Hydroxyl Acid Research Articles

Syntheses of α(2,8) Sialosides Containing NeuAc and NeuGc by Using Double Carbonyl-Protected N-Acyl Sialyl Donors.

We report on the syntheses of NeuAc and NeuGc-containing glycosides via the use of double carbonyl-protected N-acetyl sialyl donors. The 7-O,9-O-carbonyl protection of an N-acyl-5-N,4-O-carbonyl-protected sialyl donor markedly increased the α-selectivity during glycosylation, particularly when glycosylating the C-8 hydroxyl group of sialic acids. The N-acyl carbamates were selectively opened with ethanethiol under basic conditions to provide N-acyl amines. It is noteworthy that N-glycolyl carbamate was more reactive to nucleophiles by comparison with the N-acetyl carbamate due to the electron-withdrawing oxygen in the N-acyl group and however, allowed selective opening of the carbamates without the loss of N-glycolyl groups. To demonstrate the utility of the approach, we began by synthesizing α(2,3) and α(2,6) sialyl galactosides. Glycosylation of the hydroxy groups of galactosides at the C-6 position with the NeuAc and NeuGc donors provided the corresponding sialyl galactoses in good yields with excellent α-selectivity. However, glycosylation of the 2,3-diol galactosyl acceptor selectively provided Siaα(2,2)Gal. Next, we prepared a series of α(2,8) disialosides composed of NeuAc and NeuGc. Glycosylation of NeuGc and NeuAc acceptors at the C-8 hydroxyl group with NeuGc and NeuAc sialyl donors provided the corresponding α(2,8) disialosides, and no significant differences were detected in the reactivities of these acceptors.

Effect of carbon quantum dots doping on structural, optical, and antibacterial properties of barium tungstate nanocomposite material

Local bacterial infection remains an increasingly severe threat to human health worldwide, and infection control is still a challenging task. Carbon Quantum Dots (CQSs) and barium tungstate show antibacterial properties. CQDs doped Barium Tungstate (BaWO4) are synthesized by using a hydrothermal route and their optical and antimicrobial activities against the Gram-positive bacteria staphylococcus aureus and optical properties were investigated. The UV–Vis reveals a shift in the bandgap from 3.62 eV to 2.93 eV due to doping of CQDs in BaWO4. The structure of the CQDs/BaWO4 were studied by XRD, which shows CQDs doped BaWO4 samples possess tetragona4 werelite structure with the preferred orientation of (112) identified by XRD at 26° having crystallite size ∼ 31 nm. Nanocomposite BaWO4/CQDs exhibit a spherical-like shape and are composed of Ba, O, W and C according to the design of the experiment. Zeta sizer of CQDs by DLS shows the size of CQDs is 7.65 nm. The FT-IR shows the presence of functional groups in doped material like CC, CO, and COOH bonds which indicate that the C-dots are functionalized with epoxy, carbonyl, hydroxyl, and carboxylic acid groups. Their elemental composition and surface morphology were studied by EDS which shows the percentage variation of CQDs in BaWO4, SEM results show the change in shape of the sample by adding CQDs to BaWO4. The TEM image proves the presence of doped material in the BaWO4. The PL spectra reveals the emission spectra shift towards a higher wavelength and absorption increases. The qualitative analysis shows the antimicrobial activity and enlargement of the inhibition zone and quantitative analysis confirms it.

Investigation into the role of carboxylic acid and phenolic hydroxyl groups in the plant biostimulant activity of a humic acid purified from an oxidized sub-bituminous coal.

Humic substances (HS) are increasingly being applied as crop plant biostimulants because they have been shown to increase plant productivity, especially under environmentally stressful conditions. There has been intense interest in elucidating the HS molecular structures responsible for eliciting the plant biostimulant response (PBR). The polar and weakly acidic carboxylic (COOH) and phenolic hydroxyl (ArOH) functional groups play major roles in the acid nature, pH dependent solubilities, conformation, and metal- and salt-binding capabilities of HS. Reports on the role played by these groups in the PBR of HS found growth parameters being both positively and negatively correlated with COOH and ArOH functionalities. To investigate the role of COOH and ArOH in HS biostimulant activity we used a humic acid (HA), purified from an oxidized sub bituminous coal to prepare HAs with COOH groups methylated (AHA), ArOH groups acetylated (OHA), and with both COOH and ArOH groups methylated (FHA). The original HA was designated (NHA). The four HAs were subjected to elemental, 13C-NMR, FTIR, and EPR analyses and their antioxidant properties were assessed using the trolox equivalents antioxidant capacity assay (TEAC). 13C-NMR and FTIR analysis revealed significant alkylation/acetylation. To determine the effects of alkylating/acetylating these functional groups on the HA elicited PBR, the HAs were evaluated in a plant bioassay on corn (Zea mays L.) seedling under nutrient and non-nutrient stressed conditions. Treatments consisted of the four HAs applied to the soil surface at a concentration of 80 mg C L-1, in 50 ml DI H2O with the control plants receiving 50ml DI H2O. The HA-treated plants, at both fertilization rates, were almost always significantly larger than their respective control plants. However, the differences produced under nutrient stress were always much greater than those produced under nutrient sufficiency, supporting previous reports that HA can reduce the effects of stress on plant growth. In addition, for the most part, the HAs with the alkylated/acetylated groups produced plants equal to or larger than plants treated with NHA. These results suggests that COOH and ArOH groups play a limited or no role in the HA elicited PBR. Alternatively, the HA pro-oxidant to antioxidant ratio may play a role in the magnitude of the biostimulant response.

In-situ constructed solvated carbon quantum dot clusters to achieve uniform Zn plating in aqueous zinc ion batteries

Zinc ion batteries (ZIBs) have become the most competitive candidates for the next-generation energy storage systems due to its low-price, good safety and high theoretical capacity. However, the uncontrollable dendrite growth and parasitic side reactions still hinder the practical application of the zinc ion batteries. Herein, a hybrid functionalized carbon quantum dots (FCQDs)/ZnSO4 electrolyte is in-situ synthesized via a simple one-pot hydrothermal method with glucose as precursor. The created FCQDs possess abundant anionic groups like hydroxyl, carboxyl and sulfonic acid groups, and those anionic groups can strongly absorb Zn2+ ions and then the FCQDs, Zn2+ and water molecules together generate a special solvation structure of solvated carbon quantum dot clusters [FCQDsZnx(H2O)y]2x+. The solvated FCQDs clusters can help to in-situ induce the uniform Zn deposition through a co-plating of Zn atoms and the functionalized FCQDs. Additionally, this unique solvation structure promotes easier dissociation of solvation water molecules, thus decreasing the de-solvation energy. The lower de-solvation energy barrier can help to restrain the water decomposition and the related by-products. Benefiting from the construction of this unique solvated FCQDs clusters, the hybrid electrolyte with FCQDs endows a better performance of both Zn||Zn symmetric cells and full ZIBs.

Elucidating the inhibitory effects of natural organic matter on the photodegradation of organic micropollutants: Atrazine as a probe compound

Natural organic matter (NOM) is a complex mixture of heterogeneous compounds with varying functional groups and molecular sizes. Understanding the impact of NOM on the generation of photochemically produced reactive intermediates (PPRIs) and their potential inhibitory effects on photolysis has remained challenging due to the variations in the reactivities and concentrations of these functional groups. To address this gap, tannic acid (TA), gallic acid (GA), catechin (CAT), and tryptophan (Trp), were chosen as potential substitutes for NOM. Their effects on the photochemical transformation process were evaluated and compared with the widely used Suwannee River NOM (SRNOM). Atrazine (ATZ) was selected as a probe organic micropollutant (OMP). In this investigation, a significantly higher concentration of HO• was observed compared to O21, and the triplet excited state ( NOM*3). The findings suggest that the substituted phenols, particularly those with carboxylate-substitutions, played a substantial role in HO• formation, while electron-rich moieties acted as antioxidants, consuming NOM*3. Hydroxyl, carboxylic, and amino acid were the active groups for O21 formation. However, the inhibitory effects induced by the NOM surrogates were significant and mainly attributed to the direct photolysis inhibition caused by the inner filter effect. The scope of this work was further extended to include SRNOM, where similar trends with less pronounced formation of PPRIs and inner filter effects were observed. Therefore, this study sheds some light on the role of the functional groups in NOM during photochemical transformations of OMPs, thereby deepening our understanding of their fate in aqueous systems.

Micelle formation of sodium taurolithocholate

The proportion of sodium taurolithocholate (NaTLC) is extremely low in human bile salts. NaTLC forms aggregates with other lipids in the bile and functions as an emulsifying and solubilizing agent. The molecular structure of NaTLC contains hydrophilic hydroxyl and sulfonic acid groups at both ends of the steroid ring. This molecular structure is similar to bolaform amphiphilic substance having hydrophilic groups at both ends due to the characteristics of its molecular structure. This study investigated the aggregate properties of the NaTLC using surface tension measurements, light scattering, small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (cryo-TEM). Surface tension measurement showed that the surface tension of the NaTLC solution decreased to 54 mN m−1. The concentration that showed the minimum surface tension corresponded to the critical micelle concentration (CMC: 0.6 mmol L−1, 308 K) determined by the change in light scattering intensity. On the other hand, the degree of counterion (sodium ions) binding to the micelles increased with increasing NaTLC concentration. SAXS and cryo-TEM measurements showed that the NaTLC formed large string-like micelles. The surface activity and large aggregates showed the potential for use as biosurfactants. However, because of the relatively low solubility of NaTLC in water, its use as a biosurfactant is limited to a narrow concentration range.

Antioxidant Activity of Zodia (Evodia suaveolens) Protein Extract In Vitro

The zodia (Evodia suaveolens) plant is an Indonesian endemic that originated in Papua. Zodia leaves are empirically used as anti-mosquito and dysentery medications, and cooked bark is useful as a malaria fever reliever. Until present, no research has been conducted on the protein of the zodia plant extract that has demonstrated action. The goal of this study was to assess the antioxidant activity of the zodia plant protein extract as reflected by IC50 (inhibitory concentration). Various established procedures were used to determine antioxidant capacity, including radical cation, 2,2’-Azinobis 3-ethyl Benzothlazole-6-Sulfonic Acid (ABTS●+) assay, hydroxyl radical (OH●), and superoxide anion (O2●-) scavenging. Data analysis was determined using ANOVA and continued with Duncan. The soluble protein in the stem has much stronger free radical scavenging (ABTS●+, OH●, and O2●-) capabilities than the leaves and root. According to the research, soluble proteins in stems have a significant potential for usage as antioxidants.

Surface Characterization and Bulk Property Analysis of Aluminum Powders Treated with Hydrophobic Coatings: Stearic Acid and Phenyl-Phosphonic Acid

Stearic and phenyl-phosphonic acids were applied to fine aluminum particles to understand their effect on the surface chemical composition and bulk properties of the surface-treated powders. During the solution phase deposition process, the surface composition changes chemically through a condensation reaction between the acid and particle surface hydroxyl groups, forming covalent chemical bonds. The retention of both types of acids was verified through characterization using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The presence of stearic acid on the particle surface was observed through signature absorbance peaks, including interfacial C-O bonding modes, carboxylate, and carbonyl moieties, all present on both the treated powder. Spectra using XPS showed an increase in -CH relative intensity signal on the particle surface when compared to the raw material when considering the the carbon 2p photoelectron peak. Similar findings confirmed the presence of the phenyl-phosphonic acid when comparing to the raw material. The IR spectrum confirmed the presence of P-O-Al, P-O, and phosponates as a result of the surface bonding between the reagent and particles. XPS always provided evidence through the presence of phosphorous 2p and 2s photoelecton peaks at 191.3 and 133.4 eV, respectively. The bulk properties of both surface treated powders improved, as shown through improved apparent/tap density and a decreased Hausner Ratio (Group C to Group A behavior). Rheological characterization provided additional evidence by showing a reduced specific energy, flow rate index, and cohesion. The particle packing was improved as evidenced through reduced compressibility as a function of applied normal stress.

Nanocellulose as a Sustainable Polymer Electrolyte

Polymer electrolyte membranes in fuel cells and electrolyzers will play a key role in the hydrogen economy. These membranes are generally made of sulfonated fluoropolymers, which have excellent proton conductivity, impressive redox stability, and good gas barrier properties. However, the complex synthetic processes mean that they remain expensive. Their synthesis also involves ecologically damaging perfluorosulfonic acids (PFSAs), otherwise known as “forever chemicals” due to their persistence in the environment. More sustainable and lower cost hydrocarbon electrolytes should therefore be investigated.Cellulose is the most abundant biopolymer in nature, and is derived from plant matter. It is used at vast scale and low cost to make paper and cardboard. Cellulose can be chemically or mechanically treated to break up the fibers to form “nanocellulose”. Nanocellulose is a low-cost nanomaterial which can be formed into thin membranes which are much stronger than conventional cellulosic paper.We propose nanocellulose as an alternative electrolyte to replace sulfonated fluoropolymers in fuel cells. We confirmed that unmodified nanocellulose can conduct protons due to acidic hydroxyl groups. We also showed that nanocellulose membranes present a much better barrier to hydrogen compared to Nafion, and can successfully be used as an electrolyte in fuel cells. However, the current-voltage performance of unmodified nanocellulose was insufficient due to a high membrane resistance.We went on to improve the proton conductivity by introducing sulfonic acid groups and reduced the membrane resistance by using spray deposition to create thinner membranes, resulting in significantly improved fuel cell power density of 160 mW/cm2. We also implemented crosslinking with sulfosuccinic acid to simultaneously improve the ionic conductivity, increase strength, and reduce swelling in water. This work shows that nanocellulose is a promising new class of polymer electrolyte which could significantly reduce the cost and improve sustainability of fuel cell and electrolyser systems.1. Cellulose Nanocrystals Crosslinked with Sulfonic Acid as Sustainable Proton Exchange Membranes for Electrochemical Energy Applications, O. Selyanchyn, T. Bayer, D. Klotz, R. Selyanchyn, K. Sasaki, S. M. Lyth, Membranes 12 (7), 658 (2022)2. Spray Deposition of Sulfonated Cellulose Nanofibers as Proton Conducting Membranes for Fuel Cells, T. Bayer, B. Cunning, R. Selyanchyn, B. Smid, S. Fujikawa, K. Sasaki, S. M. Lyth, Cellulose, 28, 1355–1367 (2021)3. Proton Conductivity in Cellulosic Materials: A Review, O. Selyanchyn, R. Selyanchyn, S. M. Lyth, Frontiers in Energy Research: Fuel Cells, 8, 596164 (2020)4. High Temperature Proton Conductivity in Nanocellulose: Paper Fuel Cells, T. Bayer, R. Selyanchyn, S. Fujikawa, K. Sasaki, and S. M. Lyth, Chemistry of Materials, 28 (13), 4805–4814 (2016)

Reactions of CH2OO, CH3CHOO, and (CH3)2COO with Methane through the Formation of Intermediate Complex

Criegee intermediates, which are the products of the ozonolysis of alkenes, play a key role in many chemical and physical processes in the atmosphere. Their reactions with other atmospheric compounds are responsible for the formation of hydroxyl, methyl, hydrogen radicals, nitric and sulfuric acids, and others. Methane is an active greenhouse gas whose concentration has increased rapidly in the last several decades. In this work, we consider the interaction between these two important atmospheric compounds. We choose the three simple Criegee intermediate (CI) molecules: formaldehyde oxide (CH2OO), acetaldehyde oxide (CH3CHOO), and acetone oxide ((CH3)2COO). Some reactions between methane and these Cis have been studied earlier as possible pathways for deactivating methane as well as a source of methanol formation due to molecular collisions in the atmosphere. In the present study, we extend the consideration to the case when an intermediate energetically stable complex is formed after collision. We found that this complex could easily decompose to form an OH radical and another unstable fragment, which can quickly dissociate into CH3 radicals, atomic hydrogen, acetone, acetaldehyde, propaldehyde, methyl alcohol, water, and others, depending on the type of CI being reacted with. These compounds can actively interact with other atmospheric components and change their physical and chemical properties. In addition, CI with a methyl substituent is shown to have increased energy in transition states and minima, resulting in slower reaction rates.

Simultaneous removal of Methylene blue and Cadmium from aqueous solution by a novel sulfonated material: Characterization, mechanism and application

Remediation of water bodies contaminated by organic or inorganic pollution has attracted widespread attention, only a few research focused on the remediation of organic-inorganic combined water pollution. In this study, a novel sulfonated material (HMFA), modified from coal fly ash (CFA) through alkali fusion and hydrothermal methods, was synthesized for the simultaneous removal of Methylene blue (MB) and Cadmium (Cd(II)) from wastewater, achieving the waste-control-waste strategy. Characterization results showed that functional groups such as hydroxyl and sulfonic acid groups are favorable for adsorption. The environmental factors exerted influence on the adsorption, with the presence of competing ions producing the most significant inhibitory effect. Under optimal conditions, the adsorption amounts of MB and Cd(II) were 116.69 and 93.53 mg g-1 in single system and 100.23 and 85.49 mg g-1 in binary system, respectively. The results of model fitting showed that the removal of MB and Cd(II) by HMFA in single system was consistent with pseudo-second-order kinetic model and Langmuir model. Apart from electrostatic attraction, the primary adsorption mechanisms on HMFA include hydrogen bonding for MB, as well as ion exchange and complexation for Cd(II), quantitative calculations have been carried out. HMFA remained favorable recyclability, and had higher selectivity on MB in natural water bodies. In conclusion, as a low-cost and efficient adsorbent material, HMFA has great potential for dye and heavy metal pollution control, which can provide more reference and theoretical support for solid waste resource utilization and dye/heavy metal removal in wastewater.

Size Distribution and Secondary Formation of Particulate Organic Nitrates in Winter in a Coastal Area

Understanding the size distribution, variation patterns, and potential formation mechanisms of particulate organic nitrates (PONs) is crucial for assessing their influences on atmospheric chemistry, air quality, and the regional climate. This study investigates PONs in the coastal atmosphere of Qingdao, China by collecting size-resolved particulate matter samples and analyzing six types of organic nitrates, namely pinene keto nitrate (PKN229), monoterpene hydroxyl nitrate (MHN215), monoterpene dicarbonyl nitrate (MDCN247), oleic acid hydroxyl nitrate (OAHN361), oleic acid keto nitrate (OAKN359), and pinene sulfate organic nitrate (PSON295), using ultrahigh-performance liquid chromatography(mass spectrometry). The mean total concentration of organic nitrates in fine particles reaches 677 ng m−3. The predominant compound is MHN215, followed by PKN229 and MDCN247. All six organic nitrates exhibited distinct concentration peaks in the droplet mode, with MDCN247 and OAHN361 showing a minor peak in the condensation mode. In addition, an apparent concentration peak is observed in the coarse mode for OAKN359. Comparative analyses under various conditions highlight the significant influences of primary emissions and secondary formation processes on the abundance and size distribution of organic nitrates. For instance, both firework displays during festivals and high NOx emissions from fuel combustion significantly increase the concentrations of condensation-mode organic nitrates, whereas dust particles enhanced the heterogeneous formation of coarse-mode particles. Furthermore, the high humidity of the coastal area promotes aqueous formation in droplet-mode particles.

Effects of hydroxyl radicals oxidation on digestion properties of silver carp myofibrillar protein gel

The generation of hydroxyl radicals from fat oxidation during frozen storage of surimi has been confirmed to induce oxidative cross-linking of proteins, but the further effect on their digestive properties and nutritional qualities is still unclear. In this work, a simulated system composed of the silver carp myofibrillar protein (MP) and Fenton system was used to study their digestive process and activities. Affected by oxidative cross-linking, oxidized MP gels were slowly and incompletely hydrolyzed by gastrointestinal process according to free amino content, particle size and peptide amount. However, the essential amino acid proportion, reduced power and hydroxyl radical chelation of digestion products from slight oxidation group (0.1–0.5 mM H2O2) were found to be generally stronger than over-oxidation group (5.0–10.0 mM H2O2). Furthermore, the in vitro biological evaluations confirmed that there were certain antioxidant activities of digestion products without potential cytotoxicity on HepG2 cells. Oxidation treatment on MP was found to negatively maintain SOD activity and generating GSH. Nevertheless, the slight oxidation group showed great protection effects to keep HepG2 cells from cell membrane damage and release LDH. In conclusion, the slight oxidation of MP is beneficial to improve the nutritional quality and in vitro antioxidant activity of its digested products.

Impact of Calcination Temperature on Tungsten‐based Composite Catalysts for Olefins Metathesis

AbstractThe thermal treatment is one of the key procedures for the distribution and transformation of active sites for the supported metal oxide catalysts. However, the underlying impacts of thermal treatment on composite supported catalysts receives limited attention due to the additional complexity of the composite support. In this work, the progressive gradient in the metathesis activity, as the function of enhanced calcination temperature, has been observed for the tungsten‐based catalysts supported on the hierarchical ZSM‐5 zeolite‐alumina composite. The metathesis activity, reflected by ethene conversion, undergoes a stepwise growth from 24.2 % to 38.9 % along with the enhanced calcination temperature from 723 K to 923 K. The supported W‐oxo species share high similarity in structural states except their interaction with the Brønsted acidic bridge hydroxyl groups in zeolite. The density of bridge hydroxyl groups is reduced as the function of enhanced calcination temperatures, which reflects the intensified anchoring of surface W‐oxo species. It should be noted that such dependence is not observed for their counterparts based on microporous ZSM‐5 zeolite‐alumina. These sharp comparisons highlight the critical routes of thermal migration of W‐oxo species along the intrazeolite‐alumina interface in the evolution of active sites for the olefins cross‐metathesis reaction.

Efficient removal of U(VI) from aqueous solution by hydroxyapatite/graphene oxide composite microspheres

Abstract Effective treatment of uranium-containing wastewater is of great significance to the sustainable development of nuclear power and the protection of ecological environment. In this study, a highly efficient uranium adsorbent, graphene oxide (GO)/nano-hydroxyapatite (nHA) composite microspheres (nHA@rGO) was synthesized, which could effectively remove uranium from aqueous solution. Under the condition of pH = 3.5, T = 298 K, the maximum adsorption capacity reached 1672.96 mg/g. The results of batch experiments showed that the adsorption capacity of nHA@rGO microspheres was higher than that of nHA microspheres, indicating the enhancement of GO. The adsorption kinetics conformed to the pseudo second-order model. The changes of nHA@rGO microspheres before and after uranium adsorption were analyzed by FT-IR, XPS and XRD. The mechanisms of U(VI) ions adsorption onto nHA@rGO microspheres involved precipitation, surface complexation and ion exchange, in which the hydroxyl and phosphoric acid groups played important roles. The results showed that the prepared nHA@rGO microspheres can be used as an efficient and promising adsorbent for the treatment of uranium-containing wastewater.

Chemical Functionalization of Silicon Carbide Nanotube (SiCNT): First Principles DFT Study

In this study, a functionalized nano drug carrier design based on (5,5) silicon carbide nanotube and functional groups such as amine (−NH2), hydroxyl (−OH), and carboxylic acid (−COOH) were investigated using the first principles’ density functional theory. The critical need for a smart nanocarrier system aims to increase the concentration of medications to the particular tissues of interest with minimal toxicity to the patient. The simulations are carried out using Quantum ATK-Atomistic Simulation Software. The negative binding energy and the total energy difference obtained by optimization through random perturbation ensure the stability of the structures SiCNT and SiCNT-(X/2X) (X = −OH, −NH2, and −COOH). The energy bandgap obtained for the pristine structure is 1.99 eV indicating their indirect bandgap semiconducting characteristics. In comparison to SiCNT, the energy bandgap of SiCNT-(X/2X) structures decreases within a range of 0.06 eV to 1.95 eV, respectively. Partial charges and p-character were used to understand the nature of bonds between the nanotube and the functional moiety. The chemical potential analysis favors a blue shift of SiCNT-(X/2X) with respect to SiCNT. The higher values of ionic character and solvation energy predicts the solubility of nanostructures in the aqueous medium. In comparison to all analyzed systems, the findings of the ionic character, solvation, and sensing mechanism indicate SiCNT-(2NH2) system to be most favorable drug delivery nanocarrier. These findings suggest that increasing the concentration of −NH2 functional groups on the side wall of silicon carbide nanotubes helps to develop a promising and efficient targeted drug delivery system to deliver specific molecular cargo to the cells mitigating toxicity associated with nanotubes, thereby enhancing the outcomes of cancer treatment. Furthermore, surface functionalization of silicon carbide nanostructures could improve their potential solubility parameterized by higher values of dipole moment and solvation energy together with enhanced biocompatibility leading to the desired therapeutic effect.

Expanding the synthesis of a library of potent glucuronic acid glycodendrons for Dengue virus inhibition

Multivalent glycodendrons are valuable tools to mimic many structural and functional features of cell-surface glycoconjugates and its focal position scaffolds represent important components to increase specificity and affinity. Previous work in our group described the preparation of a tetravalent glucuronic acid dendron that binds with good affinity to Dengue virus envelope protein (KD = 22 μM). Herein, the chemical synthesis and binding analysis of a new library of potent glucuronic acid dendrons bearing different functional group at the focal position and different level of multivalency are described. Their chemical synthesis was performed sequentially in three stages and with good yields. Namely a) the chemical synthesis of the oligo and polyalkynyl scaffolds, b) assembling with fully protected glucuronic acid-based azide units by using a microwave assisted copper-catalysed azide-alkyne cycloaddition reaction and c) sequential deprotection of hydroxyl and carboxylic acid groups.Surface Plasmon Resonance studies have demonstrated that the valency and the focal position functional group exert influence on the interaction with Dengue virus envelope protein. Molecular modelling studies were carried out in order to understand the binding observed. This work reports an efficient glycodendrons chemical synthesis that provides appropriate focal position functional group and multivalence, that offer an easy and versatile strategy to find new active compounds against Dengue virus.

Preparation, characterization, and application of stable naphthalenediimide‐based metal–organic framework for cooperative capture low concentration uranium from wastewater

AbstractExtracting uranium from real water samples remains a great challenge due to low uranium concentration, concentrated competing ions and volumes of water. The design and preparation of uranium adsorbents with high efficiency and affinity are still difficult. Herein, we presented a facile one‐pot strategy to obtain a novel metal organic framework (denoted as Mn‐NDISA) for stable and efficient trapping of low concentration uranium. Mn‐NDISA with a built‐in hydrophobic cavity can boost the absorption affinity to 1.99 × 106 mL g−1 through the cooperative capture composed of electrostatic interaction, coordination force and hydrogen binding. Owing to the coordination‐available oxygen sites in flexible framework, a rapid kinetic equilibrium was achieved in just 25 min. Moreover, these exceptional adsorption features enabled Mn‐NDISA to successfully capture the naturally occurring uranium traces (~ppb) in wastewater samples, making it one of the most influential absorbents toward UO22+ ever reported. The experimental and theoretical studies revealed that the electrostatic attraction came from the surface negatively charged Mn‐NDISA and the positively charged UO22+. The coordination originated from Lewis basic hydroxyl, carbonyl groups, and Lewis acid UO22+, while hydrogen bonds further reinforced the as‐formed uranium binding complex. This research offered a promising cooperative capture strategy to improve the uranium affinity of the pristine MOF for trace contaminants removal in environmental remediation fields.

Preparation of Starch‐Fatty Acid Esters from Agro‐Based Raw Materials (Corn Starch, Cassava Starch, Coconut Oil, and Castor Seed Oil)

AbstractThe preparation of starch‐fatty acid esters is investigated for corn starch and cassava starch. The fatty acid contents are obtained from the hydrolysis of coconut oil and castor oil respectively and are characterized by GC/MS techniques. The major fatty acid component of coconut oil is found to be lauric acid (34%) while that of castor oil is ricinoleic acid (84%). Four different starch‐fatty esters are prepared, namely cassava starch‐coconut fatty acid esters (CacoFAE), cassava starch‐castor fatty acid ester (CacaFAE), corn starch‐coconut fatty acid ester (CocoFAE), and corn starch‐castor fatty acid ester (CocaFAE). The starch‐fatty acid esters are analyzed using FT‐IR and liquid chromatography‐mass spectrometer techniques. All the esterified starch‐fatty acid esters contain the C=O absorption peak at 1707 cm−1 which is the peak corresponding to the ester group formed between the starch hydroxyl and fatty acid carboxylic functions. The major fatty acid eluted from LC‐MS for CacoFAE and CocoFAE is lauric (dodecanoic) acid with 67.4% and 74% respectively while ricinoleic acid (58%) is obtained for CacaFAE. The data for CocaFAE are mainly dominated by the ester of the fatty acids.

Toward low-misting leathers from environmentally friendly ricinoleic acid-based fatliquoring agents

In this work, an amidated hydroxylated ricinoleic acid (MRH) was developed from natural ricinoleic acid and commercially available thioglycerol and monoethanolamine by simple and efficient thiol-ene click and amidation reactions. The resulting MRH was subsequently used as an environmentally friendly, low-misting fatliquor for premium automotive interior leathers. In addition, theoretical speculations using molecular dynamics simulations and routine experimental methods for determining the misting resistance and the percentage of free oil in the MRH-treated leather were systematically investigated. The hydroxyl groups and the amide group within MRH are able to form firm chemical bonds with collagen fibers of the leather, as evidenced by higher Ebinding (122.84 kcal/mol) and lower diffusion coefficient (0.000095 Å2/ps) obtained from molecular dynamics simulations, the lower free oil content (11.42%), and the lower misting value (4.82 mg) of MRH-treated leather. Therefore, the MRH fatliquoring agent did not migrate out of the collagen fibers. Overall, bio-derived ricinoleic acid can be modified to enable the design of sustainable fatliquors for low-misting-value automotive upholstery leather. Furthermore, the fatliquoring effluent was also biodegradable, all of which contributed to a cleaner production of leather fatliquor.