Naphthoic Acid Research Articles

Adapalene as a chemical sensor for sensitive determination of manganese

ABSTRACT The work describes the use of 6-[3-(1-adamantyl)-4-methoxyphenyl]-2- naphthoic acid, or Adapalene (ADP) as a fluorescence tagging reagent, in a straightforward and very specific spectrofluorometric approach for the trace measurement of manganese (VII) in water. The process is based on the redox interaction of ADP with manganese (VII) in an acidic solution, which forms the complex [Mn (II)-ADP] and causes fluorescence at λex max/λem max = 323/400 nm. High-intensity fluorescence at 400 nm was seen in the fluorescence spectra of the formed complex ion association, Mn (II)-ADP, at pH 4. 1.55 µg mL−1 was the quantification limit, and 0.51 µg mL−1 was the detection limit and the correlation coefficient (R2) was 0.9863. 1.2173 L mol−1 was determined to be the Stern-Volmer. Spectrofluorometric technique is used to validate the approach in environmental water samples, yielding reasonable recovery percentages (89–93%). The current approach is advised to be used for reliable and accurate assessment of manganese (VII) in all wastewater and seawater samples, without the need for complex instrumentation and lengthy procedures.

Protein-driven interaction enhanced electrochemiluminescence biosensor of hydrogen-bonded biohybrid organic frameworks for sensitive immunoassay of disease markers

The oriented design of reticular materials as emitters can significantly enhance the sensitivity of electrochemiluminescence (ECL) sensing analysis for disease markers. However, due to the structural fragility of hydrogen bonds, relational research on hydrogen-bonded organic frameworks (HOFs) has not been thoroughly conducted. Additionally, the modulation of luminescence behavior through HOFs has been rarely reported. In view of this, hydrogen-bonded biohybrid organic frameworks (HBOFs) were synthesized and recruited for ECL immunoassay applications. HBOFs was easily prepared using 6,6′,6″,6‴-(pyrene-1,3,6,8-tetrayl)tetrakis(2-naphthoic acid) as linkers via bovine serum albumin (BSA) activated hydrogen-bonded cross-linking. The material exhibited good fluorescence emission characteristics. And the highly ordered topological structure and molecular motion limitation mediated by BSA overcome aggregation-caused quenching and generate strong aggregation induced emission, expressing hydrogen-bond interaction enhanced ECL (HIE-ECL) activity with the participation of tri-n-propylamine. Furthermore, a sandwich immunosensor was constructed employing cobalt-based metal-phenolic network (CMPN) coated ferrocene nanoparticles (FNPs) as quenchers (CMPN@FNPs). Signal closure can be achieved by annihilating the excited state through electron transfer from both CMPN and FNPs. Using a universal disease marker, carcinoembryonic antigen, as the analysis model, the signal-off sensor obtained a detection limit of 0.47 pg/mL within the detection range of 1 pg/mL - 50 ng/mL. The synthesis and application of highly stable HBOFs triggered by proteins provide a reference for the development of new reticular ECL signal labels, and electron transfer model provides flexible solutions for more sensitive sensing analysis.

Synthesis of Nanocellulose Derivatives through Esterification with Naphthoic Acid as a Fluorescent Additive

Synthesis of Nanocellulose Derivatives through Esterification with Naphthoic Acid as a Fluorescent Additive

Ligand-enabled ruthenium-catalyzed meta-C−H alkylation of (hetero)aromatic carboxylic acids

Carboxylates are ideal directing groups because they are widely available, readily cleavable and excellent linchpins for diverse follow-up reactions. However, their use in meta-selective C−H functionalizations remains a substantial unmet catalytic challenge. Herein, we report the ruthenium-catalyzed meta-C–H alkylation of aromatic carboxylic acids with various functionalized alkyl halides. A bidentate N-ligand increases the electron density at the metal center of ortho-benzoate ruthenacycles to the extent that single-electron reductions of alkyl halides can take place. The subsequent addition of alkyl radicals is exclusively directed to the position para to the CAr–Ru bond, i.e., meta to the carboxylate group. The resulting catalytic meta-C−H alkylation extends to a wide range of (hetero)aromatic carboxylic acids including benzofused five-membered ring heteroarenes but no pyridine derivatives in combination with secondary/tertiary alkyl halides, including fluorinated derivatives. It also allows site-selective C5−H alkylation of 1-naphthoic acids. The products are shown to be synthetic hubs en route to meta-alkylated aryl ketones, nitriles, amides, esters and other functionalized products.

Aluminum Molecular Ring Meets Deep Eutectic Solvents: Adaptive Assembly and Optical Behavior.

Different from the previous neutral reaction solvent system, this work explores the synthesis of Al-oxo rings in ionic environments. Deep eutectic solvents (DESs) formed by quaternary ammonium salts hydrogen bond acceptor (HBA) and phenols hydrogen bond donor (HBD) further reduce the melting point of the reaction system and provide an ionic environment. Further, the quaternary ammonium salt was chosen as the HBA because it contains a halogen anion that matches the size of the central cavity of the molecular ring. Based on this thought, five Al8 ion pair cocrystals were synthesized via "DES thermal". The general formula is Q+ ⊂ {Cl@[Al8(BD)8(μ2-OH)4L12]} (AlOC-180-AlOC-185, Q+ = tetrabutylammonium, tetrapropylammonium, 1-butyl-3-methylimidazole; HBD = phenol, p-chlorophenol, p-fluorophenol; HL = benzoic acid, 1-naphthoic acid, 1-pyrenecarboxylic acid, anthracene-9-carboxylic acid). Structural studies reveal that the phenol-coordinated Al molecular ring and the quaternary ammonium ion pair form the cocrystal compounds. The halogen anions in the DES component are confined in the center of the molecular ring, and the quaternary ammonium cations are located in the organic shell. Such an adaptive cocrystal binding pattern is particularly evident in the structures coordinated with low-symmetry ligands such as naphthoic acid and pyrene acid. Finally, the optical behavior of these cocrystal compounds is understood from the analysis of crystal structure and theoretical calculation.

Engineering Internal and External Low-Coordination Atoms in Nickel-Organic Framework Nanoarrays to Promote the Electrochemical Oxygen Evolution Reaction.

Monometallic nickel-organic frameworks based on a carboxylated ligand [2,6-naphthalenedicarboxylic acid (Ni-NDC)] have abundant and uniformly distributed single-atom Ni sites, enabling superior oxygen evolution reaction (OER) activity. In theory, most of the Ni atoms inside Ni-NDC microcrystals are coordinatively saturated except for the surface. Therefore, there are no accessible low-coordination atoms (LCAs) as electrocatalytic sites for the OER. One effective way is to expose more LCAs by preparing self-supporting Ni-NDC nanoarrays (Ni-NDC NAs) with hierarchical secondary structural units. Another effective method is to create more internal LCAs by removing partial ligands or coordination atoms attached to the Ni atoms. Herein, by combining the two strategies, we engineered LCAs in the interior and exterior of Ni-NDC to synergistically accelerate the OER. In brief, ultrathick "brick-like" Ni-NDC NAs were first prepared with dissolution and coordination effects of NDC on self-sacrificial templates of "agaric-like" nickel hydroxide nanoarrays [Ni(OH)2 NAs]. Subsequently, dual-coordinated NDC was partially replaced by monocoordinated 2-naphthoic acid (NA). The Ni-NDC NAs were further tailed into ultrathin "liner leaf-like" nanoneedle arrays (LCAs-Ni-NDC NAs). As a consequence, the LCAs-Ni-NDC NAs have more internal and external LCAs, which can deliver an OER performance that is superior to that of Ni-NDC NAs.

Naphthoic Acid Derivatives as Photosensitizers for Short-wavelength α-Hydroxyacetophenone Photoinitiators

Naphthoic Acid Derivatives as Photosensitizers for Short-wavelength α-Hydroxyacetophenone Photoinitiators

NMDA Receptor Antagonists: Emerging Insights into Molecular Mechanisms and Clinical Applications in Neurological Disorders

Neurodegenerative disorders (NDs) include a range of chronic conditions characterized by progressive neuronal loss, leading to cognitive, motor, and behavioral impairments. Common examples include Alzheimer’s disease (AD) and Parkinson’s disease (PD). The global prevalence of NDs is on the rise, imposing significant economic and social burdens. Despite extensive research, the mechanisms underlying NDs remain incompletely understood, hampering the development of effective treatments. Excitotoxicity, particularly glutamate-mediated excitotoxicity, is a key pathological process implicated in NDs. Targeting the N-methyl-D-aspartate (NMDA) receptor, which plays a central role in excitotoxicity, holds therapeutic promise. However, challenges, such as blood–brain barrier penetration and adverse effects, such as extrapyramidal effects, have hindered the success of many NMDA receptor antagonists in clinical trials. This review explores the molecular mechanisms of NMDA receptor antagonists, emphasizing their structure, function, types, challenges, and future prospects in treating NDs. Despite extensive research on competitive and noncompetitive NMDA receptor antagonists, the quest for effective treatments still faces significant hurdles. This is partly because the same NMDA receptor that necessitates blockage under pathological conditions is also responsible for the normal physiological function of NMDA receptors. Allosteric modulation of NMDA receptors presents a potential alternative, with the GluN2B subunit emerging as a particularly attractive target due to its enrichment in presynaptic and extrasynaptic NMDA receptors, which are major contributors to excitotoxic-induced neuronal cell death. Despite their low side-effect profiles, selective GluN2B antagonists like ifenprodil and radiprodil have encountered obstacles such as poor bioavailability in clinical trials. Moreover, the selectivity of these antagonists is often relative, as they have been shown to bind to other GluN2 subunits, albeit minimally. Recent advancements in developing phenanthroic and naphthoic acid derivatives offer promise for enhanced GluN2B, GluN2A or GluN2C/GluN2D selectivity and improved pharmacodynamic properties. Additional challenges in NMDA receptor antagonist development include conflicting preclinical and clinical results, as well as the complexity of neurodegenerative disorders and poorly defined NMDA receptor subtypes. Although multifunctional agents targeting multiple degenerative processes are also being explored, clinical data are limited. Designing and developing selective GluN2B antagonists/modulators with polycyclic moieties and multitarget properties would be significant in addressing neurodegenerative disorders. However, advancements in understanding NMDA receptor structure and function, coupled with collaborative efforts in drug design, are imperative for realizing the therapeutic potential of these NMDA receptor antagonists/modulators.

Deep eutectic solvents as a green alternative to organic solvents for β-cyclodextrin pseudo-stationary phase in capillary electrophoresis

β-cyclodextrin (β-CD), as an important pseudo-stationary phase (PSP) in capillary electrophoresis (CE), frequently confronts challenges stemming from its limited water solubility, particularly when high concentrations are required for resolving complex analytes. Traditionally, researchers often resort to the use of (toxic) organic solvents to enhance the solubility of β-CD, establishing non-aqueous capillary electrophoresis (NACE) for specific separations. However, such practices are hazardous to health and run counter to the principles of green analytical chemistry. In this study, we demonstrate a deep eutectic solvent (DES), Proline:Urea (PU), as a promising alternative to conventional organic solvents for β-CD-based CE separations. The DES exhibits a solubility of up to 30% for β-CD, a significant improvement compared to the 1.8% solubility in the aqueous phase. Utilizing this DES-type separation medium, we achieved simultaneous baseline separation of a complex analyte composed of eight structurally similar naphthoic acid derivatives. Furthermore, we conducted a systematic comparison of β-CD's performance in aqueous CE buffers, organic solvents, and DESs, highlighting the superiority of this novel and environmentally friendly CE separation medium.

Naphthenic acids removal using N-doped hemp fibers based mesoporous carbon from aqueous waste stream

There is a substantial need for removing the contaminants from aqueous waste stream using affordable, stable, and active adsorbents, such as heteroatom-doped carbonaceous materials. Heteroatom such as N-doped carbonaceous materials greatly improve the performance of carbon materials by enhancing their conductivity, basicity, oxidation stability, catalytic activity and adsorption capacity. In this study, hemp fibers (HFs) and N-aminoguanidine were utilized as carbon and nitrogen precursors to synthesize N-functionalized mesoporous carbon materials (N-HFCs) via simultaneous activation and carbonization with ZnCl2. Higher BET surface area with a distinctive mesoporous structure and the covalent bond between N and C was developed in the prepared carbon, making N-HFCs suitable for adsorbing naphthenic acids (2-naphthoic acid and benzoic acid) from aqueous waste streams. Developed covalent bond helps to prevent the leaching of carbonaceous materials during adsorption study. The results showed that N-HFC-2 (ZnCl2: N-HFs ratio = 2:1) exhibited a higher removal efficiency of naphthenic acids (2-naphthoic acid and benzoic acid) compared to nonfunctionalized porous carbon (HFC). Adsorption of 2-naphthoic acid and benzoic acid on the adsorbents followed the typical monolayer type of Langmuir adsorption model. The maximum adsorption capacity of HFC after 48 h was evaluated as 70 and 27 mg/g for 2-naphthoic acid and benzoic acid. Likewise, the maximum adsorption capacity of N-HFC-2 for 2-naphthoic acid and benzoic acid was found to be 71 and 33 mg/g. In the adsorption kinetic experiment, adsorption of 2-naphthoic acid and benzoic acid reached equilibrium within 1 h using both the adsorbents (N-HFC-2 and HFC). Adsorption kinetics were analyzed using pseudo-first-order and pseudo-second-order kinetic models and were found to follow a pseudo-second-order kinetic model. Although changing pH from 4.4 to 8.5 did not have any significant effect on the removal efficiency of 2-napthoic acid using HFC and N-HFC-2, the removal efficiency of benzoic acid was decreased from 94 to 60 % using HFC and increased from 98 to 100 % using N-HFC-2. Comparative evaluations demonstrated that the mesoporous carbonaceous materials derived from HFs are an attractive adsorbent for removal of such contaminants from contaminated aqueous streams.

Design, Synthesis and Biological Evaluation of Novel Phenyl-Substituted Naphthoic Acid Ethyl Ester Derivatives as Strigolactone Receptor Inhibitor.

Strigolactones (SLs) are plant hormones that regulate several key agronomic traits, including shoot branching, leaf senescence, and stress tolerance. The artificial regulation of SL biosynthesis and signaling has been considered as a potent strategy in regulating plant architecture and combatting the infection of parasitic weeds to help improve crop yield. DL1b is a previously reported SL receptor inhibitor molecule that significantly promotes shoot branching. Here, we synthesized 18 novel compounds based on the structure of DL1b. We performed rice tillering activity assay and selected a novel small molecule, C6, as a candidate SL receptor inhibitor. In vitro bioassays demonstrated that C6 possesses various regulatory functions as an SL inhibitor, including inhibiting germination of the root parasitic seeds Phelipanche aegyptiaca, delaying leaf senescence and promoting hypocotyl elongation of Arabidopsis. ITC analysis and molecular docking experiments further confirmed that C6 can interact with SL receptor proteins, thereby interfering with the binding of SL to its receptor. Therefore, C6 is considered a novel SL receptor inhibitor with potential applications in plant architecture control and prevention of root parasitic weed infestation.

A prenyltransferase participates in the biosynthesis of anthraquinones in Rubia cordifolia.

Anthraquinones (AQs) constitute the largest group of natural quinones, which are used as safe natural dyes and have many pharmaceutical applications. In plants, AQs are biosynthesized through two main routes: the polyketide pathway and the shikimate pathway. The latter primarily forms alizarin-type AQs, and the prenylation of 1,4-dihydroxy-2-naphthoic acid (DHNA) is the first pathway-specific step. However, the prenyltransferase (PT) responsible for this key step remains uncharacterized. In this study, the cell suspension culture of Madder (Rubia cordifolia), a plant rich in alizarin-type AQs, was discovered to be capable of prenylating DHNA to form 2-carboxyl-3-prenyl-1,4-naphthoquinone and 3-prenyl-1,4-naphthoquinone. Then, a candidate gene belonging to the UbiA superfamily, R. cordifoliadimethylallyltransferase 1 (RcDT1), was shown to account for the prenylation activity. Substrate specificity studies revealed that the recombinant RcDT1 recognized naphthoic acids primarily, followed by 4-hydroxyl benzoic acids. The prenylation activity was strongly inhibited by 1,2- and 1,4-dihydroxynaphthalene. RcDT1 RNA interference significantly reduced the AQs content in R. cordifolia callus cultures, demonstrating that RcDT1 is required for alizarin-type AQs biosynthesis. The plastid localization and root-specific expression further confirmed the participation of RcDT1 in anthraquinone biosynthesis. The phylogenetic analyses of RcDT1 and functional validation of its rubiaceous homologs indicated that DHNA-prenylation activity evolved convergently in Rubiaceae via recruitment from the ubiquinone biosynthetic pathway. Our results demonstrate that RcDT1 catalyzes the first pathway-specific step of alizarin-type AQs biosynthesis in R. cordifolia. These findings will have profound implications for understanding the biosynthetic process of the anthraquinone ring derived from the shikimate pathway.

Aromatic acids affect the performances of constructed rapid infiltration systems based on red mud and coke: Removal efficiency, electron transport, and metabolism

This study investigated the effect of coke and red mud as fillers in a constructed rapid infiltration system on the removal of three aromatic acids in wastewater. In addition, a combination of X-ray photoelectron spectroscopy (XPS) and metagenomics sequencing was used to explore the microbial communities and metabolic mechanisms. Results showed that the removal rates of chemical oxygen demand of the three columns containing phthalic acid (PA), benzoic acid (BA), and 1-naphthoic acid (1NA) were 83.59%, 92.52%, and 88.72%, and the removal rates of ammonia nitrogen were 37.33%, 40.83%, and 38.38% of, respectively. Meanwhile, the removal efficiency of three aromatic acids by the systems was BA > PA > 1NA. Proteobacteria and Actinobacteria were among the dominant bacterial groups in the columns. The highest relative abundance of Sphingopyxis was found in the column with 1NA, which provided a certain guarantee for the degradation of 1-naphthoic acid by this column. Compared to PA and 1NA, BA upregulated the abundance of the norB gene. The relative abundance of phoBR, a regulator of the. phosphoryl regulator response, was significantly down-regulated in the PA column, leading to a decrease in total phosphorus removal at the later stage. This study provides an economical and simple process for the treatment of wastewater containing aromatic acid. These promising results also indicate that red mud can be used as a resource in wastewater treatment.

Triplet energy transfer from quantum dots increases Ln(iii) photoluminescence, enabling excitation at visible wavelengths.

Europium(iii) complexes are promising for bioimaging because of their long-lived, narrow emission. The photoluminescence (PL) from europium(iii) complexes is usually low. Thus, the effective utilization of low-energy light >400 nm and enhancement of PL are long-standing goals. Here, we show for the first time that 1-naphthoic acid triplet transmitter ligands bound to CdS quantum dots (QDs) and europium(iii) complexes create an energy transfer cascade that takes advantage of the strong QD absorption. This is confirmed by transient absorption spectroscopy, which shows hole mediated triplet energy transfer from QDs to 1-NCA, followed by triplet transfer from 1-NCA to europium(iii) complexes with an efficiency of 65.9 ± 7.7%. Smaller CdS QDs with a larger driving force lead to higher triplet transfer efficiency, with Eu(iii) PL intensity enhanced up to 21.4 times, the highest value ever reported. This hybrid QD system introduces an innovative approach to enhance the brightness of europium complexes.

Sorption behavior of three aromatic acids (benzoic acid, 1-naphthoic acid and 9-anthroic acid) on biochar: Cosolvent effect in different liquid phases

Influence of the cosolvent on the sorption of organic acids on biochar has not been well understood. For this purpose, the sorption (log Km, L kg−1) of three aromatic acids (benzoic acid (BA, pKa = 4.20), 1-naphthoic acid (1-NAPA, pKa = 3.70), and 9-anthroic acid (9-ANTA, pKa = 3.65) was evaluated as a function of methanol volume fraction (fc = 0.0, 0.25, and 0.5), liquid pH (2.5 and 7.0), ionic composition (CaCl2 and KCl) and ionic strength (0.005 M, 0.5 M, and 1 M CaCl2). A giant Miscanthus-derived biochar (ZPC of 2.86) was used as the sorbent. For all solutes, the sorption coefficients (log Km) measured at pH 2.5 (i.e., pH < pKa) tended to decrease with increasing fc, as expected from the cosolvency model, while the result obtained at pH 7.0 was not fully explained by the same model. The log Km of 1-NAPA in the CaCl2 system was always greater than in the KCl system (p < 0.05) and the impact became pronounced at high pH (>pKa) with increasing fc. Increasing the Ca2+ concentration at fc = 0.0 (from 0.005 M to 1 M) enhanced the value by 0.32 log unit of Km. These phenomena indicate a significant role of dissolved Ca2+ in the liquid phase, most likely due to the formation of cation bridges between aromatic carboxylates and the biochar surface (i.e., [R-COO--Ca2+]-{Biochar−}). A decrease in the dielectric constant of the methanol mixture could fortify the formation of this bridge. Regardless of the degree of cosolvency power (σ), as the number of aromatic rings of solutes increases, Km decreases in the order BA > 1-NAPA > 9-ANTA, where fc = 0.0. In conclusion, the sorption potential of biochar can be significantly weakened by increasing pH and fc, and in the absence of a divalent cation.

The synthesis and characterization of a series of cocrystals of an isoniazid derivative with butan-2-one and propan-2-one.

Four cocrystals containing N'-(butan-2-ylidene)pyridine-4-carbohydrazide (izbt) and one cocrystal containing N'-isopropylideneisonicotinohydrazide (izact) were synthesized by reacting isoniazid with either butan-2-one (for the former) or acetone (for the latter). The coformers used to synthesize the izbt cocrystals were 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2-chloro-4-nitrobenzoic acid and 1-naphthoic acid. 1-Naphthoic acid was also used with izact to form a cocrystal. The 1:1 cocrystals are: N'-(butan-2-ylidene)pyridine-4-carbohydrazide-1-naphthoic acid (izbt-1nta), C10H13N3O·C11H8O2, N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2,4-dihydroxybenzoic acid (izbt-2,4-dhba), C10H13N3O·C7H6O4, N'-(propan-2-ylidene)pyridine-4-carbohydrazide-1-naphthoic acid (izact-1nta), C9H11N3O·C11H8O2, N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2-chloro-4-nitrobenzoic acid (izbt-2c4n), C10H13N3O·C7H4ClNO4, and N'-(butan-2-ylidene)pyridine-4-carbohydrazide-2,5-dihydroxybenzoic acid (izbt-2,5-dhba), C10H13N3O·C7H6O4. The cocrystals containing izbt were compared to those containing the same (or similar) coformers with izact that have been reported either here or in the Cambridge Structural Database (CSD). Most of the cocrystals showed different packing despite having the same hydrogen-bonding motifs. The cocrystals were characterized by single-crystal X-ray diffraction (SC-XRD), powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC).

Analysis of naphthenic acids in produced water samples by capillary electrophoresis-mass spectrometry.

A capillary electrophoresis-mass spectrometry method was used to analyze naphthenic acids in produced water samples. It was possible to detect cyclopentanecarboxylic, benzoic, cyclohexanebutyric, 1-naphthoic, decanoic, 3,5-dimethyladamantane-1-carboxylic, 9-anthracenecarboxylic, and pentadecanoic acids within ca. 13min using a buffer composed of 40mmol/L ammonium hydroxide, 32mmol/L acetic acid and 20% v/v isopropyl alcohol, pH 8.6. The proposed method showed good repeatability, with relative standard deviation (RSD) values of 6.6% for the sum of the peak areas and less than 2% for the analysis time. In the interday analysis, the RSD values for the sum of the peak areas and migration time were 10.3% and 10%, respectively. The developed method demonstrated linear behavior in the concentration range between 5 and 50mg/L for benzoic, decanoic, 3,5-dimethyladamantane-1-carboxylic and 9-anthracenecarboxylic acids, and between 10 and 50mg/L for cyclopentanecarboxylic, cyclohexanebutyric, 1- naphthoic, and pentadecanoic acids. The detection limits values ranged from 0.31 to 1.64mg/L. Six produced water samples were analyzed and it was possible to identify and quantify cyclopentanecarboxylic, benzoic, cyclohexanebutyric, and decanoic acids. The concentrations varied between 4.8 and 98.9mg/L, proving effective in the application of complex samples.

Symbiotic study of N-bridged metal complexes as electrocatalysts for hydrogen evolution reaction

Design and fabrication of non-noble metal catalysts for the extensive generation of H2 (hydrogen) gas by water splitting is the upsurging field aiming towards the sustainable environment and need the future clean and green energy. However, scheming and understanding the basic principle regulating the activity of the catalyst is still inexplicable. Although Pt is currently the material of choice owing to its high electrocatalytic activities but need for its high loading and high cost is an intriguing issue needing amicable solution. The hybrid structures of heteroatom-based transition metal complexes are more effective and are cost effective electrocatalysts for hydrogen production. In this proposed work, the electrocatalytic behaviour of alkali (Li+, Na+, K+) and alkaline metal (Ca2+, Sr2+, Ba2+) was figured out along with their synthetic procedure and characterization. Owing to their high complexing ability, ring formation, and bidentate nature, substituted naphthoic acid and aminoguanidine were chosen as bridging ligands. The thermodynamic stability and best catalytic behaviour of synthesized alkali and alkaline earth metals were compared and presented based on electrochemical studies. Linear sweep voltammetry (LSV) curves display excellent activity and Tafel slope was found in the range of 6.38–40 mVdec−1 in 0.5 M H2SO4. The electrochemical impedance spectroscopy (EIS) test was accomplished to recognize the mechanism of HER, and charge transfer resistance was less which indicates that composites are favourable for the hydrogen evolution. The electrochemical surface area (ECSA) was figured by studying the electric double layer capacitance (C dl) and it was found to be 0.377 μFcm2 - 0.143 μFcm2. More prominent ECSA values implies, the target complexes have enhanced electrochemically active/dynamic sites and better hydrogen evolution performance. According to the results, high-performing catalytically active sites are found to be Li [1NA-AMG] metal ions, thus showing a potential method for electrocatalyst engineering. Furthermore, in a volcano plot, the position of the Li [1NA-AMG] metal ions is found to be close to the apex with near thermoneutral catalytic activity. Based on the results, we successfully designed an electrocatalyst as a prospective candidate for hydrogen evolution reaction.

Facial amphiphilic naphthoic acid-derived antimicrobial polymers against multi-drug resistant gram-negative bacteria and biofilms

Inspired by the facial amphiphilic nature and antimicrobial efficacy of many antimicrobial peptides, this work reported facial amphiphilic bicyclic naphthoic acid derivatives with different ratios of charges to rings that were installed onto side chains of poly(glycidyl methacrylate). Six quaternary ammonium-charged (QAC) polymers were prepared to investigate the structure-activity relationship. These QAC polymers displayed potent antibacterial activity against various multi-drug resistant (MDR) gram-negative pathogens such as Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Polymers demonstrated low hemolysis and high antimicrobial selectivity. Additionally, they were able to eradicate established biofilms and kill metabolically inactive dormant cells. The membrane permeabilization and depolarization results indicated a mechanism of action through membrane disruption. Two lead polymers showed no resistance from MDR-P. aeruginosa and MDR-K. pneumoniae. These facial amphiphiles are potentially a new class of potent antimicrobial agents to tackle the antimicrobial resistance for both planktonic and biofilm-related infections.

Metal-free organocatalysts for high hydrolytic stability single component polyurethane adhesives and their application in decorative insulation facades manufacturing

We focused on developing polyurethane (PU) adhesives with superior ambient thermal and hydrolytic stability, a crucial factor for industrial productivity. Our approach involved creating PU prepolymers that can withstand varying temperatures in ambient conditions. These prepolymers consist of conventional isocyanate-terminated polyurethane and metal-free acid:base organic catalysts, with the stability of the adhesive relying on the organocatalyst employed. We tested a series of 11 latent organocatalysts derived from the reaction between 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and various acids. Among these, the catalyst based on 1-naphthoic acid exhibited exceptional stability, lasting at least 3 h at 60 °C and an average relative humidity of 65% under vigorous stirring. We assessed this stability using a fan-based stirrer and analyzed the curing conditions kinetically through DSC. Furthermore, our adhesive formulation is environmentally friendly as it is free of metals, specifically tin (typically present in catalysts such as dibutyltin dilaurate). This quality enhances its sustainability. To validate the practical applicability of the adhesives, we conducted tests using decorative facade models composed of siliciclastic sandstone extracted from a quarry in Vilviestre del Pinar (Burgos, Spain. Latitude: 41.951024° N, longitude: 3.078283° W) and extruded polystyrene (XPS). The results demonstrated the excellent hydrolytic and thermal stability of the adhesives, highlighting their significant potential for panel manufacturing in this context.