Carboxylic Acid Salts Research Articles

Efficient one-pot tandem C-C formation reaction catalyzed by a multi-functionalized polyacrylonitrile fiber catalyst

A simple and straightforward method has been proposed in this work to construct a multi-functionalized polyacrylonitrile fiber catalyst containing carboxylic acid, tertiary amine, and quaternary ammonium salt to enable series one-pot C-C bond formation in water. The fiber catalyst was prepared from polyacrylonitrile fiber using a two-step method and characterized using various detection techniques. Furthermore, the activity of multi-functional synergistic catalysts can be controlled by adjusting the ratio of acid and base. It is noteworthy that the polyacrylonitrile fiber catalyst with an acid-base ratio of 3:1 (PANF-ABNCl3/1) exhibited superior catalytic activity and high yield in a variety of C-C generation reactions. Additionally, the PANF-ABNCl3/1 catalyst demonstrated exceptional recyclability (at least 10 times) and performed well in scale-up (7.4g, 96%) and continuous flow experiments (can be used continuously for 7 × 24h) using kettle and tubular fixed bed reactor respectively. These findings suggest that the PANF-ABNCl3/1 catalyst holds promise for industrialization.

Avoidance of crystallization of hydrophobic drugs in an amorphous solid dispersion during spray-drying and storage

The study examined the efficacy of additives in preventing the crystallization of functional ingredients during the spray-drying process. Spray-drying of a hydrophobic drug from alcohol in the presence of a hydrophilic carrier-forming agent was utilized as a representative scenario, which frequently leads to the crystallization of the main drug component induced by the drying process. Ibuprofen (IBP) and its four congeners were employed as representatives of readily crystallizable hydrophobic pharmaceutical compounds. Disaccharides were intentionally employed as components of the drug carrier to create conditions conducive to crystallization. Ten materials, including the IBP congeners, were investigated for their anti-crystallization properties. The findings indicated that additives with a hydrophobic moiety similar to that of IBP and a carboxylic acid salt moiety effectively prevented IBP and its congeners from crystallizing when the additive content was ≥0.2 g/g-drug during spray-drying and storage at 30 °C over silica gel.

LOW TEMPERATURE ANALYTICAL CLOUD POINT EXTRACTION. 2: PRECONCENTRATION AND SPECTROPHOTOMETRIC DETERMINATION OF GE(IV)

Cloud point extraction is a powerful tool for the analytical preconcentration of trace amounts of analytes. The standard cloud point extraction procedure requires prolonged heating of the solution, which is not always appropriate in the case of thermally unstable analytes or analytical forms and significantly limits the capabilities of the method. One of the ways to modify cloud point extraction is to find approaches to intensifying the process of analytical concentration. The main disadvantage of cloud point extraction is the need for thermal, ultrasonic, infrared or any other initiation of the formation of the surfactant rich phase. It has been shown that salts of aromatic carboxylic acids can cause instantaneous formation of a surfactant-rich phase. In this work, the conditions of micellar extraction concentration of Ge(IV) in the form of a complex with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium bromide into the micellar phase of the nonionic surfactant triton X-100 were studied and optimized. It is shown that the introduction of ammonium benzoate into the system at a pH of 1.0 and a triton X-100 concentration of 0.5 vol.% leads to the initiation of the formation of a micellar phase at room temperature. The method of spectrophotometric determination of Ge(IV) with 6,7-dihydroxy-2-phenyl-4-methylbenzopyrylium bromide after its micellar- extraction concentration has been developed. The calibration graph is linear in the concentration range of 4.36–472 μg/L, and the limits of detection and determination are 1.31 and 4.36 μg/L, respectively. The proposed method was tested in the analysis of model solutions and biologically active additives, and the relative standard deviation does not exceed 5.1%.

Analysis of aromatic carboxylic acid and calcium salt couples with gas chromatography-mass spectrometry: Implications and comparison with in situ measurements at Mars' surface

Aromatic organic salts such as benzoates or phthalates may be widespread degradation products of organic molecules at the surface of Mars. The low volatility of these aromatic carboxylic salts could have compromised their detection through thermal extraction in situ analyses such as those performed by the Viking landers. However, over the years, analytical chemistry laboratories on board current and future Martian surface missions, such as the Sample Analysis at Mars (SAM) instrument suite on board the Curiosity rover and the Mars Organic Molecule Analyzer (MOMA) instrument of the Rosalind Franklin ExoMars rover, respectively, have evolved. These instruments have improved in efficiency to detect refractory and polar organic compounds, which could influence the detection of aromatic organic salts. To evaluate the capability of detecting aromatic organic salts on Mars with in situ instruments, we performed laboratory experiments under Viking, SAM, and MOMA-like Gas Chromatography-Mass Spectrometry (GC–MS) conditions with two carboxylic acid/salt couples: phthalic acid/calcium phthalate and benzoic acid/calcium benzoate. We studied the behavior and signatures of both molecular forms when using pyrolysis and derivatization experiments and the implications of these results in the search for organic molecules on Mars. This study showed that the Viking experiments could not have detected the presence of aromatic carboxylic salts in Martian samples because its maximum pyrolysis temperature was too low (500 °C). However, we showed that calcium benzoate and calcium phthalate, despite their refractory nature, could be identified indirectly through the detection of thermal and derivatized degradation products, both with SAM and MOMA. No conclusive proof of the presence of these aromatic organic salt species have been found in the SAM in situ data but given the right instrumental set-up they could be detected if present. The conclusions of this work raise essential questions on the detectability of refractory molecules, the analytical efficiency of flight instruments, and the interpretation of in situ data.

Beyond Conventional Carbon Activation: Creating Porosity without Etching Using Cesium Effect.

Facile synthesis of porous carbon with high yield and high specific surface area (SSA) from low-cost molecular precursors offers promising opportunities for their industrial applications. However, conventional activation methods using potassium and sodium hydroxides or carbonates suffer from low yields (<20%) and poor control over porosity and composition especially when high SSAs are targeted (>2000 m2 g-1) because nanopores are typically created by etching. Herein, a non-etching activation strategy is demonstrated using cesium salts of low-cost carboxylic acids as the sole precursor in producing porous carbons with yields of up to 25% and SSAs reaching 3008 m2 g-1. The pore size and oxygen content can be adjusted by tuning the synthesis temperature or changing the molecular precursor. Mechanistic investigation unravels the non-classical role of cesium as an activating agent. The cesium compounds that form in situ, including carbonates, oxides, and metallic cesium, have extremely low work function enabling electron injection into organic/carbonaceous framework, promoting condensation, and intercalation of cesium ions into graphitic stacks forming slit pores. The resulting porous carbons deliver a high capacity of 252 mAh g-1 (567 F g-1) and durability of 100000 cycles as cathodes of Zn-ion capacitors, showing their potential for electrochemical energy storage.

Transition metal-free decarboxylative olefination of carboxylic acid salts.

The cost-effective and efficient synthesis of alkenes is highly significant due to their extensive applications in both synthetic and polymer industries. A transition metal-free approach has been devised for the chemoselective olefination of carboxylic acid salts. This modular approach provides direct access to valuable electron-deficient styrenes in moderate to good yields. Detailed mechanistic studies suggest anionic decarboxylation is followed by halogen ion transfer. This halogen transfer leads to an umpolung of reactant electronics, allowing for a rate-limiting rebound elimination.

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

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

Concentration mediated structural modulation in a family of mixed-ligand coordination polymers: Structure, sorption and luminescence study

A series of mixed-ligands Zn(II) coordination polymers (CPs) have contracted by varying the relative ratio of two ligands. A linear N,N′-donor ligand, trans 4,4′-azobispyridine (azbpy) and a sodium salt of tri carboxylic acid, 1,3,5-benzenetricarboxylate (Na3btc) have been used in different ratio, along with Zn(II) salt to synthesize three different mixed ligands multifunctional hydroxy bridged CPs, namely {[Zn2(μ2-OH)(azbpy)(btc)(H2O)]. (H2O)(MeOH)}n (1), {[Zn2(μ3-OH)(azbpy)1.5(btc)(H2O)].(azbpy)0.5(H2O)4}n (2), and {[Zn2.5(azbpy)(Hbtc)2(μ2-OH)(H2O)3].(H2O)3.5(MeOH)}n (3). All these CPs 1, 2 and 3 have been characterized by single crystal X-ray diffraction (SCXRD), elemental analysis, infrared (IR) spectroscopy, thermogravimetric (TG) analysis, UV–visible spectroscopy and powder X-ray diffraction (PXRD). The desolvated frameworks of 1 and 2 adsorb CO2 better, over N2, whereas, complex 3 shows reverse phenomenon. Solid state luminescence studies of these CPs display attentive fluorescence emission at room temperature. Change in those properties has been observed, which has been discussed here with structural correlation.

FOURIER-TRANSFORM INFRARED SPECTROSCOPY ANALYSIS OF MAULI BANANA (MUSA ACUMINATA) EXTRACT AS A POTENTIAL PULP WOUND HEALING

Background: Pulp wound healing is a critical aspect of endodontics, aiming to preserve the vitality and function of dental pulp tissues. Natural compounds have gained attention for their potential therapeutic applications in dentistry. Mauli banana (Musa acuminata) is a tropical fruit in South Kalimantan as one of the natural plants that have the ability as antibacterial, antifungal, anti-inflammatory, antioxidant, and immunomodulatory effects contains various bioactive molecules with potential pulp wound healing properties. Purpose: to identify and evaluate the functional groups present in mauli banana stem extracts. Methods: This study is true experimental research, the samples were mauli banana stem that were extracted with maceration technique and were subjected to Fourier-Transform Infrared Spectroscopy test. Results: Identification of functional groups of organic compounds from mauli banana are as follows: a) Peak 3638.95 cm-1 show O-H (nonbonded hydroxy group, OH stretch primary) component alcohol, b) Peak 3265.82 cm-1is C-H (alkane), c) Peak 2928.09 cm-1 refer to OH (carboxylic acid hydrogen bonds) and aldehydes groups, d) peak 1571.35 cm-1 refers to amide, C=O - asymetric stretching, e) peak 1400.82 cm-1, refers to CO2- symetric stretching and carboxylate (carboxylic acid salt) CH2 scissoring, f) peak 1030.17 cm-1 refers to C=C (alkanes), aliphatic phosphate, g) Peak 520.53 cm-1 refers to inorganic phosphates. Conclusion: FTIR spectra analysis of mauli banana stem extract show the presence of O-H hydroxy groups, aldehydes groups, carbonyl groups, aliphatic groups, carbonyl groups, amides groups and C-O stretching vibrations suggests that the extract contains various bioactive molecules with potential pulp wound healing properties.

Evaluation of the inhibitory effect of some derivatives of salts of long-chain carboxylic acids in relation to pitting corrosion of reinforcing steel in concrete

Derivatives of salts of long chain carboxylic acids and dimethylaminopropylamine, including those similar in composition to vegetable oils were synthesized. The structure of the molecules of new substances was reliably confirmed using physical methods of IR-Fourier spectroscopy, NMR spectroscopy, and HPLC. The inhibitory effect of the synthesized substances on 35GS grade reinforcing steel was assessed using voltammetry. Experiments were carried out in an aqueous extract from a mortar, simulating the concrete pore solution, in the presence of chlorides as activators of pitting corrosion, as well as in samples of fine-grained concrete with periodic immersion in a chloride solution. It was found that 3-(dimethylamino)propyl-1-ammonium stearate did not exhibit an inhibitory effect. The introduction of salts of fatty acids of coconut and sunflower oils increased the anti-corrosion properties. The degree of protection was 40-44% in aqueous solutions and 30-32% for concrete samples. The time before the onset of corrosion in concrete samples was found to increase by 1.75 times compared to the control composition without additives

Inhibitors of chloride corrosion of reinforcement steel in concrete based on derivatives of salts of carboxylic acids and dimethylaminopropylamine

In our study, we synthesised derivatives of salts of carboxylic acids and dimethylaminopropylamine: 3-(dimethylamino)propyl-1-ammonium acetate, 3-(dimethylamino)propyl-1-ammonium hexanoate, 3-(dimethylamino)propyl-1-ammonium octanoate, and 3-(dimethylamino)propyl-1-ammonium terephthalate. The structures of the molecules of the obtained substances were confirmed using physical methods: Fourier-transform infrared spectroscopy, NMR spectroscopy, and HPLC. Electrochemical methods (voltammetry and electrochemical impedance spectroscopy) and quantum chemical modeling were used to assess the inhibitory effect of the synthesised substances with regard to 35GS reinforcement steel. Experiments were conducted in a water extract from a mortar simulating concrete pore solution in the presence of chlorides inducing pitting corrosion. 3-(dimethylamino)propyl-1-ammonium terephthalate is expected to have the highest degree of protection (up to 71%) at a concentration of 2.0 g·dm–3. The highest degree of protection for the derivatives with alkyl radicals is 41–46% in a range of concentrations from 0.5 to 2.0 g·dm-3. The results of potentiodynamic measurements and quantum chemical modeling were close. Average level of degree of protection can be explained by a high concentration of chlorides in the model solution (1.00 mol·dm–3). The effectiveness of the obtained substances is to be further studied using fine-grained concrete. This will help to assess the impact of the additives on the capillary pore structure (permeability) of concrete and the concentration of chlorides

Ag Sinter Bonding to Si Substrate via Temporal Formation and Decomposition of Ag Carboxylate.

This paper demonstrates the in situ sinter bonding of Ag microparticle pastes to a Si substrate via the temporal formation and decomposition of Ag carboxylate on the surface of Ag microparticles. This was proposed via the investigation of Ag sinter bonding using the redox reaction between Ag2O and ethylene glycol, which achieved a bonding strength above 30 MPa even for the bonding temperature at 220 °C. Thermal analysis was used to identify the product of the redox reaction between Ag2O and ethylene glycol and determine the bonding temperature because the final reaction facilitates the interfacial sinter bonding with the substrate. Fourier-transform infrared spectroscopy and nuclear magnetic resonance results indicated the in situ formation of Ag salts of carboxylic acids, such as Ag oxalate on the surface of Ag microparticles. Therefore, the sinter bonding process enabled by the in situ formation and subsequent decomposition of these Ag salts was investigated using Ag microparticles and oxalic acid. Observations of the surface and interfacial morphology of the Ag particles after heating revealed the formation of Ag nanoparticles on the surfaces of the microparticles and the formation of sintering necks between the particles. The bonding experiments demonstrated a significant increase in strength with the addition of oxalic acid to the Ag paste due to the enhanced interfacial sinter bonding with the substrate. The in situ formation and decomposition of Ag salts are promising strategies for improving sintered bonds in electronic devices because they can provide enhanced localized sinter bonding using stable insert materials.

A Japan-UK Collaboration in Organic Synthesis.

This invited Team Profile was created by Shuo Wang, Igor Larrosa, Hideki Yorimitsu and Greg Perry. They recently published an article on carboxylic acid salts as dual-function reagents for carboxylation and carbon isotope labeling. This project brought together researchers based in Japan and the UK, and demonstrates how scientists with different cultural backgrounds can work together to build powerful results. "Carboxylic Acid Salts as Dual-Function Reagents for Carboxylation and Carbon Isotope Labeling", S. Wang, I. Larrosa, H. Yorimitsu, G. J. P. Perry, Angew. Chem. Int. Ed. 2023, e202218371.

A Japan–UK Collaboration in Organic Synthesis

AbstractThis invited Team Profile was created by Shuo Wang, Igor Larrosa, Hideki Yorimitsu and Greg Perry. They recently published an article on carboxylic acid salts as dual‐function reagents for carboxylation and carbon isotope labeling. This project brought together researchers based in Japan and the UK, and demonstrates how scientists with different cultural backgrounds can work together to build powerful results. “Carboxylic Acid Salts as Dual‐Function Reagents for Carboxylation and Carbon Isotope Labeling”, S. Wang, I. Larrosa, H. Yorimitsu, G. J. P. Perry, Angew. Chem. Int. Ed. 2023, e202218371.

Carboxylic Acid Salts as Dual‐Function Reagents for Carboxylation and Carbon Isotope Labeling

AbstractThe potassium salts of carboxylic acids are developed as efficient carboxylating agents through CO2 exchange. We describe these carboxylates as dual‐function reagents because they function as a combined source of CO2 and base/metalating agent. By using the salt of a commercially available carboxylic acid, this protocol overcomes difficulties when using CO2 gas or organometallic reagents, such as pressurized containers or strictly inert conditions. The reaction proceeds under mild conditions, does not require transition metals or other additives, and shows broad substrate scope. Through the preparation of several biologically important molecules, we show how this strategy provides an opportunity for isotope labeling with low equivalents of labeled CO2.

Carboxylic Acid Salts as Dual-Function Reagents for Carboxylation and Carbon Isotope Labeling.

The potassium salts of carboxylic acids are developed as efficient carboxylating agents through CO2 exchange. We describe these carboxylates as dual-function reagents because they function as a combined source of CO2 and base/metalating agent. By using the salt of a commercially available carboxylic acid, this protocol overcomes difficulties when using CO2 gas or organometallic reagents, such as pressurized containers or strictly inert conditions. The reaction proceeds under mild conditions, does not require transition metals or other additives, and shows broad substrate scope. Through the preparation of several biologically important molecules, we show how this strategy provides an opportunity for isotope labeling with low equivalents of labeled CO2 .

Introduction of versatile and recyclable network poly (ionic liquid)s as an efficient solvent with desired properties for application in C[sbnd]C cross-coupling reactions

Synthesis of high viscosity, ecofriendly, and low melting point poly(ionic liquid)s (LMP-PIL) with network structure has been introduced by the reaction of 1,1′,1′′‑(1,3,5‑triazine‑2,4,6‑triyl) tris(3‑methyl‑1H‑imidazol‑3‑ium) iodide ionic liquid (TAIm[I] IL) monomer with disodium salts of various open-chain carboxylic acids as well as sulfonic acids via a polycondensation on counter ions (PC-CI). Change in alkyl group length in carboxylate, as well as sulfonate, provide a broad spectrum of properties in terms of viscosity, density, and solubility for the resulting PILs. The physical properties of the PILs including, viscosity, melting point, boiling point, density,M¯n, and polydispersity (Ð), were determined in this study. Also, thermal behavior of the PILs were studied in comparison with the corresponding monomers. The ecofriendly PILs served as an efficient solvent and ligand for the Cu-catalyzed Heck and Sonogashira CC coupling reactions. High to excellent yields were obtained for various coupling products under mild conditions at melting points of the PILs. Also, the coupling products could be obtained with direct scalability. The prepared PILs could be recycled several times from the homogenous reaction mixture with preservation of the intrinsic properties. Also, a detailed study was conducted on the mechanism of the coupling reactions.

New Titanocene (IV) Dicarboxylates with Potential Cytotoxicity: Synthesis, Structure, Stability and Electrochemistry.

The search for new anticancer drugs based on biogenic metals, which have weaker side effects compared to platinum-based drugs, remains an urgent task in medicinal chemistry. Titanocene dichloride, a coordination compound of fully biocompatible titanium, has failed in pre-clinical trials but continues to attract the attention of researchers as a structural framework for the development of new cytotoxic compounds. In this study, a series of titanocene (IV) carboxylate complexes, both new and those known from the literature, was synthesized, and their structures were confirmed by a complex of physicochemical methods and X-ray diffraction analysis (including one previously unknown structure based on perfluorinated benzoic acid). The comprehensive comparison of three approaches for the synthesis of titanocene derivatives known from the literature (the nucleophilic substitution of chloride anions of titanocene dichloride with sodium and silver salts of carboxylic acids as well as the reaction of dimethyltitanocene with carboxylic acids themselves) made it possible to optimize these methods to obtain higher yields of individual target compounds, generalize the advantages and disadvantages of these techniques, and determine the substrate frames of each method. The redox potentials of all obtained titanocene derivatives were determined by cyclic voltammetry. The relationship between the structure of ligands, the reduction potentials of titanocene (IV), and their relative stability in redox processes, as obtained in this work, can be used for the design and synthesis of new effective cytotoxic titanocene complexes. The study of the stability of the carboxylate-containing derivatives of titanocene obtained in the work in aqueous media showed that they were more resistant to hydrolysis than titanocene dichloride. Preliminary tests of the cytotoxicity of the synthesised titanocene dicarboxilates on MCF7 and MCF7-10A cell lines demonstrated an IC50 ≥ 100 μM for all the obtained compounds.

Fabrication of Superhydrophobic Surface on Anodized Aluminum Through a Wet-Chemical Route

Fabrication of superhydrophobic surfaces on anodized aluminum substrates by wet-chemical grafting using cost-effective chemicals through a simple immersion process is described in this work. Formation of formate-alumoxane is possible by treating the anodized and sealed aluminum substrate with formic acid at around 50 °C. On treatment with sodium salts of higher-order carboxylic acids (stearic acid, lauric acid, and palmitic acid), the formate ions are replaced by higher-order carboxylates. A possible bonding mechanism of the longer chain carboxylic acids with aluminium surfaces has been suggested based on IRRAS and XPS studies. The as-prepared superhydrophobic aluminum substrates exhibited a static water contact angle of up to 167° with a sliding angle not higher than 6°, with decent resistance against abrasion in addition to good UV, environmental and thermal stabilities. Aluminium substrates of any size, shape and surface finish can be easily rendered robust and superhydrophobic without the use of expensive chemicals and sophisticated machinery.

Development of water-soluble phenazine-2,3-diol-based photosensitizers for singlet oxygen generation.

Phenazine-2,3-diol-based dyes, KY-1Na and KY-2Na bearing one and two carboxylic acid sodium salts, respectively, have been newly developed as water-soluble photosensitizers (PSs) possessing the ability to generate singlet oxygen (1O2). In order to evaluate the solubility of KY-1Na and KY-2Na in water, the hydrophobicity/hydrophilicity of the two PSs was investigated by experimental measurement of the logarithms (log Po/w) of the 1-octanol/water partition coefficient (Po/w) for the PS. The log Po/w values of both KY-1Na and KY-2Na were determined to be -0.9, indicating that both the PSs are more hydrophilic than Rose Bengal (-0.6) and have hydrophilicity equivalent to methylene blue (-0.9). Both the PSs in water show a broad photoabsorption band in the range of 500 to 600 nm. Thus, we estimated the 1O2 quantum yields (ΦΔ) of KY-1Na and KY-2Na in water by using 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) as a water-soluble 1O2 scavenger. It was found that in water the ΦΔ value (0.19) of KY-2Na is higher than that of KY-1Na (0.06). Density functional theory (DFT) calculations suggested that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributions for the molecular structure of KY-2Na are adequately separated, leading to a decrease in the energy gap (ΔEST) between the singlet state (S1) and the triplet state (T1) that causes efficient intersystem crossing (ISC), compared to that for the molecular structure of KY-1Na. Indeed, time-dependent DFT (TD-DFT) calculations demonstrated that the ΔEST(S1-T1) value (0.82 eV) of KY-2Na is smaller than that (0.98 eV) of KY-1Na, resulting in a relatively high ΦΔ value of KY-2Na. Consequently, we demonstrate that phenazine-2,3-diol-based PSs bearing carboxylic acid salts possess high solubility and moderate 1O2 generation ability in water.