جستجوی مقالات مرتبط با کلیدواژه "spectroscopy" در نشریات گروه "شیمی"

Z-scheme plasmonic photocatalytic Ag/AgBr/Bi2MoO6 nanocomposites were synthesized by precipitation deposition method and followed by sonochemical deposition method. Phase, morphology, chemical structure, surface area and optical properties of the products were characterized by different techniques. The analytical results reveal that the Z-scheme plasmonic nanocomposites were the co-existence of AgBr, Ag/AgBr and Bi2MoO6 to form heterostructure AgBr/Bi2MoO6 and Ag/AgBr/Bi2MoO6 nanocomposites. The surface of Bi2MoO6 nanoplates were fully covered with 10–15 nm spherical AgBr and Ag/AgBr nanoparticles. The DRS spectra were excellent absorption of visible light with absorption edges of 457 nm, 470 nm and 484 nm for Bi2MoO6, AgBr/Bi2MoO6 and Ag/AgBr/Bi2MoO6 nanocomposites, respectively. The visible-light harvest of Ag/AgBr/Bi2MoO6 nanocomposites was the highest due to the synergistic effect of Z-scheme Ag/AgBr/Bi2MoO6 heterojunctions and surface plasmon resonance (SPR) effect of metallic Ag nanoparticles. The photocatalytic activities were investigated through the photodegradation of rhodamine B (RhB) under visible radiation (λ ≥ 420 nm). Among the three different photocatalysts, Ag/AgBr/Bi2MoO6 nanocomposites have the highest decolorization efficiency of 97.37% within 80 min because of the formation of Z-scheme Ag/AgBr/Bi2MoO6 nanocomposites and excellent visible-light harvest.

Two simple, fast and novel delicate fluorimetric and spectrophotometric strategies were examined for the measure of ceftobiprole (CEF) utilizing gold nanoparticles (Au NPs). On spectrofluorimetric strategy, gold nanoparticles were utilized as a fluorescence test. The expansion of CEF to Au-NPs arrangement caused significant quenching of the outflow band of Au-NPs, which was likely due to the complexation of the medicate to gold NPs. Beneath the ideal conditions, the extinguished fluorescence (FL) escalated was straight with the examined concentration. The extinguishing instrument of CEF on the outflow band of Au-NPs was clarified by Stern-Volmer law. The moment spectrophotometric strategy was based on conglomeration of synthesized gold nanoparticles. Gold nanoparticles appeared retention at 522 nm. Upon interaction with the CEF, the band at 522 nm vanished with arrangement of a unused ruddy moved band at 673. Distinctive exploratory variables were optimized for higher affectability. The calibration bands were straight with concentration extend of 0.1-12 µg/mL for the examined medicate. The methods were connected effectively to decide the studiedddrug in minor concentrations in immaculate frame, pharmaceutical measurement shapes and organic liquids (human serum and urine samples).

This article explores the insights provided by infrared (IR) spectroscopy into the optical properties and surface morphology of polyethylene (PE) polypropylene (PP), and polyvinyl chloride (PVC) films. Notably, IR spectroscopy can identify absorption lines attributed to various functional groups in addition to those associated with lower-density linear polyethylene. The specific characteristics of IR spectra for linear low density polyethylene are influenced by polymer processing conditions, branching, and monomer content. Moreover, the IR spectrum of PVC offers valuable information about its molecular structure and composition. Comparatively, polypropylene (PP) films exhibit higher absolute light transmission in the ultraviolet and visible spectrum when contrasted with films based on PE and PVC. The utilization of atomic force microscopy (AFM) and IR spectroscopy reveals that heat-induced decomposition and subsequent cooling do not impact the surface roughness or thickness of the films, confirming the retention of structural and electrophysical attributes.

Hydrogen bonds between and within molecules are essential interactions that control how molecules behave in various chemical and biological systems. To better understand the complex nature of hydrogen bonding events, spectroscopic and computational methodologies were integrated in this abstract. Direct probing of the vibrational and electronic fingerprints linked to hydrogen bonds has been made possible by spectroscopic techniques, such as infrared and nuclear magnetic resonance spectroscopy, providing crucial details regarding bond strength, length, and dynamics. Molecular dynamics simulations and advanced computational techniques like density functional theory (DFT) have simultaneously produced a theoretical foundation for comprehending the energetics and geometry of hydrogen bonds. A thorough understanding of hydrogen bonding interactions in a variety of settings, including biomolecular systems, liquids, and solids, has been made possible by the synergistic interaction between experimental data and theoretical discoveries. The combined efforts of spectroscopic and computational research have revealed the relevance of hydrogen bonds in molecular recognition, reaction processes, and material properties, even though difficulties still exist in adequately simulating solvent effects and long-range interactions. This multidisciplinary approach continues to lead to discoveries as technology develops, providing a deeper understanding of hydrogen bonding and its ramifications across other scientific disciplines.

In the present work, Se and Mn analysis was carried out among some popular Iranian herbal drops to monitor a possible accumulation of adverse elements. In this study, five different herbal drops present in Iranian market were selected, and 45 samples of each (totally 225 samples) were collected, and analyzed for the presence and determination of selenium and manganese using graphite furnace atomic absorption spectrometry. Samples were prepared by the dry ashing method at 450 °C, and the residue was dissolved in nitric acid. Se and Mn contents were determined using calibration curves at wavelength 196.0 and 279.5 nm respectively. LOD of the methods were determined as 9.1 µgL-1 for Se and 0.9 µgL-1 for Mn. LOQs were calculated to be 30.0 and 3.0 µgL-1 for Se and Mn, respectively. The Se concentrations in the determined samples were between ND-21.0 µgL-1 and for Mn were in the range of 7.2-1840.7 µgL-1. Mean Se and Mn concentrations (µgL-1) were 4.7 and 43.7 for Vitagnus, 9.6 and 185.1 for Hypiran, 13.3 and 338.5 for Carminat, 21.0 and 1840.7 for Persica, and ND and 7.2 for Menthol, respectively. The results showed that Mn was present in all of the samples analyzed, but no selenium was detected in some herbal drop samples.

In this work, silver nanoparticles/chitosan nanocomposites were prepared for possible industrial and biomedical applications. Chemical reduction of silver nitrate salt produced silver nanoparticles (AgNPs). Low molecular weight chitosan (LMWCS) which connotes artificial chitosan (ArCS) was obtained, and biodegradable chitosan was extracted from snail shells using standard procedures. Sodium tripolyphosphate (TPP) was used to produce chitosan nanoparticles (snail shell nanochitosan (ScCSNPs) and artificial nanochitosan (ArCSNPs)) from extracted chitosan and LMWCS. AgNPs-CSNPs were produced by incorporating AgNPs into CSNPs as antimicrobial agents. Characterization of the chitosan doped silver nanoparticles was conducted using scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The morphological properties of nanochitosan (ScCSNPs and ArCSNPs) and AgNPs-nanochitosan (ScCSNPs-AgNPs and ArCSNPs-AgNPs) indicated porosity and agglomeration, while functional groups -OH, -NH, and C-H were revealed. The presence of AgNPs in the polymeric matrix of nanochitosan was confirmed by a shift in some of the adsorption bands. XRD and DSC results revealed that the nanochitosan is crystalline, and they also confirmed the presence of AgNPs in the chitosan polymeric matrix. The study established that chitosan extracted from snail shells, which contribute to environmental pollution, could be a good source for the preparation of nanocomposite materials, which are useful in a variety of industrial and biomedical applications.

The new diazo ligand, and its complexes with metals ions Cu(II), Zn(II), Cd(II), and Ag(I), were synthesized, and ligand synthesis was done via diazotization of 4,4'-Methylenedianiline (MDA), and then coupling was carried out with aniline derivative in good yields by using spectroscopic techniques such as FT-IR, UV-Visible, NMR, and elemental analysis for characterization. Also, the analytical measurements were done such as the detection of conditions of the optimal reaction (reagent concentration, pH, etc.), the detection limit, linearity, and sensitivity. Moreover, the biological activity of the synthesized diazo ligand and its complexes were tested against four types of bacteria (Staphylococcus aureus, Enterococcus feacalis, E.coli, and Pseudomonas aeroginosa,) in vitro. They showed the promising biological activity toward these examined organisms.

Dolichos is a genus of twining plants found in both the Northern and Southern hemispheres, with the most frequently grown and used species being Dolichos biflorus and Dolichos lablab. Antimicrobial, antioxidant, anticancer, anti-schistosomal, and anti-inflammatory properties have been reported in various parts of the Dolichos species, including the leaves, roots, bark, and stem. The rhizome of Dolichos pachyrhizus was cut, air-dried at ambient temperature, and macerated with n-hexane, dichloromethane, ethyl acetate, and methanol for 72 hours each using a conventional maceration procedure, with regular shaking at intervals. The mixture was decanted, filtered, and concentrated at 40 °C using a rotavapor to yield crude n-hexane, dichloromethane, ethyl acetate, and methanol extracts (R110). To obtain the pure isolate, a methanol crude extract of the rhizome of Dolichos pachyrhizus (D. pachyrhizus) was chromatographed on a silica gel column using various eluents. The preliminary phytochemical investigation of the methanolic rhizome extract of Dolichos pachyrhizus revealed the presence of seven (7) different phytochemicals, including; - alkaloids, flavonoids, glycosides, phenols, tannins, saponins and steroids. The structure of the pure isolate was successfully identified, characterized and confirmed using spectroscopic techniques such as; - Fourier transform spectroscopy (FT-IR), Gas chromatography-mass spectrometry (GC-MS) and Nuclear magnetic resonance (NMR) be Neoduline.

Bile, often known as gall, is a dark-green fluid produced by the liver of most vertebrates. It is ‎largely made up of steroidal detergent-like compounds and membrane lipids including un-‎esterified cholesterol and mixed phosphatidylcholines. A good number of animal bile has been ‎utilized ethno-medicinally for ages. Animal bile has been administered to cure liver, skin ‎disorders, malaria, diabetes, cancer, and heart disease. The extraction was achieved by solvent ‎extraction in chloroform, where 40% aqueous methanol was added to about 4 liters of the bile ‎sample, mixed thoroughly and acidified with 2M H2SO4 solution to a pH of about 3.0 - 4.0. ‎After several agitations, the mixture was allowed to stand for 24 hours, and then extracted with ‎chloroform. The crude chloroform extract was purified using standard purification techniques of ‎column chromatography (CC) and thin layer chromatography (TLC). The structure of the ‎compound was characterized using, - (1H NMR), 13C NMR, and DEPT 135 spectroscopic ‎techniques in order to propose the structure of the compound as (Methyl-3,12-dihydroxycholan-‎‎24-oate). The in-vitro antimalarial assay of the crude extract and the isolated compound was ‎carried out on Plasmodium falciparum. The results of the antimalarial activity of the crude bile ‎extract and isolated compound revealed IC50 values of 16.16 µg/mL and 32.09 µg/mL, respectively ‎which indicates the moderate antimalarial activity compared to chloroquine standard control ‎‎(0.029 µg/mL). The results of the investigation revealed that the bovine bile extract, contain ‎bioactive chemical substances which could be good, therapeutic agents against malaria..

X-ray absorption fine structure (XAFS) denotes the details of how X-ray is absorbed by an atom at energies near and above the core-level binding energies of that atom. Specifically, XAFS is the modulation of an atom’s X-ray absorption probability because of the chemical and physical state of the atom. XAFS spectra are especially sensitive to the formal oxidation state, the coordination chemistry,, and the distances, coordination number, and the species of the atoms instantly surrounding the selected element. Because of this dependency, XAFS provides a useful, and pretty simple way to determine the chemical state and the local atomic structure for a certain atomic species. XAFS can be used in a variety of systems and bulk physical environment. XAFS is normally used in a wide range of scientific fields, including biology, environmental science, catalysts research, and material science. Herein, the structures of a few inorganic compounds are investigated by XAFS.

A comparative spectral study of water–acetonitrile systems containing photochromic spiropyran and spirooxazine derivatives in the absence and in the presence of silica nanoparticles was carried out. The photoinduced formation of proton complexes beetwen phenolic oxygen of the colored forms of spirocompounds and the surface hydroxyl groups of silica nanoparticles was established for all of the derivatives. The photoinduced proton complexes of the spiropyrans exhibit positive photochromism on the surface of silica nanoparticles. It is assumed that the previously discovered negative photochromism is due to the formation of proton complexes with not only phenolic oxygen, but also the OH group at the nitrogen atom of the indoline spiropyran moiety. These complexes can also exist in the absence of nanoparticles, because of interaction with water molecules.A comparative spectral study of water–acetonitrile systems containing photochromic spiropyran and spirooxazine derivatives in the absence and in the presence of silica nanoparticles was carried out. The photoinduced formation of proton complexes beetwen phenolic oxygen of the colored forms of spirocompounds and the surface hydroxyl groups of silica nanoparticles was established for all of the derivatives. The photoinduced proton complexes of the spiropyrans exhibit positive photochromism on the surface of silica nanoparticles. It is assumed that the previously discovered negative photochromism is due to the formation of proton complexes with not only phenolic oxygen, but also the OH group at the nitrogen atom of the indoline spiropyran moiety. These complexes can also exist in the absence of nanoparticles, because of interaction with water molecules.

In the present work, Ag2C2O4/Bi2MoO6 nanocomposites containing different weight contents of Ag2C2O4 were prepared by a deposition-precipitation method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). They revealed the presence of good crystalline monoclinic Ag2C2O4 nanoparticles distributed on orthorhombic Bi2MoO6 square nanoplates. The photocatalytic properties of Bi2MoO6 and Ag2C2O4/Bi2MoO6 samples were investigated by photodegradation of rhodamine B (RhB) under visible light irradiation. In this research, 10 wt% Ag2C2O4/Bi2MoO6 nanocomposites have the highest photocatalytic performance of 78.84 % within 100 min under visible light irradiation, higher than the photocatalytic performance of pure Bi2MoO6. A photocatalytic mechanism of Ag2C2O4/Bi2MoO6 nanocomposites was also discussed according to the experimental results.

In this work, pyridine 4-carbaldehye semicarbazone Schiff base ligand (HL) was synthesized with condention of pyridine 4-carbaldehyde and semicarbazide hydrochloride in reflux method. The HL was characterized using the CHN elemental analysis, FT-IR, UV-Vis, and 1H NMR spectroscopy. The single crystals of HL prepared and used for the X-ray crystallography. Single-crystal X-ray diffraction revealed that, HL crystallized in a triclinic system with the space group P-1. The FT-IR spectra and X-ray crystallography results suggested that the HL ligand is in keto form.

The study aimed at the synthesis and antibacterial activity of ZnO nanoparticles (NPs) from organic extracts of Cola nitida and Cola acuminata leaf using zinc chloride (ZnCl2) and zinc acetate dihydrate [Zn(CH3COO)2∙2H2O] as precursors on selected Gram positive and Gram negative microbes: Staphylococcus aureus, Exiguobacterium aquaticum, (Gram +ve) and Escherichia coli, Klebsielia pneumonia, Acinetobacter baumanni (Gram –ve). Spherical and flake-like nanostructures were recorded by Scanning Electron Microscopy (SEM) for C. acuminata and C. nitida respectively for the two precursors used. The average particle size and crystallite size determined by Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) for C. acuminata and C. nitida were in the range of 32.15-43.26 nm; 69.12-84.26 nm and 14.69-17.12 nm; 23.68-23.96 nm respectively. Energy-dispersive X-ray spectroscopy (EDX), UV- visible spectroscopy (UV-vis), Atomic Absorption Spectroscopy (AAS) and Fourier-transform infrared spectroscopy (FT-IR) techniques were used to observe the purity and surface functional groups of the samples. Spectra peaks at 440-458 cm-1 and 364-370 nm confirmed the presence of ZnO in the samples by FT-IR and UV-vis, whereas AAS at 213.9 nm wavelength further confirmed elemental zinc with a percentage atomic weight of 71.37% as against 69.50%, 18.8% and 11.1% for Zinc, Oxygen and Carbon by EDX. Data from the antibacterial activity studies show an increase in inhibition rate as concentration of the ZnO NPs increases in concentration from 25-1000 ppm. ZnO NPs from the two extracts recorded the highest inhibition rate in Acinetobacter baumanni of approximately 88% and 49% using ZnCl2 and Zn(CH3COO)2∙2H2O respectively.

Cationic dye Acridine orange (AO) has wide applications especially in biologicalfields such as analysis of lysosomal and mitochondria content by flow cytometryand so on. In the current work, spectroscopy of acridine orange (AO) dye at bothlow concentrations (mdye/mwater=6.25×10-5, 3.12×10-5) and high concentrations(mdye/mwater=0.002, 0.001) was studied in confined water nanodroplets withinwater/AOT/n-hexane microemulsions (MEs) at a constant water content (W=[Water]/[AOT]=10) and as a function of mass fraction of droplet (MFD) usingabsorption and fluorescence spectroscopic techniques. The absorption spectraof the dye at high concentrations of Acridine orange (AO) dye molecules showedthat the absorption spectra of the samples deviated from Beer’s law, and arebroadened at larger MFD due to the interactions of AO dye molecules. Thefluorescence spectrum investigated at two higher concentrations (0.002, 0.001)and low concentrations (6.25×10-5, 3.12×10-5). At high concentration of the dye,quenching of fluorescence intensity observed due to the accumulation of the dyemolecules, coupled with a red shift with increasing MFD. However, in the lowerconcentration regime, enhancement of fluorescence intensity was observed withincreasing MFD. The Stokes’ shift of the dye for both high and low concentrationsincreased with MFD, but largely at high concentrations compared to that at lowconcentrations.

The nanoparticles were called nanoparticles on a scale of 1–100 nm. In addition to the composition and structure of the material, it is also one of the factors affecting the properties of materials. Nowadays, green chemistry and its benefits are stimulating researchers' interest in the environmental biosynthesis of metallic nanoparticles. In this study, a rapid, simple and green method for the synthesis of silver nanoparticles was prepared using aqueous extract of viscose album. The synthesized silver nanoparticles were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) methods. The results of SEM, XRD and UV-Vis techniques confirm the synthesis and formation of uniform and spherical shape of silver nanoparticles with average particle size of about 40-70 nm. The aqueous extract of Viscom album demonstrates the strong potential for reducing silver ions and producing silver nanoparticles using a highly cost-effective, clean, non-toxic, eco-friendly method that can be produced on a large scale. Silver synthesis with aqueous extract of tree parasite was first studied in this study.

Vanadium(IV) complex [VO((MeO-bph)2en)] (1), (MeO-bph)2en=N,N¢-bis(2-hydroxy-4-methoxybenzophenone)-1,2-ethanediamine, was synthesized and characterized by elemental analyses (CHN), FT-IR spectroscopy, thermogravimetry, SEM and single crystal X-ray diffraction. The title complex 1 was prepared by the reaction of VO(acac)2, 1,2-ethanediamine and 2-hydroxy-4-methoxybenzophenone (molar ratio 1:1:2). The single-crystal X-ray analysis of 1 shows that the vanadium(IV) ion is located in a distorted square pyramid (N2O3) environment with the tetradentate Schiff base ligand coordinated in equatorial positions and one oxygen atom in the axial position. Thermogravimetric analysis shows that the complex 1 decomposes in two stages. Finally, the complex was calcinated at 500 °C for 3 h and the V2O5 products characterized by FT-IR and SEM.