Organic Carboxylate Research Articles

Construction of Hydrogen-Bonded Self-Assembled Structures of Sodium 4-[(4-Chlorobenzoyl) Amino] Benzoate for Dispersion and Lubrication in Polypropylene

Among numerous nucleating agents, organic carboxylate nucleating agents have been demonstrated to markedly improve the crystallization of polypropylene (PP). However, poor dispersion in the PP matrix affects the modification effect. In this work, erucamide (ECM) and sodium 4-[(4-chlorobenzoyl) amino] benzoate (SCAB) form a hydrogen-bonded self-assembled structure to obtain the SCAB-ECM composite nucleating agent in order to improve the dispersion of SCAB in the PP matrix and to exert internal lubrication on the PP matrix. The molecular structure of the SCAB-ECM composite was investigated by using Fourier transform infrared spectroscopy (FT-IR), and the result showed that SCAB and ECM could form a hydrogen-bonded self-assembled structure after physical blending. The scanning electron microscopy (SEM) results visualized that ECM promoted the dispersion of SCAB due to the formation of hydrogen-bonded self-assembled structures by SCAB and ECM. The crystallization behavior was studied using differential scanning calorimetry (DSC). At the crystallization temperature of 135 °C, the K of PP, PP/ECM, PP/SCAB, and PP/SCAB-ECM were 0.0002, 0.0004, 1.1616, and 1.8539, respectively. The crystallization properties of PP/SCAB-ECM were the best, which was attributed to the fact that SCAB formed a hydrogen-bonded self-assembled structure with ECM, which promoted the dispersion of SCAB in the PP matrix. The results of the rheological behavior demonstrated that the ECM can act as a lubrication effect, which was also proved by flexural strength results.

Mixed Carboxylate Ligands Bridging Tetra-Pr3+-Encapsulated Antimonotungstate: Syntheses, Structure, and Catalytic Activity for Imidazoles Synthesis.

Multinuclear Pr-containing antimonotungstate [Pr4(H2O)10W6O13(mal)2(OAc)(B-α-SbW9O33)4]21- (Pr-1, mal = malate anion, OAc = acetate anion), bridged by organic carboxylic acid, was synthesized through a one-pot assembly reaction and structurally characterized. Pr-1 is composed of four [B-α-SbW9O33]9- fragments fused together by an organic-inorganic hybrid central [Pr4(H2O)10W6O13(mal)2(OAc)]15+ cluster core through 24 μ2-O atoms. Notably, the central cluster comprises unprecedented decanuclear Pr4(H2O)10W6O13 jointly decorated by two types of carboxylic acid ligands. This integration of rare earth-containing antimonotungstate with mixed organic carboxylate ligands is very rare in POMs chemistry. Pr-1 exhibits excellent catalytic activity in the cyclo-condensation reaction involving benzil, aldehyde, and NH4OAc. A series of 2,4,5-trisubstituted imidazoles were synthesized in remarkable yields using iPrOH as a green solvent.

Tailor-made green composts with suppressive properties against tracheofusariosis of wild rocket (Diplotaxis tenuifolia): Useful option for sustainable circular horticulture

Intensive cultivation systems of wild rocket (Diplotaxis tenuifolia) are threatened by the outbreak of tracheofusariosis caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. raphani. The disease is difficult to eradicate by curative methods due to the endophytic progression of the pathogen. Suppressive composts can help to prevent this adversity by providing organic matter carrying chemical and biological components that can directly and/or indirectly interfere with the plant-pathogen system. In this study, a collection of seven promising composts from different selected green feedstocks were investigated for their suppressive properties towards wild rocket Fusarium wilting. In planta assays identified two composts, obtained from olive tree pruning + plant and tomato residues, and from olive waste + straw + wool residues, with the highest levels of suppressiveness, influenced by both application dose and plant development stage. These active composts showed overlapping 13C NMR profiles as in vivo suppressiveness, being positively correlated with the organic aliphatic alkyl, O-Aryl and carboxyl C fractions and subsequently with the hydrophobic index and alkyl ratio, and negatively with the lignin ratio. On the contrary, although biotic compost components showed antifungal effects, biological properties did not correlate with in planta wilting suppression. Consistently, reflectance spectroscopy in the Vis-NIR-SWIR highlighted the clustering of samples depending on their feedstock and chemical composition. The results allow the hypothesis of a plant-mediated suppression mechanism. The composting of crop residues improves the circularity of horticulture and makes it possible to produce, from selected matrices, tailored compost towards the sustainable cultivation of wild rocket.

Impact of Organic Anions on Metal Hydroxide Oxygen Evolution Catalysts.

Structural metamorphosis of metal-organic frameworks (MOFs) eliciting highly active metal-hydroxide catalysts has come to the fore lately, with much promise. However, the role of organic ligands leaching into electrolytes during alkaline hydrolysis remains unclear. Here, we elucidate the influence of organic carboxylate anions on a family of Ni or NiFe-based hydroxide type catalysts during the oxygen evolution reaction. After excluding interfering variables, i.e., electrolyte purity, Ohmic loss, and electrolyte pH, the experimental results indicate that adding organic anions to the electrolyte profoundly impacts the redox potential of the Ni species versus with only a negligible effect on the oxygen evolution activities. In-depth studies demonstrate plausible reasons behind those observations and allude to far-reaching implications in controlling electrocatalysis in MOFs, mainly where compositional modularity entails fine-tuning organic anions.

Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence

A novel polymerizable BODIPY-based probe targeting carboxylates for molecularly imprinted polymers (MIPs) was developed, exhibiting selective recognition of levofloxacin, enabling detection at submicromolar concentrations.

Spatial Effect on the Performance of Carboxylate Anode Materials in Na-Ion Batteries.

Developing low-voltage carboxylate anode materials is critical for achieving low-cost, high-performance, and sustainable Na-ion batteries (NIBs). However, the structure design rationale and structure-performance correlation for organic carboxylates in NIBs remains elusive. Herein, the spatial effect on the performance of carboxylate anode materials is studied by introducing heteroatoms in the conjugation structure and manipulating the positions of carboxylate groups in the aromatic rings. Planar and twisted organic carboxylates are designed and synthesized to gain insight into the impact of geometric structures to the electrochemical performance of carboxylate anodes in NIBs. Among the carboxylates, disodium 2,2'-bipyridine-5,5'-dicarboxylate (2255-Na) with a planar structure outperforms the others in terms of highest specific capacity (210 mAh g-1), longest cycle life (2000 cycles), and best rate capability (up to 5 A g-1). The cyclic stability and redox mechanism of 2255-Na in NIBs are exploited by various characterization techniques. Moreover, high-temperature (up to 100°C) and all-organic batteries based on a 2255-Na anode, a polyaniline (PANI) cathode, and an ether-based electrolyte are achieved and exhibited exceptional electrochemical performance. Therefore, this work demonstrates that designing organic carboxylates with extended planar conjugation structures is an effective strategy to achieve high-performance and sustainable NIBs.

Cover Image

This cover image depicts the surface functionalization process of MXene with various organic ligand molecules including organic salts, catechols, phosphonates, carboxylates, and silanes. This surface chemistry facilitates favorable interactions between MXene and these ligand molecules, offering significant potential for finely adjusting MXene's physiochemical, electrical, and mechanical properties, while also greatly enhancing dispersion and oxidation stabilities—crucial for practical applications. image

Effect of organic carboxylates in coal on the production of active sites and coal self-ignition behavior

The heat release of coal oxidation lead to the thermal decomposition of carboxylic groups, which include carboxylic acid and carboxylate. However, few researchers have studied the effect of the decomposition of intrinsic carboxylate structure on coal self-ignition process. In this work, different coal samples were selected and treated with alkali solutions to form organic carboxylate structures, and the thermal decomposition of the raw and alkali-treated coals followed by the room temperature oxidation process were analyzed. The effect of the carboxylate structures on the thermal behavior, elemental distribution, and functional groups of coal was also studied by means of TGA, FTIR, XPS and EPR. The results showed that the carboxylic groups in coal were transformed into carboxylate structures by ion exchange. In addition, highly reactive free radical active sites were produced and accumulated along with the decomposition of carboxylates, thus accelerating the self-heating of coal. In the room-temperature oxidation experiment, the temperature of alkali-treated Wulan coal was spontaneously raised by 13.9℃, while that of raw coal was 4.3 ℃. The results showed that the thermal decomposition of organic carboxylate played an important role in promoting the spontaneous combustion of coal, and acid pretreatment could be a potential method to effectively inhibit the coal self-ignition process.

Ligand chemistry for surface functionalization in MXenes: A review

AbstractSurface chemistry of MXenes is of significant interest due to its potential to control their final optoelectronic and physicochemical properties, and address the oxidation and dispersion stabilities of MXenes. Surface chemistry of MXenes can be manipulated by either MXene synthesis via chemical etching or post surface functionalization method. Although numerous reviews have explored MXene synthesis methods, there has been a lack of focus on post surface functionalization. This review aims to fill this gap by summarizing recent advancements in the MXene surface functionalization chemistry, and elucidating mechanisms, properties, and future perspectives of functionalized MXenes. We discuss organic ligand molecules, such as organic salts, catechols, phosphonates, carboxylates, and silanes, which can be employed to surface‐functionalize MXene through covalent or non‐covalent bond interaction. This comprehensive review offers valuable insights for scientists and engineers in utilizing functionalized MXenes across diverse applications, including EMI shielding, energy storage, electronics, optoelectronics, and sensors.image

Chitosan decorated zirconium metal-organic framework for collaborative adsorption and photocatalytic degradation of methylene blue and methyl orange

A type of crystalline porous material known as zirconium metal-organic frameworks (UiO-66) is made up of organic carboxylate ligands and inorganic zirconium clusters. The UiO-66 has consistent pore sizes, large porosities, exceptional adsorption capabilities, and particular functional groups for increasing dye adsorption. This study reports the synthesis of Zirconium metal-organic framework (UiO-66) and chitosan composite of zirconium metal−organic framework (CS/UiO-66) for potential adsorption of methyl orange (MO) and methylene blue (MB) dyes from the aqueous media and additional, excellent photodegradation capability of the synthesized material towards selected dyes. The synthesized materials were successfully characterized for structural, morphological, surface and thermogravimetrical analysis. The exclusion of dyes onto the CS/UiO-66 followed the trend MB (2321 mg/g) > MO (900 mg/g) respectively. The maximum sorption and degradation capacity of the CS/UiO-66 were increased by 5–10 times after its composite with chitosan (CS) and the affinity of the dyes towards the different adsorbents followed the sequence CS/UiO-66 > UiO-66 > CS which is parallel to their surface properties. The negative values of the entropy i.e., − 382 for MB and − 249 for MO affirmed the controlled versatility of the MO, and MB onto CS/UiO-66 whereas the isosteric heat of adsorption i.e., − 201 kJ/mol for MB and − 153 kJ/mol for MO illustrated the exothermicity of the adsorption process. The intraparticle diffusion and Richenberge kinetic models demonstrated that pore diffusion dominates in the adsorption of MB while film diffusion has a greater involvement in the MO adsorption of CS/UiO-66. Moreover, the photocatalytic degradation study indicated that the pH and H2O2 play a significant part in the deprivation of dyes. While GC-MS analysis revealed that the photocatalytic degradation of MB resulted in the formation of six TPs. The toxicity of these TPs of MB was evaluated by ECOSAR program and the results showed that the TPs were less toxic than the parent MB molecule.

Effect of Clay Minerals on Carbonate Precipitation Induced by Cyanobacterium Synechococcus sp.

Carbonate precipitation induced by cyanobacteria is an important factor in lacustrine fine-grained carbonate rock genesis. As key components of these rocks, clay minerals play an important role in aggregating cyanobacteria. However, the formation mechanism of fine-grained carbonate under the effect of clay minerals is unclear. In this study, we investigated carbonate precipitation by Synechococcus cells under the influence of clay minerals. The results showed that clay minerals can accelerate Synechococcus aggregation, and the aggregation rate of the kaolinite group was significantly higher than that of montmorillonite. The aggregate size and Synechococcus cell content increased with an increase in clay minerals, resulting in increasing organic matter and carboxyl content in the aggregates. Due to the high affinity between carboxyl and Ca2+, the presence of Synechococcus sp. could improve the Mg/Ca molar ratio in the microenvironment of aggregates, which is conducive to aragonite precipitation. Thus, aragonite 5 to 10 μm in size precipitated when Synechococcus and clay minerals coexisted, whereas low-magnesium calcite (15 to 60 μm) was the main carbonate only in the presence of Synechococcus. This study provides important insights into the mechanisms of microbial-induced carbonate precipitation under the effect of clay minerals, which might offer theoretical support for the genesis of fine-grained lacustrine carbonate. IMPORTANCE The biogenesis of lacustrine fine-grained carbonates is of great significance to the exploitation of shale oil. Clay minerals are an important component of lacustrine fine-grained sedimentary rocks, which is conductive to the aggregation and settlement of cyanobacteria. We investigated the precipitation of carbonate induced by Synechococcus sp. with the addition of kaolinite and montmorillonite. The pH and calcium carbonate saturation of the environment increased under the effect of cyanobacteria photosynthesis. The aggregation of cyanobacteria cells increased the Mg/Ca molar ratio of the microenvironment, creating a favorable condition for the precipitation of aragonite, which was similar in size to the micritic calcite of fine-grained sedimentary rocks. This study provides theoretical support for the genesis of fine-grained carbonates.

A Tetranuclear Copper(II)/Calcium(II) Complex as Dual Chemosensor for Colorimetric and Fluorescent Detection of Non-Steroidal Anti-Inflammatory Drugs.

The tetranuclear Cu2+ /Ca2+ /Ca2+ /Cu2+ complex based on Malten ligand has been investigated as a platform for anion binding. Simple organic carboxylates and non-steroidal anti-inflammatory drugs (NSAIDs) have been tested, revealing the ability of the platform to bind them. The receiving platform hosts at least two guests in solution although a third anion can be bound, as suggested by X-ray diffraction analysis. The addition of the anions is accompanied by a color change of the solution, making the system a colorimetric sensor for carboxylates (LOD values comprised between 3.6 and 20.7 ppm). A fluorescent system consisting of the 2-(3-oxido-6-oxoxanthen-9-yl)benzoate (fluorescein anion) linked to the tetranuclear platform has been also prepared and used in a chemosensing ensemble approach to signal the presence of the selected anions (Log K between 2.6 and 5.6 for the addition of two guests). The latter also works in a paper strip test, offering the chemosensor a possible practical application.

Experimental measurement and model prediction on methane hydrate equilibrium conditions in the presence of organic carboxylic sodium salts

Gas hydrate inhibitors are employed to mitigate gas hydrate formation in pipelines. The effects of thermodynamics inhibition were evaluated by measuring the vapor - liquid aqueous solution - solid hydrate (VLH) equilibrium conditions on methane (CH4) hydrate in the presence of three organic carboxylic sodium salts (sodium formate, sodium acetate, sodium propionate) in this study. The experiments were carried out in the temperature range of 273.65 K to 281.65 K. Compared with deionized water, in the electrolyte solutions of sodium formate, sodium acetate and sodium propionate with mole fraction of 0.010 and 0.020, the VLH equilibrium pressure change (ΔP) increased by 12.93, 27.68 %; 18.78, 38.15 %; 23.51, 49.41 %, respectively. Both of the three organic carboxylic sodium salts have obvious thermodynamic inhibition effect on CH4 hydrate. The strength of hydrate inhibition is related to the carbon chain length of organic carboxylate. The dissociation enthalpy (ΔHdiss) of CH4 hydrate in three organic carboxylic sodium salts solutions remains quite uniform with deionized water, which indicates that three organic carboxylic sodium salts have not been involved in the formation of hydrate nucleus. The Chen-Guo hydrate model and N-NRTL-NRF activity model were employed to predict the VLH equilibrium conditions in electrolyte solutions. In the three organic carboxylic sodium salts solutions, the average absolute relative deviations (AARD) of the VLH equilibrium condition data between the predicted and the experimental were 0.81, 2.17, and 3.02 %, respectively. In the sodium chloride (NaCl) and potassium chloride (KCl) solutions, the AARD between the predicted and literature were 1.44, 1.69 %, respectively. The model has good universality and accuracy. Both sodium acetate and sodium propionate are food grade preservatives. Consequently, these are beneficial for the development of environmental-friendly hydrate inhibitors.

Enhanced Second-Harmonic-Generation Response in a KH2PO4-Type Calcium Nitrate Carboxylate with Unusual Three-Dimensional Inorganic and Organic Connections.

An organic carboxylate ligand was employed in the synthesis of a nonhygroscopic nitrate-based nonlinear-optical (NLO) material. The hybrid-framework solid has unusual three-dimensional inorganic and organic connections with high thermal stability. Sharing similar structural features with the well-known NLO material KH2PO4 (KDP), this compound shows an enhanced second-harmonic-generation (SHG) response of about 1.6 times that of KDP. Theoretical calculations were carried out to reveal the origin of its SHG response.

Organic carboxylate-assisted engineering for fabricating Fe, N co-doped porous carbon interlinked carbon nanotubes towards boosting the oxygen reduction reaction for Zn-air batteries

Fe-Nx sites have been identified as core descriptors for Fe-N/C based oxygen reduction reaction catalysts. However, the low density and less utilization of Fe-Nx sites render these catalysts with inefficient catalytic performance. Herein, we develop an organic carboxylate-assisted engineering to construct Fe, N co-doped porous carbon interlinked carbon nanotubes (Fe/N-CCNTs) with high-density and sufficiently exposed Fe-Nx sites based on self-catalyzed effect. The existing forms of Fe include Fe-imidazole configuration and coordination with unsaturated Zn sites via organic carboxylate as linkers, leading to high-density Fe-Nx sites after pyrolysis. Besides, hexatomic carbon rings of organic carboxylate lower cyclization energy barrier for CNT formation, resulting in CNTs interlinked with separated active sites through “active point-conductive line-active point” connections. The optimal sample (Fe-BOAc-PNC) exhibits the onset potential of 0.93 V (vs. RHE) and half-wave potential of 0.84 V in alkaline solution. The liquid-state Zn-air battery (ZAB) employing Fe-BOAc-PNC generates large power density (160 mW/cm2) and stability over 160 h. Moreover, the assembled flexible ZAB displays superb power density of 93 mW/cm2 with robust flexibility. This work provides an insightful perspective for designing Fe-N/C catalysts with high-density and sufficiently exposed active sites for energy storage application.

Structures and luminescent properties of Sm(III) and Eu(III) coordination polymers with benzoate and phthalate

Two new lanthanide coordination polymers with mixed organic carboxylates ligands were synthesized by reacting Sm(III) or Eu(III) perchlorates with benzoic acid (Hbc) and phthalic acid (H2bdc) at 170 °C by hydrothermal method. The chemical formulas of the two complexes were [Sm(bc)(bdc)(H2O)3]n (1) and [Eu(bc)(bdc)(H2O)2]n (2). The two compounds were characterized by IR spectra, element analyses and X-ray powder diffraction. The crystal structures were determined by X-ray single crystal diffraction. Complexes 1 and 2 were both two-dimensional (2D) layered structure. The two complexes produced the characteristic f-f transition luminescence of Sm(III) or Eu(III) ion with the excitations of UV-rays. The lifetimes of excited states for 4G5/2 (Sm(III)-1) and 5D0 (Eu(III)-2) were 5.5μs and 0.345 ms. The PL (photoluminescence) absolute quantum yield (Фa) for 2 was 14% (λex = 297 nm).

Efficient Decontamination of HD by an Electrophilic Iodine/Carboxylate Composite as an Active Sorbent.

The development of new and efficient decontamination methods has become more relevant in recent years, especially with regard to solid-based decontamination and detoxification systems. The majority of powders used today are dealing with the physical adsorption of chemical warfare agents (CWAs) and their removal from sites without actively destroying them. In this work, we have designed and developed an active solid composite matrix combining organic carboxylate salts and N-iodosuccinimide (NIS) for HD decontamination via oxidation. All the reactions and mechanistic studies for the sorption and degradation of CWAs were conducted using direct polarization and cross polarization solid-state magic-angle spinning nuclear magnetic resonance techniques. Performance toward the sorption and detoxification of HD was tested, exhibiting oxidation within minutes in a mild and selective manner to the nontoxic sulfoxide derivative followed by visible formation of iodine. The results indicate that carboxylate moieties in the matrix are important for stabilizing the positively charged sulfonium ion intermediate and for supplying oxygen for hydrolysis in a water-deficient environment. The NaOBz/NIS composite was shown to be the most efficient in sorbing and converting the water-insoluble agent HD to its nontoxic, water-soluble sulfoxide, which could then be removed from the site with mere water, resulting in less environmental damage and quick remediation.

Construction of ultra-high defective iron-based metal organic frameworks with small molecule acid regulator for enhanced degradation of sulfamethoxazole

In this study, Several small molecule acid FA (formic acid), HBC (benzoic acid), OA (oxalic acid), and CA (citric acid) were applied as the modulator in the preparation of high-activity defective Fe(II)-MOFs with coordinatively unsaturated sites (CUS). Due to the competitive effect caused between organic ligand and carboxyl functional group of the modulator, the addition of modulator create more CUS for PS activation. Moreover, sulfamethoxazole (SMX) degradation rates raised from 40.41% to 80.19%, 73.50%, 63.89%, and 91.96%, respectively. Fe(II)-MOF-CA displayed the most ideal catalytic activity during PS activation. Through typical physical and chemical characterizations (XRD, XPS, CV, BET, and EIS), as well as performance tests, CA was observed as the most robust modulator for improving the degree of crystallinity, porosity and coordination by slowing the rate of Fe releasing via chelation. Based on Electron paramagnetic resonance (EPR), chemical quenching experiment, and LC-MS detection results, main free radicals and degradation intermediates were identified, and the degradation pathways of SMX in the Fe(II)-MOF-CA/PS system was proposed. According to XPS, CV, and EIS results, the possible catalytic mechanism was raised. This research provided a new perspective for improving the performance of Fe-based MOFs toward PS via the construction of defect using small molecule acid, which was meaningful for further investigation and application of pollution control based on MOFs.

Dicarboxylate Modulating Molecular-Ionic Platinum Compounds with Variable Stacking and Photoluminescence.

Under solvothermal conditions, 10 molecular-ionic platinum compounds [Pt(NIA)2]·(L)·nH2O (L = dicarboxylate) were synthesized. In the reaction, acetonitrile undergoes trimerization in situ to generate N-(1-iminoethyl)acetamidine (NIA), which coordinates to PtII ions in forming the N-(1-iminoethyl)acetamidine platinum cation, while the organic carboxylates act as anions. Structural analysis shows that carboxylate ligands regulate the mode of packing of [Pt(NIA)2] in those compounds. Photoluminescence studies show that the photoluminescence behaviors of those compounds also depended on the carboxylate ligands. 1-4, 6, and 7 show blue light emission with fluorescence emission wavelengths of 437-440 nm despite the different carboxylate ligands used. 5 and 8 show green emissions with maximum intensity peak positions of 522 nm. Compared with that of 5 and 8, the emission of 9 and 10 has the same red shifts with peak positions of 567 and 528 nm. The variable-temperature photoluminescence studies reveal that 8 and 10 show two different thermal quenching (TQ) zones in the range of 80-420 K, while the emission intensity of 9 shows negative thermal quenching at low temperatures of 80-220 K and TQ in the range of 220-420 K.

Organic carboxylate salt-enabled alternative synthetic routes for bio-functional cyclic carbonates and aliphatic polycarbonates

A cyclic carbonate with an ammonium carboxylate residue was found to serve as a nucleophile for esterification with alkyl bromides via the SN2 mechanism.