the aqueous medium. The aqueous chemistry of pentavalent uranium species with three environmentally relevant PCs was probed using electrochemical and DFT methods to understand the redox energy and kinetics of conversion of the U(VI)/U(V) couple, stability, structure, stoichiometry, binding modes, etc. Interestingly, pentavalent uranium complexes with PCs are quite persistent over a wide range of pH starting from acidic to alkaline conditions. The PC chelators block the cation-cation interaction (CCI) of U(V) through strong hetero-bidentate chelation and intermolecular hydrogen bonding (IMHB) interactions which stabilize the pentavalent metal ion against disproportionation. For uranyl species in the presence of PCs, acting as chelators, CV plots were obtained at varying pH values from 2 to 8. The obtained results indicate an irreversible single redox peak involving U(VI) to U(V) conversion and association of a coupled chemical reaction with the electron transfer step. ESI-MS studies were performed to understand the speciation effect on the U(VI)/U(V) redox couple with varying pH. Speciation modelling of U(V) with the PC ligands was carried out, which indicated that the U(V) is redox stable in nearly 47% of the pH region in the presence of the PCs as compared to the carboxylate-based chelators. The free energy and reduction potential of the U(V) complexes and the reduction free energy and disproportionation free energy for the U(VI)/U(V) couple were determined by DFT computations in the presence of the PCs. In situ spectroelectrochemical spectra were recorded to provide evidence for the existence of U(V) species with PCs in the aqueous medium and to acquire its absorption spectra. The present study is highly significant for understanding the coordination chemistry of pentavalent uranium species, accurate modelling of uranium, and isolation of U(V). [ABSTRACT FROM AUTHOR]

The drawbacks inherent to traditional antibacterial therapies, coupled with the escalating prevalence of multi-drug resistant (MDR) microorganisms, have prompted the imperative need for novel antibacterial strategies. Accordingly, the emerging field of piezocatalysis in semiconductors harnesses mechanical stress to drive chemical reactions by utilizing piezo-generated free charge carriers, presenting a promising technology. To the best of our knowledge, this study is the first to provide a comprehensive overview of the eradication of pathogenic S. aureus bacteria using few-layer black phosphorus (SCBP) piezo catalyst under mechanical stimuli, along with the exploration of temperature dependent dielectric properties. The synthesis of the piezo catalysts involved a one-step cost-effective sonochemical method, and its structural, morphological, elemental, optical, and overall polarization properties were thoroughly characterized and compared with the traditional method-derived product (TABP). The synthesis-introduced defects, reduced crystalline diameters, modified bandgap (1.76 eV), nanoparticle aggregation, photoluminescence quenching, along with interfacial polarization, synergistically contribute to SCBP's exceptional dielectric response (4.596 × 107 @40 Hz), which in turn enhanced the piezocatalytic activity. When subjected to soft ultrasound stimulation at 15 kHz, the piezo catalyst SCBP demonstrated significant ROS-mediated antibacterial activity, resulting in a ∼94.7% mortality rate within 40 minutes. The impact of this study extends to cost-effective energy storage devices and advances in antibacterial therapy, opening new dimensions in both fields. [ABSTRACT FROM AUTHOR]

This work evaluates sustainability indicators of the biorecovery of platinum group metals (PGM) from spent automotive catalysts (SAC) with due consideration of the environment and efficiency and forms the basis for the evaluation of environmental sustainability. Green chemistry metrics have been quantified for all the processes involved in the bioextraction of PGM from SAC under different experimental conditions. Three different cyanogenic (hydrogen cyanide forming-HCN) bacteria namely Pseudomonas fluorescens, Bacillus megaterium, and Chromobacterium violaceum were used in two-step bioleaching. These bacteria produce cyanide as a secondary metabolite that forms water-soluble complexes with PGM. Bioleaching experiments were performed at different pulp densities (i.e., 0.5% w/v, 1% w/v, 2% w/v, and 4% w/v) to examine their effects on PGM extraction and green metrics. For green metrics calculations, metal and cyanide limiting reactions were performed and four different boundary conditions were defined. Boundary conditions were defined based on the limiting reactants, desired metals, and chemical reactions. Furthermore, green metrics were calculated for an individual metal (i.e., platinum, palladium, or rhodium) and for the overall bioleaching process. This is the first study that reports an in-depth analysis of the environmental sustainability of the PGM biorecovery process by quantifying the green metrics under diverse experimental conditions. [ABSTRACT FROM AUTHOR]

Chemiluminescence (CL) refers to the light-emitting phenomenon resulting from chemical reactions. Due to its simplicity in terms of instrumentation and high sensitivity, CL plays a critical role in analytical chemistry and has developed rapidly in recent years. In this review, we discuss the efforts made by our group in the field of CL. This includes exploring new luminophores that function under neutral pH conditions, developing oxidant- and reactive oxygen species-based coreactants (e.g. artemisinin and thiourea dioxide) for luminol and lucigenin CL, utilizing nanomaterial-based CL signal amplification and employing innovative ultrasound devices for CL and their analytical applications. We discussed the CL amplification mechanisms of these systems in detail. Finally, we summarize the challenges and prospects for the future development of CL. [ABSTRACT FROM AUTHOR]

In view of the growing demand for synthetic molecules or materials by researchers from both the core sciences and interdisciplinary sectors, the field of organic synthesis needs to be strategically more powerful to produce more molecules in a shorter time. Ensuring a reduction in the use of solvents, catalysts, reagents, time, effort, and waste is essential during green chemical syntheses. Keeping those criteria in mind, the integration of chemical reactions is very much needed. Integrated organic synthesis can be considered the ideal replacement for stepwise synthesis to fulfill demand while maintaining green parameters. The electrochemical cascade process satisfies the essential criteria of greener integrated synthesis to a great extent, providing a modern strategic tool in the arsenal of synthetic chemists. The strategy is applied extensively by researchers, as evidenced by the growing number of publications, amounting to more than a hundred papers on the development of synthesis methods using electrochemical cascade reactions. A thorough understanding of the process is needed to implement the strategy further in targeted synthesis and methodology development for cutting-edge research. To grow the concept among researchers, a concise account of published articles on the topic, depicting the mechanisms, prospects, and problems of the developed methods, is highly desirable. Quenching the thirst herein, we present a concise review of electrochemical cascade processes reported in the literature since 2015. The precedent reactions developed earlier are also discussed in this context. Electrochemical multicomponent reactions involving the cascade process are also covered, expanding the scope of the review. The sections are classified based on the types of functionalization. The mechanistic details of each category of reactions are thoroughly covered to present a clear idea of the redox behavior of different reagents under electrochemical conditions. The prospects and problems associated with the methods are also discussed. [ABSTRACT FROM AUTHOR]

Single-electron reduction of a carbonyl by photoredox catalysis enables the generation of ketyl radicals, providing a benign procedure for constructing C–C bonds. However, external photocatalysts are required. In this paper, photoinduced generation of ketyl radicals and application in C–C coupling are reported, which require no use of any external photocatalyst. Irradiation of carbonyl with purple light in the presence of a tertiary amine generates highly reactive ketyl radicals, enabling a series of important reactions in synthetic chemistry, such as the reductive coupling of aldehydes, ketones, and imines, the allylation of aldehydes, the Barbier reaction, reductive arylation, and aldehyde–aniline coupling. We also present evidence to support the ketyl radicals being formed via photoinduced intermolecular electron transfer from the tertiary amine to aryl aldehydes. [ABSTRACT FROM AUTHOR]

An efficient and mild multicomponent reaction (MCR) for the preparation of vinyl sulfone is reported, which is achieved by the hydrogenation/difunctional sulfonylation of an alkynyl ester with the corresponding N-allyl bromodifluoroacetamide, DABSO and H2O under visible light conditions without the need for any metal catalysts or additives. This transformation is the first example of a conversion using H2O as the hydrogen source to interact with DABCO to form [DABCO-H]+, which ultimately reacts with the vinyl group, with the advantage of high chemoselectivity and step economy. Notably, the method produces different sulfonylation products with the same substrate regulated by the presence or absence of H2O, which greatly reduces the cost of the chemical reaction and exhibits good functional group tolerance and substrate range. In addition, gram-scale experiments proceeded smoothly, proving the practicality of the methodology. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO2)-based electronic materials and gas sensors have attracted extensive attention from academia and industry. Herein we report the preparation of two-dimensional (2D) porous SnO2 flakes by thermal oxidation of 2D SnS flakes that serve as a self-sacrificial template. An oxidation-enabled, temperature-dependent matter conversion from SnS through three-phase SnS–SnS2–SnO2 (400 °C) and two-phase SnS2–SnO2 (600 °C) to pure-phase SnO2 (≥800 °C) is disclosed by means of combined XRD, TG-DSC and XPS studies. Meanwhile, the associated chemical reactions and the mass and heat changes during this solid-state conversion process are clarified. The as-prepared 2D SnO2 flakes exhibit structural porosity with tunable pore sizes and crystallite sizes/crystallinity, resulting in superior potential for NO2 sensing. At the optimized operating temperature of 200 °C, the prototype gas sensors made of porous SnO2 flakes show competitive sensing parameters in a broad NO2 concentration range of 50 ppb–10 ppm in terms of high response, faster response/recovery speeds, and good selectivity and stability. A sensing mechanism involving the adsorption and desorption of NO2/O2 molecules and the possible surface reactions is further rationalized for the SnO2 NO2 gas sensors. [ABSTRACT FROM AUTHOR]

The formose reaction is a unique chemical reaction for the preparation of saccharides from formaldehyde, a single carbon compound. We applied zeolite materials as heterogeneous catalysts to the formose reaction. The simple addition of Linde type A zeolite containing calcium ions (Ca-LTA) to an aqueous solution of formaldehyde and glycolaldehyde produced saccharides at room temperature. A quantitative analysis performed by high-performance liquid chromatography revealed that triose, tetrose, pentose, and hexose saccharides were produced with few byproducts. Ca-LTA was recovered from the reaction mixture by filtration, and the retrieved zeolite was found to be reusable under the same conditions. The catalytic activity of Ca-LTA was higher than those of conventional calcium catalysts and other solid materials such as silica, alumina, and hydroxyapatite. Several other types of zeolites with different crystal structures and alkali/alkali-earth metal ions also showed catalytic activity for saccharide formation. Based on the analytical results obtained by infrared spectroscopy, temperature-programmed desorption profiles and NMR measurements, we propose a reaction mechanism in which C–C bond formation is promoted by the mild basicity of the oxygen atoms and acidity on the metal ions of the aluminosilicate on the zeolite surfaces with low SiO2/Al2O3 ratios. [ABSTRACT FROM AUTHOR]

Owing to their unique molecular structure and chemical reactivity, Keggin-Al13 ([AlO4Al12(OH)24(H2O)12]7+) ions demonstrate versatility in various chemical reactions. Herein, ruthenium oxide nanosheets are introduced as a promising host material for the intercalation of Keggin-Al13 ions with the aim to enhance electrochemical energy storage. Ruthenium oxide, known for its high energy density as an anode material in lithium-ion batteries, faces limitations in terms of cycling stability caused by volume expansion during lithiation. To address these limitations, an approach involving the intercalation of Keggin-Al13 ions into ruthenium oxide nanosheets is developed. The resulting Al13-treated RuO2 (AR-150), heated at 150 °C, maintained the increased interlayer spacing, compared to that of the pristine layered ruthenium oxide. The AR-150 consisting of restacked nanosheets exhibits a considerably increased pseudocapacitance contribution (83.8% at 0.8 mV s−1). In addition, the expanded lamellar structure of AR-150 effectively mitigates volume expansion during repeated lithiation, demonstrating impressive cycling stability. It maintains a reversible capacity of 379.0 mA h g−1 with a capacity retention of 75.0% after 120 cycles at 100 mA g−1. This strategy based on the intercalation chemistry utilizes the unique properties of ruthenium oxide nanosheets to advance their applications in electrochemical energy storage. [ABSTRACT FROM AUTHOR]

A chemical reaction network has been utilized as an energy and radical source to drive a polymerization of acrylonitrile monomer in an aqueous solution. The polymer is formed in a polymerization-induced self-assembly fashion. The carbonization of polyacrylonitrile leads to the formation of nanoporous carbon nitride. Ru species are observed in the porous polymer and carbon nitride. Tris (2,2′-bipyridyl) ruthenium(II) chloride hexahydrate, a catalyst used in the B–Z reaction, remains in the carbon nitride framework, enhancing the electronic and chemical properties of the composites. The electrochemical properties of the composites were studied using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The specific capacitance of the electrode was found to be 763 F g−1 at 0.3 A g−1 current densities. The excellent specific capacitance behavior is mainly attributed to micro/mesopores structure, active sites for a superior redox reaction, intimate contact between Ru/RuO2 nanoparticles with amorphous carbon nitride, rapid transportation of ions, and fast electrolyte transfer process. [ABSTRACT FROM AUTHOR]

An ultrasensitive fluorescent biosensor is reported for glucose detection based on a Fenton-like reaction triggered chemical redox-cycling signal amplification strategy. In this amplified strategy, Cu2+ oxidizes chemically o-phenylenediamine (OPD) to generate photosensitive 2,3-diaminophenazine (DAP) and Cu+/Cu0. On the one hand, the generated Cu0 catalyzes the oxidation of OPD. On the other hand, H2O2 reacts with Cu+ to produce hydroxyl radicals (˙OH) and Cu2+ through a Cu+-mediated Fenton-like reaction. The generated ˙OH and recycled Cu2+ ions take turns oxidizing OPD to produce more photoactive DAP, triggering a self-sustaining chemical redox-cycling reaction and a remarkable fluorescent enhancement. It is worth mentioning that the cascade reaction did not stop until OPD molecules were completely consumed. Benefiting from H2O2-triggered chemical redox-cycling signal amplification, the strategy was exploited for the development of an ultrasensitive fluorescent biosensor for glucose determination. Glucose content monitoring was realized with a linear range from 1 nM to 1 μM and a limit of detection of 0.3 nM. This study validates the practicability of the chemical redox-cycling signal amplification on the fluorescent bioanalysis of glucose in human serum samples. It is expected that the method offers new opportunities to develop ultrasensitive fluorescent analysis strategy. [ABSTRACT FROM AUTHOR]

Non-electronic wearables that utilize skin-interfaced microfluidic technology have revolutionized the collection and analysis of human sweat, providing valuable biochemical information and indicating body hydration status. However, existing microfluidic devices often require constant monitoring of data during sweat assessment, thereby impeding the user experience and potentially missing anomalous physiological events, such as excessive sweating. Moreover, the complex manufacturing process hampers the scalability and large-scale production of such devices. Herein, we present a self-feedback microfluidic device with a unique dehydration reminder through a cost-effective "CAD-to-3D device" approach. It incorporates two independent systems for sweat collection and thermal feedback, including serpentine microchannels, reservoirs, petal-like bursting valves and heating chambers. The device operates by sequentially collecting sweat in the channels and reservoirs, and then activating thermal stimulators in the heating chambers through breaking the valves, initiating a chemical exothermic reaction. Human trials validate that the devices effectively alert users to potential dehydration by inducing skin thermal sensations triggered by sweat sampling. The proposed device offers facile scalability and customizable fabrication, and holds promise for managing hydration strategies in real-world scenarios, benefiting individuals engaged in sporting activities or exposed to high-temperature settings. [ABSTRACT FROM AUTHOR]

Networks, consisting of vertices connected by edges, are an important mathematical concept used to describe relationships between people, roads between cities, reactions between chemicals, and many other interactions. Such a network can be created by extracting cocrystals from the Cambridge Structural Database (CSD). This network describes which compounds can form cocrystals together and can, for example, be used to predict new cocrystals using link-prediction techniques. Bipartiteness is an important property of some networks wherein the vertices can be separated into two groups such that edges only point from one group to the other. Knowing whether a network is bipartite can make studying its structure considerably easier. If a network is nearly bipartite except for a number of outlying edges, one might want to identify and remove those edges, thereby bipartising the network. The CSD cocrystal network was previously found to be close to bipartiteness. Truly bipartising it could improve the accuracy of link-prediction and give insight into the hidden structure of the network. Many algorithms exist for exactly finding the optimal bipartisation for a nearly-bipartite network, but the time it takes to complete such algorithms increases exponentially with the size of the problem. In some cases, an exact solution is unnecessary and a 'good enough' bipartisation is sufficient. We have developed an algorithm that can find a near-optimal bipartisation within reasonable time, even for very large networks, and used it to unravel the structure of the CSD cocrystal network. We obtained a bipartisation that leaves 96% of the network intact, and we were able to identify 'universal' coformers that do not conform to the bipartite nature of the network. By applying a clustering algorithm to the bipartised network, we were also able to identify anticommunities of coformers. [ABSTRACT FROM AUTHOR]

The development of artificial biomimetic systems with real-world applications relies on a profound understanding of all photophysical and photochemical processes taking place upon light absorption by a chromophoric unit. Efficient photoinduced charge separation in photosensitizers or specialized photocatalysts is the process triggering most of the chemical reactions in the production of solar fuels, and hence, its proper characterization is of utmost importance. In this work, we investigated photoinduced charge separation processes in a perfluorinated Zn-tetraphenylporphyrin photosensitizer (ZnF20). Ascorbate and 1,4-diazabicyclo[2.2.2]octane (DABCO) were used as reversible electron donors for nanosecond-resolved pump–probe experiments using both optical absorption and resonance Raman scattering as probes. Our results indicate that in spite of similar charge separation efficiencies, the DABCO-containing system exhibits a much faster kinetics of charge-separated state formation and decay. This is attributed to its inherent ability to coordinate to the metal center. Time-resolved resonance Raman measurements allow for the detection of vibrational modes specific to both the triplet excited state of ZnF20 and its reduced state, complementing transient absorption data to fully characterize the charge separation process. [ABSTRACT FROM AUTHOR]

Time-resolved serial femtosecond crystallography (TR-SFX) has emerged as a crucial tool for studying the structural dynamics of proteins. In principle, TR-SFX has the potential to be a powerful tool not only for studying proteins but also for investigating chemical reactions. However, non-protein systems generally face challenges in indexing due to sparse Bragg spots and encounter difficulties in effectively exciting target molecules. Nevertheless, successful TR-SFX studies on chemical systems have been recently reported in a few instances, boding well for the application of TR-SFX to study chemical reactions in the future. In this context, we review the static SFX and TR-SFX studies conducted on chemical systems reported to date and suggest prospects for future research directions. [ABSTRACT FROM AUTHOR]

Impressive applications of artificial intelligence in the field of chemical reaction prediction heavily depend on abundant reliable datasets. The automated extraction of reaction procedures to build structured chemical databases is of growing importance. Here, we propose a novel model named DACRER for large-scale reaction extraction, in which transfer learning and a data augmentation strategy were employed. This model was evaluated for chemical datasets and shows good performance in identifying and processing chemical texts. [ABSTRACT FROM AUTHOR]

Direct utilization of high-energy photons to drive chemical reactions presents a promising approach for the achievement of green reaction process. Herein, we developed a simple photochemical route that utilized 172 nm vacuum ultraviolet (VUV) photons as drivers for CO2 hydrogenation to CO and transformation of CH4 to H2 and C2H6. It was demonstrated that the reactions could proceed efficiently at catalyst-free and ambient conditions, and water could further promote the transformation of CH4. The reaction mechanism was proposed on the basis of control experiments. This study provides a green alternative to conventional catalytic processes for important reactions, i.e., CO2 hydrogenation or CH4 conversions triggered by high-energy photons under ambient conditions, which have promising potential in applications due to some obvious advantages. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) must use a catalyst to reduce the overpotential and accelerate the chemical reaction of the electrolysis process. Pt stands out because of its very good catalytic properties. However, the extremely low content of Pt in the Earth's crust and the high price of Pt severely limit the large-scale use of this precious metal. In order to reduce the use of Pt and enhance catalytic activity, we designed a composite structure by combining the plasmon effect characteristics of Au with Pt particles. In this work, we investigated the synthesis and growth mechanism of Au@Pt nanostars with gold nanostars (Au NS) as the core, and explored the application efficiency of Au@Pt nanostars in photocatalysis. The Au NS were produced by a "one-step synthesis", and the Au@Pt nanostars were synthesized by growing Pt on the nanostar surface. More branched Au NS formed catalysts with Pt clusters for metal ionization enhancement. The catalytic activity of the structure was increased by the presence of Pt. The synergistic advantages of the heterogeneous composite nanostructures mean the structures have high photoelectrocatalysis activity at the edge and corner positions. Benefiting from the synergistic effect and the plasmon-induced accelerated molecular transformations, the Au@Pt nanostars manifest outstanding plasmon-enhanced electrochemical activity toward the HER with a low overpotential of 23.08 mV for achieving the current density of 10 mA cm−2, which surpasses the commercial Pt/C catalyst. At the same time, the Au NS also exhibit excellent photocatalytic performance with a smaller initial overpotential (ΔV = 9.03 mV) than that in the absence of light. This shows that the study of this structure can be used for the development and application of new energy and hydrogen energy. [ABSTRACT FROM AUTHOR]

Amide and peptide bonds are found in numerous natural products and biologically active compounds, including pharmaceuticals; and the formation of these bonds constitutes one of the most important reactions in organic chemistry. Herein, we report the first method for halogen-bonding-mediated formation of amide and peptide bonds, which was accomplished by using a coupling system comprising N-iodosuccinimide, 1,4-diazabicyclo[2.2.2]octane (DABCO), and an N-heterocyclic carbene precursor. The method could be used not only for synthesizing amides from carboxylic acids and amines but also for synthesizing peptides from both standard and sterically hindered amino acids in good to excellent yields without racemization. Remarkably, the coupling system allowed us to smoothly synthesize a protected form of the pentapeptide neurotransmitter Leu-enkephalin. Moreover, we also were able to use potassium persulfate, an inexpensive readily available inorganic oxidant, along with DABCO and the carbene precursor for efficient synthesis of various dipeptides. Density functional theory calculations and experimental studies showed that the bond-formation reactions involve a 2-iodobenzimidazolium intermediate that has an activated carboxyl group that forms a reactive acyloxybenzimidazolium intermediate; this intermediate is then attacked by the amino group of an amine or amino acid to afford an amide or a peptide. [ABSTRACT FROM AUTHOR]

Electrochromic polymer film preparation methods such as spin coating, spray coating, and electrochemical polymerization, are commonly used. At present, developing new film preparation technology is an important aspect in the field of electrochromics. Herein, a continuous in situ self-growing method based on the chemical reaction occurring on the surface of an ITO glass between a metal oxide and organic acid groups was successfully applied to prepare electrochromic polymer films at a mild room temperature. SEM, FT-IR spectroscopy, XPS, and XRD characterization methods were combined to reveal the process and mechanism of film formation. The following notable electrochromic properties were observed: switching time within 6 s, contrast reached 35%, and minimal decrease of stability after 600 cycles. Finally, the patterned films were obtained through the directional growth of polymers in solution. This study provides an effective strategy for designing and preparing electrochromic films by self-growing methods in future applications. [ABSTRACT FROM AUTHOR]

Core–shell structure AuNP@UIO-66/Au nanoparticles were fabricated, consisting of a 50 nm AuNP core, a UIO-66(Zr) shell, and a 4 nm AuNP layer on the shell. AuNP@UIO-66/Au offers highly sensitive and stable SERS performance for probing 4-aminothiophenol (4-ATP) because the ∼3 nm ultrathin shell guarantees both the adsorption of UIO-66 and sustains good SERS activity. Benefiting from the abundant carboxyl group of UIO-66, the 4 nm AuNPs were in situ grown on the shell surface. Two-dimensional finite-difference time-domain simulation was employed to investigate the electromagnetic field distribution of AuNP@UIO-66/Au. In addition, this new SERS substrate offers excellent catalyst activity due to the 4 nm AuNP layer. The AuNP@UIO-66/Au can thus offer in situ label-free monitoring of the chemical reaction process by SERS. As a proof of concept, this application was evaluated by SERS monitoring of the reductive degradation process of 4-nitrophenol (4-NP), as well as the oxidative degradation process of crystal violet (CV), without adding extra catalysts. The new nanoparticle structure has great potential to simultaneously catalyze and monitor other surface chemical reactions and is thus favourable to further investigate the reaction mechanism. [ABSTRACT FROM AUTHOR]

Determining kinetic reaction parameters with great detail has been of utmost importance in the field of chemical reaction engineering. However, commonly used experimental and computational methods however are unable to provide sufficiently resolved spatiotemporal information that can aid in the process of understanding these chemical reactions. With our work, we demonstrate the use of a custom designed single-bounce ATR-integrated microfluidic reactor to obtain spatiotemporal resolution for in situ monitoring of chemical reactions. Having a single-bounce ATR accessory allows us to individually address different sensing areas, thereby providing the ability to obtain spatially and temporally resolved information. To further enhance the spatial resolution, we utilize the benefits of synchrotron IR radiation with the smallest beam spot-size ∼150 μm. An on-flow modular microreactor additionally allows us to monitor the chemical reaction in situ, where the temporal characterization can be controlled with the operational flowrate. With a unique combination of experimental measurements and numerical simulations, we characterize and analyse a model SN2 reaction. For a chemical reaction between benzyl bromide (BB) and sodium azide (SA) to produce benzyl azide (BA), we successfully show the capability of our device to determine the diffusion coefficients of BB and SA as 0.367 ± 0.115 10−9 m2 s−1 and 1.17 ± 0.723 10−9 m2 s−1, respectively. Finally, with the above characteristics of our device, we also calculate a reaction rate of k = 0.0005 (m3s−1mol−1) for the given chemical reaction. [ABSTRACT FROM AUTHOR]

The reaction of ethane with an atom or radical is the benchmark system to study the kinetics and dynamics of the polyatomic chemical reaction. The rate constants and kinetic isotope effects for C2H6 + X (X = H, Cl, OH) reactions are calculated using the quantum instanton method with the path integral Monte Carlo technique. In order to reveal the influence of the van der Waals well at the reactant complex on rate constants, both the direct and steady state rate constants are computed. Owing to the absence of the recrossing effect, the quantum instanton method overestimates the rate constants of C2H6 + H by several tens of percent as compared to the RPMD and experimental results. The direct rate constants are always larger than the steady state ones for C2H6 + Cl and C2H6 + OH, which is mainly due to the difference of free energy barrier height and quantum tunneling. The results reveal that if the reaction barrier height remains unchanged, the experimental rate constants will switch from the direct ones to the steady state ones upon increasing the depth of the van der Waals well. In addition, the direct kinetic isotope effects are consistent with experiment, while they become smaller than the steady state kinetic isotope effects as the van der Waals well is deepened. [ABSTRACT FROM AUTHOR]

The oxidative crosslinking of thiols via a disulfide (SS) bond is a fundamental chemical reaction in the industrial production of protein- and peptide-based formulations. In this study, we developed a new heterogeneous catalyst/mediator, polystyrene-resin-immobilized cyclic telluride [(S)-tetrahydrotellurophen-3-amine] (RSTe), which significantly promotes the oxidation of thiols to disulfides (SS formation). Under solid–liquid biphasic reaction conditions, RSTe exhibited glutathione-peroxidase-like activity in the oxidative SS formation of 15 organic solvent- and water-soluble thiols using a peroxide (H2O2 or tBuOOH) as an oxidant. Notably, all reactions were completed within 90 min, and RSTe and the peroxide could be removed by filtration and concentration, respectively, thereby affording the target disulfides in sufficient yield and purity without further purification. This reaction system could also be utilized for SS formation in cysteine-containing polypeptide chains, suggesting the potential application of RSTe in oxidative folding, which is an essential process in the production of bioactive proteins. [ABSTRACT FROM AUTHOR]

Flow NMR is a powerful tool to monitor chemical reactions under realistic conditions. Here, we describe ultrafast (UF) 2D NMR schemes that make it possible to acquire broadband homonuclear 2D NMR spectra in 90 seconds or less for a continuously flowing sample. An interleaved acquisition strategy is used to address the spectral width limitation of UF 2D NMR. We show how, for a flowing sample, the use of a transverse axis for spatial encoding makes it possible to achieve the very high scan-to-scan stability required for interleaved acquisition. We also describe an optimised solvent suppression strategy that is effective for interleaved acquisition in continuous flow. These developments open the way to online monitoring with flow 2D NMR at high time resolution, as we illustrate with the monitoring of an organocatalysed condensation reaction. [ABSTRACT FROM AUTHOR]

Zn-based materials (ZnO/ZnS) have multiple uses, such as photo-anode, passivation layer, and sensitizer in quantum dot sensitized solar cells (QDSSCs), sensors, UV light-emitting-diodes, and photocatalytic applications. Several synthesis conditions/parameters are accountable for obtaining desired Zn-based products via wet-chemical synthesis. These parameters collectively influence chemistry within the reaction matrix, following the nucleation-growth process, and are finally reflected in the properties of the synthesized product. Importantly, for pure ZnS and ZnO nanoparticle/quantum dot formation, the role of zinc precursors and capping agents is critical. Furthermore, the solubility of precursor salt and metal-ion/complex ratio is the fundamental criteria for the availability of zinc cations in the solution, which will eventually combine with the sulfur anions. In addition, the capping agent's selection and effect are indispensable as they help stabilize the nanomaterials sterically/electrostatically along with the surface passivation of nanoparticle/quantum dots by mediating the growth. In this perspective, we have studied the role of zinc precursors and capping agents in the chemical reaction mechanism, which formulate ZnS and ZnO, and their effect on the optical, structural, and morphological properties of prepared nanoparticles or quantum dots. The final findings show the limitation of using zinc acetate precursor (formation of mixed-phase). Pure ZnS (using zinc sulfate) and pure ZnO (using zinc chloride) will help us for our potential future work to improve the efficiency of QDSSC by choosing optimized chemicals and synthesis conditions, where ZnO can be used in photoanode; ZnS can act as a passivation layer, photoanode, and sensitizers, solving band offset problem at the interface of electron transport material and as exciton absorber. Eventually, the final compositions, synthesis conditions, and materials establish a base and will help researchers with applications such as solar cells, sensors, LEDs, and bioimaging, based on material properties. [ABSTRACT FROM AUTHOR]

We proved that ice crystallized from water molecules within as-synthesized graphene oxide (GO) can be used as a spacer among individual GO sheets to form an expanded GO aerogel with a three-dimensional porous network structure. This designed specific structure can be retained during further processes to form graphene paper. Due to the fact that the as-fabricated graphene paper contains carbon defects and space in its infrastructure, this creates more electroactive surfaces and interfaces to significantly increase the Faradaic reaction efficiency. With the introduction of redox-electrolyte K3Fe(CN)6 into a KOH electrolyte, we can obtain a 95-fold increase in the specific capacitance compared with the value obtained in the traditional KOH electrolyte. The ice-crystallization formed graphene paper electrode showed high electroactivity because the specific porous structure can favor the fast transfer of electrolyte ions, such as Fe(CN)63- ions. The presented results prove that ice-crystallization formed GO can serve as a chemically tunable platform for electrochemical energy storage applications. [ABSTRACT FROM AUTHOR]

Alumina materials, as one of the cornerstones of the modern chemical industry, possess physical and chemical properties that include excellent mechanical strength and structure stability, which also make them highly suitable as catalyst supports. Alumina-supported Pd-based catalysts with the advantages of exceptional catalytic performance, flexible regulated surface metal/acid sites, and good regeneration ability have been widely used in many traditional chemical industry fields and have also shown great application prospects in emerging fields. This review aims to provide an overview of the recent advances in alumina and its supported Pd-based catalysts. Specifically, the synthesis strategies, morphology transformation mechanisms, and structural properties of alumina with various morphologies are comprehensively summarized and discussed in-depth. Then, the preparation approaches of Pd/Al2O3 catalysts (impregnation, precipitation, and other emerging methods), as well as the metal–support interactions (MSIs), are revisited. Moreover, Some promising applications have been chosen as representative reactions in fine chemicals, environmental purification, and sustainable development fields to highlight the universal functionality of the alumina-supported Pd-based catalysts. The role of the Pd species, alumina support, promoters, and metal–support interactions in the enhancement of catalytic performance are also discussed. Finally, some challenges and upcoming opportunities in the academic and industrial application of the alumina and its supported Pd-based are presented and put forward. [ABSTRACT FROM AUTHOR]

A bottom-up synthesis of titanate nanoflakes with euhedral shapes was accomplished by an aqueous solution process. Crystal growth by bottom-up synthesis utilizing chemical reactions has a possibility to produce crystals with euhedral shapes. Close packing of nanoflakes with a euhedral shape and a uniform size in the in-plane direction would enable the fabrication of large polycrystalline nanosheet thin films. However, the bottom-up synthesis of metalate nanosheets that we have been studying is prone to yielding small and indistinct nanoflakes. In this study, it is revealed that both the removal of an amorphous phase and relatively large lateral sizes are required for the formation of euhedral shapes. The addition of organic ligands to reaction sols is useful for such a synthesis of titanate nanoflakes. The addition of lactic acid and triethanolamine yielded transparent aqueous sols containing titanium species by inhibiting the formation of insoluble amorphous phases. Moreover, the combination of triethanolamine as an organic ligand and tetrabutylammonium hydroxide as a base exhibited a high sol-state stabilization effect because of their interaction with the surface of formed titanate nanoflakes. Furthermore, further crystal growth of preformed titanate nanoflakes in a fresh reaction sol including both triethanolamine and tetrabutylammonium hydroxide provided many titanate nanoflakes with rhombic shapes, which are euhedral shapes. [ABSTRACT FROM AUTHOR]

Neobavaisoflavone (Neo) is a prenylated isoflavone-type compound found in several plant species, including Psoralea corylifolia. It has been reported to exhibit a wide range of health benefits, notably anti-inflammatory and anti-cancer properties. In the present study, the antioxidant and antinitrosant activities as well as the xanthine oxidase (XO) inhibitory capacity of Neo have been systematically investigated using computational approaches. The antioxidant and antinitrosant potencies were evaluated by modeling the chemical reactions of Neo with hydroperoxyl radical (HOO˙) and nitrogen dioxide (NO2) as model radicals under physiological conditions. The XO inhibitory capacity was evaluated using a blind docking consensus approach and molecular dynamic simulations. The findings indicate that Neo is a very good scavenger of both HOO˙ and NO2 in water through the SPLET (sequential proton loss electron transfer) mechanism, while it is a moderate scavenger in lipid media via the FHT (formal hydrogen transfer) mechanism. The kinetic study revealed that the 14-OH group is the most favorable site for free radical attack, despite the thermodynamic preference of the 17-CH group. The overall reaction rate coefficient of Neo in water was found to be higher than that of Trolox and BHT for scavenging HOO˙ and comparable to that of syringic acid for scavenging NO2. Consequently, Neo is a promising radical scavenger in physiological polar media. On the other hand, Neo was expected to be a good inhibitor of XO, inhibiting the same pathway as quercetin. [ABSTRACT FROM AUTHOR]

We report a novel hydrogel for pre-concentration, fluorescent labelling, and light-triggered release of proteins for detection of low abundance biomarkers. The hydrogel was a co-polymer of acrylamide/bisacrylamide and methacrylamide attached to fluorescein isothiocyanate via a light cleavable bond and a poly(ethylene glycol) spacer arm of molecular weight of 3400 g mol−1. Unlike previous work, proteins were captured by an irreversible chemical reaction rather than by non-covalent affinity binding or physical entrapment. Because the protein-reactive group was attached to fluorescein, which in turn was coupled to the hydrogel by a photocleavable bond, on release the protein was labelled with fluorescein. Our hydrogel offered a pre-concentration factor of up to 236 for a model protein, streptavidin. Each protein molecule was labelled with 85 fluorescein molecules, and 50% of the proteins in the hydrogel were released after UV exposure for ∼100 s. The proteins released from the hydrogel were captured in biotinylated microtitre plates and detected by fluorescence, allowing measurement of at least 0.01 ppm (or ∼166 pM) of protein in sample solutions. The reported hydrogel is promising for detection of low abundance proteins while being less laborious than enzyme-linked immunosorbent assay and less affected by changes in environmental conditions than label-free biosensors. [ABSTRACT FROM AUTHOR]

SARS-CoV-2, the pathogen of COVID-19, has introduced massive confirmed cases and millions of deaths worldwide, which poses a serious public health threat. For the early diagnosis of COVID-19, we have constructed an electrochemical biosensor-combined magnetic separation system with copper nanoflower-triggered cascade signal amplification strategy. In the proposed system, magnetic beads were utilized to fabricate the recognition element for capturing the conserved sequence of SARS-CoV-2. As the copper ions source, oligonucleotides modified copper nanoflowers with special layered structure provide numerous catalysts for click chemistry reaction. When target sequence RdRP_SARSr-P2 appears, copper nanoflowers will be bound with magnetic beads, thus prompting the Cu(I)-catalyzed azide–alkyne cycloaddition reaction through the connection of the SARS-CoV-2 conserved sequence. Then, a large number of signal molecules FMMA can be grafted onto the modified electrode surface by electrochemically mediated atom-transfer radical polymerization to amplify the signal for the quantitative analysis of SARS-CoV-2. Under optimal conditions, a linear range from 0.1 to 103 nM with a detection limit of 33.83 pM is obtained. It provides a powerful tool for the diagnosis of COVID-19, which further benefits the early monitoring of other explosive infectious diseases effectively, thus guaranteeing public health safety. [ABSTRACT FROM AUTHOR]

According to the requirements of sustainable green development, the efficient green synthesis of fluorine chemical products is an inevitable trend. In this work, we used ionic liquids as an effective catalyst in an important fluorochemical reaction – hexafluoropropylene dimerization for the first time. The effects of ionic liquids with different spatial positions, substituents and nucleophilic anions on the catalytic performance of hexafluoropropylene dimerization were systematically studied. The results showed that the strong nucleophilic trisubstituted thiocyanate imidazole ionic liquid [C6mmim][SCN] had the highest activity under the optimum reaction conditions, the turnover frequency (TOF) was 108.36 h−1 and the selectivity was 97.96%. Compared with the traditional metal salt catalyst system, the catalytic activity of ionic liquids was double. In addition, based on the XPS analysis results and density functional theory (DFT), a possible reaction mechanism was proposed. The effective catalytic activity of ionic liquids was mainly attributed to the strong nucleophilicity of anions and the weak interaction between cations and anions. This work will successfully provide a green synthesis route for hexafluoropropylene dimerization and further promote the efficiency and greening of fluorine chemical reactions. [ABSTRACT FROM AUTHOR]