Ester Functional Groups Research Articles

Unraveling the mechanisms of organic contamination on gold pulse compression gratings: From cluster formation to stratified adsorption

Organic contamination on gold pulse compression gratings significantly hampers the performance of high-power laser systems under intense laser irradiation. Investigating the adsorption mechanisms of organic contaminants on microstructured gratings is essential for addressing contamination issues and mitigating damage. In this article, we determine the microstructured surface aggregation characteristics of volatile dibutyl phthalate (DBP), the stratified distribution pattern of amorphous DBP clusters, and the distribution points of molecules within microstructures using experiments and cross-scale simulations (molecular dynamics and quantum chemistry). Our analysis of the Reduced Density Gradient (RDG) and charge transfer reveals that adsorption between organic molecules and the gold substrate primarily stems from non-covalent van der Waals and electrostatic forces induced by ester functional groups. Based on this theoretical study, we propose the "molecule-substrate" and "bimolecular" adsorption modes of DBP to elucidate the adsorption mechanisms. Investigating organic compounds' distribution and adsorption mechanisms on optical component surfaces is fundamental to high-power laser-induced damage studies. These insights facilitate the efficient, non-destructive removal of organic contaminants from gold gratings, enhancing the energy output threshold of inertial confinement fusion devices.

Chemical composition and properties of Ski wax: A comprehensive analysis of fluorinated, non-fluorinated, and bio-based waxes

This study analyzes the chemical composition and thermal properties of various ski wax materials, including fluorinated, non-fluorinated petroleum-based, and bio-based waxes. Advanced characterization techniques (FTIR, EDS, and DSC) were used to investigate the chemical functionality, elemental composition, and thermal behavior of these waxes. Fluorinated powder waxes were found to be composed almost entirely of fluorocarbons, while solid fluorinated waxes are primarily hydrocarbons with minimal fluorine content. Bio-based waxes exhibit unique ester and carboxylic acid functional groups. Different brands, models, and suggested temperature uses of waxes within the same physical and chemical type show similar chemical compositions. While petroleum-based compared to bio-based waxes show a significant difference in chemical structure. EDS analysis identified silicon, magnesium, and aluminum in certain waxes, possibly indicating the use of additives. DSC results showed similar thermal behavior at sub-freezing temperatures. This research lays the groundwork for understanding ski wax material science and opens up new avenues for future investigation and innovation in the ski and ski wax industry.

A Thermogravimetric Analysis of Biomass Conversion to Biochar: Experimental and Kinetic Modeling

This study investigates the pyrolytic decomposition of apple and potato peel waste using thermogravimetric analysis (TGA). In addition, using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), the influence of pyrolysis temperature on the physicochemical characteristics and structural properties of biochar was studied. The degradation of biomass samples was studied between 25 °C and 800 °C. Although apple and potato peel decomposition present similar thermogravimetric profiles, there are some differences that can be evidenced from DTG curves. Potato peel showed one degradation peak in the range 205–375 °C with 50% weight loss; meanwhile, the apple peel exhibited two stages: one with a maximum at around 220 °C and about 38% weight loss caused by degradation of simple carbohydrates and a second peak between 280 °C and 380 °C with a maximum at 330 °C, having a weight loss of approximately 24%, attributed to cellulose degradation. To gain more insight into the phenomena involved in biomass conversion, the kinetics of the reaction were analyzed using thermal data collected in non-isothermal conditions with a constant heating rate of 5, 10, 20, or 30 °C /min. The kinetic analysis for each decomposed biomass (apple and potato) was carried out based on single-step and multi-step type techniques by combining the Arrhenius form of the decomposition rate constant with the mass action law. The multi-step approaches provided further insight into the degradation mechanisms for the whole range of the decomposition temperatures. The effect of temperature on biomass waste structure showed that the surface morphologies and surface functional groups of both samples are influenced by the pyrolysis temperature. A higher pyrolysis temperature of 800 °C results in the disappearance of the bands characteristic of the hydroxyl, aliphatic, ether, and ester functional groups, characteristic of a porous surface with increased adsorption capacity. Therefore, this study concludes that biomass waste samples (apple and potato) can produce high yields of biochar and are a potential ecological basis for a sustainable approach. The preliminary adsorption tests show a reasonably good nitrate removal capacity for our biochar samples.

Development of Technologies for Processing Polypropylene Foil Waste and Their Use in the Production of Finished Products.

This work aims to assess the possibility of using packaging industry waste to modify polypropylene products (PPs). The products were made in the form of extruded foil and injected samples. The products were produced using regranulate made of polypropylene cast foil. Maleic anhydride-modified polypropylene (MAPP) and polyolefin elastomer (POE) with a glycidyl ester functional group were used to modify the polypropylene. The samples were produced based on 50% foil waste reground and 50% pure PP. The rheological properties of the blends were assessed using the melt mass flow rate (MFR) technique; thermal properties using the differential scanning calorimetry method (DSC). The products manufactured using the injection molding method were subjected to an analysis of mechanical properties, such as tensile strength and impact strength. Also, in the case of film samples, tensile strength was assessed. Color-change assessments with CIE L*a*b* were carried out for all materials. Injection-molded products based on recycled metallized cast foil showed favorable mechanical properties such as tensile strength (1 MAPP = 26.7 MPa; 2 MAPP = 27.1 MPa), which was higher than the original material (cPP = 20.7 MPa). Also, for the films produced from regrind, the tensile strength was at a level similar (1 MAPP = 24.6 MPa; 2 MAPP/POE = 25.1 MPa) to the films extruded from virgin materials (cPP = 24.9 MPa). The introduction of a POE additive to the blends resulted in increased impact strength (1 MAPP/POE = 31 kJ/mol; 2MAPP/POE = 18 kJ/mol; 3 MAPP/POE = 11 kJ/mol) in relation to unmodified samples (cPP = 7 kJ/mol). The introduction of a POE additive to the tested mixtures improved the impact strength of the injected products by almost 4 times for sample 1 MAPP/POE and 2.5 times for sample 2 MAPP/POE in comparison to virgin cPP. These studies confirmed that foil waste can be successfully used to modify polypropylene products shaped both in the injection and extrusion processes.

LuCl3/B(C6F5)3 Cocatalyzed Reductive Deoxygenation of Ketones, Aldehydes, Alcohols, and Ethers to Alkanes with Pinacolborane.

This report describes the LuCl3/B(C6F5)3 cocatalyzed reductive deoxygenation of 67 ketones, aldehydes, alcohols, and ethers to alkanes under mild conditions. The strategy tolerates reactive amino, hydroxyl, nitro, halogen, vinyl, and ester functional groups, and the results demonstrate rare chemoselective deoxygenation of α,β-unsaturated ketones. Isotopic labeling experiments, control experiments, and derivatization studies are used to elucidate the reaction mechanism.

Integrated Sensing Platform Validated for the Efficient and On-Site Screening of Amine-Containing Illicit Drugs.

Efficient and reliable technologies for the on-site detection of illicit drugs are important in drug-facilitated crime investigations. However, the development of such technologies is challenging. Based on the synthetic optimization, introducing a boron ester functional group to the two furanic indicators endows the stimulus-responsive properties synergistically. The ring-opening reaction of the indicators in the presence of amine-containing illicit drugs generated well-known donor-acceptor Stenhouse adducts, accompanied by strong color changes. A small-size and lightweight laminated sensor was integrated based on the outstanding ratiometric variations of the two active furanic indicators. A prototype platform was fabricated equipped with a circuit control, a mini pump, and a signal processing system. A user-friendly detection and efficient screening of amine-containing illicit drugs, including phenethylamines, amphetamines, cathinones, and tryptamines in the liquid states were conducted. The ratiometric response of the sensor was linear in the concentration range of 2.1-10.6 μg·mL-1 for methamphetamine·HCl and methcathinone ·HCl. The detection limits for the two illicit drugs at the sublevel (ng·mL-1) were found to be 8.4 and 9.0 ng·mL-1, respectively. Double-blind field tests and different illicit drugs were evaluated with good screening capability. Successful trials showed the potential applications of the developed prototype platform for efficient and on-site analytical determination.

Effect of Hydrophilic Function Groups on the Properties of Short‐Chain Fluorocarbon Surfactants

AbstractShort‐chain fluorocarbon surfactants grafted with alcohol, carboxyl and ester functional groups were prepared by quaternization with short‐chain perfluorobutyl sulfonyl fluoride as raw material. The structures of surfactants were characterized by infrared spectroscopy, nuclear magnetic resonance and mass spectrum. The surface activity, micelle formation process and micelle aggregation behavior of surfactants were studied by surface tensiometer, dynamic light scattering particle size analyzer and fluorescent spectrophotometer. The results show that the critical micelle concentration (CMC) of surfactants are 19.3, 7.8 and 2.2 mmol L−1, and the surface tension of the surfactant solution at CMC are as low as 17.3, 19.2 and 18.5 mN m−1, respectively. The standard Gibbs free energy ( ) values of surfactants are negative, and the absolute values of are less than the standard Gibbs adsorption energy ( ), illustrating that the adsorption process is easier than the micelle formation process. In addition, the size distribution of the aggregates is much larger than that of spherical micelles, showing that the surfactant self‐assembled into larger aggregates in solution. The grafted hydrophilic functional groups show a significant effect on the performance of surfactants. The ester‐based surfactant has a lower CMC value, which has the advantages of small dosage, good economy and excellent application value.

Effect of mixed metal oxide‐based catalysts for the removal of hydrophobic phthalates from water

AbstractContaminants of emerging concern (CECs) such as phthalic acid esters (PAEs) are ubiquitous, toxic and persistent in aquatic environments. Current study explored mixed metal oxide catalysts derived from magnesium aluminium (MAH), magnesium aluminium ruthenium (MAR‐H), magnesium aluminium nickel (MANH) hydroxides and copper aluminium hydroxides of ammonium (CAM‐Am) and sodium molybdate (CAM‐Na) to remove dibutyl phthalate (DBP) and di‐2‐ethyl hexyl phthalate (DEHP) from water. Powder X‐ray diffraction (XRD) studies of the catalysts before and after the treatment showed that their structures were stable and robust. During Fourier Transform Infrared (FTIR) studies, vibrational bands or peaks of ester and alkane functional groups of DBP and DEHP were observed at all the catalysts after treatment. Thermogravimetric analysis (TGA) confirmed phthalate adsorption at the five catalysts. Hydrolysis of DBP and DEHP was observed during treatment using CAM‐Am and CAM‐Na that was analysed and quantified using total organic carbon (TOC), high performance liquid chromatography (HPLC) and high‐resolution mass spectrometry (HRMS). From TOC analyses, optimal conditions of 500 mg L−1 catalyst dosage and 30 h treatment time were deduced for catalytic hydrolysis of DBP and DEHP. Present study illustrated that the catalysts MAH and MANH can adsorb PAEs while CAM‐Na can adsorb and hydrolyse them.

Comparative Investigation of Lubricant Properties of Pongamia and Castor Oil Bio Lubricant Blended with (SAE20W40) Mineral Oil

The present work deals with the comparative evaluation of physicochemical, rheological FTIR and tribological properties between pongamia and castor oil blended with SAE20W40 by varying their proportions ranging from 10-30% (by volume) as bio-lubricant. Among all the blends, the flash point and pour point of castor blend S4 were found to be 281°C and -19°C which can be comparable to SAE20W40. The viscosity at 40°C and 100°C and viscosity index of castor blends were approximately 100 mm2/s, 14 mm2/s and 145 respectively. FTIR analysis also confirms the presence of vital carbonyl ester functional group in castor blends with oxidation onset temperature of 243°C. The tribological studies that were carried out using pin on disc tribometer as per ASTM G99-95a standards also showed that blend S4 had coefficient of friction 0.056 at higher load which was comparable to SAE20W40. Although all the blends had low oxidation stability temperature, yet castor blend S4 showed equivalent properties with commercial lubricant SAE20W40. This confirmed its suitability as a bio-lubricant base stock, supported by its physiochemical, rheological, FTIR, tribological properties.

Structure-Activity Relationship Studies in Benzothiadiazoles as Novel Vaccine Adjuvants.

Extracellular vesicles (EVs) can transfer antigens and immunomodulatory molecules, and such EVs released by antigen-presenting cells equipped with immunostimulatory functions have been utilized for vaccine formulations. A prior high-throughput screening campaign led to the identification of compound 634 (1), which enhanced EV release and increased intracellular Ca2+ influx. Here, we performed systematic structure-activity relationship (SAR) studies to investigate the scaffold for its potency as a vaccine adjuvant. Synthesized compounds were analyzed in vitro for CD63 reporter activity (a marker for EV biogenesis) in human THP-1 cells, induction of Ca2+ influx, IL-12 production, and cell viability in murine bone-marrow-derived dendritic cells. The SAR studies indicated that the ester functional group was requisite, and the sulfur atom of the benzothiadiazole ring replaced with a higher selenium atom (9f) or a bioisosteric ethenyl group (9h) retained potency. Proof-of-concept vaccination studies validated the potency of the selected compounds as novel vaccine adjuvants.

Comparative study of PLA composites reinforced with graphene nanoplatelets, graphene oxides, and carbon nanotubes: Mechanical and degradation evaluation

The effect of different reinforcements such as graphene nanoplatelets (GNPs), Graphene oxides (GO), and carbon nanotubes (CNTs), into PLA was studied in this research work. Distinct suspensions of GO, GNPs, and CNTs have been utilized to fabricate the PLA/GO, PLA/GNPs, and PLA/CNTs composites through solution casting. All composites were compared based on mechanical and degradation results. FTIR results confirm the ester and alcohol functional groups in PLA and composites. EDX results indicate the weight % of carbon, oxygen, and chlorine elements. The tensile results showed that adding GO and GNPs significantly enhanced the tensile strength compared to pure PLA, while CNTs slightly increased strength. The ductility of all the composites was decreased by adding carbon-based reinforcements. The addition of GO and GNPs slightly decreases the degradation rate of PLA, while the addition of CNTs accelerates the degradation of PLA. Among the PLA/GO, PLA/CNTs, and PLA/GNP, PLA/GO samples exhibit comparatively better degradation and tensile properties.

Bait type affects the diversity assessment of cetoniid beetles in the Brazilian Cerrado

AbstractCetoniidae (Coleoptera), known as flower and fruit beetles, form a diverse group, feed on nectar, pollen, plant exudates, and are highly attracted to fermented fruits. To evaluate their diversity in natural and agricultural areas, traps baited with fermented fruits are used. The objective of this study was to compare the effectiveness of various types of fruit used as bait, with or without the addition of sugarcane juice to accelerate fruit fermentation, on the assessment of Cetoniidae diversity in the Brazilian Cerrado. The study was conducted in two conservation units in Brasília (DF, Brazil). Two experiments were conducted, the first aiming to select the most attractive fruits (banana, pineapple, mango, grape, or cagaita), and the second to verify whether there is interference of sugarcane juice in the fruit fermentation process and, consequently, in the attractiveness to Cetoniidae. The chemical profiles of the types of bait were evaluated by identifying and quantifying the main volatile organic compounds released by the fruit traps. Insect collections were conducted weekly using fruit‐baited traps for 1 month, without interruption. We found that the diversity estimate of Cetoniidae was higher for banana‐based baits relative to grape and cagaita fruit, but not relative to pineapple, mango, and sugarcane juice. Additionally, no increase in attractiveness was observed with the addition of sugarcane juice to banana, pineapple, and mango bait. Most compounds in the fruit extracts belong to alcohol, ester, and terpene functional groups. Our results suggest that banana, pineapple, mango, and sugarcane juice, used alone, may be used for Cetoniidae diversity studies, and that banana bait seems to be the most suitable for Cetoniidae collection in the Cerrado, because it enables the collection of a high diversity of species and also of species considered rare.

Bioprospecting for moderately halophilic eubacteria for potential biotechnological applications from Sambhar Lake, Rajasthan, India

Sambhar Lake an athalassohaline habitat located at 27°58′N 75°55′E, Rajasthan, India is a major source of salt production in the country. From surface lake water, soil, and shore sediments, fifty-nine moderate halophiles were isolated which were subsequently grouped according to shape, colony characteristics, and staining into twenty-two isolates. Fourier transform infrared spectroscopy profiling identifiedthese isolates as eubacterial with characteristic C=O stretching of ester functional groups. Observations further indicatedsimilarity within some Halomonasisolates indicating potential phylogenetic lineages. The FASTA sequences obtained after sequencing with universal bacterial primers were processed for phylogenetic analysis. Predominantly Gram-positive genera like Alkalibacillus, Amphibacillus, Marinococcus, Piscibacillus, Planococcus, Salinicoccus, Staphylococcusand Virgibacilluswith only two Gram-negative strains of Halomonaswere identified. The genus Amphibacilluswas recognizedfor the first time in the study of Sambhar Lake. Despite being moderately halophilic, several isolates exhibited high salt tolerance with growth in 25% salt. All isolates were mesophilic with growth observed between 18-42°C which matches the temperature profile of the region. Analysis of hydrolytic potential identified eighteen isolates as protease producers, thirteen as lipase producers, and ten as cellulase-producing strains. Further evaluation showed the dominance of C10:0, C12:0, C13:0, C14:0, C15:0, C16:0, C17:0, C18:0, C18:1 FAMEs, among which presence of C16:0 and C18:1 fatty acid indicated probable antimicrobial potentials of these strains.

Effect of Dicarboxylic Acid Chain Length on the Tribological Properties of Aqueous Polyether Esters

ABSTRACTThis article presents the preparation of environmentally friendly water‐soluble lubricant additives. Adipic acid (AA), sebacic acid (SA) and dodecanedioic acid (DA) were individually subjected to esterification reactions with polyethylene glycol 1500 (PEG1500) to prepare a class of water‐soluble polyether esters (AAPEE1500, SAPEE1500 and DAPEE1500) (referred to as XAPEE1500s) that exhibit excellent water solubility and do not contain environmentally harmful elements. First, the molecular structure characterisation and functional group analysis of these additives will be conducted using an infrared spectrometer and a nuclear magnetic resonance spectrometer. Subsequently, the frictional properties of the additives in the base liquid (deionised water) will be investigated using an SRV‐V tribometer, Falex pin‐on‐disc tribometer and screw torque tester. The surface morphology of wear scars will be characterised and analysed using scanning electron microscopy (SEM) and a non‐contact 3D profilometer. Finally, the lubrication mechanism of the DAPEE1500 additive will be analysed using X‐ray photoelectron spectroscopy (XPS). The results indicate that the optimal lubrication performance is achieved when the added mass fraction of DAPEE1500 is at 3%. Compared with 0.5 wt% DAPEE1500, the average friction coefficient of 3 wt% DAPEE1500 decreased from 0.285 to 0.122, and the wear volume decreased from 25.52 × 10−5 μm3 to 10.96 × 10−5 μm3. The lubrication mechanism of polyether ester is the result of the combined action of its polar ester functional groups and long carboxylic acid chains in the structure. These polar functional groups can form a relatively firm adsorption film on the friction surface, while the long carboxylic acid chains act as a brush‐like isolating layer, thus demonstrating superior anti‐wear and anti‐friction performance.

Optimization of Transesterification Process for Biodiesel Production using Jatropha Oil

Biodiesel has attracted considerable attention during the past decade as a renewable, biodegradable, and nontoxic fuel alternative to fossil fuels. Biodiesel can be obtained from vegetable oils (both edible and non-edible) and from animal fat. Biodiesel was produced through esterification of Jatropha oil using an alkaline catalyst. The process was carried out at the reaction temperatures of 63 and 55°C, with a 6:1-11:1 oil to methanol molar ratio, and the concentration was verified. In this research work, a yield of 91.78% and 80% was achieved. Furthermore, the flash point of 129.1°C obtained indicates that the biodiesel is within the specification of ASTM. Jatropha curcas Linnaeus, a multipurpose plant, contains a high amount of oil in its seeds which can be converted to biodiesel. J. curcas is probably the most highly promoted oilseed crop at present in the world. The availability and sustainability of sufficient supplies of less expensive feedstock in the form of vegetable oils, particularly J. curcas, and efficient processing technology to biodiesel will be crucial determinants of delivering competitive biodiesel. Oil contents, physicochemical properties, and fatty acid composition of J. curcas are reported in research. The fuel properties of Jatropha biodiesel are comparable to those of fossil diesel and conform to the ASTM standard. The objective of this review is to give an update on the J. curcas L. plant, the production of biodiesel from the seed oil, and research attempts to improve the technology of converting vegetable oil to biodiesel and the fuel properties of Jatropha biodiesel. There is also a need to carry out a lifecycle assessment and assess the environmental impacts of introducing large-scale plantations. Furthermore, there is still a dearth of research about the influence of various cultivation-related factors and their interactions and influence on seed yield. The formation of biodiesel was confirmed by FT-IR and GC-MS analysis, and the conversion of ester functional group into methyl esters was verified, and characteristic properties of biodiesel were successfully determined. Keywords: Biodiesel, Jatropha oil, transesterification, catalyst, optimization, renewable energy and sustainability

Diagnostic Positron Emission Tomography Imaging with Zirconium-89 Desferrioxamine B Squaramide: From Bench to Bedside.

Molecular imaging with antibodies radiolabeled with positron-emitting radionuclides combines the affinity and selectivity of antibodies with the sensitivity of Positron Emission Tomography (PET). PET imaging allows the visualization and quantification of the biodistribution of the injected radiolabeled antibody, which can be used to characterize specific biological interactions in individual patients. This characterization can provide information about the engagement of the antibody with a molecular target such as receptors present in elevated levels in tumors as well as providing insight into the distribution and clearance of the antibody. Potential applications of clinical PET with radiolabeled antibodies include identifying patients for targeted therapies, characterization of heterogeneous disease, and monitoring treatment response.Antibodies often take several days to clear from the blood pool and localize in tumors, so PET imaging with radiolabeled antibodies requires the use of a radionuclide with a similar radioactive half-life. Zirconium-89 is a positron-emitting radionuclide that has a radioactive half-life of 78 h and relatively low positron emission energy that is well suited to radiolabeling antibodies. It is essential that the zirconium-89 radionuclide be attached to the antibody through chemistry that provides an agent that is stable in vivo with respect to the dissociation of the radionuclide without compromising the biological activity of the antibody.This Account focuses on our research using a simple derivative of the bacterial siderophore desferrioxamine (DFO) with a squaramide ester functional group, DFO-squaramide (DFOSq), to link the chelator to antibodies. In our work, we produce conjugates with an average ∼4 chelators per antibody, and this does not compromise the binding of the antibody to the target. The resulting antibody conjugates of DFOSq are stable and can be easily radiolabeled with zirconium-89 in high radiochemical yields and purity. Automated methods for the radiolabeling of DFOSq-antibody conjugates have been developed to support multicenter clinical trials. Evaluation of several DFOSq conjugates with antibodies and low molecular weight targeting agents in tumor mouse models gave PET images with high tumor uptake and low background. The promising preclinical results supported the translation of this chemistry to human clinical trials using two different radiolabeled antibodies. The potential clinical impact of these ongoing clinical trials is discussed.The use of DFOSq to radiolabel relatively low molecular weight targeting molecules, peptides, and peptide mimetics is also presented. Low molecular weight molecules typically clear the blood pool and accumulate in target tissue more rapidly than antibodies, so they are usually radiolabeled with positron-emitting radionuclides with shorter radioactive half-lives such as fluorine-18 (t1/2 ∼ 110 min) or gallium-68 (t1/2 ∼ 68 min). Radiolabeling peptides and peptide mimetics with zirconium-89, with its longer radioactive half-life (t1/2 = 78 h), could facilitate the centralized manufacture and distribution of radiolabeled tracers. In addition, the ability to image patients at later time points with zirconium-89 based agents (e.g. 4-24 h after injection) may also allow the delineation of small or low-uptake disease sites as the delayed imaging results in increased clearance of the tracer from nontarget tissue and lower background signal.

Metabolite identification of salvianolic acid A in rat using post collision-induced dissociation energy-resolved mass spectrometry

BackgroundAs one of the most famous natural products, salvianolic acid A (SAA) is undergoing clinical trials for the treatments of angina pectoris and coronary heart disorders. However, the in vivo metabolites of SAA have only been tentatively identified, leading to a barrier for precise therapeutical drug monitoring.MethodsUltra-high performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry (UPLC–Qtof-MS/MS) was firstly employed to acquire high-resolution MS1 and MS2 spectra for all metabolites. Through paying special attention onto the features of ester bond dissociation, metabolism sites were restricted at certain regions. To further determine the metabolism site, such as the monomethylated products (M23, M25, and M26), post collision-induced dissociation energy-resolved mass spectrometry (post-CID ER-MS) was proposed through programming progressive exciting energies to the second collision chamber of hybrid triple quadrupole-linear ion trap mass spectrometry (Qtrap-MS) device.ResultsAfter SAA oral administration, 29 metabolites (M1–M29), including five, thirteen, and sixteen ones in rat plasma, urine, and feces, respectively, were detected in rats. The metabolism route was initially determined by applying well-defined mass fragmentation pathways to those HR-m/z values of precursor and fragment ions. Metabolism site was limited to SAF- or DSS-unit based on the fragmentation patterns of ester functional group. Through matching the dissociation trajectories of concerned 1st-generation fragment ions with expected decomposition product anions using post-CID ER-MS strategy, M23 and M25 were unequivocally assigned as 3'-methyl-SAA and 3''-methyl-SAA, and M26 was identified as 2-methyl-SAA or 3-methyl-SAA. Hydrolysis, methylation, glucuronidation, sulfation, and oxidation were the primary metabolism channels being responsible for the metabolites' generation.ConclusionTogether, the metabolism regions and sites of SAA metabolites were sequentially identified based on the ester bond dissociation features and post-CID ER-MS strategy. Importantly, the present study provided a promising way to elevate the structural identification confidence of natural products and metabolites.Graphical abstract

Recognition site modifiable tetrapodal receptor and the effect of alkane chains on monosaccharide recognition

Traditional molecular recognition studies usually focus on obtaining strong host–guest interactions, which may lead to the neglect of important tendencies caused by other factors. Moreover, most receptors typically fix their recognition sites in the backbone of the receptor, resulting in great synthetic challenges for varying recognition functional groups. In this contribution, we developed a new class of tetrapodal receptors. The terminal functional groups of the receptor can be varied by simple chemistry. Through 1H NMR titration experiments and binding constant analysis, the influence of the size and shape of alkane chains on monosaccharide recognition was investigated. The introduction of ester functional groups allows the access of moderate binding affinity to unveil otherwise masked contribution of dispersion force in saccharide recognition. These results also imply that stronger forces may not always be beneficial for host–guest binding while functional groups with a particular shape may favor the discrimination of isomers through steric hindrance effect. Thereby, these tetrapodal receptors and their analogues provide an ideal platform for comparing the effects of various functional groups on molecular recognition.

Dissolution Mechanism for Dendrite‐Free Aqueous Zinc‐Ions Batteries

AbstractThe commercialization of aqueous Zn‐ion batteries (AZIBs) for power‐grid energy storage systems is hindered by the safety concerns arising from the Zn dendrite growth. The primary approach in addressing this issue is to induce planar depositions. However, modulating the Zn dissolution process which directly reshapes surface morphology and reserves growth sites has long been overlooked. Herein, by utilizing ester compounds as an illustration, it is revealed that engineering the dissolution energy barrier is a pivotal factor in promoting homogeneous Zn dissolution. Ester adsorbents effectively redistribute charge densities at the electrode–electrolyte interface due to the presence of zincophilic ester functional group and conductive π‐conjugation structure. This effect eventually facilitates Zn dissolution across the surface, transforming the potholed and defective dissolution morphology into a smooth and consistent form. Thus, enhanced cycling stability can be achieved in both half‐cells and full‐cells, offering an extensive lifespan of thousands of hours for the dissolution and deposition cycles. This work provides a principle for the selection of Zn dissolution improvers to suppress Zn metal dendrite growth by regulating Zn dissolution behavior.

Sequential Infiltration Synthesis of Silicon Dioxide in Polymers with Ester Groups-Insight from In Situ Infrared Spectroscopy.

New strategies to synthesize nanometer-scale silicon dioxide (SiO2) patterns have drawn much attention in applications such as microelectronic and optoelectronic devices, membranes, and sensors, as we are approaching device dimensions shrinking below 10 nm. In this regard, sequential infiltration synthesis (SIS), a two-step gas-phase molecular assembly process that enables localized inorganic material growth in the targeted reactive domains of polymers, is an attractive process. In this work, we performed in situ Fourier transform infrared spectroscopy (FTIR) measurements during SiO2 SIS to investigate the reaction mechanism of trimethylaluminum (TMA) and tri(tert-pentoxy) silanol (TPS) precursors with polymers having ester functional groups (poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), polycaprolactone (PCL), and poly(t-butyl methacrylate) (PBMA)), for the purpose of growing patterned nanomaterials. The FTIR results show that for PMMA and PEMA, a lower percentage of functional groups participated in the reactions and formed weak and unstable complexes. In contrast, almost all functional groups in PCL and PBMA participated in the reactions and showed stable and irreversible interactions with TMA. We discovered that the amount of SiO2 formed is not directly correlated with the number of interacting functional groups. These insights into the SiO2 SIS mechanism will enable nanopatterning of SiO2 for low-dimensional applications.