Carboxylic Function Research Articles

Rational design of interlayer binding towards highly reversible anion intercalation cathode for dual ion batteries

Abstract Dual ion batteries are one of the emerging substitutes for lithium ion batteries with high operating voltages and energy density, but their recent advancements have been limited by unsatisfactory cathode stability in the form of irreversible exfoliation. To address this bottleneck, a strategy to selectively incorporate carboxylic anhydride functionality between graphite layers is developed to enforce a stabilizing effect to the crystal structure, which allows for effective performance optimization through particles downsizing and interlayer distance tuning without the compromises of intercalation site disruption and voltage deduction. The resulting graphite cathode experienced significant capacity, rate capability and stability improvements, achieving a highly reversible capacity of 91.2 mAh g−1 at 2 C, which then cycled consistently for over 1,000 cycles. Overall, this work removes a major handicap that has limited the development of dual ion batteries and demonstrates a design pathway for high performance graphite intercalation cathode suitable for anion intercalation with both enhanced stability and discharge capacity.

Phosphine Carboxylate-Probing the Edge of Stability of a Carbon Dioxide Adduct with Dihydrogenphosphide.

We present a new adduct of carbon dioxide with dihydrogenphosphide, that may be prepared either by direct reaction of NaPH2 with carbon dioxide or by hydrolysis of the phosphaethynolate ion (PCO- ). In this hydrolysis transformation, a new mechanism is proposed for the electrophilic reactivity of the phosphaethynolate ion. Protonation to form phosphine carboxylic acid (PH2 COOH) and functionalization to form esters is shown to increase the strength of the P-C interaction, allowing for comparisons to be drawn between this species and the analogous carbamic (NH2 COOH) and carbonic acids (H2 CO3 ). Functionalization of the oxygen atom is found to stabilize the phosphine carboxylate while also allowing solubility in organic solvents whereas phosphorus functionalization is shown to facilitate decarboxylation. Substituent migration occurs in some cases.

Phosphine Carboxylate—Probing the Edge of Stability of a Carbon Dioxide Adduct with Dihydrogenphosphide

AbstractWe present a new adduct of carbon dioxide with dihydrogenphosphide, that may be prepared either by direct reaction of NaPH2 with carbon dioxide or by hydrolysis of the phosphaethynolate ion (PCO−). In this hydrolysis transformation, a new mechanism is proposed for the electrophilic reactivity of the phosphaethynolate ion. Protonation to form phosphine carboxylic acid (PH2COOH) and functionalization to form esters is shown to increase the strength of the P–C interaction, allowing for comparisons to be drawn between this species and the analogous carbamic (NH2COOH) and carbonic acids (H2CO3). Functionalization of the oxygen atom is found to stabilize the phosphine carboxylate while also allowing solubility in organic solvents whereas phosphorus functionalization is shown to facilitate decarboxylation. Substituent migration occurs in some cases.

Targeted Nanoparticles for Fluorescence Imaging of Folate Receptor Positive Tumors.

This report presents the synthesis and folate receptor target-specificity of amino-functionalized polyacrylamide nanoparticles (AFPAA NPs) for near-infrared (NIR) fluorescence imaging of cancer. For the synthesis of desired nano-constructs, the AFPAA NPs (hereafter referred to as NPs) were reacted with a NIR cyanine dye (CD) bearing carboxylic acid functionality by following our previously reported approach, and the resulting conjugate (NP-CD) on further reaction with folic acid (FA) resulted in a new nano-construct, FA-NP-CD, which demonstrated significantly higher uptake in folate receptor-positive breast cancer cells (KB+) and in folate receptor over-expressed tumors in vivo. The target-specificity of these nanoparticles was further confirmed by inhibition assay in folate receptor-positive (KB+) and -negative (HT-1080) cell lines. To show the advantages of polyacrylamide (PAA)-based NPs in folate receptor target-specificity, the CD used in preparing the FA-NP-CD construct was also reacted with folic acid alone and the synthetic conjugate (CD-FA) was also investigated for its target-specificity. Interestingly, in contrast to NPs (FA-NP-CD), the CD-FA conjugate did not show any significant in vitro or in vivo specificity toward folate receptors, showing the advantages of PAA-based nanotechnology in delivering the desired agent to tumor cells.

Semisynthetic Vitamin E Derivatives as Potent Antibacterial Agents against Resistant Gram-Positive Pathogens.

New 5-substituted vitamin E derivatives were semisynthesized, and their antibacterial activity against human Gram-positive and Gram-negative pathogens was evaluated. Several vitamin E analogues were active against methicillin-resistant Staphylococcus aureus (MRSA) and/or methicillin-resistant Staphylococcus epidermidis (MRSE); structure-activity relationships (SARs) are discussed. As a result, it is shown that the presence of a carboxylic acid function at the C-5 position and/or at the end of the side chain is crucial for the antibacterial activity. The bactericidal or bacteriostatic action of three compounds against MRSA and MRSE was confirmed in a time-kill kinetics study, and the cytotoxicity on human cells was evaluated. The preliminary mechanism study by confocal microscopy indicated that those vitamin E analogues led to bacterial cell death through membrane disruption.

Retracted: A porous Co(II)‐containing metal–organic framework: Selective CO2 capture and clinical nursing values on the myocardial infarction by regulating the mi‐RNA16 expression

AbstractIn the present research, a porous metal–organic framework (MOF) has been synthesized via utilizing 2‐amino[1,1:3,1‐terphenyl]‐4,4,5‐tricarboxylic acid, the amino‐functionalized ligand as the raw material under the solvothermal conditions, and its chemical formula is {[Co3(OH)(ATTCA)2(H2O)]·C2H6NH2·4DMF·H2O} (1). At 273 K, activated MOF (1a) reflects highly selective adsorption of CO2 over CH4 (11.7) and N2 (292.5) and strong CO2‐skeleton interaction. It is significant that the exposure of water vapor does not influence the several carbon dioxide cycles on absorption and release and/or surface area, indicating porous structures have the latent capacity of long‐term use in the wet conditions. In biological research, its therapeutic activity on the myocardial infarction was assessed, and at the same time, the detailed mechanism was investigated. Firstly, real‐time reverse transcription polymerase chain reaction (RT‐PCR) method was conducted to determine the mi‐RNA16 expression levels in the cardiomyocytes. Then, the expression level of the target protein of the mi‐RNA16, XOSC was evaluated with western blotting assay. Furthermore, molecular docking simulation shows that the carboxyl function groups are the origin of the biological activity, which could form multiple binding interactions to the protein.

Application of a heterogeneous physical model for the adsorption of Cd2+, Ni2+, Zn2+ and Cu2+ ions on flamboyant pods functionalized with citric acid

• Functionalization of flamboyant pods with citric acid was used to remove Cd 2+ , Ni 2+ , Zn 2+ and Cu 2+ . • Carboxylic and phenol functionalities played an important rolein heavy metal adsorption. • Endothermic adsorption of tested heavy metals was associated to physisorption. • Adsorption mechanism was analyzed via a physical model with two adsorption sites. A heterogeneous physical model with two bindings sites (HPMTBS) was successfully used to explain the adsorption of Cd 2+ , Ni 2+ , Zn 2+ , and Cu 2+ ions on flamboyant pods functionalized with citric acid. Experimental results and statistical physics modeling showed that carboxylic and phenolic functionalities of this adsorbent played a relevant role for the adsorption of Cd 2+ , Ni 2+ , Zn 2+ , and Cu 2+ ions. Calculations performed with HPMTBS suggested that the removal of these cations was a multi-ionic adsorption process at tested operating conditions. This adsorbent was more effective to remove Cd 2+ , Ni 2+ , Zn 2+ and Cu 2+ ions at high solution temperatures thus indicating an endothermic process with adsorption energies ranging from 20.3 to 29.5 kJ/mol, which were associated to physisorption. The total adsorption capacities varied from 0.10 to 0.32, 0.28 to 0.39, 0.19 to 0.25 and 0.20 to 0.31 mmol/g for Cd 2+ , Ni 2+ , Zn 2+ and Cu 2+ , respectively. This difference in adsorption capacities could be attributed to the ionic radius of tested adsorbates. This functionalized biomass can be considered as an alternative adsorbent for facing water pollution by heavy metal ions.

Nitrilotriacetic acid functionalization on Fe3O4 nanoparticle via amino and carboxylic functionalization

Nitrilotriacetic acid functionalization on Fe3O4 nanoparticle via amino and carboxylic functionalization

Carbon Nanodots in Electrochemical Sensors and Biosensors: A Review

AbstractThis Review presents the latest advances in designing electrochemical sensors by using carbon nanodots (CNDs), carbon dots (CDs), and graphene quantum dots (GQDs), as a new class of photoluminescent nanomaterials, which can be employed in a vast number applications, such as biomedicine, biosensing, optical sensing, catalysis, solar cells, imaging, and electrochemical sensing. Recently, the application of CDs and GQDs in electrochemical sensing has increased significantly because of their unique features such as quantum size, excellent biocompatibility, enzyme‐like activity, high active area, and abundance of hydrophilic groups, such as hydroxyl, carboxyl, or amine functionalities. The applications of CDs and GQDs for the electrochemical sensing of hydrogen peroxide, glucose, other organic molecules, as well as metal ions are presented. The utilization of CDs and GQDs for immunosensing and aptasensing is also reported.

Proof of Concept Study: Mesoporous Silica Nanoparticles, From Synthesis to Active Specific Immunotherapy

Nanomaterials are increasingly valued tools in drug delivery research as they offer enhanced stability, controlled release and more effective drug encapsulation. Though yet to be introduced in clinical trial, mesoporous silica nanoparticles are promising delivery systems, due to their high chemical and mechanical stability while remaining biodegradable. This work provides proof of concept for particle based vaccines as cost-effective alternatives for dendritic cell immunotherapy. Synthesis and surface chemistry of the nanoparticles are optimized for protein conjugation and nanoparticles are characterized for their physicochemical properties and biodegradation. Ovalbumin is used as a model protein to load nanoparticles to produce a nanovaccine. The vaccine is tested in vitro on dendritic cultures to verify particle and vaccine uptake, toxicity, maturation effects and explicitly ovalbumin cross-presentation on MHC class I molecules. The optimized synthesis protocol renders reproducible mesoporous silica nanoparticles, resistant against agglomeration, within the required size range and have carboxylic surface functionalization necessary for protein conjugation. They are biodegradable over a time span of 1 week. This period is adjustable by changing synthesis parameters. UV sterilization of the particles does not induce quality loss, nor does it have toxic effects on cells. Treatment with mesoporous silica nanoparticles increases expression of MHC and costimulatory molecules of dendritic cells, indicating an adjuvant effect of nanoparticles on the adaptive immune system. Nanovaccine uptake and cross-presentation of ovalbumin are observed and the latter is increased when delivered by nanoparticles as compared to control conditions. This confirms the large potential of mesoporous silica nanoparticle based vaccines to replace dendritic-based active specific immunotherapy, offering a more standardized production process and higher efficacy.

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

In this paper we describe the synthesis of a new carbohydrate-based building block functionalized with azido or amino groups on the 2 and 4 positions. The building block can be synthesized in anomerically pure form in only five scalable steps starting from commercially available levoglucosan. It was shown that the building block could undergo alkylations under strongly basic conditions. The building block with azido groups could furthermore take part in CuAAC reactions, generating derivatives with ester or carboxylic acid functionalities. In addition, the anomeric mixture of the building block was used for the synthesis of a molecule that could act as an emulsifier only in the presence of Zn2+ ions.

Nondestructive Analysis of Mummification Balms in Ancient Egypt Based on EPR of Vanadyl and Organic Radical Markers of Bitumen.

The black matter employed in the funeral context by ancient Egyptians is a complex mixture of plant-based compounds with variable amounts of bitumen. Asphaltene, the most resistant component of bitumen, contains vanadyl porphyrins and carbonaceous radicals, which can be used as paramagnetic probes to investigate embalming materials without sample preparation. Electron paramagnetic resonance (EPR) at the X-band, combining in-phase and out-of-phase detection schemes, provides new information in a nondestructive way about the presence, the origin, and the evolution of bitumen in these complex materials. It is found that the relative EPR intensity of radicals and vanadyl porphyrins is sensitive to the origin of the bitumen. The presence of nonporphyrinic vanadyl complexes in historical samples is likely due to the complexation of VO2+ ions by carboxylic functions at the interface between bitumen and other biological components of the embalming matter. The absence of such oxygenated vanadyl complex in natural bitumen and in one case of historical human mummy acquired by a museum in the 19th century reveals a possible, nondocumented, ancient restoration of this mummy by pure bitumen. The linear correlation between in-phase and out-of-phase EPR intensities of radicals and vanadyl porphyrins in balms and in natural bitumen reveals a nanostructuration of radicals and vanadyl porphyrin complexes, which was not affected by the preparation of the balm. This points to the remarkable chemical stability of paramagnetic probes in historical bitumen in ancient Egypt.

Latex particles by emulsion and dispersion polymerizations: sensitization with specific antigens of leptospirosis and application to immunoagglutination

The controlled synthesis of polymer nanoparticles is of great interest in the production of latexes with well defined characteristics. These products can be applied in biomedicine as carriers of biomolecules (e.g. proteins and enzymes), and in particular as latexes for immunoassays used for example in immunoagglutination test, which allow amplify the antigen–antibody reaction, being simple, quick and inexpensive diagnostic tools. The synthesis of polystyrene (PS) latex particles and of core–shell particles, with controlled size distribution, functional groups and surface charge densities is considered here. PS latexes were synthesized in the 100–1100 nm diameter range, by either emulsion or dispersion polymerization. Such latexes were then used as seeds in emulsion copolymerizations of styrene and a functional monomer (methacrylic acid or glycidyl methacrylate), thus producing particles with carboxyl or epoxy functionalities, respectively. Changes in the polymerization recipes employed under batch operation were analyzed. Latex characterization involved measurements of mean particle diameters, the polydispersity index, functional group densities and zeta potential. Finally, latexes were sensitized (by either physical adsorption or covalent coupling) with specific antigens to obtain latex–protein complexes, and one of them was tested as agglutination assay for detecting leptospirosis disease in bovine samples, as an example of the potential application of the latexes produced.

Salicylic Acid Appended Naphthalene Diimide Organic Linkers: A Systematic Investigation towards Electronic Aspects

AbstractA series of organic linkers (NDI‐1, NDI‐2, NDI‐3) constructed from electron‐deficient naphthalene diimide (NDI) ligand equipped with two terminal salicylic acid having carboxylic and hydroxyl functionality located at different positions provided NDI linkers as a structural platform with tunable properties is presented here. Evaluating the structure and functional relationship offered by prepared NDI organic linkers is a topic of interest related to the design of functionally active building blocks. In this study, synthesis and characterization of all the designed organic linkers were investigated and their photo‐physical properties along with computational studies were performed to establish a correlation between structural design, self‐assembly and intrinsic properties like electrical conductivity and so on. The hydrogen‐bonding assisted conducting properties of the linkers were presented which revealed the possible application of linkers as electro‐active building blocks.

Functional monodisperse microspheres fabricated by solvothermal precipitation co-polymerization

Simultaneous achievement in high solid content and high microsphere yield is deemed a challenge in the fabrication of monodisperse microspheres by precipitation polymerization. We herein demonstrate that micro-sized monodisperse poly(methacrylic monomer-divinylbenzene) microspheres containing epoxy, lauyl, carboxyl and hydroxyl functions can be fabricated by solvothermal precipitation co-polymerization at 20% (mass) monomer loading with over 94% microsphere yield. The morphology and porosity of the obtained particles can be readily tuned by cosolvent-acetonitrile binary solvents. Addition of a small amount of cosolvent that has similar solubility parameter to that of the functional monomer can significantly improve the monodispersity of the obtained microspheres. When tetrahydrofuran was used as the co-solvent, the surface area of the highly porous microspheres achieved higher than 400 m 2 ·g −1 . Solvothermal precipitation co-polymerization can be expected in scale-up fabrication of various monodisperse functional microspheres free of any surfactant and additive.

In-situ multi-step pulsed vapor phase surface functionalization of zirconia nanoparticles via copper-free click chemistry

We report on multi-step copper-free vapor phase azide-alkyne click reactions for the functionalization of metal oxide nanopowders, automated with the atomic layer deposition (ALD) technique. The synthetic approach consists of the following reaction steps: chemisorption of propiolic acid (PA) to ZrO2 from the gas phase, followed by the formation of a triazole ring through a click reaction with 1,4-bis(azidomethyl)benzene (BisA), and, in the final step, click-coupling of the pendant azide groups with a second dose of propiolic acid (PA). The chemical composition and nature of the chemical bonding in the samples obtained after each of the ALD processing steps were investigated in detail by ATR-FTIR and XPS. As confirmed by an additional ALD deposition of ZnO, the latter reaction step introduces free polar carboxylic acid functionalities to the nanomaterial surface, which enhance the stability of the chemically modified zirconia in ethanolic dispersion. This proof-of-concept study offers great potential toward the fabrication of functional organic layers on metal oxide surfaces by sequential azide-alkyne cycloadditions performed in ALD.

Newly Synthesized Nonvacuum Processed High‐k Polymeric Dielectrics with Carboxyl Functionality for Highly Stable Operating Printed Transistor Applications

AbstractSolution‐processed polar hydroxyl containing polymers such as poly(4‐vinylphenol) are widely utilized in organic filed‐effect transistors (OFETs) due to their high dielectric constant (k) and excellent insulating properties owing to the crosslinking through their hydroxyl groups. However, hydroxyl functionalities can function as trapsites, and their crosslinking reactions decrease the k value of materials. Hence, in this study, new solution‐processable copolymers containing both carboxyl and hydrophobic functionalities are synthesized. A fluorophenyl azide (FPA) based UV‐assisted crosslinker is also employed to promote the movement of polar carboxyl groups toward the bulk region and the hydrophobic functionalities to the surface region, thereby maintaining the high‐k characteristics and hydrophobic surface in thin film. Thus, the addition of an FPA crosslinker eliminates the trapsites on the surface, allowing a stable operation and efficient charge transport. Additionally, the solution‐processability enables the production of uniform and thin films to yield OFETs with stable and low‐voltage driving characteristics. The printed layers are also applied as gate dielectrics for floating gate memory devices and in integrated one‐transistor‐one‐transistor based memory cells, displaying their excellent memory performance. The synthesis and fabrication strategies employed in this study can become useful guidelines for the production of high‐k dielectrics for stable OFETs and other applications.

Improved α-Sialylation through the Synergy of 5-N,4-O-Oxazolidinone Protection and Exocyclic C-1 Neighboring Group Participation.

Stereoselective construction of α-sialyl linkages is one of the most significant challenges in carbohydrate chemistry. In this research, we developed a novel strategy for stereoselective synthesis of α-linked sialosides by protecting the 5-N,4-O-positions of a sialyl donor with an oxazolidinone group and its C-1 carboxylic functionality with a cyanoethyl ester to promote α-glycosylation. We also adopted the more electrophilic N-bromosuccinimide as a promoter to readily activate p-tolyl thiosialoside at -78 °C. The sialylation using this sialyl donor gave excellent yields and α-selectivity. The new synthetic method was used to successfully construct naturally occurring α-sialosides having sialic acid linked to the 6-O- or 3-O-position of galactoside, or 8-O-position of another sialic acid, respectively, as well as other α-linked sialosides.

Synthesis of novel thin film composite (TFC) forward osmosis (FO) membranes incorporated with carboxylated carbon nanofibers (CNFs)

In this study, thin film composite (TFC) membranes were modified using carbon nanofibers (CNFs) for forward osmosis (FO) applications. Carboxyl functionalization of CNFs was performed to increase their surface hydrophilicity and dispersion in a polysulfone (PSF) matrix as the membrane substrate. Different concentrations of both carboxyl functionalized CNFs (f-CNFs) (0.1, 0.3, and 0.5 wt%,) and raw CNFs (0.3 wt%) were incorporated in the polymer matrix and hydrophilicity, porosity, surface roughness, tensile strength and morphology of the nanocomposite substrates were characterized. The optimal membrane was achieved based on the best performance (higher water flux and lower reverse solute flux). Thereby, the TFC membrane containing 0.3 wt% of the f-CNFs was selected as the optimal membrane. The FO water flux of this membrane was almost 2 times higher than the neat TFC membrane in both FO (active layer facing FS) and PRO (active layer facing DS) modes of operation. Water flux of 13.08 L m− 2 h− 1 and specific reverse solute flux of 0.24 g L− 1 were achieved when 1 M NaCl was used as the draw solution (DS) and Deionized (DI) water was used as the feed solution (FS) under the FO mode. Furthermore, incorporation of the f-CNFs decreased the structural parameter (S) of the TFC membranes leading to lower internal concentration polarization (ICP). From the results, it was concluded that the f-CNFs is a suitable candidate for TFC-FO membranes modification to achieve high membrane performance.

Application of laccase immobilized rice straw biochar for anthracene degradation.

The present study explores the immobilization of ligninolytic enzyme-laccase on the surface of rice straw biochar and evaluates its application for anthracene biodegradation. The rice straw biochar was acid-treated to generate carboxyl functionality on its surface, followed by detailed morphological and chemical characterization. The surface area of functionalized biochar displayed a two-fold increase compared to the untreated biochar. Laccase was immobilized on functionalized biochar, and an immobilization yield of 66% was obtained. The immobilized enzyme demonstrated operational stability up to six cycles while retaining 40% of the initial activity. Laccase immobilization was further investigated by performing adsorption and kinetic studies, which revealed the highest immobilization concentration of 500 U g-1 at 25°C. The adsorption followed the Langmuir isotherm model at equilibrium, and the kinetic study confirmed pseudo-second-order kinetics. The equilibrium rate constant (K2) at 25°C and 4°C were 3.6×10-3g U-1 min-1 and 4×10-3g U-1 min-1 respectively for 100 U g-1 of enzyme loading. This immobilized system was applied for anthracene degradation in the aqueous batch mode, which resulted in complete degradation of 50mgL-1 anthracene within 24h of interaction exposure.