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1.
Acta Crystallogr F Struct Biol Commun ; 80(Pt 5): 98-106, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38699971

RESUMEN

Molybdenum- or tungsten-dependent formate dehydrogenases have emerged as significant catalysts for the chemical reduction of CO2 to formate, with biotechnological applications envisaged in climate-change mitigation. The role of Met405 in the active site of Desulfovibrio vulgaris formate dehydrogenase AB (DvFdhAB) has remained elusive. However, its proximity to the metal site and the conformational change that it undergoes between the resting and active forms suggests a functional role. In this work, the M405S variant was engineered, which allowed the active-site geometry in the absence of methionine Sδ interactions with the metal site to be revealed and the role of Met405 in catalysis to be probed. This variant displayed reduced activity in both formate oxidation and CO2 reduction, together with an increased sensitivity to oxygen inactivation.


Asunto(s)
Desulfovibrio vulgaris , Formiato Deshidrogenasas , Desulfovibrio vulgaris/enzimología , Desulfovibrio vulgaris/genética , Formiato Deshidrogenasas/química , Formiato Deshidrogenasas/genética , Formiato Deshidrogenasas/metabolismo , Dominio Catalítico , Cristalografía por Rayos X , Oxidación-Reducción , Modelos Moleculares , Formiatos/metabolismo , Formiatos/química , Dióxido de Carbono/metabolismo , Dióxido de Carbono/química , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo
2.
Cell Chem Biol ; 31(5): 932-943.e8, 2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38759619

RESUMEN

Nucleotides perform important metabolic functions, carrying energy and feeding nucleic acid synthesis. Here, we use isotope tracing-mass spectrometry to quantitate contributions to purine nucleotides from salvage versus de novo synthesis. We further explore the impact of augmenting a key precursor for purine synthesis, one-carbon (1C) units. We show that tumors and tumor-infiltrating T cells (relative to splenic or lymph node T cells) synthesize purines de novo. Shortage of 1C units for T cell purine synthesis is accordingly a potential bottleneck for anti-tumor immunity. Supplementing 1C units by infusing formate drives formate assimilation into purines in tumor-infiltrating T cells. Orally administered methanol functions as a formate pro-drug, with deuteration enabling kinetic control of formate production. Safe doses of methanol raise formate levels and augment anti-PD-1 checkpoint blockade in MC38 tumors, tripling durable regressions. Thus, 1C deficiency can gate antitumor immunity and this metabolic checkpoint can be overcome with pharmacological 1C supplementation.


Asunto(s)
Carbono , Ratones Endogámicos C57BL , Purinas , Animales , Ratones , Purinas/química , Purinas/farmacología , Carbono/química , Carbono/metabolismo , Inhibidores de Puntos de Control Inmunológico/farmacología , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/metabolismo , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Linfocitos T/metabolismo , Linfocitos T/inmunología , Linfocitos T/efectos de los fármacos , Formiatos/química , Formiatos/metabolismo , Formiatos/farmacología , Metanol/química , Metanol/farmacología , Femenino , Humanos , Línea Celular Tumoral
3.
J Inorg Biochem ; 257: 112594, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38749080

RESUMEN

We have characterized the catalytic cycle of the Helicobacter pylori KatA catalase (HPC). H. pylori is a human and animal pathogen responsible for gastrointestinal infections. Multifrequency (9-285 GHz) EPR spectroscopy was applied to identify the high-valent intermediates (5 ≤ pH ≤ 8.5). The broad (2000 G) 9-GHz EPR spectrum consistent with the [Fe(IV) = O Por•+] intermediate was detected, and showed a clear pH dependence on the exchange-coupling of the radical (delocalized over the porphyrin moiety) due to the magnetic interaction with the ferryl iron. In addition, Trp• (for pH ≤ 6) and Tyr• (for 5 ≤ pH ≤ 8.5) species were distinguished by the advantageous resolution of their g-values in the 285-GHz EPR spectrum. The unequivocal identification of the high-valent intermediates in HPC by their distinct EPR spectra allowed us to address their reactivity towards substrates. The stabilization of an [Fe(IV) = O Trp•] species in HPC, unprecedented in monofunctional catalases and possibly involved in the oxidation of formate to the formyloxyl radical at pH ≤ 6, is reminiscent of intermediates previously identified in the catalytic cycle of bifunctional catalase-peroxidases. The 2e- oxidation of formate by the [Fe(IV) = O Por•+] species, both at basic and acidic pH conditions, involving a 1H+/2e- oxidation in a cytochrome P450 peroxygenase-like reaction is proposed. Our findings demonstrate that moonlighting by the H. pylori catalase includes formate oxidation, an enzymatic reaction possibly related to the unique strategy of the neutrophile bacterium for gastric colonization, that is the release of CO2 to regulate the pH in the acidic environment.


Asunto(s)
Proteínas Bacterianas , Catalasa , Formiatos , Helicobacter pylori , Oxidación-Reducción , Helicobacter pylori/enzimología , Espectroscopía de Resonancia por Spin del Electrón/métodos , Catalasa/metabolismo , Catalasa/química , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Formiatos/química , Formiatos/metabolismo , Concentración de Iones de Hidrógeno , Hierro/química , Hierro/metabolismo
4.
Sci Rep ; 14(1): 10899, 2024 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-38740854

RESUMEN

In order to obtain the best mass spectrometry identification results for using the most appropriate methods in clinical practice, we explore the optimal pretreatment methods for different species and morphologies of filamentous fungi. 98 fungal strains were treated with formic acid sandwich method, dispersion method, extraction method, and other methods using a medium element mass spectrometer (EXS3000) as a platform. Each strain had three targets, and the identification rates and confidence differences under different pre-treatment methods were compared to evaluate the identification effects of these methods. The mass spectrometry identification rates of 98 filamentous fungi obtained after pre-treatment with formic acid sandwich method, dispersion method, and extraction method were 85.71%, 82.65%, and 75.51%, respectively. The identification rate of the formic acid sandwich method was significantly higher than the other two methods (P < 0 005) has the best identification ability and the obtained confidence is also higher than the other two methods. The use of formic acid sandwich method for mass spectrometry identification of filamentous fungi can achieve ideal identification results, which is suitable for mass spectrometry identification of filamentous fungi in conventional laboratories.


Asunto(s)
Hongos , Espectrometría de Masas , Hongos/aislamiento & purificación , Hongos/clasificación , Espectrometría de Masas/métodos , Formiatos/química , Formiatos/análisis , Micosis/microbiología , Micosis/diagnóstico , Humanos
5.
Environ Res ; 252(Pt 2): 118897, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38621631

RESUMEN

The mesoporous metal oxide semiconductors exhibit unique chemical and physical characteristics, making them highly desirable for catalysis, electrochemistry, energy conversion, and energy storage applications. Here, we report the facial fabrication of mesoporous gray SnO2 (MGS) electrocatalysts employing an evaporation-induced co-assembly (EICA) approach, utilizing poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers Pluronic P123 (PEO-PPO-PEO) triblock copolymer as a template for electrochemical CO2 reduction reaction (eCO2RR). By sustaining the co-assembly conditions and utilizing a thermal treatment technique based on carbon, gray mesoporous SnO2 materials with a high density of active sites and oxygen vacancies can be constructed. The MGS materials were employed in eCO2RR in a flow cell type, which exhibits excellent catalytic activity and selectivity toward formate with a high partial current density of -234 mA cm-2 and Faradaic efficiency (FE) of 93.60 % at -1.3 V vs. reversible hydrogen electrode (RHE). Interestingly, the mesoporous SnO2 with a 1.5 wt% ratio of Sn precursor to P123 surfactant (MS-1.5@350N-400A) electrode exhibits a high level of Faradaic efficiency (FE) of (98%) at a low overpotential of -0.6 VRHE, which is a seldom recorded performance for similar systems. A stable FE of 96 ± 1% was observed in the range of -0.6 to -1.2 VRHE, which is the result of a large surface area (184 m2/g) and a high number of active sites and oxygen vacancies within the mesostructured framework.


Asunto(s)
Dióxido de Carbono , Formiatos , Oxidación-Reducción , Compuestos de Estaño , Catálisis , Compuestos de Estaño/química , Dióxido de Carbono/química , Formiatos/química , Porosidad , Técnicas Electroquímicas/métodos
6.
Waste Manag ; 181: 114-127, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38608526

RESUMEN

In this study, phenolic compounds using deep eutectic solvents (DES) were extracted from cork dust, and the biogas production potential of DES-treated cork dust samples was determined. The DES treatment was carried out using choline chloride and formic acid (1:2 M ratio) at various temperatures (90, 110 and 130 °C) and treatment times (20, 40 and 60 min) at a solid-to-solvent ratio of 1:10 g mL-1. The highest total phenolic content (137 mg gallic acid equivalent (GAE) g-1 dry cork dust) was achieved at 110 °C/20 min. The extracts exhibited an antioxidant capacity of up to 56.3 ± 3.1 % 1,1-diphenyl-2-picrylhydazyl (DPPH) inhibition at a dilution rate of 100. DES treatment resulted in minimal sugar solubilization at low temperatures, while approximately 42 % of the xylan fraction in the biomass degraded under severe conditions (e.g., 130 °C/60 min). Catechin, 4-hydroxybenzoic acid and gallic acid were the major phenolics in DES extracts. The biogas yield of DES-treated cork dust increased with treatment severity. The highest biogas yield (115.1mLN gVS-1) was observed at 130 °C/60 min, representing an increase of 125 % compared to the untreated sample. SEM images revealed that the surface structure of the samples became smoother after mild pretreatment and rougher after harsh pretreatment. Compositional and FTIR analyses indicated that a higher biogas formation potential was associated with increased cellulose content in the substrate, which could be attributed to hemicellulose solubilization in the hydrolysate. Overall, DES pretreatment effectively enhanced phenol extraction and anaerobic degradability.


Asunto(s)
Biomasa , Disolventes Eutécticos Profundos , Polvo , Fenoles , Fenoles/análisis , Polvo/análisis , Disolventes Eutécticos Profundos/química , Anaerobiosis , Quercus/química , Biocombustibles/análisis , Antioxidantes/análisis , Formiatos/análisis , Formiatos/química
7.
Int J Biol Macromol ; 267(Pt 1): 129256, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38493823

RESUMEN

In the present study, the commercially available three different fabrics cotton, nylon and cotton/nylon were modified by chitosan and silver nanoparticles using a crosslinker triethyl orthoformate (TEOF). Resulted cotton­silver (Ag-Cs-Cot), nylon­silver (Ag-Cs-Nyl) and cotton-nylon silver (Ag-Cs-Cot-Nyl) fabrics showed significant anti-bacterial activity even after 50 washing cycles. Silver nanoparticles were prepared by reducing silver nitrate through sodium borohydride at 0 °C. In FTIR spectra the peak at near 1650 cm-1 confirmed that TEOF mediated attachment of chitosan with fabrics (due to C=N) and the stretching of secondary amine near the 3375 cm-1 indicated the silver attachment to the amine group of the chitosan. In Scanning Electron Microscope (SEM) images smooth surfaces of fabrics without any damage by modification process were observed. The antibacterial activity was Analyzed by agar diffusion and broth dilution assays against Escherichia coli and Staphylococcus aureus bacterial strains and results showed 90% bacterial inhibition against E. coli and 89% bacterial inhibition against S. aureus. For testing the antibacterial durability, the modified fabrics were washed with non-ionic detergent (10g/l) for 15 minutes under aggressive stirring (100 rpm) at room temperature. The modified fabrics retained antibacterial activity over the 50 washing cycles. Finally, the commercial potential of cotton-silver fabric was evaluated by stitching it with the socks of football players and interestingly results showed that the modified fabric on the socks showed more than 90% bacterial inhibition as compared to the plain fabric after 70 minutes of playing activity.


Asunto(s)
Antibacterianos , Quitosano , Fibra de Algodón , Escherichia coli , Nanopartículas del Metal , Nylons , Plata , Staphylococcus aureus , Textiles , Quitosano/química , Quitosano/farmacología , Plata/química , Plata/farmacología , Nanopartículas del Metal/química , Antibacterianos/farmacología , Antibacterianos/química , Nylons/química , Escherichia coli/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Formiatos/química
8.
Int J Biol Macromol ; 266(Pt 2): 131182, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38554898

RESUMEN

Formic acid is utilized to induce esterification and chemical gelatinization in starch, particularly in the fabrication of electrospun fibers for nanomaterial production. This study investigated the impact of different concentrations (15, 20, 25, and 30 %) of cassava starch and formic acid as a solvent on the characteristics of the resultant polymeric solutions and electrospun fibers. Morphology, size distribution, thermogravimetric properties, diffraction patterns, and relative crystallinity were evaluated for the electrospun fibers. The amylose content of starch varied from 16.5 to 23.7 %, decreasing with esterification, achieving a degree of substitution of approximately 0.93. The solution-rheology exhibited elastic behavior, with viscosity increasing as starch concentration increased, hindering the fabrication of fibers at 25 and 30 % starch. Successful electrospun fibers were formed using 15 % and 20 % starch, displaying homogeneous morphologies with mean diameters of 165 nm and 301 nm, respectively. Esterification influenced thermogravimetric properties, leading to fibers with reduced degradation temperatures and mass loss compared to native starches. The electrospun fibers presented an amorphous structure, indicating a drastic reduction in relative crystallinity from 35.2 % in native starch to 8.5 % for esterified starches. This study highlights the intricate relationship between starch concentration, esterification, and solution viscosity, affecting the electrospinnability and properties of starch-polymeric solutions.


Asunto(s)
Formiatos , Manihot , Almidón , Manihot/química , Esterificación , Formiatos/química , Almidón/química , Viscosidad , Amilosa/química , Reología , Termogravimetría
9.
J Am Chem Soc ; 146(13): 8865-8876, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38470125

RESUMEN

Formate is a major reactive carbon species in one-carbon metabolism, where it serves as an endogenous precursor for amino acid and nucleic acid biosynthesis and a cellular source of NAD(P)H. On the other hand, aberrant elevations in cellular formate are connected to progression of serious diseases, including cancer and Alzheimer's disease. Traditional methods for formate detection in biological environments often rely on sample destruction or extensive processing, resulting in a loss of spatiotemporal information. To help address these limitations, here we present the design, synthesis, and biological evaluation of a first-generation activity-based sensing system for live-cell formate imaging that relies on iridium-mediated transfer hydrogenation chemistry. Formate facilitates an aldehyde-to-alcohol conversion on various fluorophore scaffolds to enable fluorescence detection of this one-carbon unit, including through a two-color ratiometric response with internal calibration. The resulting two-component probe system can detect changes in formate levels in living cells with a high selectivity over potentially competing biological analytes. Moreover, this activity-based sensing system can visualize changes in endogenous formate fluxes through alterations of one-carbon pathways in cell-based models of human colon cancer, presaging the potential utility of this chemical approach to probe the continuum between one-carbon metabolism and signaling in cancer and other diseases.


Asunto(s)
NAD , Neoplasias , Humanos , Hidrogenación , NAD/metabolismo , Carbono , Formiatos/química
10.
Bioresour Technol ; 393: 130027, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37977496

RESUMEN

Bioconversion of CO2 to high-valuable products is a globally pursued sustainable technology for carbon neutrality. However, low CO2 activation with formate dehydrogenase (FDH) remains a major challenge for further upcycling due to the poor CO2 affinity, reduction activity and stability of currently used FDHs. Here, we present two recombined mutants, ΔFDHPa48 and ΔFDHPa4814, which exhibit high CO2 reduction activity and antioxidative activity. Compared to FDHPa, the reduction activity of ΔFDHPa48 was increased up to 743 % and the yield in the reduction of CO2 to methanol was increased by 3.16-fold. Molecular dynamics identified that increasing the width of the substrate pocket of ΔFDHPa48 could improve the enzyme reduction activity. Meanwhile, the enhanced rigidity of C-terminal residues effectively protected the active center. These results fundamentally advanced our understanding of the CO2 activation process and efficient FDH for enzymatic CO2 activation and conversion.


Asunto(s)
Dióxido de Carbono , Formiato Deshidrogenasas , Dióxido de Carbono/metabolismo , Formiato Deshidrogenasas/genética , NAD/metabolismo , NADH Deshidrogenasa , Oxidación-Reducción , Formiatos/química
11.
Artículo en Inglés | MEDLINE | ID: mdl-38029665

RESUMEN

Diabetic kidney disease (DKD), a common microvascular complication of diabetes, currently lacks specific diagnostic indicators and therapeutic targets, resulting in miss of early intervention. To profile metabolic conditions in complex and precious biological samples and screen potential biomarkers for DKD diagnosis and prognosis, a rapid, convenient and reliable quantification method for carboxyl compounds by gas chromatography-mass spectrometry (GC-MS) was established with isobutyl chloroformate derivatization. The derivatives were extracted with hexane, injected into GC-MS and quantified with selected ion monitoring mode. This method showed excellent linearity(R2 > 0.99), good recoveries (81.1%-115.5%), good repeatability (RSD < 20%) and sensitivity (LODs: 0.20-499.90 pg, LOQs: 2.00-1007.00 pg). Among the 37 carboxyl compounds analyzed, 12 metabolites in short-chain fatty acids (SCFAs) metabolism pathway and amino acid metabolism pathway were linked with DKD development and among them, 6 metabolites were associated with both development and prognosis of DKD in mice. In conclusion, a reliable, convenient and sensitive method based on isobutyl chloroformate derivatization and GC-MS analysis is established and successfully applied to quantify 37 carboxyl compounds in biological samples of mice and 12 potential biomarkers for DKD development and prognosis are screened.


Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Humanos , Cromatografía de Gases y Espectrometría de Masas/métodos , Nefropatías Diabéticas/diagnóstico , Formiatos/química , Biomarcadores
12.
Phys Rev Lett ; 130(23): 233001, 2023 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-37354420

RESUMEN

We investigate the intermolecular nonradiative charge transfer process in a double hydrogen-bonded formic acid (FA) dimer, initiated by electron-collision induced double ionization of one FA molecule. Through fragment ions and electron coincident momentum measurements and ab initio calculations, we obtain direct evidence that electron transfer from the neighboring FA molecule to fill one of the two vacancies occurs by a potential energy curve crossing of FA^{++}+FA with FA^{+}+FA^{+*} curves, forming an electronic excited state of dicationic dimers. This process causes the breaking of two hydrogen bonds and subsequently the cleavage of C─H and C─O covalent bonds in the dimers, which is expected to be a general phenomenon occurring in molecular complexes and can have important implications for radiation damage to biological matter.


Asunto(s)
Formiatos , Formiatos/química , Iones
13.
Adv Sci (Weinh) ; 10(20): e2300752, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37162224

RESUMEN

Promoting the activity of biological enzymes under in vitro environment is a promising technique for bioelectrocatalytic reactions, such as the conversion of carbon dioxide (CO2 ) into valuable chemicals, which is a promising strategy to address the environmental issue of CO2 in the atmosphere; however, this technique remains challenging. Herein, a nanocage structure for enzyme confinement is synthesized to enable the in situ encapsulation of formate dehydrogenase (FDH) in a porous metal-organic framework, which acts as a coenzyme and boosts the hybrid synergistic catalysis using enzymes. This study reveals that the synthesized FDH@ZIF-8 nanocage-structured hybrid (CSH) catalyst exhibits an improved catalytic ability of the enzymes and increases the hydrophobicity of the electrode and its affinity to CO2 . Thus, CSH can trap CO2 and control its microenvironments. The CSH catalyst boosts the conversion rate of CO2 to formic acid (HCOOH) to 28 times higher than that when using pure FDH. The in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) spectra indicates that OCHO* is the key intermediate. Density functional theory (DFT) calculations show that CSH has extremely low overpotential and is particularly effective for producing formate. This protection architecture for enzymes considerably promotes their biological application under in vitro environments.


Asunto(s)
Dióxido de Carbono , Formiatos , Dióxido de Carbono/química , Catálisis , Formiatos/química , Formiato Deshidrogenasas/química
14.
Angew Chem Int Ed Engl ; 62(6): e202212224, 2023 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-36465058

RESUMEN

Metal-based formate dehydrogenases are molybdenum or tungsten-dependent enzymes that catalyze the interconversion between formate and CO2 . According to the current consensus, the metal ion of the catalytic center in its active form is coordinated by 6 S (or 5 S and 1 Se) atoms, leaving no free coordination sites to which formate could bind to the metal. Some authors have proposed that one of the active site ligands decoordinates during turnover to allow formate binding. Another proposal is that the oxidation of formate takes place in the second coordination sphere of the metal. Here, we have used electrochemical steady-state kinetics to elucidate the order of the steps in the catalytic cycle of two formate dehydrogenases. Our results strongly support the "second coordination sphere" hypothesis.


Asunto(s)
Formiato Deshidrogenasas , Molibdeno , Formiato Deshidrogenasas/metabolismo , Molibdeno/química , Dominio Catalítico , Formiatos/química , Oxidación-Reducción , Cinética
15.
Biochim Biophys Acta Bioenerg ; 1864(1): 148919, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-36152681

RESUMEN

Formate hydrogenlyase-1 (FHL-1) is a complex-I-like enzyme that is commonly found in gram-negative bacteria. The enzyme comprises a peripheral arm and a membrane arm but is not involved in quinone reduction. Instead, FHL-1 couples formate oxidation to the reduction of protons to molecular hydrogen (H2). Escherichia coli produces FHL-1 under fermentative conditions where it serves to detoxify formic acid in the environment. The membrane biology and bioenergetics surrounding E. coli FHL-1 have long held fascination. Here, we review recent work on understanding the molecular basis of formic acid efflux and influx. We also consider the structure and function of E. coli FHL-1, its relationship with formate transport, and pay particular attention to the molecular interface between the peripheral arm and the membrane arm. Finally, we highlight the interesting phenotype of genetic mutation of the ND1 Loop, which is located at that interface.


Asunto(s)
Escherichia coli , Formiato Deshidrogenasas , Formiatos , Fermentación , Formiato Deshidrogenasas/química , Formiatos/química , Hidrógeno
16.
Molecules ; 27(21)2022 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-36364197

RESUMEN

To reveal the nature of CO2 reduction to formate with high efficiency by in situ hydrogen produced from hydrothermal reactions with iron, DFT calculations were used. A reaction pathway was proposed in which the formate was produced through the key intermediate species, namely iron hydride, produced in situ in the process of hydrogen gas production. In the in situ hydrogenation of CO2, the charge of H in the iron hydride was -0.135, and the Fe-H bond distance was approximately 1.537 Å. A C-H bond was formed as a transition state during the attack of Hδ- on Cδ+. Finally, a HCOO species was formed. The distance of the C-H bond was 1.107 Å. The calculated free energy barrier was 16.43 kcal/mol. This study may provide new insight into CO2 reduction to formate in hydrothermal reactions with metal.


Asunto(s)
Hidrógeno , Hierro , Hidrógeno/química , Hierro/química , Dióxido de Carbono/química , Formiatos/química
17.
Molecules ; 27(21)2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36364257

RESUMEN

With several major polarity and weak optical properties, the sensitive detection of HCOOH remains a major challenge. Given the special role of HCOOH in assisting in the catalytic hydrogenation process of Ir complexes, HCOOH (as a hydrogen source) could rapidly activate Ir complexes as catalysts and further reduce the substrates. This work developed a facile and sensitive HCOOH fluorescence sensor utilizing an optimal catalytic fluorescence generation system, which consists of the phenyl-pyrazole-type Ir-complex PP-Ir-Cl and the coumarin-type fluorescence probe P-coumarin. The sensor demonstrates excellent sensitivity and specificity for HCOOH and formates; the limits of detection for HCOOH, HCOONa, and HCOOEt3N were tested to be 50.6 ppb, 68.0 ppb, and 146.0 ppb, respectively. Compared to previous methods, the proposed sensor exhibits good detection accuracy and excellent sensitivity. Therefore, the proposed HCOOH sensor could be used as a new detection method for HCOOH and could provide a new design path for other sensors.


Asunto(s)
Formiatos , Hidrógeno , Hidrógeno/química , Fluorescencia , Catálisis , Formiatos/química , Cumarinas
18.
Phys Chem Chem Phys ; 24(40): 24748-24758, 2022 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-36196917

RESUMEN

Halide-formic acid complexes have been studied utilising a combined experimental and theoretical approach. Formic acid exists as two conformers, distinguished by the relative rotation about the C-OH bond. Computational investigation of the formic acid isomerisation reaction between the two conformers has revealed the ability of halide anions to catalyse the formation of, and preferentially stabilise, the higher energy conformer. Anion photoelectron spectroscopy has been used to study the halide-formic acid complexes, with the experimental vertical detachment energies compared with simulated photodetachment energies with respect to halide complexes with both formic acid conformers. The existence of experimental spectral features associated with halide complexes of the higher energy formic acid confomer confirms in situ generation, likely as a result of the halide mediated catalytic formation.


Asunto(s)
Formiatos , Formiatos/química , Espectroscopía de Fotoelectrones , Aniones/química , Catálisis
19.
Angew Chem Int Ed Engl ; 61(48): e202213930, 2022 11 25.
Artículo en Inglés | MEDLINE | ID: mdl-36194372

RESUMEN

On-site hydrogen peroxide production through electrocatalytic and photocatalytic oxygen reduction reactions has recently attracted broad research interest. However, practical applications have thus far been plagued by the low activity and the requirement of complex equipment. Here, inspired by the process of biological hydrogen peroxide synthesis catalyzed by enzymes, we report a Pt-Au alloy to mimic the catalytic function of natural formate oxidase for hydrogen peroxide synthesis through aerobic oxidation of formic acid. The mass activity of the Pt-Au alloy is three times higher than that of formate oxidase. Density functional theory calculations revealed that the efficient dehydrogenation of formic acid and the high selectivity of the subsequent reduction of oxygen to hydrogen peroxide account for the high hydrogen peroxide productivity. In addition, the formic acid aqueous solution provides an acidic environment, which is conducive to the utilization of the in situ generated hydrogen peroxide for oxidation reactions, including C-H bond oxidation and sterilization.


Asunto(s)
Peróxido de Hidrógeno , Platino (Metal) , Platino (Metal)/química , Aleaciones de Oro , Formiatos/química , Oxidación-Reducción , Aleaciones/química , Oxidorreductasas , Oxígeno
20.
Molecules ; 27(17)2022 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-36080185

RESUMEN

Dimethyl carbonate is a generally used chemical substance which is environmentally sustainable in nature and used in a range of industrial applications as intermediate. Although various methods, including methanol phosgenation, transesterification and oxidative carbonylation of methanol, have been developed for large-scale industrial production of DMC, they are expensive, unsafe and use noxious raw materials. Green production of DMC from CO2 and methanol is the most appropriate and eco-friendly method. Numerous catalysts were studied and tested in this regard. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. Electron-assisted activation of CO2 and membrane reactors which can separate products in real-time giving a maximum yield of DMC are also being used in the quest to find more effective production method. In this review paper, we deeply addressed green production methods of DMC using Zr/Ce/Cu-based nanocomposites as catalysts. Moreover, the relationship between the structure and activity of catalysts, catalytic mechanisms, molecular activation and active sites identification of catalysts are also discussed.


Asunto(s)
Dióxido de Carbono , Metanol , Dióxido de Carbono/química , Formiatos/química , Metanol/química , Óxidos
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