Tertiary Amine Groups Research Articles

Application of three types of aminated lignins for efficient removal of Cd(II) and Pb(II) ions in aqueous solution

Lignin is a renewable natural aromatic polymer that is generated as a co-product during lignocellulosic biorefinery processes, and it has been applied widely as a functional biomaterial. In this study, the adsorption behavior of Cd(II) and Pb(II) metal ions was investigated via ion chelation using aminated lignins (ALs) with primary, secondary, and tertiary amine groups. ALs exhibited optimal Cd(II) and Pb(II) adsorption capacities in solution under neutral conditions due to their chelating, electrostatic, and cationic–π interactions with metal ions. The AL with the primary amine group showed the highest adsorption capacities for both Cd(II) and Pb(II), reaching 83.2 and 159.7 mg·g-1, respectively, followed by the ALs with secondary and tertiary amine groups. The adsorption kinetics and isotherm analysis demonstrated that all adsorption behaviors followed the Langmuir isotherm and pseudo-second-order kinetics. Thermodynamic studies revealed that the adsorption processes of Cd(II) and Pb(II) using the ALs were spontaneous and endothermic. These results demonstrate that ALs are promising adsorbents for the removal of Cd(II) and Pb(II) metal ions.

PH-Responsive Hyperbranched Polymer Nanoparticles to Combat Intracellular Infection by Disrupting Bacterial Wall and Regulating Macrophage Polarization.

Intracellular bacterial infections pose a serious threat to public health. Macrophages are a heterogeneous population of immune cells that play a vital role in intracellular bacterial infection. However, bacteria that survive inside macrophages could subvert the cell signaling and eventually reduce the antimicrobial activity of macrophages. Herein, dual pH-responsive polymer (poly[(3-phenylprop-2-ene-1,1-diyl)bis(oxy)bis(enthane-2,1-diyl)diacrylate-co-N-aminoethylpiperazine] (PCA)) nanoparticles were developed to clear intracellular bacteria by activating macrophages and destructing bacterial walls. The presence of acid-labile acetal linkages and tertiary amine groups in the polymer's backbone endow hyperbranched PCA dual pH-response activity that shows acid-induced positive charge increase and cinnamaldehyde release properties. The biodegraded PCA nanoparticles could significantly inhibit the growth of bacteria by damaging the bacterial walls. Meanwhile, PCA nanoparticles could uptake by macrophages, generate reactive oxygen species (ROS), and remodel the immune response by upregulating M1 polarization, leading to the reinforced antimicrobial capacity. Furthermore, PCA nanoparticles could promote bacteria-infected wound healing in vivo. Therefore, these dual pH-responsive PCA nanoparticles enabling bacteria-killing and macrophage activation provide a novel outlook for treating intracellular infection.

Soft Elastomers Based on the Epoxy–Amine Chemistry and Their Use for the Design of Adsorbent Amphiphilic Magnetic Nanocomposites

Poly(ethylene glycol) (PEG)-based soft elastomers, bearing tertiary amine and hydroxyl groups, were synthesized in bulk from the epoxy–amine reaction between poly(ethylene glycol) diglycidyl ether (PEGDE) and a poly(etherdiamine), Jeffamine ED600. High gel fractions (≥0.95) and low glass transition temperatures (Tg ≈ −50 °C) were attained after complete curing of the systems in bulk. The amphiphilicity of the network allowed the swelling of the materials in both aqueous solutions and a variety of organic solvents. Magnetic nanocomposites were synthesized by in situ coprecipitation of magnetic nanoparticles (MNPs) in the elastomeric matrix. The obtained materials were processed by cryogenic milling to obtain powders that were tested as potential magnetic adsorbents and that showed a fast and strong response to the action of a permanent magnet. These materials showed removal rates of at least 50% in 10 min when used in the adsorption of Cu+2 ions from an aqueous solution, making them interesting candidates for the design of magnetically separable metal ion adsorbents.

N-substituted methyl ethylenediamine derivatives as corrosion inhibitors for carbon steel in 1 M hydrochloride acid

Three N-substituted methyl ethylenediamine derivatives, tetramethylethylenediamine (TDA), pentamethyldiethylenetriamine (PTA), and hexamethyltriethylenetetramine (HTA) were prepared for the corrosion inhibition of 20# steel in 1 M HCl solution. Their corrosion inhibition properties were investigated using weight loss, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) measurements, and surface analysis techniques. Quantum chemical calculations and molecular dynamics (MD) simulations were applied to analyze the molecular structure-activity relationship of corrosion inhibitors. The results indicated that all three methyl ethylenediamine derivatives exhibited excellent inhibition properties. The order of inhibition efficiency of these inhibitors was TDA < PTA < HTA. Furthermore, all three inhibitors act as mixed-type inhibitors and mainly inhibited the cathodic reaction. The adsorption mechanism of corrosion inhibitors follows the Langmuir isotherm and proceeds by physisorption and chemisorption. The results of quantum chemical calculations and MD simulations effectively support the experimental results. The excellent corrosion inhibition property is attributed to the interaction between tertiary amine groups and Fe, which effectively inhibits corrosion.

Quenching singlet oxygen via intersystem crossing for a stable Li-O2 battery

Aprotic Li-O2 batteries are a promising energy storage technology, however severe side reactions during cycles lead to their poor rechargeability. Herein, highly reactive singlet oxygen (1O2) is revealed to generate in both the discharging and charging processes and is deterimental to battery stability. Electron-rich triphenylamine (TPA) is demonstrated as an effective quencher in the electrolyte to mitigate 1O2 and its associated parasitic reactions, which has the tertiary amine and phenyl groups to manifest excellent electrochemical stability and chemical reversibility. It reacts with electrophilic 1O2 to form a singlet complex during cycles, and it then quickly transforms to a triplet complex through nonradiative intersystem crossing (ISC). This efficiently accelerates the conversion of 1O2 to the ground-state triplet oxygen to eliminate its derived side reactions, and the regeneration of TPA. These enable the Li-O2 battery with obviously reduced overvoltages and prolonged lifetime for over 310 cycles when coupled with a RuO2 catalyst. This work highlights the ISC mechanism to quench 1O2 in Li-O2 battery.

Xanthone derivatives as potential telomeric G-quadruplex stabilizing and cytotoxic agents: Effects of substitution on quadruplex binding affinity and cytotoxicity

A series of xanthone derivatives (2a-2e) as telomeric quadruplex stabilizing ligands were designed, synthesized and evaluated by molecular docking, drug-likeness prediction, spectroscopy assay, melting profiles, PCR stop analysis. The ligands possessed the rigid aromatic xanthone scaffold and the flexible basic side chain with the appropriate length. Molecular docking and quadruplex binding property studies revealed that the ligands could stack on the external G-quartets, and the basic side chain could contribute to the stabilizing ability. Introduction of a tertiary amine group with high pKa value and small steric hinderance was favorable for improving the binding ability. Such as bis-dimethylamine derivative (2a), exhibited stronger binding ability and higher affinity toward G-quadruplex than duplex DNA. Cytotoxicity assay showed that the xanthone derivatives could inhibit the viabilities of HeLa, MCF-7, SGC-7901 and A549 cells in different degrees. AO/EB staining and flow cytometry assay indicated that the cytotoxicity of xanthones was related to induced apoptosis. These results suggested that the ligands could be further studied as potential new G-quadruplex stabilizers and potent antitumor agents, especially 2a.

Effective construction of anti-fouling zwitterion-functionalized ceramic membranes for separation of oil-in-water emulsion based on PDA/PEI co-deposition

Ceramic membranes have been widely used in oil-water separation owing to their characteristics of high flux, excellent chemical stability, strong hydrophilicity, and good fouling resistance. To further enhance their anti-fouling performance, a co-deposition reaction was employed for the surface modification of the ceramic membranes in this study. Polyethyleneimine and dopamine were used to introduce tertiary amine groups on the surface of the ceramic membranes, and sodium 2-bromoethanesulfonate was used for the quaternization reaction with tertiary amine groups. According to the water contact angle measurements, the ceramic membrane functionalized via zwitterionic modification exhibited better hydrophilicity and thus could absorb water droplets faster than pristine ceramic membranes. Consequently, the zwitterion-functionalized ceramic membrane achieved double the permeance (40 L m−2 h−1 bar-‍1) compared to the original ceramic membrane (20 L m−2 h−1 bar-‍1) during the separation of the oil-in-water emulsion, suggesting good anti-fouling performance.

Highly selective separation of Pb(II) with a novel aminophosphonic acid chelating resin from strong-acidic hexa-solute media

The aminophosphonic acid chelating resin of PMAA-P bearing tertiary diphosphonic amine and amide groups, was newly prepared based on poly(methyl acrylate) and ethylenediamine. Due to the extra amide group and 4.64 mmol/g of high grafting molar mass of phosphonic acid groups, PMAA-P was found to combine with Pb(II) through ionic and coordinate bonds to form more stable tridentate and tetradentate coordination modes, resulting in much higher adsorption capacity and selectivity for Pb(II) than the commercial resin S950 even from strongly acidic media (pH 2.0). The maximum adsorption capacity of PMAA-P for Pb(II) was 1.548 mmol/g, exceeding that of S950 by 78.14%. Additionally, as to the hexa-solute system, PMAA-P showed the selectivity order of Pb(II) ≫ Cu(II) > Cd(II) > Zn(II) > Co(II) > Ni(II), with such high separation factors of αHMCsPb(II) as 5.45-+∞ and the high Pb(II) adsorption amount of 1.010 mmol/g, which was 77.19% higher than S950. Moreover, because of the strong replacement effect, the maximum effluent concentration of Ni(II) exceeded 123.60% of its influent concentration in dynamic separation tests. Furthermore, the adsorption amount of Pb(II) remained above 1.241 mmol/g after being regenerated for five cycles. Above all, PMAA-P has great potential in highly selective separation of Pb(II) from strong-acidic media and thus explores an efficient way of treating lead-acid battery wastewaters.

CO2 and temperature dual-responsive dendrimer-based draw solutes for forward osmosis process

Forward osmosis (FO) is promising as an alternative to conventional pressure-driven membrane processes for water separation. Ideally, the draw solution (DS) for the FO process should have high osmotic pressure, easy reusability, and low reverse solute flux. In this study, novel CO2/temperature dual-responsive dendrimers were prepared, and their performance as DSs were evaluated. Aqueous solutions of the synthesized dendrimers showed the lower critical solution temperature (LCST) type phase separation at moderate temperature. Therefore, the dendrimers could be easily recovered from the aqueous solution and reused as DS. Moreover, the dendrimer solutions showed high osmotic pressure after CO2 absorption owing to the tertiary amine groups of the dendrimer, which could generate bicarbonate ions via neutralization reaction. Additionally, the dendrimer solution showed a low reverse solute flux through the FO membrane because of the branched structure of the dendrimers. Owing to the preferable properties of the CO2/temperature dual-responsive dendrimers as the DS, the aqueous solution of the dendrimer showed high DS performance. This study demonstrated that CO2/temperature dual-responsive dendrimers are potential candidates for constituting high-performance DSs.

Effect of pH on the physicochemical properties of 2-dimethylaminoethyl starch and its desizability

Tertiary amine groups can exhibit and lose cationic properties at different pH levels, and this group can be introduced to starch chains to satisfy the demand for sizing and desizing. However, the effect of pH on tertiary amine groups in toughening starch film and improving adhesion is still unclear. Therefore, 2-dimethylaminoethyl starch (DMAES) was prepared via tertiary aminated starch with 2-dimethylaminoethyl chloride hydrochloride. The influences of pH on the mechanical properties of DMAES films and the adhesion to cotton fiber were investigated. In addition, the desizability and biodegradability of DMAES were measured. It was found that introducing the group of 2-dimethylaminoethyl could toughen the starch film and increase the adhesion to cotton fiber. DMAES has a higher zeta potential and the adhesion to cotton fibers in acidic conditions than in alkaline conditions. In addition, it is easy to remove the DMAES from the yarns and obtain higher desizing efficiency with alkali desizing. Tertiary amination of starch with the 2-dimethylaminoethyl group was a good way for starch to improve adhesion and obtain a higher desizing efficiency.

In situ reactive coating of porous filtration membranes with functional polymer layers to integrate boron adsorber property

The state-of-the-art reverse osmosis membranes for seawater desalination have limited competence to efficiently remove boron. One promising approach for boron removal is to integrate membrane-based separation with selective adsorption of boron in pre- or posttreatment of seawater desalination; the porous support layer of established filtration membranes, constituting the largest part of total membrane volume shall be utilized for this function. Therefore, this study focuses on performing in situ modification of commercial polyethersulfone (PES) microfiltration membranes toward reactive coating the pore surface with a boron affinity polymer-based hydrogel. Modification is carried out in two steps: 1) adsorption of an amphiphilic copolymer which contains tertiary amine groups as co-initiator for surface-selective free radical generation; 2) grafting of a hydrogel layer by using a monomer solution comprising polyol-containing monomer as boron ligand, a cross-linker monomer, and the redox initiator ammonium persulfate (APS). The entire modification process is performed under flow-through conditions. Membranes with different pore sizes were modified; modification parameters, such as molar mass of macromolecular co-initiator as well as composition of reactive monomer solution, were systematically varied. It was found that using an “integrated” initiation system with low molecular weight co-initiator N,N,N′,N′-tetraethyl ethylenediamine (TEMED) added to the reactive solution, yielded significantly higher degree of grafting and therefore superior adsorber properties. Boron binding capacity of modified membranes was evaluated in terms of boron adsorption isotherms, adsorption kinetics, break-through behavior under filtration conditions and regeneration of the adsorber. The trade-off between permeance and boron binding capacity of modified membrane was studied in order to identify promising materials with competitive overall separation performance, i.e. high permeance at a specific filter cut-off in combination with high boron binding capacity.

Dynamically Cross-Linked Waterborne Polyurethanes: Transalkylation Exchange of C–N Bonds Toward High Performance and Reprocessable Thermosets

Thermosetting waterborne polyurethanes (WPUs) have received wide attention because of their excellent chemical resistance, mechanical properties, and low water absorption. However, their permanent network structure hinders their reprocessing applications, making it vital to prepare reprocessable thermosetting WPUs to minimize plastic pollution. Herein, for the first time, the cross-linked WPUs with excellent reprocessability were designed and synthesized by introducing covalent adaptable networks (CANs) in the form of quaternary ammonium alkyl chains. Our methodology combined CO2-triggered WPUs (CO2-triggered WPUs) with 1,6-diiodohexane. After the CO2 evaporated during film formation, the CO2-triggered WPUs left tertiary amine groups as reaction precursors, which could cross-link into a WPU CAN with 1,6-diiodohexane. All cross-linked WPUs possessed classic vitrimer performance including stress relaxation and malleability, as confirmed by stress-relaxation and hot-press tests. The results showed that cross-linked WPUs had excellent reprocessability and high mechanical properties, and the recovery ratios of the mechanical properties for the recycled samples were over 80% and the tensile strength was more than 17 MPa. More importantly, the cross-linked WPUs’ antibacterial rates of Staphylococcus aureus and Escherichia coli were 94.3 and 89.5%, respectively. This research offers a new method to synthesize high-performance WPUs via facile quaternary ammonium reversible cross-linking and demonstrates that WPU CANs have great potential as sustainable materials.

Dual-responsive polyacrylonitrile-based electrospun membrane for controllable oil-water separation

Membrane separation based on smart materials with responsive wettability has attracted great attention due to the excellent performance of controllable oil-water separation. Herein, responsive copolymer originated from N-isopropylacrylamide and 2-(dimethylamino) ethyl methacrylate was synthesized and electrospun with polyacrylonitrile to fabricate smart composite membrane. The introduction of the responsive copolymer endowed the membrane with stimuli-responsive wettability to pH and temperature. Specifically, at the initial state, water was selectively blocked while oil passed through the membrane. After treatment with acidic water or CO2, the reverse separation was realized due to the protonation of the tertiary amine group in the copolymer. Water was selectively passed through the membrane after heat treatment because of the structural change of membrane upon temperature. The developed membrane was able to separate different types of oil-water mixtures and surfactant-stabled emulsions with high efficiency. Additionally, two membranes controlled by temperature and pH were designed to construct a logic AND gate for oil-water separation, and the results demonstrated that only the temperature and acidity of the solution were simultaneously satisfied, the water could flow through the valve combination, and such capability made this smart membrane great potential for remotely controlling the oil-water separation process.

Electrical Response of Poly(N-[3-(dimethylamino)Propyl] Methacrylamide) to CO2 at a Long Exposure Period.

Amine-functionalized polymers (AFPs) are able to react with carbon dioxide (CO2) and are therefore useful in CO2 capture and sensing. To develop AFP-based CO2 sensors, it is critical to examine their electrical responses to CO2 over long periods of time, so that the device can be used consistently for measuring CO2 concentration. To this end, we synthesized poly(N-[3-(dimethylamino)propyl] methacrylamide) (pDMAPMAm) by free radical polymerization and tested its ability to behave as a CO2-responsive polymer in a transducer. The electrical response of this polymer to CO2 upon long exposure times was measured in both the aqueous and solid phases. Direct current resistance measurement tests on pDMAPMAm films printed along with the silver electrodes in the presence of CO2 at various concentrations reveal a two-region electrical response. Upon continuous exposure to different CO2 flow rates (at a constant pressure of 0.2 MPa), the resistance first decreased over time, reaching a minimum, followed by a gradual increase with further exposure to CO2. A similar trend is observed when CO2 is introduced to an aqueous solution of pDMAPMAm. The in situ monitoring of pH suggests that the change in resistance of pDMAPMAm can be attributed to the protonation of tertiary amine groups in the presence of CO2. This two-region response of pDMAPMAm is based on a proton-hopping mechanism and a change in the number of free amines when pDMAPMAm is exposed to various levels of CO2.

Electrochemical and light-driven CO2 reduction by amine-functionalized rhenium catalysts: A comparison between primary and tertiary amine substitutions

Properly positioned second-coordination sphere functional groups can play an integral role in enhancing catalytic activity, altering product selectivity, and/or reducing the energy cost for desired chemical transformations. In this context, we have investigated the effect of second-sphere tertiary amine groups in the fac-Re(bpy)(CO)3Cl (ReBpy) catalyst scaffold (bpy is 2,2′-bipyridine). A family of isomeric Re(bpy) catalysts bearing N,N-dimethylaniline (DMA) substituents at the 6 position of 2,2′-bipyridine has been synthesized and characterized, where the -NMe2 group of each complex is installed at the ortho, meta, or para position of the pendant phenyl ring to systematically vary the distance between the amine and the rhenium metal center. The para-substituted complex (Re-pNMe2) leads the series with the highest turnover frequency (168 s−1) and highest turnover number (80) measured under optimized electrochemical and photochemical conditions, respectively. Spectroelectrochemical experiments were performed to identify reduced intermediates that are involved in the catalytic cycles of these complexes. In addition, the catalytic parameters have been compared with the analogous and previously reported series of Re catalysts bearing –NH2 functionality in the second-coordination sphere. Our results demonstrate that, unlike the aniline-substituted primary amine systems, catalysis with the DMA-substituted tertiary amine complexes is predominantly governed by inductive electronic effects.

Mechanism and Origin of Enantioselectivity in Bifunctional Squaramide‐Catalyzed α‐Thiolation of Azlactones

AbstractThe full mechanism of the asymmetric α‐thiolation of azlactones catalyzed by a cinchona alkaloid‐derived squaramide was carefully investigated through theoretical calculations. The results revealed that the reaction proceeds in two sequential steps. First, the azlactone α‐deprotonation by the catalyst tertiary amine group (which for the major product is the rate‐limiting step) affords a chiral molecular aggregate containing the azlactone enolate. Next, three proposals were evaluated concerning the enantiodetermining step (carbon‐sulfur bond formation). It was possible to exclude the azlactone enol as a key intermediate. The most viable pathway consists of a Münchnone‐type activation mode, which associated with secondary hydrogen bonding interactions between the catalyst and the thiolating reagent (bifunctional catalysis), is responsible for the asymmetric induction process. Thus, by using two different reaction conditions, the theoretical enantiomeric excesses were computed and compared with literature data, presenting a good correlation with the reported experimental values.

Adsorption of CO2 by amine-modified novel nanomaterials

The greenhouse effect has a serious impact on our living environment. The development of novel amine-modified porous organic polymer materials is of great significance to achieve the capture of greenhouse gas CO2. In this study, hexadecyltrimethyl ammonium bromide (CTAB) was used as template, resorcinol formaldehyde resin adhesive was synthesized by polycondensation reaction between 1,3 resorcinol and formaldehyde, and ethyl orthosilicate (TEOS) was used as inorganic precursor (prepared by reaction of silicon tetrachloride and ethanol). Choline, tetramethylammonium hydroxide, plant growth regulators, herbicides, strong base anionic and cationic resins, dye levelling agents, and a range of basic colours all are manufactured from trimethylamine. Trimethylamine is recognized by gas sensors used it to check for seafood freshness. One-step sol-gel method was used. A novel nanoporous carbon silicon material (NNCMR) was synthesized. Using the composite porous material as a carrier, the isomers triethylene tetraamine (TETA) and tri (2-aminoethyl) amine (TAEA) as modifiers, respectively. New amine-modified porous carbon-silicon materials (NNCMR-TETA-X and NNCMR-TAEA-X) were prepared by impregnation method. Triethylenetatramine (TETA) is an orphaned medication that treats copper excess in tissues. It is a selective divalent Cu(II) chelator. Trientine, a salt form of D-penicillamine, was released in 1969 as a substitute for D-penicillamine. The results show that this kind of material has rich microporous structure and ordered mesoporous structure, and realizes the framework fusion of carbon and silicon oxide, and uniformly loads the amine material. NNCMR-TETA-50 showed the best adsorption performance among the new nanoporous carbon and silicon materials, with a maximum adsorption capacity of 4.21 mmol/g. The composite porous materials with different amine structures as modifiers have different effects on CO2 capture performance. In the presence of water vapor, NNCMR-TAEA-50 showed the best adsorption performance, with a maximum adsorption capacity of 4.96 mmol/g, since the tertiary amine group could not effectively capture CO2 in the absence of water vapor, but could work well in the presence of water vapor. This can help us design suitable adsorbent materials for CO2 capture in different practical applications. At the same time, the new nanoporous carbon silicon material has good thermal stability and recycling.

The N,N,O-Trisubstituted Hydroxylamine Isostere and Its Influence on Lipophilicity and Related Parameters.

The influence of substitution of an N,N,O-trisubstituted hydroxylamine (-NR-OR'-) unit for a hydrocarbon (-CHR-CH2-), ether (-CHR-OR'-), or amine (-NR-CHR'-) moiety on lipophilicity and other ADME parameters is described. A matched molecular pair analysis was conducted across five series of compounds, which showed that the replacement of carbon-carbon bonds by N,N,O-trisubstituted hydroxylamines typically leads to a reduction in logP comparable to that achieved with a tertiary amine group. In contrast, the weakly basic N,N,O-trisubstituted hydroxylamines have greater logD 7.4 values than tertiary amines. It is also demonstrated that the N,N,O-trisubstituted hydroxylamine moiety can improve metabolic stability and reduce human plasma protein binding relative to the corresponding hydrocarbon and ether units. Coupled with recent synthetic methods for hydroxylamine assembly by N-O bond formation, these results provide support for the re-evaluation of the N,N,O-trisubstituted hydroxylamine moiety in small-molecule optimization schemes in medicinal chemistry.

Study on the novel usnic acid derivatives: Design, synthesis, X-Ray crystal structure of Cu(II) complex and anti-AD activities

More and more evidence suggested that bio-metals including iron, zinc and copper play an important role in Alzheimer's disease (AD). Metal chelation agents may play an important role through promoting the metal homeostasis for AD treatment. In this study, UA (usnic acid), a natural product with antioxidant activity and metal chelation sites was selected as a lead compound. Different types of tertiary amine groups were introduced to synthesize four UA derivatives 1–4 as metal chelators and cholinesterase inhibitors since tertiary amine moiety was the key pharmacophore to inhibit cholinesterase. And the related activities such as antioxidant, anti-cholinesterase and metal chelation were evaluated. Results showed that 1–4 displayed excellent anti-oxidant activity, with lowest IC50 of 0.433 µM for ·OH scavenging ability and 8.808 µM for ·O2− scavenging ability. The mechanisms of anti-oxidant activities were furtherly studied by cyclic voltammetry. Besides, 1–4 also showed good anti-cholinesterase activities with lowest IC50 of 0.269 µM for acetylcholinesterase (AChE) and 0.361 µM for butyrylcholinesterase (BuChE). The results of molecular docking with AChE and BuChE were consistent with the experimental results. 1–4 displayed obvious chelating abilities with Cu(II) and Fe(III) by UV–vis spectra analysis and the metal complexes also showed good anti-AD activities. Interestingly, single crystal of Cu(II) complex of the hydrolyzed mono-substituted ligand was obtained which further substantiated the metal binding ability and provided clues to the anti-AD activities of the metal complex. Meanwhile, hydrolysis ratio of 4 was also tested by HPLC. Finally, BBB permeability of 1–4 was acceptable by ADMET prediction. Overall, these findings demonstrated that compounds 1–4 might be considered as potential candidates in the anti-AD therapy.

A hyperbranched P/N/B-containing oligomer as multifunctional flame retardant for epoxy resins

Flame-retardant epoxy resins (EPs) with superior optical, mechanical and dielectric properties are highly desired in high-tech industries. In this work, a multifunctional hyperbranched additive (BDHDP) was synthesized for EPs. Our results showed that BDHDP catalyzed the curing of epoxy resin because of its tertiary amine and hydroxyl groups. At a low addition level (<3.0 wt%), BDHDP increased the glass-transition temperature and maintained the optical transmittance of epoxy thermoset . Meanwhile, BDHDP improved the mechanical strength and toughness, and reduced the dielectric constant and loss of EP because of the rigid phosphaphenanthrene groups and intra-molecular cavities. Moreover, BDHDP reduced the heat release and smoke generation during the EP combustion. Adding 1.5 wt% of BDHDP led to a UL-94 V-0 rating, and reduced the total smoke production by 16.4%. Hence, this study offers an effective method to create transparent EP thermosets with outstanding mechanical, dielectric and fire-retardant properties via incorporating a P/N/B-containing hyperbranched oligomer .