Functional Amino Research Articles

Synthesis and characterization of amino-functionalized guar gum based polyurea: Preparation of iodine complexes, structural investigation and release studies

Biobased materials are expanding dramatically in various industrial applications due to their unique intrinsic properties. In this study, various chemical functionalization procedures were used to synthesize guar gum, a naturally occurring polysaccharide-based polyurea, and its iodine complexes. Firstly, guar gum was subjected to tosylation reaction using p-toluene sulphonyl chloride to introduce tosyl moieties in the polymer chain with the degree of substitution (DS) ranging between 0.16 and 1.54. Sample having the highest degree of tosyl moiety was further reacted with tris(2-aminoethyl) amine to produce 6-deoxy-6-tris(2-aminoethyl) amine derivative via nucleophilic substitution reaction to impart amino functional groups. The degree of substitution in 6-deoxy-6-tris(2-aminoethyl) amine derivative was found to be 0.59. 6-deoxy-6-tris(2-aminoethyl) amine derivative was reacted with different diisocyanates (Toluene-2,4-diisocyanate (TDI), 1,6-diisocyanatohexane (HMDI)) to produce guar gum based polyurea. Iodine complexes of the resulting polyurea were prepared by reacting with different iodinating agents. Different chemical reactions, formation of polyurea and its iodine complexes were thoroughly analyzed by different analytical techniques such as FT-IR, NMR, elemental analysis, XRD, UV–Vis spectroscopy, and a reaction scheme has been proposed. Morphological and rheological characteristics were analyzed by SEM and viscosity measurement. Thermal analysis was carried out by TGA and DSC studies. Finally, by examining the complex's UV–Vis spectra, the iodine release characteristics from polyurea‑iodine complexes were investigated.

Amino Functionality Enables Aqueous Synthesis of Carboxylic Acid-Based MOFs at Room Temperature by Biomimetic Crystallization.

Enzyme immobilization within metal-organic frameworks (MOFs) is a promising solution to avoid denaturation and thereby utilize the desirable properties of enzymes outside of their native environments. The biomimetic mineralization strategy employs biomacromolecules as nucleation agents to promote the crystallization of MOFs in water at room temperature, thus overcoming pore size limitations presented by traditional postassembly encapsulation. Most biomimetic crystallization studies reported to date have employed zeolitic imidazole frameworks (ZIFs). Herein, we expand the library of MOFs suitable for biomimetic mineralization to include zinc(II) MOFs incorporating functionalized terephthalic acid linkers and study the catalytic performance of the enzyme@MOFs. Amine functionalization of terephthalic acids is shown to accelerate the formation of crystalline MOFs enabling new enzyme@MOFs to be synthesized. The structure and morphology of the enzyme@MOFs were characterized by PXRD, FTIR, and SEM-EDX, and the catalytic potential was evaluated. Increasing the linker length while retaining the amino moiety gave rise to a family of linkers; however, MOFs generated with the 2,2'-aminoterephthalic acid linker displayed the best catalytic performance. Our data also illustrate that the pH of the reaction mixture affects the crystal structure of the MOF and that this structural transformation impacts the catalytic performance of the enzyme@MOF.

Transformation mechanisms of antidepressants in biological wastewater treatment: Removal kinetic, transformation products and pathways

The extensive detection of antidepressants in wastewater has raised increasing concerns for human beings. During biological wastewater treatment processes, antidepressants cannot be completely removed and mineralized, which caused the formation of transformation products (TPs). To date, knowledges on TPs that participated in the transformation processes of antidepressants were scarce. To fill this gap, molecular networking nontarget screening based on lab-scale batch assays were employed to explore the removal and transformation of five antidepressants (amitriptyline (AMI), clomipramine (CLO), duloxetine (DUL), nortriptyline (NOR) and paroxetine (PAR)). The removal rate constants per unit of biomass (kbio) of the five antidepressants were found to range from 0.29 to 0.56 L/(gMLSS*d). Comparatively, clomipramine was removed more slowly than other antidepressants, which attributed to its lower electrophilic properties. Subsequently, 22 TPs were tentatively identified, among which 19 ones were newly found in the present study. The proposed transformation pathways indicated that demethylation, N-formylation, N-acetylation, N-succinylation, N-hydroxylation, dealkylation, hydrolysis and nitrosation participated in the transformation of antidepressants in wastewater. Particularly, N-acylation and N-hydroxylation were found as characteristics reactions for antidepressants in wastewater and these reactions consistently occurred at the site of amino functional group, where high electrophilic activity was the dominant causes for the observed characteristics reactions. In silico results revealed that TPs formed during biological wastewater treatment generally had lower toxicity, lower bioaccumulation and higher bioavailability than their parent compounds. Collectively, the present study provides insights into the transformation processes of antidepressants in wastewater, indicating that characteristic transformation reactions occur across different antidepressants, which is theoretically useful to effectively remove pharmaceuticals from wastewater.

Synthesis and characterization of sustainable blue dyes: Enhancing diffusion on nylon fabrics with supercritical CO2 for eco-friendly dyeing methods

A very convenient method was developed to synthesize five dispersed anthraquinone dyestuffs using the readily available starting material 1,4-diaminoanthroquinone. This dye was prepared for coloration on nylon fabrics with supercritical carbon dioxide (ScCO2). All the synthesized dyes were characterized by 1H NMR, 13C NMR, and HRMS techniques. The UV-Vis absorbance measurements for all the dyes were carried out, and the results indicated that the absorption peak wavelength of the dyes was approximately 570–641 nm in the blue region. Further, these dispersed dyes were dyed on nylon fabrics with supercritical CO2. After dyed fabrics were tested, the color strength of K/S value and color fastness were tested using like washing, crocking, and sunlight. Additionally, it determines the sweat fastness of dyed nylon fabrics under acidic and basic conditions. The dyes are readily involved in the nucleophilic addition of amino (-NH2, nylon) functional groups to nylon fabrics in an alkaline medium. Therefore, our results showed that these dyes are commercially the most satisfactory, environmentally efficient dyes and practically exhibit sufficient color uniformity.

Organometallic Chirality Sensing via "Click"-Like η6-Arene Coordination with an Achiral Cp*Ru(II) Piano Stool Complex.

Piano stool complexes have been studied over many years and found widespread applications in organic synthesis, catalysis, materials and drug development. We now report the first examples of quantitative chiroptical molecular recognition of chiral compounds through click-like η6-arene coordination with readily available half sandwich complexes. This conceptually new approach to chirality sensing is based on irreversible acetonitrile displacement of [Cp*Ru(CH3CN)3]PF6 by an aromatic target molecule, a process that is fast and complete within a few minutes at room temperature. The metal coordination coincides with characteristic circular dichroism inductions that can be easily correlated to the absolute configuration and enantiomeric ratio of the bound molecule. A relay assay that decouples the determination of the enantiomeric composition and of the total sample amount by a practical CD/UV measurement protocol was developed and successfully tested. The introduction of piano stool complexes to the chiroptical sensing realm is mechanistically unique and extends the scope of currently known methods with small-molecule probes that require the presence of amino, alcohol, carboxylate or other privileged functional groups for binding of the target compound. A broad application range including pharmaceutically relevant multifunctional molecules and the use in chromatography-free asymmetric reaction analysis are also demonstrated.

Organometallic Chirality Sensing via “Click”‐Like η6‐Arene Coordination with an Achiral Cp*Ru(II) Piano Stool Complex

AbstractPiano stool complexes have been studied over many years and found widespread applications in organic synthesis, catalysis, materials and drug development. We now report the first examples of quantitative chiroptical molecular recognition of chiral compounds through click‐like η6‐arene coordination with readily available half sandwich complexes. This conceptually new approach to chirality sensing is based on irreversible acetonitrile displacement of [Cp*Ru(CH3CN)3]PF6 by an aromatic target molecule, a process that is fast and complete within a few minutes at room temperature. The metal coordination coincides with characteristic circular dichroism inductions that can be easily correlated to the absolute configuration and enantiomeric ratio of the bound molecule. A relay assay that decouples the determination of the enantiomeric composition and of the total sample amount by a practical CD/UV measurement protocol was developed and successfully tested. The introduction of piano stool complexes to the chiroptical sensing realm is mechanistically unique and extends the scope of currently known methods with small‐molecule probes that require the presence of amino, alcohol, carboxylate or other privileged functional groups for binding of the target compound. A broad application range including pharmaceutically relevant multifunctional molecules and the use in chromatography‐free asymmetric reaction analysis are also demonstrated.

Mechanistical Insights into the Ultrasensitive Detection of Radioactive and Chemotoxic UO22+ Ions by a Porous Anionic Co-Metal-Organic Framework.

Development of a simple, cost-efficient, and portable UO22+ sensory probe with high selectivity and sensitivity is highly desirable in the context of monitoring radioactive contaminants. Herein, we report a luminescent Co-based metal-organic framework (MOF), {[Me2NH2]0.5[Co(DATRz)0.5(NH2BDC)]·xG}n (1), equipped with abundant amino functionalities for the selective detection of uranyl cations. The ionic structure consists of two types of channels decorated with plentiful Lewis basic amino moieties, which trigger a stronger acid-base interaction with the diffused cationic units and thus can selectively quench the fluorescence intensity in the presence of other interfering ions. Furthermore, the limit of detection for selective UO22+ sensing was achieved to be as low as 0.13 μM (30.94 ppb) with rapid responsiveness and multiple recyclabilities, demonstrating its excellent efficacy. Density functional theory (DFT) calculations further unraveled the preferred binding sites of the UO22+ ions in the tubular channel of the MOF structure. Orbital hybridization between NH2BDC/DATRz and UO22+ together with its significantly large electron-accepting ability is identified as responsible for the luminescence quenching. More importantly, the prepared 1@PVDF {poly(vinylidene difluoride)} mixed-matrix membrane (MMM) displayed good fluorescence activity comparable to 1, which is of great significance for their practical employment as MOF-based luminosensors in real-world sensing application.

A novel poly(2-hydroxyethyl acrylamide) copolymer for the fabrication of transparent antifogging coatings on polycarbonate substrates

Although polycarbonate (PC) is widely used in various applications, its inherent hydrophobicity limits its potential in applications that require high light transmittance due to surface fog caused by changes in temperature or humidity in the environment. This work presents a facile method to fabricate transparent antifogging coatings on PC substrates based on poly(2-hydroxyethyl acrylamide-co-2-aminoethyl methacrylate) (P(HEAA-co-AEMA)), in which the AEMA segments have an amino functional group that can react with the ester group on the surface of the PC substrate to form covalent urethane bonds during the heat curing process, avoiding the problems of coating susceptibility to mechanical damage, ease of peeling, etc. Moreover, HEAA units are employed as hydrophilic groups, providing antifogging performance. These antifogging coatings can be easily obtained by coating P(HEAA-co-AEMA) copolymers on PC substrates at room temperature and then curing them by thermal treatment. These transparent coatings exhibited excellent antifogging and self-cleaning performance. Furthermore, the coatings exhibited good adhesion in the cross-cut test and thermal stability in the hot water resistance test. Therefore, the present P(HEAA-co-AEMA) copolymer coatings are promising for practical antifogging applications.

Enhanced adsorption and removal of Cd(II) from aqueous solution by amino-functionalized ZIF-8

Zeolite imidazolate framework-8 (ZIF-8), which is a special subgroup of metal–organic frameworks (MOFs), was synthesized and modified by ethylenediamine (ZIF-8-EDA) to prepare an efficient adsorbent for the high sorption of Cd2+ ions from solution. The synthesized and modified ZIF-8 (ZIF-8-EDA) were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FE-SEM) with energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) analysis. The optimum conditions for dosage of adsorbent, initial ion concentration, pH, and contact time were 0.05 g/l, 50 mg/l, 6, and 60 min, respectively, for cadmium ion sorption from aqueous solutions with a removal efficiency of 89.7% for ZIF-8 and 93.5% for ZIF-8-EDA. Adsorption kinetics and equilibrium data were analyzed using the Langmuir and Freundlich equations. The Langmuir model fitted the equilibrium data better than the Freundlich model. According to the Langmuir equation, the maximum uptake for the cadmium ions was 294.11(mg/g). The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicated that the adsorption process was feasible, spontaneous, and endothermic at 20–50 °C. Based on the results, the amino functionalized ZIF-8 had improved adsorption performance due to the replacing of the starting linker with organic ligands that had effective functional groups, leading to chemical coordination due to the interaction of metal ions with the non-bonding pair of electrons on the N atoms of the amino functional group. The selectivity toward metal ion adsorption by ZIF-8-EDA was Cd2+ > Pb2+ > Ni2+‏.

Detoxification of V-Nerve Agents Assisted by a Microperoxidase: New Pathway Revealed by the Use of a Relevant VX Simulant.

The biocatalyzed oxidative detoxification of the V-series simulant PhX, by mean of the microperoxidase AcMP11, affords the corresponding phosphonothioate as the prominent product instead of the classical P-S and P-O bond cleavage. While PhX is structurally very close to the live agent VX (the methyl group is replaced by a phenyl), assessment with other surrogates missing the nucleophilic amino function displayed more resistance under the same conditions with no phosphonothioate observed. These encouraging results highlight 1) the efficacy of AcMP11 microperoxidase to efficiently detoxify V-series organophosphorus nerve agents (OPNA), and 2) the necessity to use representative alkyl or aryl phosphonothioates simulants such as PhX bearing the appropriate side chain as well as the P-O and P-S cleavable bond to mimic accurately the V-series OPNA to prevent false positive or false negative results.

Directed C(sp3)-H Arylation of Free α-Aminophosphonates: Dual Models Exploration via Palladium Catalysis.

In this report, we present the dual activation models for transient directing group-directed and amino-self-directed Pd-catalyzed α-aminophosphonate side-chain C(sp3)-H arylation. Both strategies showed facile, efficient, and single regioselectivity in the reaction between free α-aminophosphonates and aryl iodides. Furthermore, the modification of amino and late-stage functionalization of the C(sp3)-P bond from products indicates potential applications for α-aminophosphonates.

Potential of amino acids-modified biochar in mitigating the soil Cu and Ni stresses – Targeting the tomato growth, physiology and fruit quality

Trace heavy metals (HMs) such as copper (Cu) and nickel (Ni) are toxic to plants, especially tomato at high levels. In this study, biochar (BC) was treated with amino acids (AA) to enhance amino functional groups, which effectively alleviated the adverse effects of heavy metals (HMs) on tomato growth. Hence, this study aimed to evaluate the effect of glycine and alanine modified BC (GBC/ABC) on various tomato growth parameters, its physiology, fruit yield and Cu/Ni uptake under Cu and Ni stresses. In a pot experiment, there was 21 treatments with three replications having two rates of simple BC and glycine/alanine enriched BC (0.5% and 1% (w/w). Cu and Ni stresses were added at 150 mg kg−1 respectively. Plants were harvested after 120 days of sowing and subjected to various analysis. Under Cu and Ni stresses, tomato roots accumulated more Cu and Ni than shoots and fruits, while GBC and ABC application significantly enhanced the root and shoot dry weight irrelevant to the stress conditions. Both rates of GBC decreased the malondialdehyde and hydrogen peroxide levels in plants. The addition of 0.5% GBC with Cu enhanced the tomato fruit dry weight by 1.3 folds in comparison to the control treatment; while tomato fruit juice content also increased (50%) in the presence of 0.5% GBC with Ni as compared to control. In summary, these results demonstrated that lower rate of GBC∼0.5% proved to be the best in mitigating the Cu and Ni stress on tomato plant growth by enhancing the fruit production.

Accelerated peroxidase-like activity of ultrathin amine-tagged bimetallic MOF-74 nanozyme for construction of versatile bioassays from small molecules to enzymes and bacteria

The exquisite design of nanostructures for enzyme-biocatalyzed active sites mimicking has become a prospective method to significantly boost biocatalytic properties, which is profitable to response amplification for bioanalysis scenarios. Metal-organic frameworks (MOFs) with customizable compositions, diverse microstructures and open catalytic sites are considered to deal with challenges in conventional materials of unfriendly microenvironment and inexact coordination. Herein, by combining a metal doping and post-synthetic modification approach, amine-tagged Fe-Ni bimetallic MOF-74 nanozyme (FeNi-MOF-74-NH2) with ultrathin structure and improved peroxidase-mimicking bioactivity is synthesized through a layered double hydroxide (LDH) directed method. The boosted biocatalytic property largely benefits from the synergistic effects of Fe-Ni species, attributing to the dual mechanism (electron transfer and generation of hydroxyl radicals). On the basis of the enhanced enzyme-mimicking property and accessible amino functionalization of FeNi-MOF-74-NH2, versatile applications were carried out for the ultrasensitive detection of analytes from bioactive small molecules (H2O2 and ascorbic acid), biomacromolecules (alkaline phosphatase, ascorbic acid oxidase, and α-glucosidase), and pathogenic bacteria (Staphylococcus aureus). The nanozyme-based biosensing platform without complex enzymatic techniques serves as a proof-of-concept to facilitate the application of MOF nanozymes in biochemical analysis, clinical diagnosis, and biomedical research.

Amino-Functionalizing Ce-Based MOF UiO-66 for Enhanced CO2 Adsorption and Selectivity.

Metal-organic frameworks (MOF) hold great promise for CO2 adsorption due to their high surface areas, tunable pore sizes, and the ability to modify their chemical properties to enhance CO2 affinity. MOFs tagged with functional groups either at linker or metal sites have shown improved CO2 uptake capacity and selectivity. This study focuses on investigating the potential of selective CO2 adsorption using amino functionalization of linker forming Ce-UiO-66. The physicochemical properties and characteristics of MOFs to determine the degree of amino functionalization and structural stability were examined using powder X-ray diffraction (PXRD), Fourier transformer infra-red (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N2 porosimetry and specific surface area (BET). This work unveils a novel array of results on CO2, N2 and water vapour adsorption on Ce-UiO-66-NH2. The amino-functionalized Ce-UiO-66-NH2 shows 63 % higher CO2 uptake and 84 % higher CO2/N2 selectivity at 273 K and 1 bar over Ce-UiO-66. Ce-UiO-66-NH2 also shows excellent structural stability after gas and vapour sorption making Ce-UiO-66-NH2 potential adsorbent for CO2 capture.

2D and 3D anticancer properties of C2-functionalised glucosamine-Pt (IV) prodrugs based on cisplatin scaffold.

A series of C2-functionalied Pt (IV) glycoconjugates based on glucosamine have been synthesised, characterised and tested as anticancer agents on a series of different 2D and 3D cancer cell lines. The carbohydrate will act as a targeted delivery system to improve the selectivity, exploiting the Warburg Effect and the GLUTs receptors that are overexpressed in most of the cancer cells. The hydroxyl at C2 of the carbohydrates does not participate in hydrogen bonding with the GLUTs receptors, making C2 an attractive position for drug conjugation as seen in literature. In this study, we use the amino functionality at the C2 position in glucosamine and Copper-catalysed Azide-Alkyne Cycloaddition "click" (CuAAC) reaction to connect the prodrug Pt (IV) scaffold to the carbohydrate. We have investigated complexes with different linker lengths, as well as acetyl protected and free derivatives. To the best of our knowledge, this study represents the first series of Pt (IV) glucosamine-conjugates functionalised at C2.

Coupling of Single-Stranded poly-T DNA with Small Heterocyclic compounds via Peptide Linkage

This study introduces a versatile method for coupling single-stranded DNA with small heterocyclic compounds, leveraging the reactivity of amino and carboxylic functional groups. By employing COMU and Collidine, BNIMZ and BNTZA were successfully coupled with poly-T DNA. The conjugation technique was successfully confirmed by high accuracy MALDI-TOF MS. This approach offers a reliable and efficient strategy for constructing DNA-conjugates with tailored properties.

UiO-67 metal-organic frameworks with dual amino/iodo functionalization, and mixed Zr/Ce clusters: Highly selective and efficient photocatalyst for CO2 transformation to methanol

Metal-organic frameworks (MOFs) are promising tools for photocatalytic CO2 reduction (PCR) to produce valuable added-value products. However, existing MOFs demonstrate significantly weaker potential for PCR to MeOH compared to fuels like CO, CHOOH, and CH4. This study address this challenge by exploring a series of bifunctional UiO-67 MOFs containing NH2 and I groups with varying Ce to Zr metal node ratios (0, 10, 20, 29, and 40 % Ce). These MOFs, denoted as Zr/CeX%-UiO-67(NH2, I), were probed for their ability to convert CO2 to MeOH under solar irradiation without the need for a photosensitizer. The results demonstrate a remarkable increase in both selectivity and efficiency for MeOH production with increasing Ce content. Notably, Zr/Ce29%-UiO-67(NH2, I) achieves 100 % selectivity for MeOH production, along with MeOH productivity of 44.7 µmolh−1g−1, significantly surpassing previously reported UiO-based MOFs for PCR-to-MeOH conversion. Furthermore, this MOF exhibits exceptional CO2 uptake capacity compared to pristine UiO-67 and many established MOFs, further highlighting its catalytic efficacy. The outstanding photocatalytic performance of Zr/Ce40%-UiO-67(NH2, I) can be attributed to a synergistic combination factors: (i) the optimal incorporation of redox-active Ce metal sites, (ii) enhanced CO2 capture facilitated by the cooperative interaction of NH2 and I groups, and (iii) the introduction of amino functions that broaden the light absorption range of the MOF. This work demonstrates a successful strategy for incorporating various functionalities into MOFs, paving the way for the design of highly selective and efficient PCR catalysts for MeOH production.

Combination Mechanism of Soil Dissolved Organic Matter and Cu2+ in Vegetable Fields, Forests and Dry Farmland in Lujiang County

Dissolved organic matter (DOM) serves as a critical link in the migration and transformation of heavy metals at the soil–solid interface, influencing the migration behaviour and transformation processes of Cu2+ in soil. There have been studies on the combination mechanisms between DOM and Cu2+ in paddy soils. However, the adsorption/complexation and redox processes between DOM and Cu2+ in other agricultural soil types (such as dry farmland and vegetable fields) are unclear. In order to reveal the combination process of DOM with Cu in different agricultural soil types and the dynamic changes in chemical behaviour that occur, this study analysed the variability of DOM components and structure in three soils using three-dimensional fluorescence spectroscopy and X-ray photoelectron spectroscopy. In addition, the priority order of different DOM compounds in combination with Cu and the change process in relation to the Cu valence state in the soil of Lujiang County, Anhui Province, was revealed based on laboratory experiments. The results showed that the composition of soil DOM was mainly composed of humic-like and fulvic-like substances with a clear terrestrial origin and that the organic matter showed a high degree of decomposition characteristics. The results indicated that the composition of soil DOM is mainly composed of humic and fulvic acid-like substances, and they have obvious characteristics of terrestrial origin. In addition, the soil organic matter showed high decomposition characteristics. The complex stability constants (lgKM) of humic acid-like substances with Cu2+ follow the order of forest land (lgKM = 5.21), vegetable land (lgKM = 4.90), and dry farmland (lgKM = 4.88). The lgKM of fulvic acid-like substances with Cu2+ is in the order of dry farmland (lgKM = 4.51) and vegetable land (lgKM = 4.39). Humic acid-like substances in soil DOM combine preferentially with Cu2+, showing a stronger chelating affinity than fulvic acid-like substances. Cu2+ complexes mainly include hydroxyl, phenolic hydroxyl and amino functional groups are included in soil DOM, accompanied by redox reactions. In comparison to dry farmland, the soil DOM in forest and vegetable fields undergoes more intense redox reactions simultaneously with the chelation of Cu2+. Therefore, the application of organic fertilisers to vegetable and forest soils may lead to uncertainties concerning the fate of heavy metals with variable chemical valence. These results contribute to a deeper understanding of the interaction mechanisms between DOM and Cu2+ in agricultural soils.

SYNTHESIS AND CHARACTERIZATION OF CHITOSAN FROM WASTE SHELLS OF Tagelus Plebeiu OBTAINED FROM OYOROKOTOR, RIVERS STATE, NIGERIA

The investigation was carried out to synthesize chitosan using waste shell of Tagelus plebeiu collected from Oyorokotor as an alternative to other kinds of shells. Standard procedures such as demineralization, deproteinization and deacetylation were used. Methods such as fourier transformed infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and scanning electron microscope (SEM) were used for characterization to obtain results. Results reveals FTIR spectra bands at 3637.9 cm-1 for hydroxyl and 3384.4 cm-1 for amino functional group as well as 18.20 at 2 titha from XRD pattern. The degree of deacetylation was recorded as 80.48 %, moisture content as 0.101 %, yield was 53.24 % and ash content was recorded as 25 %. It is therefore concluded that the waste shell of Tagelus plebeiu can be used in producing quality chitosan as an alternative to other kinds of shells.

2-Amino-terephthalic acid derived N-doped CNTs to modify Na3V2(PO4)3 with enhanced pseudocapacitance behavior

The compound Na3V2(PO4)3 (NVP) shows potential as a viable option owing to its notable stability and three-dimensional framework. Nevertheless, its effective use is impeded by its inadequate inherent electron conductivity. In this study, we have introduced a novel approach to overcome this limitation. We synthesized a Na3V2(PO4)3 material (NVP/C/N) coated with N-doped carbon nanotubes (CNTs) using 2-amino-terephthalic acid (NPTA) as the carbon source. The presence of the amino functional group serves a dual purpose: catalyzing the in-situ growth of a CNTs coating layer and incorporating N into the CNTs coating layer. When utilized as cathode materials, NVP/C/N exhibit exceptional rate capability, with discharge capacities of 108.8 mAh g−1 at 0.5C and 87.6 mAh g−1 at 50C, respectively, as well as remarkable cycling stability over long periods of time, maintains its capacity for 10,000 cycles at 50C, with only 0.00094 % capacity decay each cycle. The remarkable characteristics of this compound can be attributed to the enhanced conductivity and augmented active sites resulting from the coating layer of N-doped CNTs, as well as the enhanced pseudocapacitance behavior and reduced volume expansion during charge and discharge. Overall, this work holds immense potential for the advancement of energy storage systems that are both high-performing and reliable.