Dimethylformamide Research Articles

Enhanced nonlinear optical and optical limiting responses of 7-diethylamino-4-methyl coumarin functionalized with silver nanoparticles: A combined experimental and DFT study

The present study accounts for the enhanced nonlinear optical and optical limiting activity of 7-diethylamino-4-methyl coumarin (7DMC) after the addition of silver nanoparticles. The theoretical calculations were done in three different solvents water, methanol, and dimethyl formamide (DMF), and on the basis of the energy gap, DMF was selected as the most suitable solvent. Further, the liquid samples were prepared in DMF. The natural bond orbitals show the active participation of the lone pairs of electrons of 2O and 35Ag as donor and acceptor moieties respectively. The values of first-order hyperpolarizability of the 7DMC+Ag3 combination were raised to 2002.71 × 10−30 esu, 778.72 × 10−30 esu, and 677.12 × 10−30 esu in water, methanol, and DMF. The valley-like structure in the Z-Scan spectra indicated the occurrence of reverse saturable absorption in the prepared samples. The optical limiting threshold of the 7DMC+AgNps was decreased from that of the probe 7DMC and AgNps indicating the early attenuation of the optical limiting nature of the combination. Thus, the overall results validated the enhanced optical nonlinearity of the combination. Moreover, it can be stated that the proposed nanoparticles combination 7DMC+AgNps has potential candidature to be used for the fabrication of laser safety devices and eye aids.

The impact of PAC-loaded polymer membrane thickness on chloroform removal and comparison of solvent and thermal membrane regeneration methods.

Powdered activated carbon (PAC) has better adsorption performance than granular activated carbon (GAC) and is widely used in water purification. In most cases, PAC is dosed into water directly, then precipitated as sludge, and landfilled. In this study, PAC was mixed with a polymer and dissolved in dimethylformamide (DMF) solvent to form a PAC-loaded membrane, which was then tested for chloroform removal. The chloroform adsorption capacity of the PAC membrane increased with increasing membrane thickness because of higher carbon loading. However, regardless of membrane thickness, the flux of the PAC membranes was similar since flux resistance predominantly occurred at the top dense polymer surface. This dense surface can be removed by sandpaper polishing, where the adsorption capacity of the polished PAC membranes was 20% higher than the unpolished membranes because of more even distribution of feed water on the polished surface. Removal of the dense surface via polishing increased the flux by 97% to 130%, exceeding the flux of typical household carbon block filters. Using DMF to regenerate the membrane recovered 48% to 66% of the initial adsorption capacity. Thermal regeneration of the exhausted PAC membrane at 250°C was more effective than DMF regeneration (both in terms of cost and performance), with 83% to 94% PAC membrane regeneration efficiency over four regeneration recycles. After four thermal regeneration cycles, flux increased by 300% and the membrane became brittle because of thermal aging of the polymer, indicating that a total of 6h of regeneration time (equivalent to three cycles in this study) was the limit for effective PAC membrane performance. PRACTITIONER POINTS: Powdered activated carbon was immobilized on a membrane to remove chloroform from water. Thicker membranes increased adsorption capacity but did not impact flux. Flux and capacity increased using polishing to remove the dense polymer surface and more evenly distribute flow across the membrane. Thermal regeneration of the membrane at 250°C was effective for up to three cycles and outperformed solvent-based regeneration. PAC-loaded filters are relevant for applications such as household carbon block filtration.

Green synthesis of Cr-BDC@ɣ-Al2O3 granular adsorbents for effective removal of monoethylene glycol (MEG) from industrial wastewater

A novel environmentally friendly approach was developed to synthesize Cr-BDC@ɣ-Al2O3 granular adsorbents for the purpose of removing mono-ethylene glycol (MEG) as an organic pollutant. The synthesis method employed ethanol and water as greener alternatives to dimethylformamide (DMF). Although the granular form of the adsorbent exhibited slightly lower performance compared to the powdered form, it demonstrated superior suitability for separation, regeneration, and industrial applications, such as packed-bed systems. To investigate the influential parameters, the response surface methodology (RSM) was applied, revealing that variations in pH had an insignificant effect on the efficiency of adsorption. The maximum adsorption capacity of 124.45 mg/g was achieved at the highest concentration of the pollutant, attributed to the abundance of pollutant molecules. Based on the RSM results, the optimal conditions for MEG removal were determined as pH 7, a pollutant concentration of 500 ppm, and an adsorbent dosage of 2 g/L. The adsorption kinetics followed the pseudo-quadratic model, with the majority of adsorption occurring within the initial 70 minutes. Thermodynamic studies confirmed the spontaneous and exothermic nature of the adsorption process. The experimental data fitting exhibited good agreement with both the Langmuir and Dubinin-Radushkevich (D-R) isotherms, indicating predominant physisorption and a maximum Langmuir adsorbent capacity of 166.667 mg/g. Additionally, the granular adsorbent demonstrated excellent regeneration capability and remarkable stability even after six consecutive cycles. This study highlights the potential of Cr-BDC@ɣ-Al2O3 granular adsorbents as effective and environmentally friendly materials for the removal of organic pollutants from aqueous systems.

Correlating Molecular Precursor Interactions with Device Performance in Solution-Processed Cu2ZnSn(S,Se)4 Thin-Film Solar Cells.

Research efforts aimed at improving the crystal quality of solution-processed Cu2ZnSn(S,Se)4 (CZTSSe) absorbers have largely employed delicate pre- and postprocessing strategies, such as multistep selenization, heat treatment in mixed chalcogen atmospheres, and multinary extrinsic doping that are often complex and difficult to reproduce. On the other hand, understanding and tuning chemical interactions in precursor inks prior to the thin-film deposition have received significantly less attention. Herein, we show for the first time how the complexation of metallic and chalcogen precursors in solution have a stark influence on the crystallization and optoelectronic quality of CZTSSe absorbers. By varying thiourea to metal cation ratios (TU/M) in dimethylformamide (DMF) and isopropyl alcohol (IPA)-based inks, we observed the formation of nanoscale metal-organic complexes and submicron size aggregates which play a key role in the morphology of the precursor layers obtained by spin-coating and drying steps. We also identify the primary cations in the complexation and assembling processes in solution. The morphology of the precursor film, in turn, has an important effect on grain growth and film absorber structure after the reactive annealing in the presence of Se. Finally, we establish a link between metal complexes in precursor solutions and device performance, with power conversion efficiency increasing from approximately 2 to 8% depending on the TU/M and Cu/(Zn + Sn) ratios.

Mechanical properties of carbon nanotube (CNT) reinforced polymers using electron‐deficient aromatics as additives

AbstractIn initial experiments the effects of aromatic model substances on carbon nanotube (CNT) dispersions in dimethylformamide (DMF) were investigated. Electron‐deficient aromatics interact strongly with CNTs, causing increased agglomeration and sedimentation. Conversely, electron‐donating aromatics stabilize CNT dispersions in DMF. Polymers with electron‐deficient aromatics, such as polydinitrostyrene (PDNS), exhibit a concentration‐dependent effect: low concentrations lead to stabilization of dispersions, while higher concentrations lead to sedimentation. This suggests that such polymers can enhance attraction between the matrix of CNT‐reinforced polymers as well as stabilize the dispersed CNTs. Polycarbonate, modified with polydinitrocarbonate (PDNC) and reinforced with CNTs showed improved mechanical properties. The addition of 6 wt.% CNTs and 6 wt.% PDNC resulted in a notable improvement with a 22% increase in tensile strength, a 29% increase in flexural strength, a 39% increase in Young's modulus and a 47% increase in flexural modulus. This enhancement resulted in an overall mechanical performance comparable to the high‐performance polymer polyetherimide. However, there must be noted, that the addition of PDNC increases the CNT particle size, which can negatively affect mechanical properties. The results highlight the additive's dual role in enhancing adhesive interactions while potentially increasing CNT agglomerate sizes.Highlights Interactions of CNTs dispersed in DMF and various aromatics were investigated. Polydinitrocarbonate (PDNC) was synthesized as a new additive for CNT‐composites. Polycarbonate/CNT‐composites were obtained using extrusion. Test specimens with CNT contents up to 6 wt.% were obtained. Mechanical properties of polycarbonate reached the level of polyetherimide.

Validated Area Under Curve Quantitative UV Spectrophotometric Analysis of Rebamipide in Drug Formulations

A very simple, accurately perfect, precisely repeatable procedure has been proposed for the estimate of rebamipide in medicines. Evaluation of previous works indicates the fact that, so far no UV spectrophotometric scheme for quantifiable estimate by area under curve technique for the drug rebamipide is not described. Therefore, there was a need to plan a different methodology to analyze the medicine employing dimethyl formamide in the form of solvent. This medication monitors Beer’s law in the range of concentration 20 to 200 ìg/mL in the ultraviolet range, particularly areas between 320 and 340 nm for are under curve because the absorption maximum was found to be 330 nm in the selected solvent. The recovery readings proved the offered technique’s accuracy and outcomes were authenticated par accordance with the International Council for Harmonisation (ICH) references. The discoveries were reasoned to be consistent as well as agreeable. As a consequence, this optional technique was successfully used to estimate rebamipide quantitatively in conventional analytical applications.

Effect of composite processing technique on tribological properties of 3D printed PLA-graphene composites

The present study investigates the effect of processing method on the tribological behavior of 3D-printed Polylactic acid (PLA)/graphene composite samples. Two different methods, electrochemical (EG) and chemical exfoliation (HG) of graphite, are used to prepare graphene fillers. The PLA/graphene composites are processed using two different solvents, chloroform (CHCl3) and dimethylformamide (DMF). Various PLA/graphene composite combinations are prepared by varying filler type, solvent type, and filler loading. The 3D printable composite feedstock filaments are prepared using a single-screw Desktop extruder. Fused Filament Fabrication (FFF) is employed to print samples for tribological tests. The coefficient of friction (COF) and wear rate are evaluated using the ball-on-flat reciprocating sliding wear tests. It was observed that COF was reduced by 76 % with 0.5 wt% loading of filler. The wear mechanism has changed from predominant abrasive wear in neat PLA to adhesive wear for composites. Further, the interactive effect of process parameters is studied using ANOVA. The results indicate that filler type and filler loading significantly influence weight loss. The solvent type has a minimum effect.

Metformin drugs under simulated gastric conditions can generate high nitrite-dependent levels of N-nitrosodimethylamine

N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), group 2A carcinogens, were detected in finished drug products, including metformin, ranitidine, sartans and other drugs which caused multiple recalls in the USA and Europe. Important studies also reported the formation of NDMA when ranitidine and nitrite were added to simulated gastric fluid. Our objective was to screen finished drug products from Europe and USA for nitrosamine impurities and investigate the formation of NDMA in metformin finished drug products when added to simulated gastric fluid. One dosage unit of 30 different commercially available drugs, including metformin, sartans, and ranitidine were tested for NDMA, NDEA, and dimethylformamide (DMF) impurities, using a liquid chromatography-mass spectrometry (LC–MS) method. Then, 6 metformin finished drug products were tested in stomach conditions for 2 h at 37 °C in a 100 mL solution with a pH of 2.5 and different nitrite concentrations (40, 10, 1, 0.1 mM) and tested for NDMA, and DMF using LC–MS. We measured NDMA, NDEA, and DMF in 30 finished drug products. NDMA and DMF were quantified for metformin drug products in simulated gastric fluid with different nitrite concentrations. None of the 30 drugs showed concerning levels of NDMA, NDEA, or DMF when tested as single tablets. However, when metformin tablets are added to simulated gastric fluid solutions with high nitrite concentrations (40 mM and 10 mM), NDMA can reach amounts of thousands of nanograms per tablet. At the closest concentration to physiologic conditions we used, 1 mM, NDMA is still present in the hundreds of nanograms in some metformin products. In this in vitro study, nitrite concentration had a very important effect on NDMA quantification in metformin tablets added to simulated gastric fluid. 1 mM nitrite caused an increase above the acceptable daily intake set by the U.S. Food and Drug Administration (FDA) for some of the metformin drugs. 10 mM, 40 mM nitrite solutions generated NDMA amounts exceeding by more than a hundred times the acceptable daily intake set by the FDA of 96 nanograms. These findings suggest that metformin can react with nitrite in gastric-like conditions and generate NDMA. Thus, patients taking metformin could be exposed to NDMA when high nitrite levels are present in their stomach, and we recommend including a statement within the Patient Package Inserts/Instructions for use.

Antimicrobial Composites Based on Methacrylic Acid-Methyl Methacrylate Electrospun Fibers Stabilized with Copper(II).

This study presents fibers based on methacrylic acid-methyl methacrylate (Eudragit L100) as Cu(II) adsorbents, resulting in antimicrobial complexes. Eudragit L100, an anionic copolymer synthesized by radical polymerization, was electrospun in dimethylformamide (DMF) and ethanol (EtOH). The electrospinning process was optimized through a 22-factorial design, with independent variables (copolymer concentration and EtOH/DMF volume ratio) and three repetitions at the central point. The smallest average fiber diameter (259 ± 53 nm) was obtained at 14% w/v Eudragit L100 and 80/20 EtOH/DMF volume ratio. The fibers were characterized using scanning electron microscopy (SEM), infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and differential scanning calorimetry (DSC). The pseudo-second-order mechanism explained the kinetic adsorption toward Cu(II). The fibers exhibited a maximum adsorption capacity (qe) of 43.70 mg/g. The DSC analysis confirmed the Cu(II) absorption, indicating complexation between metallic ions and copolymer networks. The complexed fibers showed a lower degree of swelling than the non-complexed fibers. The complexed fibers exhibited bacteriostatic activity against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. This study successfully optimized the electrospinning process to produce thin fibers based on Eudragit L100 for potential applications as adsorbents for Cu(II) ions in aqueous media and for controlling bacterial growth.

Bilayer Scaffolds of PLLA/PCL/CAB Ternary Blend Films and Curcumin-Incorporated PLGA Electrospun Nanofibers: The Effects of Polymer Compositions and Solvents on Morphology and Molecular Interactions.

Tissue engineering scaffolds have been dedicated to regenerating damaged tissue by serving as host biomaterials for cell adhesion, growth, differentiation, and proliferation to develop new tissue. In this work, the design and fabrication of a biodegradable bilayer scaffold consisting of a ternary PLLA/PCL/CAB blend film layer and a PLGA/curcumin (CC) electrospun fiber layer were studied and discussed in terms of surface morphology, tensile mechanical properties, and molecular interactions. Three different compositions of PLLA/PCL/CAB-60/15/25 (TBF1), 75/10/15 (TBF2), and 85/5/10 (TBF3)-were fabricated using the solvent casting method. The electrospun fibers of PLGA/CC were fabricated using chloroform (CF) and dimethylformamide (DMF) co-solvents in 50:50 and 60:40 volume ratios. Spherical patterns of varying sizes were observed on the surfaces of all blend films-TBF1 (17-21 µm) > TBF2 (5-9 µm) > TBF3 (1-5 µm)-caused by heterogeneous surfaces inducing bubble nucleation. The TBF1, TBF2, and TBF3 films showed tensile elongation at break values of approximately 170%, 94%, and 43%, respectively. The PLGA/CC electrospun fibers fabricated using 50:50 CF:DMF had diameters ranging from 100 to 400 nm, which were larger than those of the PLGA fibers (50-200 nm). In contrast, the PLGA/CC electrospun fibers fabricated using 60:40 CF:DMF had diameters mostly ranging from 200 to 700 nm, which were larger than those of PLGA fibers (200-500 nm). Molecular interactions via hydrogen bonding were observed between PLGA and CC. The surface morphology of the bilayer scaffold demonstrated adhesion between these two solid surfaces resembling "thread stitches" promoted by hydrophobic interactions, hydrogen bonding, and surface roughness.

Synthesis and Characterization of Ni based Metal Organic Framework for Enhancing the Removal of Typical Organic Dyes

In this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes.

Date palm wood-derived cellulose aerogel dissolved in ionic liquids as a green thermal insulation construction material

Heat insulation materials used in the construction industry are essential for energy conservation. Nonetheless, the majority of current commercial heat insulators are fossil-fuel derived materials; thus, it is vital to provide sustainable, biodegradable, and environmentally friendly alternatives. In this work, an innovative method for producing cellulose II aerogels extracted from date palm waste and from microcrystalline lab-grade cellulose, targeting thermal insulation applications in the construction industry was introduced. A key aspect of the investigated approach is the use of a co-solvent system that combines 1-butyl-3-methylimidazolium chloride (Bmim)Cl and dimethylformamide (DMF), chosen for its efficiency in dissolving cellulose. The cellulose (at 3, 5, 7, and 9 wt%) was dissolved in a co-solvent system of 70 wt% (Bmim)Cl ionic liquid and 30 wt% DMF, saving costs associated with using purely ionic liquid solvents. The prepared aerogels exhibited low thermal conductivity (0.033–0.065 W/m⋅K), low densities (0.08–0.15 g/cm3), high porosity (89.85–94.69 %) and good thermal diffusivity (0.06–0.022 mm2/s). Furthermore, the developed insulators required a compressive strength of 75 kPa to reach 50 % strain and exhibited a sound absorption coefficient of 0.9. Structural characterization of the materials, including X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis, highlights the prospect of cellulose extracted from date palm wood in aerogel preparation and the potential for the (Bmim)Cl/DMF co-solvent system in dissolving cellulose.

Poly[[{μ2-5-[(dimethylamino)(thioxo)methoxy]benzene-1,3-dicarboxylato-κ4 O 1,O 1′:O 3,O 3′}(μ2-4,4′-dipyridylamine-κ2 N 4:N 4′)cobalt(II)] dimethylformamide hemisolvate monohydrate

In the crystal structure of the title compound, {[Co(C11H9NSO5)(C10H9N3)]0.5C3H7NO·H2O} n or {[Co(dmtb)(dpa)]·0.5DMF·H2O} n (dmtb2– = 5-[(dimethylamino)thioxomethoxy]-1,3-benzenedicarboxylate and dpa = 4,4′-dipyridylamine), an assembly of periodic [Co(C11H9NSO5)(C10H9N3)] n layers extending parallel to the bc plane is present. Each layer is constituted by distorted [CoO4N2] octahedra, which are connected through the μ 2-coordination modes of both dmtb2– and dpa ligands. Occupationally disordered water and dimethylformamide (DMF) solvent molecules are located in the voids of the network to which they are connected through hydrogen-bonding interactions.

A Self‐Assembly of New Cobalt Coordinating Polymer Based on Fluorinated Secondary Building Unit and Pyrazine

AbstractThe direct two‐step synthesis of new coordination polymer [Co2(pyz)(tfa)2(dmf)6(H2O)][Co3(μ3‐F)(tfa)6(pyz)(dmf)]2 ⋅ 2dmf, (where pyz=pyrazine, Htfa=trifluoroacetic acid, dmf=dimethyl formamide) containing the fluoro‐centered secondary building block [Co3(μ3‐F)(tfa)6], is reported. The substance characterization using single‐crystal XRD, powder XRD, IR‐spectroscopy and thermogravimetry was performed. SCXRD data revealed the presence of cationic and anionic subsystems, both containing cobalt(II) ions and pyrazine bridging ligands. The magnetic proper‐ties of the compound were collected and discussed. Temperature dependence of magnetic susceptibility shows Curie–Weiss like behavior at all studied temperatures.

Electrochemical Detection of Glyphosate in Surface Water Samples Based on Modified Screen-Printed Electrodes.

This study addresses the necessity to monitor the presence of glyphosate (Gly) in waters, highlighting the need for on-site detection of Gly by using electrochemical sensors in environmental and agricultural monitoring programs. Two approaches were employed: (1) modification with graphene decorated with gold nanoparticles (AuNPs-Gr) and dispersed in either dimethylformamide (DMF) or a solution containing Nafion and isopropanol (NAF), and (2) molecularly imprinted polymers (MIPs) based on polypyrrole (PPy) deposited on gold SPEs (AuSPE). Electrochemical characterization revealed that sensors made of AuNPs-Gr/SPCE exhibited enhanced conductivity, larger active area, and improved charge transfer kinetics compared to unmodified SPEs and SPEs modified with graphene alone. However, the indirect detection mechanism of Gly via complex formation with metallic cations in AuNPs-Gr-based sensors introduces complexities and compromises sensitivity and selectivity. In contrast, MIPPy/AuSPE sensors demonstrated superior performance, offering enhanced reliability and sensitivity for Gly analysis. The MIPPy/AuSPE sensor allowed the detection of Gly concentrations as low as 5 ng/L, with excellent selectivity and reproducibility. Moreover, testing in real surface water samples from the Olt River in Romania showed recovery rates ranging from 90% to 99%, highlighting the effectiveness of the detection method. Future perspectives include expanding the investigation to monitor Gly decomposition in aquatic environments over time, providing insights into the decomposition's long-term effects on water quality and ecosystem health, and modifying regulatory measures and agricultural practices for mitigating its impact. This research contributes to the development of robust and reliable electrochemical sensors for on-site monitoring of Glyphosate in environmental and agricultural settings.

Exploring the solubility and intermolecular interactions of biologically significant amino acids l-serine and L-cysteine in binary mixtures of H2O + DMF, H2O + DMSO and H2O + ACN in temperature range from T = 288.15 K to 308.15 K

In the presented work, a study on the solubility and intermolecular interactions of l-serine and L-cysteine was carried out in binary mixtures of H2O + dimethylformamide (DMF), H2O + dimethylsulfoxide (DMSO), and H2O + acetonitrile (ACN) in the temperature range of T = 288.15 K to 308.15 K. l-serine exhibited the highest solubility in water, while L-cysteine was more soluble in water-DMF. The solvation process was assessed through standard Gibbs energy calculations, indicating the solvation stability order: water-ACN > water-DMSO > water-DMF for l-serine, and water-DMF > water-DMSO > water-ACN for L-cysteine. This study also explored the influence of these amino acids on solvent–solvent interactions, revealing changes in chemical entropies and self-association patterns within the binary solvent mixtures.

An oxo‐acetato‐bridged trinuclear cobalt(III) cluster‐persuaded cobalt oxide active electrocatalyst for efficient hydrogen evolution activity

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)…H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity.

Measurement and correlation of solubility data for sodium picosulphate in selected pure solvents and mixed-solvent systems from 298.15 K to 328.15 K

An investigation was carried out to determine the solubility of the stimulant laxative drug Sodium Picosulphate (SP). A wide range of pure solvents were studied, including methanol, ethanol, 1-propanol, 1-butanol, dimethyl formamide, dimethyl sulfoxide, acetonitrile, 1,4-dioxane, acetic acid, and water. More to the point, the solubility of the compound was determined using mixed solvent systems; methanol + acetonitrile and water + acetonitrile. Experimental mole fraction solubility of SP was determined by the gravimetric method over a range of temperatures (298.15 K to 328.15 K) under atmospheric pressure (p=0.1MPa). According to experimental results, a temperature-dependent relationship exists between solubility and temperature. Further, we correlated the experimental mole fraction solubility data with theoretical models including Apelblat, Yaws, Van't Hoff, Modified Jouyban-Acree, CNIBS/R-K models. It appears that the results are well in agreement with the experimental results due to the small values of relative average deviation (RAD) and root mean square deviation (RMSD).The solubility data might be useful in the various areas such as modification, production, crystallization, and separation of SP.

Formation and Fluorescent Mechanism of Multiple Color Emissive Carbon Dots from o-Phenylenediamine.

Carbon dots (CDs) have received considerable attention in many application areas owing to their unique optical properties and potential applications; however, the fluorescent mechanism is an obstacle to their applications. Herein, three-color emissive CDs are prepared from single o-phenylenediamine (oPD) by regulating the ratio of ethanol and dimethylformamide (DMF). Fluorescent mechanism of these CDs is proposed as molecular state fluorescence. Reaction intermediates are identified using liquid chromatrography-mass spectroscopy (LC-MS) and 1H nuclear magnetic resonance (NMR) spectra. 1H-Benzo[d]imidazole (BI), 2,3-diaminophenazine (DAP), and 5,14-dihydroquinoxalino[2,3-b] phenazine (DHQP) are proposed to be the fluorophores of blue, green, and red emissive CDs by comparing their optical properties. As per the LC-MS and 1H-NMR analysis, DHQP with red emission tends to form from DAP and oPD in pure ethanol. By adding DMF, BI formation is enhanced and DHQP formation is suppressed. The prepared CDs exhibit green emission with DAP. When the DMF amount is >50%, BI formation is considerably promoted, resulting in DAP formation being suppressed. BI with blue emission then turns into the fluorophore of CDs. This result provides us an improved understanding of the fluorescent mechanism of oPD-based CDs, which guides us in designing the structure and optical properties of CDs.

Barbituric acid‐derived azo dye metal complexes: Synthesis, characterization, DFT, and antimicrobial analysis

Two novel metal complexes, C1 and C2, were synthesized through the reaction of an azo dye ligand, obtained by coupling 4‐chloroaniline with 1,3‐dimethyl barbituric acid. The structure of the ligand was confirmed using Fourier‐transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance (NMR). UV–Vis spectroscopy was employed to assess the ligand's sensing ability toward six different metal ions. Comprehensive characterization of the synthesized metal complexes was conducted using elemental analysis, X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis–difference thermogravimetry (TGA‐DTG), FTIR, UV–Vis spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and single‐crystal X‐ray diffraction (SC‐XRD). X‐ray analysis revealed octahedral coordination geometry with a 2:1 ligand‐to‐metal ratio and dimethylformamide (DMF) coordination with the metal atom in both complexes. Hirshfeld analysis and 2D fingerprint plots were employed to investigate supramolecular and intermolecular interactions within the crystal system. Density functional theory (DFT/B3LYP) calculations were utilized to compute energy gaps and other important theoretical features. Sensing experiments with tetrabutylammonium fluoride (TBAF) were conducted at a concentration of 1 × 10−5 M. Furthermore, the bioactivity of the synthesized metal complexes and ligand L was evaluated through molecular docking studies against Protein Data Bank (PDB IDs) 4XUY (Staphylococcus aureus) and 3BQW (Aspergillus niger). Also, antimicrobial activity was assessed using the agar well diffusion technique, revealing that complexes C1 and C2 exhibited enhanced antimicrobial activities against the tested organisms compared to the parent azo dye ligand. The computational and experimental bioactivity data are in good agreement with each other.