Amine Salts Research Articles

Identification of Phormidium sp, (kützing ex Gomont 1892): a potential exopolymer for effective bioremediation

The autotrophic cyanobacterium Phormidium sp. is filamentous, blue-green, sheath-prominent, and trichome-constricted. DNA barcoding of the 16S rRNA sequence was submitted to NCBI-GenBank under the accession number MW436689, with a similarity of 97–99% with varied sequences. The Phormidium sp. barcode region had a high G + C content (52.7%). An investigation is underway to extract and characterize exocellular polymeric substances from Phormidium sp. (EPS-P) for efficacy analysis. FTIR, GC-MS, and NMR were used to characterize (EPS-P). FTIR suggests the presence of hydroxy groups (O-H moieties) and amine salts (N-H). GCMS shows D-galactose, L-rhamnose, D-mannose, uronic acid, and D-glucuronic acid. The specific chemical shifts could be identified in the 1H NMR spectra. EPS has been used in a variety of industrial and environmental applications. The ability to emulsify EPS-P (0.1%) was analyzed with various oils. The emulsifying index (EI) was observed to be gingelly oil > brake oil > neem oil > coconut oil > petrol oil > diesel oil (EI24-EI120 hours). EPS-P performed bio-flocculating activity at various concentrations (10-50 mg mL1). The flocculating activity of EPS-P shows 89.5% at 50 mg ml−1. The EPS-P could be an excellent candidate for bio-flocculation and bio-emulsification aspects that are also eco-friendly.

Phytogenic-Mediated Zinc Oxide Nanoparticles Using the Seed Extract of Citrullus lanatus and Its Integrated Potency against Multidrug Resistant Bacteria.

In the current research study, zinc oxide nanoparticles (ZnO-NPs) were synthesized via a green synthesis technique using the seed extract of Citrullus lanatus. The study further intended to evaluate the potential synergistic effects of ZnO-NPs with antibiotics against multidrug resistant (MDR) bacteria. It was observed that C. lanatus seed extracts obtained by n-hexane and methanolic solvents revealed the presence of constituents, such as tannins, flavonoids, and terpenoids. Furthermore, the extract of n-hexane displayed the strongest antibacterial activity against Yersinia species (17 ± 1.2 mm) and Escherichia coli (17 ± 2.6 mm), while the methanolic extract showed the maximum antibacterial activity against E. coli (17 ± 0.8 mm). Additionally, the ZnO-NP synthesis was confirmed by ultraviolet-visible analysis with a characteristic absorption peak at 280 nm. The Fourier transform infrared spectroscopy analysis suggested the absorption peaks in the 500-3800 cm-1 range, which corresponds to various groups of tertiary alcohol, aldehyde, amine, ester, aromatic compounds, thiol, amine salt, and primary amine. The scanning electron microscopy spectra of ZnO-NPs demonstrated the presence of zero-dimensional spherical particles with well-dispersed character. Moreover, encapsulation with ZnO-NPs improved the antimicrobial activity of antibiotics against the panel of MDR bacteria, and the increases in the effectiveness of particular antibiotics against MDR bacteria were significant (P = 0.0005). In essence, the synthesized ZnO-NPs have the potential as drug carriers with powerful bactericidal properties that work against MDR bacterial strains. These outcomes are an indication of such significance in pharmaceutical science, giving possibilities for further research and development in this field.

Cooperative Covalent–Noncovalent Organocatalysis of the Knoevenagel Condensation Based on an Amine and Iodonium Salt Mixture

AbstractThe experimentally obtained kinetic data has indicated the existence of a synergetic cocatalytic effect provided by an iodonium salt in the base‐catalyzed Knoevenagel condensation. The diphenyliodonium triflate serving as the halogen bond‐donating Lewis acid provides the higher cocatalytic effect than zinc(II) triflate or triflic acid serving, respectively, as the metal cation‐based Lewis acid and Brønsted acid. Such a cocatalytic effect remains the same for a broad scope of carbonyl compounds covering aldehydes featuring electron‐withdrawing or electron‐donating substituents, as well as ketone involved in the reaction.

Evaluation of Two Soil Surfactants for Soil Water Management of Creeping Bentgrass on a Wettable Clay Loam Rootzone During an Imposed Dry-down Period1

Abstract The use of soil surfactants is an established practice in turfgrass management. However, a reduction in irrigation water inputs has seldom been quantified on a mineral soil. The purpose of this one-season “proof-of-concept” field study was to apply soil surfactants to creeping bentgrass (Agrostis stolonifera ‘L-93’) on a clay loam rootzone and measure the amount and frequency of irrigation water needed to maintain a daily volumetric water content (VWC) above 25% with a maximum threshold of 35% during an imposed dry-down period. OARS HS (15.9 L·ha−1; 5 fl oz·1000 ft−2) or PBS150 (15.9 L·ha−1; 5 fl oz·1000 ft−2) soil surfactants each were applied three times (30 March, 27 April, 26 May 2016; 28-day interval) prior to a 63-day dry-down period (8 June - 9 August 2016). Compared to maintaining untreated plots irrigated to 35% VWC daily or untreated plots irrigated by threshold, plots treated with OARS HS or PBS150 resulted in a mean range of 36.5 to 41.9% reduction in water applied, and a mean range of 41.6 to 69.7% reduction of irrigation events. Use of soil surfactants in this field study resulted in a statistically significant (p < 0.05) savings in both amount and frequency of irrigation water inputs while maintaining acceptable turfgrass quality. Species used in this study: creeping bentgrass (Agrostis stoloniferous L. ‘L-93’). Chemical soil surfactants used in this study: PBS150 (100% polyoxyalkylene polymers; AquaAid Solutions, Rocky Mount, NC); OARS HS (85% octahydroxy polyoxyalkyene polymers, 7.5% amine salt of alkyl substituted maleic acid, and 7.5% inert ingredient; AquaAid Solutions, Rocky Mount, NC).

Effect of Water in the Trimer‐Cyclisation of Alkynyl Ketone

AbstractA trimer‐cyclisation reaction of propiolate esters yielded 1,3,5‐benzenetricarboxylate tri‐esters in water. The reaction proceeded selectively in the presence of secondary or tertiary amine salts in pure water solvent. Other organic solvents, such as dimethyl formamide, tetrahydrofuran, and ethanol, afforded a 1 : 1 adduct of propiolate and amine. The hydrogen bonding characteristics of water stabilised the proposed intermediate in a conformation that promoted the final cyclisation. The synthesis can be successfully conducted in water–a universal and an eco‐friendly solvent.

Preparation and Properties of Mechanically Robust, Colorless, and Transparent Aramid Films.

In this study, various diamine monomers were used to synthesize aramid polymer films via a low-temperature solution condensation reaction with diacid chloride. For diamines with relatively high basicity, the reaction system became opaque because amine salt formation inhibited polymer synthesis. Meanwhile, low-basicity diamines with strong electron-withdrawing groups, such as CF3 and sulfone, were smoothly polymerized without amine salt formation to provide highly viscous solutions. The acid byproduct HCl generated during polymerization was removed by adding propylene oxide to the reaction vessel and converting the acid into highly volatile inert substances. The resulting solutions were used as varnishes without any additional purification, and polymer films with an excellent appearance were easily obtained through a conventional casting and convection drying process. The films neither tore nor broke when pulled or bent by hand; furthermore, even when heated up to 400 °C, they did not decompose or melt. Moreover, polymers prepared from 2,2-bis(trifluoromethyl)benzidine (TFMB) and bis(4-aminophenyl)sulfone (pAPS) did not exhibit glass transition until decomposition. The prepared polymer films showed a high elastic modulus of more than 4.1 GPa and a high tensile strength of more than 52 MPa. In particular, TFMB-, pAPS-, and 2,2-bis(4-aminophenyl)hexafluoropropane-based polymer films were colorless and transparent, with very high light transmittances of 95%, 96%, and 91%, respectively, at 420 nm and low yellow indexes of 2.4, 1.9, and 4.3, respectively.

Corrosion Investigation of Carbon Steel in Different Amine-Based CO2 Removal System

The steel industry is a major source of CO2 emissions, which is affecting the corrosion behavior of carbon steel. The corrosion behavior of carbon steel (C1018) absorbed for CO2 removal is examined in different blends of amine solution by adding a heat-stable salt neutralizer and increasing amine concentration. Corrosion of carbon steel using different methyldiethanolamine (MDEA)/ (5% piperazine amine solution) which had 26% amine solution that contained heat stable amine salts treated with neutralizer at 80 °C and CO2 loading was investigated. The effect of the treated solutions on the corrosion behavior was observed using either the K2CO3 treatment solution to reach 30% amine or increasing the concentration to 33% amine solution using weight loss, potentiodynamic polarization, cyclic voltammetry, and impedance measurements. A visual examination of the corroded samples of the different amine solutions was performed. XRD for phase identification and SEM for microstructure examination were used to describe the corroded surfaces and analyze the corrosion products on the specimen surfaces under different conditions. After nine days in the 30% amine solution, these analyses showed the formation of the FeCO3 protective layer. The carbon steel in 30% amine solution provides better protection, and the lowest corrosion resistance (39.9 µm/Y).

Phytoconstituents, Fourier-Transform Infrared Characterization, and Antioxidant Potential of Ethyl Acetate Extract of Corchorus olitorius (Malvaceae)

Oxidative stress is a condition that is characterized by the generation of reactive oxygen species more than the amount endogenous antioxidants can absorb. Several diseases are associated with oxidative stress, notably during disease progression. Thus, the present study aimed to determine the phytoconstituents and antioxidant potential of the ethyl acetate leaf extract of Corchorus olitorius (ELEC). The phytochemicals were qualitatively and quantitatively determined, followed by characterization using Fourier-transform infrared (FTIR) spectroscopy. The antioxidant potential was determined in vitro. Alkaloids, saponins, and flavonoids were detected in concentrations of 8.50 ±2.65, 11.83 ±0.73, and 19.17% ±0.73, respectively. The FTIR spectrum revealed 9 peaks including six at the group frequency region corresponding to alcohols, carboxylic acid, amine salts, alkenes, alkyne, esters, and oxime functional groups. The ELEC exhibited lower total reducing power (11.06 ±1.34 AAE µg/ml) compared to its total antioxidant capacity (49.26 ±2.44 AAE µg/ml) with a higher (60.47% ±2.44) percentage inhibition of peroxidation than AA (37.98% ±1.88). Furthermore, the ELEC exhibited a lower (0.20 ±0.01 nmol/ml) MDA concentration than AA (0.42 ±0.02 nmol/ml). Conclusively, C. olitorius might be applied for the management of oxidative stress-linked ailments and a source of novel therapeutics for these ailments.

Design, synthesis and anticholinergic properties of novel α-benzyl dopamine, tyramine, and phenethylamine derivatives

Due to the important biological properties of dopamine, phenethylamine, and tyramine derivatives in the central nervous system, herein the synthesis of novel α-benzyl dopamine, phenethylamine, and tyramine derivatives is described. The title compounds were synthesized starting from 3-phenylpropanoic acids and methoxybenzenes in six or seven steps. Firstly, 3-(2,3-dimethoxyphenyl)propanoic acid (11) and 3-(3,4-dimethoxyphenyl)propanoic acid (12) were selectively brominated with N-bromosuccinimide (NBS). The Friedel–Crafts acylation of methoxylated benzenes with these brominated acids or commercially available 3-phenylpropanoic acid in polyphosphoric acid gave the desired dihydrochalcones. α-Carboxylation of dihydrochalcones, reduction of benzylic carbonyl groups, hydrolysis of esters to acid derivatives, and the Curtius rearrangement reaction of acids followed by in situ synthesis of carbamates from alkyl isocyanates and hydrogenolysis of the carbamates afforded the title compounds in good total yields. Alzheimer's disease (AD) and Parkinson's disease (PD) are chronic neurodegenerative diseases that become serious over time. However, the exact pathophysiology of both diseases has not been revealed yet. There have been many different approaches to the treatment of patients for many years, especially studies on the cholinergic system cover a wide area. Within the scope of this study, the inhibition effects of dopamine-derived carbamates and amine salts on the cholinergic enzymes AChE and BChE were examined. Dopamine-derived carbamate 24a-i showed inhibition in the micro-nanomolar range; compound 24d showed a Ki value of 26.79 nM against AChE and 3.33 nM against BChE, while another molecule, 24i, showed a Ki range of 27.24 nM and 0.92 nM against AChE and BChE, respectively. AChE and BChE were effectively inhibited by dopamine-derived amine salts 25j-s, with Ki values in the range of 17.70 to 468.57 µM and 0.76–211.23 µM, respectively. Additionally, 24c, 24e and 25m were determined to be 60, 276 and 90 times more selective against BChE than AChE, respectively.

Highly efficient DES-based catalytic systems for carbon dioxide utilization via cycloaddition with epoxide substrates

The accumulation of greenhouse gases (GHG) in the atmosphere, with carbon dioxide being the most significant contributor, is a major environmental problem as it impacts significantly on climate change. The development of new catalysts and chemical reactions that incorporate CO2 are needed to reduce its further emission significantly. Deep eutectic solvents (DES) have garnered increasing attention as environmentally friendly catalysts in the cycloaddition of carbon dioxide (CO2) with epoxide substrates to produce cyclic carbonates. Their appeal stems from their facile synthesis, cost-effectiveness, low vapour pressure, and thermal stability. In this study, we present a convenient solvent-free synthesis method for nine deep eutectic solvents (DES), utilizing varying compositions of quaternary amine salts (N,N,N-triethyldodecan-1-aminium hydroxide, [TEA-12][OH]) and quinaldic acid [Q-COOH]. These deep eutectic solvents were thoroughly characterized using several techniques, including FTIR, NMR, DSC, and TGA. Moreover, their efficacy for the solvent-free fixation of CO2 to cyclic carbonates were evaluated. Among the tested compositions, [TEA-12]:[Q-COOH] (0.9:0.1) exhibited the lowest melting point (100.17 °C) and highest catalytic activity, showcasing an optimized Turn-Over Frequency (TOF) of 1466 h−1. This remarkable result represents a significant advancement in the application of DES for CO2 fixation, exceeding the previous highest catalytic activity observed with TBAB:Citric acid (2.5:1) by more than tenfold.

Copper-catalyzed carbonylative multi-component borylamidation of alkenes for synthesizing γ-boryl amides with CO as both methylene and carbonyl sources.

A multi-component carbonylation reaction is an efficient strategy for the synthesis of valuable carbonyl compounds from simple and readily available substrates. However, there remain challenges in carbonylation reactions where two CO molecules are converted to different groups in the target product. Considering the merit of complex amides, we reported here a copper-catalyzed multi-component borylamidation for the synthesis of γ-boryl amides. This method provides access to a wide range of functional γ-boryl amides from alkenes, amines, B2pin2, and CO with good yields and excellent diastereomeric ratios. Notably, two CO molecules were converted to methylene and carbonyl groups in the target amides. A series of amines were successfully involved in the transformation, including arylamines, aliphatic amines, and hydrochloride salts of secondary aliphatic amines.

Concentration-tuned diverse response to selective biogenic amines using a reusable fluorophore: monitoring protein-rich food spoilage.

Maintaining the freshness of food is essential for a healthy and quality life. Nevertheless, it remains a global challenge. Hence, an easy detection and monitoring protocol would be highly desirable. A cyanoacrylic acid (CAA)-based fluorophore is manifested as a reusable platform that responds diversely against different concentrations of selective aliphatic biogenic amines (BAs) in both solution and vapor phases. Slow spoilage of the protein-rich food is progressively monitored through emission shifts visible to the naked eye. This fluorophore provides easy and naked-eye detection of the BA vapor through a change in emission, i.e., red → orange → orange-yellow → cyan → green and quantum yield enhancement, which occur in stepwise increments of vapor concentrations. The probe design includes π-conjugated functionalized fluorescent molecules linked to multiple twisting sites, resulting in both solid and solution-state emission. The attached carboxylic acid responds quickly with selective BAs, mainly putrescine (PUT), cadaverine (CAD), and spermidine (SPM), where the concentration-based emission variation has appeared to be distinct and prominent against PUT [sensitivity (μM): 2 (solution); 3.3 (vapour)]. The selectivity towards diamine can be clarified by the formation of carboxylic acid salts and the consequent proton exchanges between free and protonated amines. In addition, -CN···H interaction is likely to develop within this ammonium carboxylate system, providing extra stability. Such ammonium carboxylate salt formation and gradual change in the molecular arrangement, resulting in symmetry development, are validated by FT-IR and wide-angle X-ray diffraction studies. Besides, this fact is supported by DFT studies that validate intramolecular H-atom exchange between free amine and ammonium salt units. A fluorophore-coated coverslip, filter paper, or silica gel-coated Al-plate is fruitfully utilized to detect the freshness of fish and chicken, which reveals the potential of this probe to prevent food waste and control food safety.

Synthesis of Zinc Oxide Nanoparticles using Extract of Cynodon dactylon and Assessment of their Biological Activity against Staphylococcus aureus and Escherichia coli

Nanotechnology is a groundbreaking technology that that has been widely applied in creating materials which are useful in various fields. It's important to maintain eco-friendly approaches for synthesis of nanoparticles by diversifying the substrate sources. In this study, the researchers used aqueous extract of Cynodon dactylon to synthesize zinc oxide nanoparticles (ZnONPs). Quantitative phytochemical analysis of the extract showed high concentrations of alkaloids, flavonoids, carbohydrates, proteins, amino acids, and phenolic compounds. In contrast, moderate concentrations of tannins, oils, and fats, and low concentrations of phlorotannins, saponin, triterpenoids, and cardiac glycosides were found. Sterols, anthraquinone glycosides, gums, and mucilages were not detected in the extract. The synthesized ZnONPs showed absorbance ranging from 293 nm to 336 nm, with a peak at 307 nm. Fourier transform infrared (FTIR) spectroscopy revealed that the surface of the ZnONPs contained alcohol (intermolecular bonded), alkyne, amine salt, alkane, alkyne, aromatic compounds, conjugated alkene, amine, nitro compound, sulfonyl chloride, alkylaryl ether, and sulfoxide. Dynamic light scatering (DLS) analysis of the ZnONPs showed that its average size was 35.34±1.64 nm, and the polydispersity index was 0.6335. Spectrum of X ray diffraction indicated that peaks formed at 2θ and their corresponding orientation planes are 31.92o (100), 34.62o (002), 36.44o (101), 47.64o (102), 56.84o (110), 63.3o (200), and 68.16o (112). Transmission electron micrograph revealed the spherical shape, and nonuniform sizes of ZnONPs, which ranged from 0.52 nm to 8.32 nm. Antibacterial analysis of biosynthesized ZnONPs recorded 16±3.2 mm and 6.0±2.2 mm; 6.7±2.1 mm and 4.33±1.3 mm, 0.0±0.0 mm and 1.0±1.41 mm, against Staphylococcus aureus and Escherichia coli, at 53.3 mg/mL, 26.7 mg/mL and 13.3 mg/ml concentrations, respectively. At sub-inhibitory concentrations, biosynthesized ZnONPs demonstrated effective dose-dependent antibiofilm formation activity against E. coli and S. aureus. Consequently, extract of Cynodon dactylon is suitable for biosynthesis of ZnONPs with effective antibacterial and antibiofilm formation activities.

Application of Amine Salts of Glycyrrhizinic Acid for Prevention of Grape Rot during the Storage Period

Application of Amine Salts of Glycyrrhizinic Acid for Prevention of Grape Rot during the Storage Period

Modulating the Distribution of Formamidinium Iodide by Ultrahigh Humidity Treatment Strategy for High-Quality Sequential Vapor Deposited Perovskite.

The quality of two-step processed perovskites is significantly influenced by the distribution of organic amine salts. Especially, modulating the distribution of organic amine salts remains a grand challenge for sequential vapor-deposited perovskites due to the blocking effect of bottom compact PbI2. Herein, an ultrahigh humidity treatment strategy is developed to facilitate the diffusion of formamidinium iodide (FAI) from the top surface to the buried bottom interface on the sequential vapor-deposited bilayer structure. Both experimental and theoretical investigations elucidate the mechanism that moisture helps to i) create FAI diffusion channels by inducing a phase transition from α- to δ-phase in the perovskite, and ii) enhance the diffusivity of FAI by forming hydrogen bonds. This ultrahigh humidity treatment strategy enables the formation of a desired homogeneous and high-quality α-phase after annealing. As a result, a champion efficiency of 22.0% is achieved and 97.5% of its initial performance is maintained after aging for 1050 h under ambient air with a relative humidity of up to 80%. This FAI diffusion strategy provides new insights into the reproducible, scalable, and high-performance sequential vapor-deposited perovskite solar cells.

Proanthocyanidins from Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Leaves Effectively Inhibit the Formation of Biogenic Amines in the Brewing Soy Sauce

Biogenic amines are a group of metabolites generated in the process of soy sauce brewing, which can result in severe negative impacts on human health at high concentrations. In this study, we innovatively proposed natural extracts (0.1 wt%), of proanthocyanidins, from Chinese bayberry (Myrica rubra Sieb. et Zucc.) leaves to alternate commercial additives (0.1 wt%), i.e., sodium benzoate and potassium sorbate, for lowering the harmful biogenic amine formation during the fermentation of soy sauce. HPLC results showed that natural extracts from Chinese bayberry leaves could effectively decrease the content of cadaverine, putrescine, histamine, tyramine, phenylethylamine, and agmatine (p < 0.05). In contrast to the inhibitory influence exhibited by commercial sodium benzoate and potassium sorbate, extracts from bayberry leaves can maintain spermidine, spermine, and tryptamine at certain concentrations. Furthermore, both sodium benzoate and potassium sorbate significantly reduced the production of ammonium salt and characteristic components (p < 0.05), like soluble saltless solids, total nitrogen, and amino acid nitrogen, during the 40-day fermentation of soy sauce, whereas proanthocyanidins extracted from Chinese bayberry leaves slightly inhibited the content of ammonium salt. Thus, we can conclude that, while inhibiting the biogenic amine and ammonium salt production, extracts from Chinese bayberry leaves facilitate or maintain the production of characteristic indicators compared to commercial sodium benzoate and potassium sorbate. Taken together, natural extracts from Chinese bayberry leaves can be considered a natural additive to significantly improve the quality of traditional brewing soy sauce.

Ammonium-Amine Co-Activation: Promoting the Sulfurization of Azurite and Its Effect on Xanthate Adsorption.

Enhanced sulfurization has always been the focus of research on the flotation of copper oxide minerals. In this study, combined ammonium-amine salts were innovatively applied to improve the sulfurization of azurite. Flotation tests were carried out to evaluate the promoting effect of ammonium-amine co-activation on the sulfurization-xanthate flotation of azurite, and the microstructure evolution of sulfurized products was investigated to reveal the mechanism underlying this promoting effect. Compared with single ammonium (amine) salt activation, ammonium-amine co-activation improved the floatability of azurite to a greater extent, i.e., the flotation recovery increased by over 4 percentage points. ToF-SIMS, ICP-OES, FESEM-EDS, AFM, XRD, and UV-vis analyses indicated that ammonium-amine co-activation combined the advantages of inorganic ammonium for buffering pH and organic amine for copper ion complexation, thus promoting the growth of sulfurized crystal products (covellite) and enhancing the adhesion stability of sulfurized products on azurite. Therefore, increasing amounts of copper sulfide components were generated under the ammonium-amine-Na2S system, promoting the adsorption of additional xanthate on azurite. This study provides theoretical support for the application of combined ammonium-amine salts for the sulfurization flotation of copper oxide.

Synthesis of mixed phase morphologies of copper oxide nanoparticles using bis(n-benzyl-salicydenaminato)copper(II) as a precursor

A primary amine, salicylaldehyde and copper salt were combined to prepare the bis(Nbenzyl-salicydenaminato)copper (II) complex. The copper (II) complex was then used as a precursor to synthesize mixed phase morphological copper oxide nanoparticles via thermal decomposition method using trioctylphosphine oxide as a capping molecule at different temperatures of 120, 180, and 240 ºC. The XRD patterns of copper oxide nanoparticles synthesized at lower temperatures exhibit a mixture of monoclinic structure of CuO whereas the nanoparticles synthesized at higher temperature reveals the peaks that are attributed to mainly face-centered-cubic metallic Cu. The TEM images showed spherical particles that were increasing in sizes when the temperature was raised.

Mussel-inspired antibacterial sponge for highly efficient water purification and sterilization

With the current expansion of urban areas and industrial development, the increasing discharge of wastewater containing bacteria poses a threat to human health. Although substantial advancements have been made in antibacterial materials, there is still a need for an efficient method that can thoroughly remove bacteria through sterilization and adsorption during wastewater treatment. Here, we report a mussel-inspired antibacterial sponge with outstanding antibacterial efficiency exceeding 95% and a high removal ratio of the bacterial corpses for water purification after contacting for 30 min. The high-efficient antibacterial performance is attributed to the stable releasing property of Ag+ and the charge interaction with quaternary amine salts. Combining the key features, including high-efficient, synergistic mechanism, and corpse capture, the antibacterial sponge shows excellent disinfection effects. This study provides a new method for water purification without bacterial residue.

Syntheses and structural characterization of tris- and tetrakis(aminopyridinate) complexes of lanthanum

Treatment of three equivalents of potassium salts of N-arylated 2-pyridyl amines, [HN(C6H3Pri2-2,6)(2-C5H3N)] (1) and [HN(C6H3Pri2-2,6)(2-C5H3N-6-Me)] (2) with anhydrous LaBr3 in tetrahydrofuran (THF), afforded after workup in hexane the corresponding rare examples of tris(amiopyridinate) La(III) complexes, [La{N(C6H3Pri2-2,6)(2-C5H3N)}3(thf)] (3) and [La{N(C6H3Pri2-2,6)(2-C5H3N-6-Me)}3] (4) in 77% and 71% yields, respectively. X-ray analysis of 4 further confirms the monomeric nature in the solid state. Owing to the low steric bulk of the aminopyridine ligand in 3, one thf ligand is coordinated to La atom. Attempted reduction of 3 with KC8 in the presence of 12-crown-4-ether to synthesize the corresponding La(II) complex, instead resulted in the formation of [La{N(C6H3Pri2-2,6)(2-C5H3N)}4{K(12-crown-4-ether)] (5). In contrast, the analogous reaction with 4 led to [K{N(C6H3Pri2-2,6)(2-C5H3N-6-Me)}{(12-crown-4-ether)2}] along with unidentified products. Complex 5 is the first example of mononuclear tetrakis(aminopyridinate) lanthanoidate complexes.