Ester Functional Groups Research Articles

Additive Manufacturing Polyurethane Acrylate via Stereolithography for 3D Structure Polymer Electrolyte Application.

Additive manufacturing (AM), also known as 3D-printing technology, is currently integrated in many fields as it possesses an attractive fabrication process. In this work, we deployed the 3D-print stereolithography (SLA) method to print polyurethane acrylate (PUA)-based gel polymer electrolyte (GPE). The printed PUA GPE was then characterized through several techniques, such as Fourier transform infrared (FTIR), electrochemical impedance spectroscopy (EIS), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM). The printed GPE exhibited high ionic conductivity of 1.24 × 10−3 S cm−1 at low-lithium-salt content (10 wt.%) in ambient temperature and favorable thermal stability to about 300 °C. The FTIR results show that addition of LiClO4 to the polymer matrix caused a shift in carbonyl, ester and amide functional groups. In addition, FTIR deconvolution peaks of LiClO4 show 10 wt.% has the highest amount of free ions, in line with the highest conductivity achieved. Finally, the PUA GPE was printed into 3D complex structure to show SLA flexibility in designing an electrolyte, which could be a potential application in advanced battery fabrication.

New Synthetic Route to Water-Soluble Prism[5]arene Hosts and Their Molecular Recognition Properties.

We report that the direct macrocyclization of naphthalene monomers bearing ethyl ester functional groups delivers prism[5]arene derivatives, which can be deprotected to yield water-soluble prism[5]arenes (H1 and H3). 1 H NMR spectroscopy showed that dicationic guests bind with the hydrophobic cores buried inside the anisotropic magnetically shielding cavity. Isothermal titration calorimetry measurements showed that H1 and H3 are high-affinity hosts in PBS-buffered water with Ka values exceeding 109 M-1 for a select guest. The complexation events are driven by the non-classical hydrophobic effect, CH⋅⋅⋅π interactions, and electrostatic interactions. Host H1 displays somewhat higher affinity toward a common guest than pillar[6]arene bearing carboxylic acid functional groups but is significantly less potent than pillar[6]arene bearing sulfate groups. H1 and H3 should be considered alongside other high affinity hosts for a variety of chemical and biological applications.

A lethal case of 4F-MDMB-BINACA poisoning

Quantify 4F-MDMB-BINACA and its metabolites, 4F-MDMB-BINACA-butanoic acid and 4F-MDMB-BINACA-4-OH, in postmortem blood samples of a synthetic cannabinoid (SC) poisoning case. 1 mL of bloods was mixed with 3 mL of 0.1 M phosphate buffer (pH 6.0). JWH-018-D9 and JWH-018-N-5-OH-D5 (100 μL, 500 pg/mL) was spiked as internal standards. The samples were vortexed vigorously and sonicated for 15 min. After centrifugation at 3500 rpm for 5 min, the supernatant was loaded onto the Bond Elut Certify cartridge (Agilent Technologies) preconditioned with methanol and 0.1 M phosphate buffer (pH 6.0), sequentially. The cartridge was washed with 3 mL of DW and 2 mL of 0.2 M acetic acid sequentially, and eluted with 3 mL of chloroform-acetone (50:50) and 3 mL of ethyl acetate-ammonia (98:2). The eluates were collected in a glass tube, and evaporated to dryness under nitrogen gas at 45 °C. The residues were reconstituted with 150 μL of methanol and filtered (0.22 μm, PVDF). Finally, 5 μL aliquot was injected into LC-MS/MS. The chromatographic separation was performed in a Zorbax Eclipse Plus C18 (RRHD 2.1 × 100 mm, 1.8 μm, Agilent Technologies). The mobile phase was a gradient prepared from 2 mM ammonium formate/0.2% formic acid in water (A) and in methanol (B). The flow rate was 300 μL/min, and the total run time was 12 min. The multiple reaction monitoring (MRM) data were achieved with electrospray ionization in positive ion mode. Two MRM transitions were selected for each analyte. A 29 year-old male Kazakh worker was found unconscious in his bath room by his brother. There was a small amount of herbal powder near the victim. He died soon after sent to a hospital. No noticeable damage except for chest fractures caused by CPR was found during autopsy. 4F-MDMB-BINACA was detected in the herbal powder. 4F-MDMB-BINACA and its metabolites were found in his bloods. The concentrations of 4F-MDMB-BINACA, 4F-MDMB-BINACA-butanoic acid, and 4F-MDMB-BINACA-4-OH in his femoral blood were 0.80 μg/L, 18.36 μg/L, and 0.36 μg/L, and those in his heart blood were 2.05 μg/L, 52.58 μg/L, and 0.46 μg/L, respectively. 4F-MDMB-BINACA was not found in his gastric content. The concentrations of 4F-MDMB-BINACA and its metabolites in the victim's bloods were relatively high according to a previous study (4F-MDMB-BINACA 0.10-2.90 μg/L, 4F-MDMB-BINACA-butanoic acid 0.12–9.05 μg/L, 4F-MDMB-BINACA-4-OH 0.21 μg/L in 6 postmortem bloods, Yeter O, JOTCSA, 2020, 7(3), 827-32). The especially high 4F-MDMB-BINACA-butanoic acid concentration might result from degradation due to the poor stability of a methyl ester functional group of 4F-MDMB-BINACA in blood (Krotulski A, Journal of Analytical Toxicology, 2021, 45, 60-8), which implies that the initial blood concentration of 4F-MDMB-BINACA could have been much higher. 4F-MDMB-BINACA and its metabolites were quantified in the bloods of a fatal SC poisoning case victim for the first time in South Korea. The concentrations of 4F-MDMB-BINACA and 4F-MDMB-BINACA-butanoic acid should be both considered for the interpretation of 4F-MDMB-BINACA fatal toxicity.

Polyhydroxyalkanoate recovery from newly screened Bacillus sp. LPPI-18 using various methods of extraction from Loktak Lake sediment sample

BackgroundNowadays, the conventional plastic wastes are very challenging to environments and its production cost also creates an economic crisis due to petrochemical-based plastic. In order to solve this problem, the current studies were aimed at screening and characterizing these polyhydroxyalkanoate (PHA)-producing isolates and evaluating the suitability of some carbon source for newly screened PHA-producing isolates. Material and methodsSome carbon sources such as D-fructose, glucose, molasses, D-ribose and sucrose were evaluated for PHA production. Data were analyzed using SPSS version 20. The 16SrRNA gene sequence of these isolates was performed. These newly isolated taxa were related to Bacillus species. It was designated as Bacillus sp. LPPI-18 and affiliated Bacillus cereus ATCC 14577T (AE01687) (99.10%). Paenibacillus sp. 172 (AF273740.1) was used as an outgroup. ResultsBacillus sp. LPPI-18 is a gram-positive, rod-shaped, endospore former, and citrate test positive. This isolate showed positive for amylase, catalase, pectinase, and protease test. They produced intracellular PHA granules when this isolate was stained with Sudan Black B (SBB) and Nile blue A (NBA) preliminary and specific staining dyes, respectively. Both temperature and pH used to affect polyhydroxyalkanoates (PHA) productivity. Bacteria are able to reserve PHA in the form of granules during stress conditions. This isolate produces only when supplied with carbon sources. More PHA contents (PCs) were obtained from glucose, molasses, and D-fructose. In this regard, the maximum mean value of PC was obtained from glucose (40.55±0.7%) and the minimum was obtained from D-ribose (12.4±1.4%). Great variations (P≤0.05) of PCs were observed among glucose and sucrose, molasses and sucrose, and D-fructose and sucrose carbon sources for PHA productivity (PP) of cell dry weight (CDW) g/L. After extraction, PHA film was produced for this typical isolate using glucose as a sole carbon source. Fourier transform infrared spectrum was performed for this isolate and showed the feature of polyester at 1719.64 to 1721.16 wavelengths for these extracted samples. The peak of fingerprinting (band of carboxylic acid group) at this wavelength is a characteristic feature of polyhydroxybutyrate (PHB) and corresponds to the ester functional group (C=O). ConclusionIn this study, newly identified Bacillus sp. LPPI-18 is found to be producing biodegradable polymers that are used to replace highly pollutant conventional plastic polymers. This isolate is also used to employ certain cost-effective carbon sources for the production of PHA polymers. Graphical Abstract▪

Investigation of the photoisomerization property of donor-acceptor Stenhouse adducts on ester-modified glass

The isomerization process of donor-acceptor Stenhouse adducts (DASAs) is closely related to its surrounded physicochemical environment, this work focuses on the promotion of ester-modified glass fiber to the isomerization process of DASAs compared with the untreated glass fiber. The ester-modified glass fiber is prepared through a two-stage method, the coating procedure is stepwise monitored through the scanning electron microscope(SEM) and the energy dispersive spectrometer(EDS). The ester functional groups on the outmost layer of glass fiber act as a catalyst, lowering the energy level of the intermediate state of DASAs and therefore promoting isomerization performance of DASAs where the time to reach cyclic dominant states shorten from 116 s to 82 s and the efficiency of cyclic-to-linear increased almost 6 folds.

Investigating properties and intermolecular interactions of sludge bio-oil modified asphalt

Bio-asphalt is a binder composed of bio-oil and petroleum asphalt under certain conditions. In this study, sludge bio-oil (wt 10%) was added into matrix asphalt to prepare sludge bio-asphalt for the first time. The effects of sludge bio-oil on asphalt performance and the essence of interaction between components were investigated using performance test, molecular dynamics (MD) simulation, and density functional theory (DFT). Chemical analysis showed that the ester compound containing ester functional group (COOH) was the main component of sludge bio-oil. Physical and rheological tests were performed to examine whether the properties of sludge bio-asphalt could be improved. The results found that sludge bio-oil can be used to soften the hard asphalt. Furthermore, the existence of bio-oil reduced complex modulus G* of master curves and stiffness, also increased Jnr and m-value, which means that sludge bio-oil had a positive effect on the low-temperature thermal cracking resistance performance while sacrificing the high-temperature rutting resistance performance to some extent. Fourier infrared spectroscopy (FTIR) and fluorescence spectrum (FM) analysis indicated that sludge bio-oil evenly dispersed in the asphalt, and the bio-asphalt structure resembled that of the conventional binder. The results of MD simulation further showed that O atom of COOH and H atom in the asphalt molecules formed hydrogen bond (OH⋯O, OH⋯C) interaction. This changed originally existed conformational packing of agglomeration and further prevented the agglomeration of component molecules. In addition, the analysis of cohesive energy density (CED) and solubility parameters (SP) revealed that sludge bio-oil significantly influenced the compatibility of asphaltene-asphaltene, resin-resin, and asphaltene-resin components. These, in turn, may explain some of the observed improvements in rheological properties.

Investigation of pyrene vs Anthracene-based oxime esters: Role of the excited states on their polymerization initiating abilities

In this work, two series of oxime esters (OXE) based on Pyrene and Anthracene chromophores were synthesized and tested as Type Ⅰ photoinitiators for the Free Radical Photopolymerization (FRP) under visible irradiation at 405 nm using light-emitting diodes (LED) as the irradiation source. Interestingly, the two series of oxime esters only differ by the nature of the substituents connected to the oxime ester functional group. As a result of this modification, the reactivity of the different compounds only depends on the rate of decomposition from their excited states as well as the reactivity of the generated radicals. Remarkably, the 18 Pyrene-based OXEs (Py-OXE) and 17 Anthracene-based OXEs (An-OXE) were never synthesized prior to this work. Pyrene and Anthracene chromophores were selected as benchmark structures reacting mainly from their first excited singlet (S1) and triplet (T1) states, respectively. This will allow to shed some light on the excited states responsible of the cleavage of OXEs. Therefore, originality of this study relies in the difference of the initiation ability between these two families. In fact, the results showed that Py-OXEs (0.5 % w) are the most efficient systems compared to An-OXEs, so that higher final conversions and rates of polymerization could be obtained with Py-OXEs. Influence of the OXE structure (both chromophores and leaving groups) is discussed on the basis of different characterization techniques such as: UV–visible absorption spectroscopy, photolysis experiments, real-time Fourier transform infrared spectroscopy (RT-FTIR), stationary fluorescence and time-resolved fluorescence. Therefore, a global mechanism is finally provided based on the complementary characterization data. Oxime ester derivatives were also tested under air for the generation of 3D patterns (by Direct Laser Write DLW) using a diode laser at 405 nm.

A theoretical study of potential energy surface and some chemo-physical descriptors of Aspirin, Coupling the rotation of the ester and carboxyl groups

In this paper, the effect of the simultaneous rotation of the carboxyl (COOH) and ester (R'COOR) functional groups on the potential energy surface (PES) of aspirin is studied. Relative energies are reported at the HF/aug-cc-pVDZ and B3LYP/aug-cc-pVDZ levels of theory. To understand the activity and selected electrophilic attack sites, electric dipole moments, atomic charges, HOMO-LUMO energy gap, natural bond orbital (NBO), and molecular electrostatic potential (MEP) analyses, as well as the main structural parameters of the identified conformers, are studied at the same theoretical level. Finally, an NBO analysis is used to demonstrate charge transfer between lone pairs and localized bonds.

Isolation, Characterization, and Breast Cancer Cytotoxic Activity of Gyrophoric Acid from the Lichen Umbilicaria muhlenbergii

Lichens produce a large variety of secondary metabolites with diverse bioactivities, chemical structures, and physicochemical properties. For this reason, there is a growing interest in the use of lichen-derived bioactive molecules for drug discovery and development. Here, we report on the isolation, identification, and cytotoxic evaluation of gyrophoric acid (GA) from the lichen Umbilicaria muhlenbergii, a largely unexplored and scantly described lichen species. A simple purification protocol was developed for the fractionation of lichen crude extracts with silica gel column chromatography using solvents with changing polarity. GA was identified in one of the fractions with Fourier transform infrared spectroscopy (FTIR), ion trap mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR). The FTIR spectra demonstrated the presence of aromatic and ester functional groups C=C, C-H, and C=O bonds, with the most remarkable signals recorded at 1400 cm−1 for the aromatic region, at 1400 cm−1 for the CH3 groups, and at 1650 cm−1 for the carbonyl groups in GA. The MS spectra showed a molecular ion [M-1]− at (m/z) 467 with a molecular weight of 468.4 and the molecular formula C24H20O10. that correspond to GA. The 1H-NMR and 13C-NMR spectra verified the chemical shifts that are typical for GA. GA reduced the cell viability of breast cancer cells from the MCF-7 cell line by 98%, which is indicative of the strong cytotoxic properties of GA and its significant potential to serve as a potent anticancer drug.

MALDI-TOF Mass Spectrometric Detection of SARS-CoV-2 Using Cellulose Sulfate Ester Enrichment and Hot Acid Treatment.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the ongoing coronavirus disease 2019 (COVID-19) pandemic. Here we report a novel strategy for the rapid detection of SARS-CoV-2 based on an enrichment approach exploiting the affinity between the virus and cellulose sulfate ester functional groups, hot acid hydrolysis, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Virus samples were enriched using cellulose sulfate ester microcolumns. Virus peptides were prepared using the hot acid aspartate-selective hydrolysis and characterized by MALDI-TOF MS. Collected spectra were processed with a peptide fingerprint algorithm, and searching parameters were optimized for the detection of SARS-CoV-2. These peptides provide high sequence coverage for nucleocapsid (N protein) and allow confident identification of SARS-CoV-2. Peptide markers contributing to the detection were rigorously identified using bottom-up proteomics. The approach demonstrated in this study holds the potential for developing a rapid assay for COVID-19 diagnosis and detecting virus variants from a variety of sources, such as sewage and nasal swabs.

A green approach in the biological base oil process

Abstract This article presents a green approach in the biological base oil synthesis from catfish fat by-product using the hydrodynamic cavitation technique. The effects of parameters on the yield of reaction were investigated. The application of the cavitation technique has improved the process efficiency significantly. The catfish polyester oil yield reached at high value (94.6%) at the inlet pressure of 60 psi, the molar ratio of acetic anhydride/epoxy of 1.25/1, 85°C, and only 10 min, and also under these reaction conditions, magnetic stirring technique could only give the limited yield of catfish oil polyester of 12%. The results of Fourier transform infrared resonance, 1H nuclear magnetic resonance (NMR), and 13C NMR analyses and characteristic properties of materials and products have demonstrated that the chemical structure of polyester catfish oil was triglyceride chains containing saturated alkyl R chains and branched by methyl ester functional groups and the polyester catfish oil has met the quality standards of SN150 and SN500 mineral base oils. It could be said that the biological base oil process from catfish fat by-products under the assistance of cavitation techniques would develop sustainably.

Structure-activity relationships reveal a 2-furoyloxychalcone as a potent cytotoxic and apoptosis inducer for human U-937 and HL-60 leukaemia cells

Synthetic flavonoids with new substitution patterns have attracted attention as potential anticancer drugs. Here, twelve chalcones were synthesized and their antiproliferative activities against five human tumour cells were evaluated. This series of chalcone derivatives was characterized by the presence of an additional aromatic or heterocyclic ring linked by an ether, in the case of a benzyl radical, or an ester or amide functional group in the case of a furoyl radical. In addition, the influence on cytotoxicity by the presence of one or three methoxy groups or a 2,4-dimethoxy-3-methyl system on the B ring of the chalcone scaffold was also explored. The results revealed that the most cytotoxic chalcones contain a furoyl substituent linked by an ester or an amide through the 2′-hydroxy or the 2′-amino group of the A ring of the chalcone skeleton, with IC50 values between 0.2 ± 0.1 μM and 1.3 ± 0.1 μM against human leukaemia cells. The synthetic chalcone 2′-furoyloxy-4-methoxychalcone (FMC) was, at least, ten-fold more potent than the antineoplastic agent etoposide against U-937 cells and displayed less cytotoxicity against human peripheral blood mononuclear cells. Treatment of U-937 and HL-60 cells with FMC induced cell cycle arrest at the G2-M phase, an increase in the percentage of sub-G1 and annexin-V positive cells, the release of mitochondrial cytochrome c, activation of caspase and poly(ADP-ribose) polymerase cleavage. In addition, it inhibited tubulin polymerization in vitro in a concentration dependent manner. Cell death triggered by this chalcone was decreased by the pan-caspase inhibitor z-VAD-fmk and was dependent of the generation of reactive oxygen species. We conclude that this furoyloxychalcone may be useful in the development of a potential anti-leukaemia strategy.

Regioselective difunctionalization of alkene: A simple access to haloether, haloesters and halohydrins

We have demonstrated a protocol to generalize regioselective 1,2-difunctionalization of alkenes, which is a simple and efficient method for the preparation of haloethers, haloesters and halohydrins using alcohol as nucleophiles with inexpensive and commercially available N-halosuccinimide (NXS) as the halogenating reagent with low catalyst loading under mild reaction condition. The methodology is also applicable for the easy access of various alkenes such as terminal, internal, heterocyclic ones and cyclic endoene with the striking features of high product yields (up to 99%). Moreover, a bioactive molecule was employed as substrate to test this reaction, the corresponding products were successfully prepared with moderate to good yield without losing their ester functional group. The given protocol has the following advantages such as a direct difunctionalization of alkenes, operational simplicity, good functional group tolerance and a wide substrate scope.

Decomposition of Irganox 1010 in plastic bonded explosives

AbstractDegradation pathways of Irganox 1010 in aged plastic bonded explosive (PBX) 9501 were investigated using ultrahigh performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC‐QTOF). Using a targeted approach, a total of 44 Irganox 1010 decomposition products were discovered. These decomposition products were formed through hydrolysis, scission, and/or oxidation of Irganox 1010. The hydrolytic decomposition of Irganox is a straightforward process resulting in the cleavage of the ester group(s) while oxidation and scission are more complicated and can happen at multiple locations on the Irganox 1010 molecule. Moreover, due to the symmetric nature of Irganox 1010, multiple decomposition reactions can occur. Indeed some decomposition products exhibited hydrolysis, oxidation, and scission. In order to probe any trends in the aged PBX 9501 samples, principal component analysis (PCA) was implemented. The greatest chemical differences between the aged PBX samples was hydrolysis of the ester functional groups on Irganox 1010. Despite the negative connotations of hydrolysis, the Irganox 1010 decomposition products are still able to function as a radical scavenger in PBX 9501 as intended.

Effects of Long-Term Storage on the Quality of Palm Oil Biodiesel and Canola Oil Biodiesel

Effective storage of biodiesel has proven to be a challenge, which the Indonesian government has invested billions of Indonesian rupiahs (IDR) in to overcome. It is thus important to investigate how different storage methods can affect the quality of biodiesel. The purpose of this study was to determine how storage at room temperature in the dark affects the quality of palm oil biodiesel (POB) and canola oil biodiesel (COB). POB and COB were stored in closed containers at 22 °C in the dark for 12 months. The results showed that POB was more significantly damaged than COB. This study found increases of density (POB by 51.52 kg/m3 and COB by 17.52 kg/m3), kinematic viscosity (POB by 0.67 mm2/s and COB by 0.32 mm2/s), acid value (POB by 0.27 mg-KOH/g and COB by 0.25 mg-KOH/g), total glycerol (POB by 0.58%-mass and COB by 0.60%-mass), and peroxide value (POB by 48 meq-O2/kg and COB by 54 meq-O2/kg), whereas there were decreases in fatty acid methyl esters (POB by 7.11%-mass and COB by 9.36%-mass). Gas chromatography-mass spectrometry results for POB and COB showed decreases in 9-octadecenoic acid methyl ester and 9,12-octadecadienoic acid (Z,Z)-methyl ester, and increases in 9-octadecenoic acid and 9,12-octadecadienoic acid (Z,Z). Fourier transform infrared spectroscopy (FTIR) results revealed the presence of methyl ester functional groups. The storage of biodiesel in a closed container at 22 °C in the dark can minimize biodiesel oxidation, as evidenced by the findings of this study, namely, the insignificant formation of ketone and aldehyde groups in the biodiesel oxidation process during storage, based on the results of FTIR.

Invivo detection of triacylglycerols through Nile red staining and quantification of fatty acids in hyper lipid producer Nannochloropsis sp. cultured under adequate nitrogen and deficient nitrogen condition

The green alga Nannochloropsis sp. was grown in a medium containing adequate (1.5 g/L sodium nitrate) and absence of nitrogen (0 g/L sodium nitrate) for improving the triacylglycerols (TAGs) level and fatty acid content for sustainable biodiesel production. Initially, the biomass yield of Nannochloropsis sp. was determined from the day of inoculation till 18th day and it is observed that on 14th day higher biomass yield at about 1.4 g/L was obtained. The Nile red stained cells from nitrogen sufficient and nitrogen starvation conditions observed under confocal microscopy revealed that neutral lipids exist as oil bodies were higher in nitrogen starved condition and also, the TAG content was 13.31% dryweight in nitrogen starved cells than nitrogen amended (10.46%) Nannochloropsis cells. The extracted lipids subjected for FTIR study showed the presence of TAG functional group in both condition and similarly, the FAME obtained from both condition showed the vibration at 1743 cm−1 for ester functional group. The fatty acid composition of nitrogen deplete condition revealed oleic acid methyl ester (28.7%), Behenic acid methyl ester (14.2%), cis-11, 14, 17-Eicosatrienoic acid methyl ester (8.8%) as predominant fatty acids than nitrogen supplied condition. The TAG content and FAME composition reported in this study makes Nannochloropsis sp. as plausible candidate for pilot scale biodiesel production.

A Molecular Study of Aspirin and Tenofovir Using Gold/Dextran Nanocomposites and Surface-Enhanced Raman Spectroscopy.

In this study, we show how surface enhanced Raman spectroscopy (SERS) can be used to monitor the molecular behaviour of aspirin and tenofovir as a means of screening medication for quality control purposes. Gold-coated slides combined with gold/dextran nanoaggregates were used to provide signal enhancement of the drugs using SERS. Aspirin (10% w/v) and tenofovir (20% v/v) were analysed in the presence of the nanomaterials to determine trends in molecular response to changes in gold/dextran concentrations. Qualitative analysis of the functional groups showed specific trends where the peak area increased with polarizability, electron density and decreased atomic radii. Steric hinderance effects also affected the trends in peak area due to the amount of gold/dextran nanoparticles in solution. Statistical analysis provided accurate and precise linear relationships (R2 = 0.99) for the ester and adenine functional groups of aspirin and tenofovir, respectively. From the above findings, the combined use of gold nano-scaffolds and gold/dextran nanomaterials amplified the Raman signal from the drugs to allow for systematic evaluation of their molecular properties. Although more experiments to correlate the findings are still needed, this SERS approach shows great potential as a screening method in the quality control of medications.

A key role of soft and refractory coke in the deactivation of γ–Al2O3 catalysts during low-temperature methyl oleate epoxidation: An experiment and DFT study

This work studies the deactivation of the γ-Al2O3 catalyst in a low-temperature methyl oleate epoxidation reaction. The performance at each cycle of spent catalyst correlated to the formation of soft and refractory coke on the catalyst was probed by the temperature-programmed oxidation analysis and FT-IR. As a result, soft coke contributed as the major coke species, including an ester functional group. Furthermore, the coke adsorption on the surface and the electron transfer was analyzed by density functional theory-based calculation. It was found that the strongly adsorbed refractory coke on the catalyst is prone to adsorb on the main Al active site blocking the formation of the Al–OOH site. This phenomenon is responsible for the main reaction in contrast to the soft coke that prefers the other Al sites. Thus, controlling the refractory coke formation is crucial to control the overall catalyst performance, although present in a small amount.

Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity.

For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown that consumption of these plants reduce the risk of lung, breast, and prostate cancers. The high chemopreventive and anticancer potential of cruciferous plants results from the presence of a large amount of glucosinolates, which, under the influence of myrosinase, undergo an enzymatic transformation to biologically active isothiocyanates (ITCs). Natural isothiocyanates, such as benzyl isothiocyanate, phenethyl isothiocyanate, or the best-tested sulforaphane, possess anticancer activity at all stages of the carcinogenesis process, show antibacterial activity, and are used in organic synthesis. Methods of synthesis of sulforaphane, as well as its natural or synthetic bifunctional analogues with sulfinyl, sulfanyl, sulfonyl, phosphonate, phosphinate, phosphine oxide, carbonyl, ester, carboxamide, ether, or additional isothiocyanate functional groups, and with the unbranched alkyl chain containing 2–6 carbon atoms, are discussed in this review. The biological activity of these compounds are also reported. In the first section, glucosinolates, isothiocyanates, and mercapturic acids (their metabolites) are briefly characterized. Additionally, the most studied anticancer and antibacterial mechanisms of ITC actions are discussed.

Construction of hierarchical proton sieving-conductive channels in sulfated UIO-66 grafted polybenzimidazole ion conductive membrane for vanadium redox flow battery

Sieving of H+/Vn + ions is essential to vanadium redox flow battery (VRFB). Herein, the interconnected hierarchical proton sieving-conductive channels are constructed through the graft of sulfated UIO-66 (UIO–66OSO3) along the polybenimidazole (PBI) backbone with the highly reactive and acidic sulfate ester functional group. Highly porous UIO-66OSO3 provides numerous angstrom scale sieving channels (about 5 Å) to transport proton and repel vanadium ion, and the sulfated groups ended flexible side chains are densely bonded to UIO-66 and aggregate into broad nanoscale ionic clusters (∼8 nm) for fast proton conduction between UIO-66OSO3 nanoparticles. The as-prepared membrane exhibits low vanadium permeability (7.88 × 10−9 cm2s−1) and area resistance (0.23 Ω cm−2, lower than that of Nafion 212). High energy efficiency (86.1%) and low discharge capacity decay (0.15% per cycle) are achieved even after 100 charge-discharge cycles at 100 mA cm−2, and the battery keeps running for 2000 cycles without morphological and chemical changes. The VRFB proprieties are far superior to Nafion 212 membrane VRFB proprieties (energy efficiency 74.9%, decay rate 0.71% per cycle), and also surpasses most recently reported porous, dense and hybrid ion conductive membranes.