UV Measurements Research Articles

Tailoring of magnetic phase: Co-doped SiC thin films grown by RF sputtering

In the present work, we investigate the influence of cobalt (Co) doping on the structural and magnetic properties of cobalt-doped silicon carbide (Co-SiC) thin films. The films were fabricated using DC/RF magnetron sputtering technique on Si (100) substrates at a temperature of 1200°C, with varying Co concentrations ranging from 5 to 16 at. (at%. X-ray diffraction (XRD) analysis unveiled the co-existence of CoSi2 and SiC phases in all the thin films. Surface morphological study through atomic force microscopy (AFM) revealed the densely packed nature of the films. Field emission scanning electron microscopy (FE-SEM) study showed that particles are uniformly distributed at the surface of the substrate. According to UV measurements, the films have high transmittance in the visible range, and as Co concentration rises, transmittance decreases. A magnetic phase transition from superparamagnetic to ferromagnetic behavior occurred with Co content surpassing 8 at% in the SiC thin films. Moreover, an increase in coercivity was observed from 38 Oe to 316 Oe as the doping concentration increased from 10 to 16 at%. This study represents an exploration into the induction of ferromagnetism through moderate Co doping in SiC thin films.

AGN STORM 2. IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-Ray Spectroscopy

We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multiwavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the AGN Space Telescope and Optical Reverberation Mapping 2 (AGN STORM 2) Project. The campaign revealed an unexpected and transient obscuring outflow, never before seen in this source. Of our four XMM-Newton/NuSTAR epochs, one fortuitously taken during a bright X-ray state has strong narrow absorption lines in the high-resolution grating spectra. From these absorption features, we determine that the obscurer is in fact a multiphase ionized wind with an outflow velocity of ∼5200 km s−1, and for the first time find evidence for a lower ionization component with the same velocity observed in absorption features in the contemporaneous Hubble Space Telescope spectra. This indicates that the UV absorption troughs may be due to dense clumps embedded in diffuse, higher ionization gas responsible for the X-ray absorption lines of the same velocity. We observe variability in the shape of the absorption lines on timescales of hours, placing the variable component at roughly 1000 R g if attributed to transverse motion along the line of sight. This estimate aligns with independent UV measurements of the distance to the obscurer suggesting an accretion disk wind at the inner broad line region. We estimate that it takes roughly 200 days for the outflow to travel from the disk to our line of sight, consistent with the timescale of the outflow's column density variations throughout the campaign.

Systematic Comparison of Extract Clean-Up with Currently Used Sorbents for Dispersive Solid-Phase Extraction

Dispersive solid-phase extraction (dSPE) is a crucial step for multiresidue analysis used to remove matrix components from extracts. This purification prevents contamination of instrumental equipment and improves method selectivity, sensitivity, and reproducibility. Therefore, a clean-up step is recommended, but an over-purified extract can lead to analyte loss due to adsorption to the sorbent. This study provides a systematic comparison of the advantages and disadvantages of the well-established dSPE sorbents PSA, GCB, and C18 and the novel dSPE sorbents chitin, chitosan, multi-walled carbon nanotube (MWCNT), and Z-Sep® (zirconium-based sorbent). They were tested regarding their clean-up capacity by visual inspection, UV, and GC-MS measurements. The recovery rates of 98 analytes, including pesticides, active pharmaceutical ingredients, and emerging environmental pollutants with a broad range of physicochemical properties, were determined by GC-MS/MS. Experiments were performed with five different matrices, commonly used in food analysis (spinach, orange, avocado, salmon, and bovine liver). Overall, Z-Sep® was the best sorbent regarding clean-up capacity, reducing matrix components to the greatest extent with a median of 50% in UV and GC-MS measurements, while MWCNTs had the largest impact on analyte recovery, with 14 analytes showing recoveries below 70%. PSA showed the best performance overall.

Enhancement of multiferrocity in CuCrO2 compounds through effective doping induced optimization of localized carrier holes and reduction in helical disorder

The bulk pristine CuCrO2, doped CuCr0.96M0.03V0.01O2 (M = Ti, Mn, Ga and Nb), CuCr0.96V0.04O2, CuCr0.97Mg0.03O2, CuCr0.97Ni0.03O2, and CuCr1-xFexO2 (x = 0.03, 0.06, and 0.09) compounds with single rhombohedral phase were investigated through low-temperature dc resistivity, field-dependent magnetization, and dielectric measurements. The room-temperature UV measurements were also carried out to determine possible changes in the optical bandgap due to the dopants mentioned above. The present work provides significant evidence of novel methodology for optimizing the number of localized carrier holes along with a reduction in helical disorder around MO6 octahedra, which leads to enhancement of the double exchange along the Cr-O-M-O linkages or superexchange between M3+/4+-Cr3+ mediated via oxygen. The nonmagnetic substitution in magnetic sublattice disrupts the spin spiral and a net weak component is realized in magnetization measurements.

Investigation of thermal, optical properties, AC conductivity and broadband dielectric spectroscopy of poly(ethyl methacrylate)/poly(vinyl chloride) polymer blend

This work reports the structural, thermal, optical and electrical properties of PEMA, PVC and their polyblends. These properties are investigated by FTIR, TGA, UV/Vis and broadband dielectric spectroscopy. FTIR spectra showed that the characteristic bands of PEMA and PVC are affected by blending and displayed red and blue shifts confirming that an intermolecular interaction between PEMA and PVC is occurred. Thermal degradation kinetics of PEMA, PVC and its polyblend samples is investigated in details and the thermal properties of each decomposition stage are estimated. UV measurements analysis revealed that Urbach energy (EU) is increased while optical bandgap decreased upon increasing the PVC content. The indirect and direct band gap (Eig/Edg) values are decreased from (3.95/4.21) to (3.10/3.92) eV. Also, upon increasing the content of PVC, the lattice dielectric constant (εL) is increased from 2.71 to 7.83. Wemple-DiDomenico model is applied for investigating the refractive index dispersion and to calculate the oscillator and dispersion energies. It is observed that the linear/nonlinear parameters are increased nonlinearly with increasing the PVC content. χ(1), χ(3) and n2 values are found to increase from 0.104, 0.213 × 10−13 and 4.01 × 10−12 to 0.363, 31.26 × 10−13 and 5.33 × 10−12. These results make PEMA/PVC polyblend strong candidates for use in the development and design of advanced optoelectronic devices. AC conductivity (σac) and dielectric measurements are carried out at various temperatures in wide frequency range. Jonscher power law is applied and showed that the predominant conduction mechanism in our samples is overlapping large-polaron tunneling (OLPT). The dielectric constant and electrical impedance are found to be frequency and temperature dependent. The investigation of the electric modulus (M*) revealed that M′ is increased non-linearly with increasing the frequency, while M″ spectra displayed two different modes of relaxation. The interfacial polarization (IP) is observed in low frequency region, while, dipolar relaxation is detected in high frequency region.

Preparation and properties of poly (ethylene-co-vinyl acetate)/boron nitride nanocomposite for energy storage devices

A simple open-mill mixing approach was employed to develop thermally and mechanically stable nanocomposites consisting of poly (ethylene- co-vinyl acetate) (EVA) as the matrix and boron nitride (BN) as a reinforcing nanofiller. The development of nanocomposites was examined by FT-IR, UV spectroscopy, XRD, TEM, TGA and DSC. The attachment of BN to EVA was confirmed by the characteristic BN band at 602 cm−1 in the FT-IR spectra. The UV measurements revealed a red shift in the nanocomposites due to nanoparticle interactions with polymer chains and the bandgap energy decreased with the nanofiller concentration. The XRD TEM analysis indicated the presence of a crystalline BN phase in EVA. Enhanced thermal stability and glass transition temperature of the polymer with the addition of BN nanoparticles were revealed from TGA and DSC, respectively. The EVA with 5% BN nanocomposite was discovered to have higher mechanical properties, electrical conductivity and lower optical bandgap energy. The tensile strength, tear resistance, impact strength and hardness of EVA increased with the inclusion of BN, whereas elongation at break was reduced. The findings of the experiments showed that the EVA/BN nanocomposites would provide excellent options for mechanically and thermally stable materials for energy storage applications.

Synthesis of zero valent copper/iron nanoparticles using Piper betle leaves for the removal of pharmaceutical contaminant atorvastatin

In this study, bimetallic Cu–Fe nanoparticles were synthesized using the green approach with Piper betle leaves, and the removal efficiency of one of the pharmaceutical compounds, Atorvastatin, was investigated. UV, SEM, FTIR, EDAX, particle size, and zeta potential measurements were used to confirm nanoparticle fabrication. The removal efficiency of Atorvastatin (10 mg/L) by bimetallic Cu–Fe nanoparticles was 67% with a contact time of 30 min at pH 4, the adsorbent dosage of 0.2 g/L, and stirring at 100 rpm. Piper betle bimetallic Cu–Fe nanoparticles have demonstrated excellent stability, reusability, and durability, even after being reused five times. Furthermore, the synthesized bimetallic Cu–Fe nanoparticles demonstrated remarkable antimicrobial properties against gram-negative strains such as Escherichia coli and Klebsiella pneumoniae, gram-positive strains such as Staphylococcus aureus and Bacillus subtilis, and fungi such as Aspergillus niger. In addition, the antioxidant properties of the synthesized bimetallic Cu–Fe nanoparticles were assessed using the DPPH radical scavenging assay. The results indicated that the nanoparticles had good antioxidant activity. Thus, using Piper betle extract to make Cu–Fe nanoparticles made the procedure less expensive, chemical-free, and environmentally friendly, and the synthesized bimetallic Cu–Fe nanoparticles helped remove the pharmaceutical compound Atorvastatin from wastewater.

Okra leaves extract as green corrosion inhibitor for steel in sulfuric acid: Gravimetric, electrochemical, and surface morphological investigations

Utilizing plant extracts as an alternative source for corrosion inhibitors holds significant promise in minimizing the risk of corrosion. In this study, an okra leaf extract (OLE) was employed as a corrosion inhibitor for N80 steel in 1.0 M H2SO4. The corrosion rate was assessed concerning temperature (30, 40, 50, and 60 °C) and inhibitor concentrations (blank, 25, 50, 75, and 100 ml/l) through weight loss and electrochemical polarization techniques. The results indicated that OLE functions as a mixed-type corrosion inhibitor, with corrosion rates increasing with temperature and decreasing with inhibitor concentration. The maximum corrosion inhibition efficiency reached 96 % at 30 °C and 100 ml/l. Adsorption studies revealed that OLE physically adsorbed onto the mild steel surface, following the Langmuir adsorption isotherm. Gravimetrical and electrochemical techniques were confirmed by FTIR and UV measurements, which showed the presence of a protective layer on the metal surface. Optical microscopy, AFM, and SEM images demonstrated the formation of a protective layer on the metal surface. Thermogravimetric analysis (TGA) highlighted the thermal stability exhibited by inhibitor molecules, which showed that OLE was thermally stable up to 85 °C.

Innovative multifunctional nanocapsules with antibacterial, perfume, and UV-initiated coating properties

Polymer nanocapsules containing fragrance were fabricated for antibacterial, pleasing scent and UV-coating applications. Poly (2-methacryloyloxy dodecyl dimethyl ammonium chloride-4-allyloxy-2-hydroxybenzophenone)-block-polymethyl methacrylate-iodide (P(QAC12-BP)-b-PMMA-I) was first synthesized by solution iodine transfer polymerization (solution ITP) for use as a polymerizable surfactant in miniemulsion polymerization where benzalkonium chloride (BKC) was used as a cosurfactant. The nanocapsules were prepared using poly(methyl methacrylate–divinylbenzene) (P(MMA–DVB)) as a shell, whereas mangosteen oil (MO) was used as a fragrance core model for aroma. High colloidal stability nanocapsules with a size of about 213 nm were obtained. The nanocapsule surface contained QAC12 segments of 15.10 µmol/g-capsule (UV measurement), giving the high positive charge (+70 mV). An essential oil encapsulated inside the nanocapsule had a high encapsulation efficiency (>90%). The nanocapsules effectively inhibited bacterial growth because of QAC12 and BKC on their surface. The nanocapsules are able to coat the substrate via UV-activated covalent bonds of the BP segment.

Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets

The Decadal Survey on Astronomy and Astrophysics 2020 has recommended that NASA realize a large IR/optical/UV space telescope optimized for high-contrast imaging and spectroscopy of ∼25 exo-Earths and transformative general astrophysics. The NASA Exoplanet Exploration Program (ExEP) has subsequently released a list of 164 nearby (d < 25 pc) targets deemed the most accessible to survey for potentially habitable exoplanets with the Habitable Worlds Observatory (HWO). We present a catalog of system properties for the 164 ExEP targets, including 1744 abundance measurements for 14 elements from the Hypatia Catalog and 924 photometry measurements spanning from 151.6 nm to 22 μm in the GALEX, Strömgren, Tycho, Gaia, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer bandpasses. We independently derive stellar properties for these systems by modeling their spectral energy distributions with Bayesian model averaging. Additionally, by consulting the literature, we identify TESS flare rates for 46 stars, optical variability for 78 stars, and X-ray emission for 46 stars in our sample. We discuss our catalog in the context of planet habitability and draw attention to key gaps in our knowledge where precursor science can help to inform HWO mission design trade studies in the near future. Notably, only 33 of the 164 stars in our sample have reliable space-based UV measurements, and only 40 have a mid-IR measurement. We also find that phosphorus, a bioessential element, has only been measured in 11 of these stars, motivating future abundance surveys. Our catalog is publicly available and we advocate for its use in future studies of promising HWO targets.

Photo-switchable Collectors for the Flotation of Lithium Aluminate for the Recycling of the Critical Raw Material Lithium.

Flotation of the mineral lithium aluminate by application of the natural product punicine from Punica granatum and some derivatives as collectors is examined. Punicines, 1-(2',5'-dihydroxyphenyl)-pyridinium compounds, are switchable molecules whose properties can be changed reversibly. They exist as cations, neutral mesomeric betaines, anions, and dianions depending on the pH. In light, they form radicals. Five punicine derivatives were prepared which possess β-methyl, β-chlorine, γ-tert.-butyl, and γ-acetyl groups attached to the pyridinium ring, and a pyrogallol derivative. On the other hand, LiAlO2 reacts with water to give species such as LiAl2(OH)7 on its surface. Flotations were performed applying the punicines in daylight (3000 lux), in darkness (<40 lux) and under UV-irradiation (4500 lux, 390-400 nm). The pH of the suspension, the collector's concentration, the conditioning time as well as the flotation time were varied. The recovery rates strongly depend on these parameters. For example, the recovery rate of lithium aluminate was increased by 116 % on changing the lighting condition from daylight to darkness, when the pyrogallol derivative of punicine was applied. UV, FTIR, TGA and zeta potential measurements as well as DFT calculations were performed in order to gain insight into the chemistry of punicines on the surface of LiAlO2 and LiAl2(OH)7 in water which influence the flotation's results.

One-pot multicomponent reaction: An efficient synthesis of 4-(HET)Aryl-substituted pyrazolo-quinolinones.

Pyrazolo-quinolinones (PQs) are a versatile class of Organic chemistry and it was found that they have very advanced functionally promising as selective compounds due to their scaffold and demonstrated low toxicity and considerable clinical promise. Moreover, these compounds have an important role in different applications such as analytical reagents, technical, pharmaceutical development, and biological markers. So, we aimed to synthesize and characterize new 4-(Het)aryl-substituted Pyrazole-quinolinones. Synthesis of One-Pot Multicomponent Reaction was carried out with the reaction of 5-amino-3-methyl-1H-pyrazole 1a, and 5-amino-3-phenyl-1H-pyrazole 1b and dimedone 2 with some (het)aryl aldehydes 3 using ethanol. Characterizations such as the linear structures and the regiospecificity of the reactions were determined by using NMR, GC-MS, IR, and UV measurements. This research will be very useful for all methods and procedures using multi-one-point reactions which are very popular in the synthesis of heterocyclic systems for pyrazole- quinoline skeleton synthesis.

Separation of ethylene glycol from propylene glycol via selective adsorption with basic anion-exchange resin

Ethylene glycol (EG) is a common impurity in bio-derived 1,2-propylene glycol (PG). EG was isolated from PG via selective adsorption on basic ion-exchange resin. A small amount of moisture improved the porosity of resin, thereby reinforcing the intraparticle diffusion and adsorption performance. The adsorption equilibrium could be reached within 1 min, indicating that EG can be instantly removed. The real adsorption capacity for PG was much lower than that for EG, and the selectivity was up to 5.5 at 60 °C due to the susceptibility of PG adsorption to temperature. The PG content was increased from 90 to 95.7 wt% in a continuous-flow process with low bed pressure drop. The EG adsorption process agreed with the Langmuir isotherm model, and the apparent EG adsorption capacity reached 250.6 mg/g at 60 °C, while real PG adsorption capacity was negligible. The different interactions between diols and OH− ions were proven by UV and surface-tension measurements, and the stronger acidity of hydroxyl group in EG contributed to its stronger acid-base interaction with basic materials. The resin adsorbent could be reused and completely regenerated without leaching via elution with 20 wt% NaOH. Based on the acidity of EG, this work presents an unprecedented cost-effective strategy to separate diols.

UV imaging for the rapid at-line content determination of different colourless APIs in their tablets with artificial neural networks

This paper presents a novel high-resolution and rapid (50 ms) UV imaging system, which was used for at-line, non-destructive API content determination of tablets. For the experiments, amlodipine and valsartan were selected as two colourless APIs with different UV induced fluorescent properties according to the measured solid fluorescent spectra. Images were captured with a LED-based UV illumination (385–395 nm) of tablets containing amlodipine or valsartan and common tableting excipients. Blue or green colour components from the RGB colour space were extracted from the images and used as an input dataset to execute API content prediction with artificial neural networks. The traditional destructive, solution-based transmission UV measurement was applied as reference method. After the optimization of the number of hidden layer neurons it was found that the relative error of the content prediction was 4.41 % and 3.98 % in the case of amlodipine and valsartan containing tablets respectively. The results open the possibility to use the proposed UV imaging-based system as a rapid, in-line tool for 100 % API content screening in order to greatly improve pharmaceutical quality control and process understanding.

Constraining on the non-standard cosmological models combining the observations of high-redshift quasars and BAO

In this work, we studied four types of cosmological models with different mechanisms driving the accelerated expansion of the universe, include Braneworld models, Chaplygin Gas models, Emergent Dark Energy models, and cosmological torsion models. Considering that the dynamics of these models at low redshifts are very similar and difficult to distinguish, we used the latest and largest UV and X-ray measurements of quasars (QSOs) observations covering the range of redshift 0.009<z<7.5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.009<z<7.5$$\\end{document}. However, the high intrinsic dispersion of this sample and the degeneracy between cosmological model parameters, we added 2D-BAO and 3D-BAO datasets to help us constrain the parameters of these cosmological models. Our results suggest that standard cold dark matter scenario may not be the best cosmological model preferred by the high-redshift observations. The Generalized Chaplygin Gas (GCG) and cosmological constant plus torsion (named Case II) models perform best by Akaike Information Criterion (AIC), but the Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda $$\\end{document}CDM is the best cosmological model preferred by Bayesian Information Criterion (BIC). Our work also supports that the Phenomenologically Emergent Dark Energy and cosmological torsion models may alleviate the Hubble tension, the reported value of the Hubble constant obtained from QSO+BAO datasets combination lies between Planck 2018 observations and local measurements from the SH0ES collaboration, while other cosmological models all support that the Hubble constant tends to be closer to recent Planck 2018 results, but these model are penalized by information criterion.

Poly (aniline-co-aniline-2,5-disulfonic acid) / L-ascorbic acid / Ag@SiO2 / polysafranin nanocomposite: synthesis, characterization and anomalous electrical behaviour.

We report the synthesis of sulfonated copolyaniline/polysafranin/L-ascorbic acid/Ag@SiO2 fine powdered nanocomposites and investigate the influence of incorporating the dye on their conductivity. The composite was characterized via IR, UV, cyclic voltammetry (CV), electric, dielectric, SEM, TEM, TGA and DSC measurements. Microscopy images revealed intensified spherical particles that were dispersed across the entire surface, and the SiO2/Ag particles were distributed on the surface. The XRD results exhibited peaks at many 2q values, and their interatomic spacing (d) and crystallite (grain) sizes were calculated. The thermal degradation curves exhibited an interesting model of stability. The cyclic voltammogram exhibited redox peaks identical to those of the reported analogues. The d.c. conductivity of the oligomer varied from 0.06 - 0.016 (s/cm), and that of the composite varied from 0.008 to 0.016 (s/cm). The material changed from a semiconductor to a metallic material. The observed conductivity is mainly attributed to self-doping between the sulfonate groups and the charged nitrogen atoms in the polymer chains. The frequency dependence of the permittivity, ε', showed a marked effect on the frequency window under consideration. The permittivity, ε', is independent of the increase in the frequency of the oligomer and the composite. This behavior supports the non-Debye dependency by confirming the occurrence of electrode polarization and space charge effects. In conclusion, the incorporation of safranin dye with a thermally stable, highly sulfonated polyaniline derivative/Ag@SO2 nanocomposite achieved improved conductivity after heating. The d.c. conductivities are comparable to those of many commercial inorganic or organic composites, and because of their attractive electrical properties, we suggest that these materials are promising for electronic field applications.

Molecular interaction of nonsteroidal anti‐inflammatory prodrug nepafenac with ionic surfactants

AbstractDrug‐surfactant interaction increases the solubility of poorly water‐soluble drugs and design better pharmaceutical formulations. The degree of interaction of nepafenac (NP), a nonsteroidal anti‐inflammatory prodrug was studied with ionic surfactant molecules such as cationic surfactant cetrytrimethyl ammonium bromide (CTAB) and anionic surfactant sodium dodecyl sulphate (SDS) in an aqueous medium at room temperature. NP made mixed micelles with CTAB and SDS. To investigate the influence of interactions, conductivity measurements, UV–visible spectroscopy, and fluorescence measurements were recorded. The quantification of NP–surfactant interactions was investigated using various mathematical models. The CMC values determined from conductivity measurements of pure surfactants were 0.96 mM for CTAB and 8.14 mM for SDS near to their literature values. At different mole fractions of NP in UV measurements, binding constants from lnKb were found 0.025 and 0.123 and number of NP molecules per micelles (n) 67, 46 for CTAB and SDS, respectively. The mixed micelles of NP–CTAB and NP–SDS revealed that CTAB has a strong interaction with NP than SDS. The Benesi–Hildebrand relationship, Stern–Volmer and Kawamura replica for the partition coefficient were used to confirm the findings. We are confident that the host–guest interaction mechanism can contribute to a better understanding of molecular recognition in the phospholipid membrane model.

Preparation and characterization of green‐based anti‐ultraviolet and antidripping biodegradable film

AbstractThe biodegradable materials cannot meet the requirements as the agricultural film due to the poor UV resistance and antidripping performance. The work herein thus presented the development of the green‐based anti‐ultraviolet and antidripping multifunctional composite films using poly(butyleneadipate‐co‐terephthalate), microfibrillated cellulose (MFC), and soybean protein isolate (SPI) as the raw materials in the presence of other agents. The resulting composite films were systematically characterized using scanning electron microscope, thermogravimetry analysis (TG), UV, and rheometer measurements. The morphology changed obviously after introducing the MFC and SPI into the substrate film. In addition, the results indicated that the addition of MFC and SPI had a positive effect on the thermal stability and heat preservation of the film, respectively. The contact angle results indicated that SPI was an ideal antidripping agent and the MFC could be used as the release agent. The time of the first water drop of the film containing 2.5 g MFC and 2.0 g SPI was 6 min and 46 s, and the time of each 10 drops was less than 60 s, showing the advantages of using MFC as the release agent and SPI as the antidripping agent. The resulting multifunctional biodegradable films can be widely used in the agricultural and packaging fields.

Synthesis, spectral, DFT, and antibacterial studies of Nickel(II) and Cobalt(II) complexes with aminoantipyrine based Schiff base ligands

Schiff base complexes are a class of molecules that have sparked a great deal of attention due to their interesting chemical and physical properties, as well as their diverse applicability in a variety of scientific fields. Schiff bases and aminoantipyrine derivatives are continuously being investigated, despite their widespread use as medicines and bioactive compounds. In this study, we present the synthesis of new Ni(II) and Co(II) Schiff base complexes [M(L1-5)2Cl2] using the following ligands: 1,5-dimethyl-2-phenyl-4-((3,4,5-trimethoxy-benzylidene)amino)-1H-pyrazol-3(2H)-one (L1), 4-((4-methoxybenzylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (L2), 4-((3,4-dimethoxy-benzyli-dene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (L3), 4-((1-([1,1′-biphenyl]-4-yl)ethyli-dene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (L4), 4-((4-hydroxy-3-methoxy-benzylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (L5), derived from aminoantipyrine. Various approaches, including UV, IR, NMR (1H, 13C), DFT analyses, and molar conductance measurement, have been employed to characterise freshly synthesised compounds. The antimicrobial screening results indicate that the anti-bacterial activities of the metal complexes are more active than the free ligands. All the synthesized compounds were found to be active against both Gram positive and Gram negative bacteria. Compound [Ni(L4)2Cl2] was found to show best activity. According to the reactivity parameter factors, compound Co(L2)2Cl2 has a higher value of hardness (η = 1.677 eV) and a lower value of softness (σ = 0.596 eV), It suggests that compound [Co(L2)2Cl2] is less reactive and more stable.

Structural, dielectric, and antimicrobial evaluation of PMMA/CeO2 for optoelectronic devices

In the current report, we have successfully synthesized nanocomposites of PMMA incorporating different doping of CeO2 through a chemical approach. XRD results reflects decent matching for CeO2 nanoparticles with 29 nm crystallite size. FTIR spectroscopy demonstrates the characteristic functional groups validating the successful formation of the composite. The optical study of PMMA and the nanocomposites has proven that the optical properties such as band gap, refractive index, optical permittivity, and loss tangent factor are affected by adding CeO2 to the PMMA matrix.The peak residing around 420 nm by UV measurements is allocated to occurring electrons photoexcitation from the valence to conduction band inherent in CeO2. The dielectric measurements were achieved using broadband dielectric spectroscopy upon a wide span of frequencies (10–1–107 Hz) and within temperatures from − 10 to 80 °C with a step of 10 °C. The permittivity decreases by adding CeO2 and the dielectric parameters are thermally enhanced, however, the temperature influence is based on CeO2 content, the higher the CeO2 amount, the higher the influence of temperature. The results of the nanocomposites revealed antibacterial activity counter to gram-positive bacteria strain (S. aureus, and B. subtilis), and gram-negative bacteria (E. coli, and K. pneumoniae), yeast (C. albicans, as well as fungi (A. niger). Inherently, the change in CeO2 concentration from 0.01 to 0.1 wt% delivers maximum influence against gram-negative bacteria. These PMMA CeO2-doped composites are beneficial for optoelectronic areas and devices.