Characteristic Absorption Bands Research Articles

Synthesis and Magnetic Properties of a Dimerized Trinuclear Ni String Complex, [Ni6Cl2(dpa)8](I5)2·0.25I2 (dpa- = 2,2'-Dipyridylamide Anion).

Metal string complexes, linearly aligned transition metal arrays coordinated with the multidentate organic ligands, have gained much attention both in unique electronic/structural properties and in potential applications as conductive molecular nanowires. Here we report on a dimerized NiII trinuclear complex, [Ni6Cl2(dpa)8](I5)2·0.25I2 (dpa- = 2,2'-dipyridylamide anion). X-ray structural analysis revealed that two trinuclear moieties are bridged by a Cl anion to form a dimerized string structure. This is the first example of two Ni string complexes that are connected. In the electronic absorption and Raman spectra, characteristic absorption bands and a vibration mode based on the dimer string structure were observed. In the solid state, dimer complexes align in one dimension in an MMMXMMMX (M = metal, X = halogen) manner, leading to the intra- and interdimer antiferromagnetic interactions.

Investigation of Crystal Structure, Electrical and Magnetic Properties of Spinel Mn-Cd Ferrite Nanoparticles

Cd1 − xMnxFe2O4 (x = 0, 0.25, 0.5, 0.75, 1) spinel ferrite nanoparticle samples were synthesized using a flash auto-combustion technique and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The inspection of dielectric and magnetic properties of the prepared ferrites was carried out by using broadband dielectric spectroscopy (BDS) and vibration sample magnetometer (VSM) measurements, respectively. X-ray diffraction analysis verified the formation of the main cubic phase with space group Fd3m and a decrease in lattice constants with the increase in Mn-content. FTIR study revealed the two characteristic absorption bands of spinel ferrites and their dependence on Mn-content was investigated and explained. Elastic moduli, bulk modulus, rigidity modulus, Young modulus, and calculated Debye temperature have been studied and found to decrease with the increase in Mn-content. SEM analysis revealed nanoparticles agglomeration of uniform grains with increasing in the average grain size as Mn-content increased. The VSM measurements showed an increase in saturation magnetization accompanied by a decrease in coercivity as Mn-content increased. Dielectric investigations showed very high values of permittivity and dielectric loss at lower frequencies (between 105 and 106 @ 0.1 Hz according to the manganese content) reflecting the combination of exchange of electrons between ferrous and ferric ions and ions’ transport. The ac-conductivity showed a plateau that yields the dc-conductivity at lower frequencies followed by a characteristic frequency at which it tends out to follow a power law. The relation between these two parameters confirms the empirical BNN-relation.

Systematic Investigation of Solution-State Aggregation Effect on Electrical Conductivity in Doped Conjugated Polymers

Systematic Investigation of Solution-State Aggregation Effect on Electrical Conductivity in Doped Conjugated Polymers

Laser-based inactivation of pathogenic microorganisms

In the context of studying the possibility of inactivation of pathogenic microorganisms, the dynamic transmission spectra of femtosecond laser radiation in the mid-IR range by bacteria of the Pseudomonaus aeruginosa culture planted on a silicon substrate were investigated. Irradiation revealed a blue shift in the characteristic absorption bands of bacteria, indicating the breaking of hydrogen bonds responsible for the formation of the secondary and tertiary structure of the proteins.

Influence of ZnF2/PbF2 on physical and structural characteristics of bismuth borate glasses reinforced with chromium ions

This study presents the preparation of zinc, lead co-doped fluoride based bismuth borate glasses reinforced with Cr3+ ions with the chemical formula ZPBBCR: xZnF2-(25-x) PbF2-25Bi2O3- 49.8B2O3-0.2Cr2O3 (where x = 0, 5, 10, 15, 20, and 25 mol%). These ZPBBCR samples were characterized using various physical and structural analyses. For density values the decreasing trend is followed with increase in ZnF2 content while the molar volume followed the increasing trend. Characteristic absorption bands at 450 nm, 610 nm, and 710 nm are assigned to their respective transitions which are observed in UV-Visible spectra. The acquired optical band gap values shown enhancement in their magnitude with excess ZnF2 content. The interactions and characteristic of the Cr3+ ion is observed in EPR spectra. Fourier Transform Infrared (FTIR) in hand with Raman spectra supports the decrease in density values with increase in ZnF2 concentration in ZPBBCR glasses.

Investigation on Green Synthesis, Biocompatibility, and Antibacterial Activity of Silver Nanoparticles Prepared Using Cistus incanus.

This paper describes the plant-mediated preparation of silver nanoparticles with aqueous extract and infusion of Cistus incanus leaves. To evaluate aqueous extract and infusion antioxidant capacity and total phenolic content the DPPH and Folin–Ciocalteau methods were utilized. The antioxidant capacity and total phenolic content of extract and infusion were equal to 85.97 ± 6.54 mg gallic acid equivalents per gram of dry weight.; 10.76 ± 0.59 mg/mL and 12.65 ± 1.04 mg gallic acid equivalents per gram of dry weight.; 3.10 ± 0.14 mg/mL, respectively. The formed nanoparticles displayed the characteristic absorption band in the 380–450 nm wavelength range. The average size of particles was in the 68.8–71.2 nm range. Morphology and phase composition analysis revealed the formation of spherical nanoparticles with a face-centred cubic structure. Immune compatibility tests of nanoparticles and plant extracts showed no activation of the THP1-XBlue™ monocyte. Cytotoxicity tests performed with L929 mice fibroblasts showed that nanoparticles should be utilized at a concentration of 16 ppm. The minimum inhibitory concentrations determined with the microdilution method for nanoparticles prepared with plant infusion for S. aureus and S. epidermidis were 2 ppm and 16 ppm, respectively.

Liquid fuel oil produced from plastic based medical wastes by thermal cracking

The present work is an effort to produce liquid fuel oil from plastic based medical wastes through thermal cracking process under oxidizing conditions. The mixed plastics from medical wastes were considered as a feedstock, shredded into small pieces and heated at 773 ± 10 K for 40 min with a heating rate of 20 K/min in a batch reactor for thermal cracking process. The feedstock was characterized by proximate and ultimate analysis along with thermogravimetric investigation. Moreover, chemical compositions of the liquid fuel oil were examined by FTIR and GC–MS spectroscopy. The properties of liquid product were also examined and compared to the commercial fuel oil. The average yield of brownish and sticky liquid fuel was obtained to be 52 wt% and the gross calorific value of the liquid was found 41.32 MJ/kg which is comparable to that of commercial diesel. FTIR spectrum showed characteristic absorption bands of C–H and =CH2 groups indicating presence of alkane and alkene compounds. GC–MS study demonstrated the chemical constituents of the liquid product that is mostly aliphatic compounds of mainly alkanes (16.28%), alkenes (10.67%), alcohols (14.65%) and ester groups (10.38%) including iso-phthalate (40.02%) as a predominant product. This experiment concludes that the liquid oil derived from thermal cracking of mixed plastics comprised of a composite mixture of organic components. A significant amount of non-degraded constituents like plasticizers, precursors, etc. remained in the product having some economic values with human health and environmental impacts during burning has been addressed in the current issue.

Spectral-Coding-Based Compressive Single-Pixel NIR Spectroscopy in the Sub-Millisecond Regime.

In this contribution, we present a high-speed, multiplex, grating spectrometer based on a spectral coding approach that is founded on principles of compressive sensing. The spectrometer employs a single-pixel InGaAs detector to measure the signals encoded by an amplitude spatial light modulator (digital micromirror device, DMD). This approach leads to a speed advantage and multiplex sensitivity advantage atypical for standard dispersive systems. Exploiting the 18.2 kHz pattern rate of the DMD, we demonstrated 4.2 ms acquisition times for full spectra with a bandwidth of 450 nm (5250–4300 cm−1; 1.9–2.33 µm). Due to the programmability of the DMD, spectral regions of interest can be chosen freely, thus reducing acquisition times further, down to the sub-millisecond regime. The adjustable resolving power of the system accessed by means of computer simulations is discussed, quantified for different measurement modes, and verified by comparison with a state-of-the-art Fourier-transform infrared spectrometer. We show measurements of characteristic polymer absorption bands in different operation regimes of the spectrometer. The theoretical multiplex advantage of 8 was experimentally verified by comparison of the noise behavior of the spectral coding approach and a standard line-scan approach.

Crystallization, spectroscopic and dielectric properties of CuO-added magnesium aluminosilicate-based glasses

In this work, CuO-doped MgO-Al2O3-SiO2 based glasses have been synthesized successfully through conventional melt quenching method, and the effect of CuO content on the structure and properties of the glasses was investigated. The results revealed that CuO could act as a glass modifier to depolymerize the silicate network and its effect was superior to that of MgO. In addition, the main crystalline phase was α-cordierite (Mg2Al4Si5O18), indicating that copper ions did not participate in the formation of the crystalline phase, and still existed in the interstitial position. The characteristic absorption band around 750 nm owing to the 2B1g→2B2g transition of Cu2+ ions appeared on the optical transmittance spectra, which confirmed the existence of Cu2+ ions in the tetragonally distorted octahedral sites. The luminescence center was caused by Cu+ ions, and the luminescence lifetime decreased with the addition of CuO. The dielectric constant and dielectric loss increased with the increase of CuO content, indicating an increase in the insulation performance. Finally, the obtained chromaticity coordinate parameters indicate that the prepared CuO-doped magnesium aluminosilicate-based glasses can be applied in optical and electrical fields.

Tunable cationic distribution and structure-related magnetic and optical properties by Cr3+ substitution for Zn2+ in nanocrystalline Ni-Zn ferrites

We report a microwave-combustion synthesis and structure-related physical properties of Ni0.4Zn0.6−xCrxFe2O4 (0.0 ≤ x ≤ 0.6) nanocrystals in a study of effects by substitution among cations with different oxidation states, Cr3+ for Zn2+. High-quality nanocrystals with an average particle size of 26–33 nm and crystallite size ranged in 23–32 nm are revealed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Structural properties and cationic redistribution are studied by the XRD Rietveld analysis implying different preferences of Zn2+ and Cr3+ ions to occupy the tetrahedral and octahedral sites, respectively. Further characterization for the characteristic IR absorption bands, ionic valence states, chemical compositions and morphology have been performed by employing the Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron dispersive X-ray spectroscopy (SEM-EDX). XPS analysis indicates partial reduction of Fe3+ to Fe2+ and further confirms the estimated cationic distribution. UV–Vis absorbance measurements indicated a gradual decrease in the optical energy gap which implies the emergence of sub-band-gap energy levels by the Cr substitution. The magnetic properties were investigated by magnetization measurements showing highly soft magnetic behavior. The values and trend of the observed magnetic moment are consistent with the theoretically calculated magnetic moment based on cationic distributions estimated from the XRD and XPS. Ni-Zn-Cr spinel nanoferrites with soft magnetic properties, magnetization up to 106 emu/g and coercivity down to 70 Oe, tunable by cationic redistribution are introduced for high-frequency power applications.

Sulfation of wheat straw soda lignin: Role of solvents and catalysts

Sulfation of wheat straw soda lignin by the sulfamic acid–urea mixture in different solvents has been investigated for the first time. The effect of a catalyst used in the lignin sulfation process on the yield of the lignin sulfates and sulfur content in them has been explored. It has been found that the optimal medium for the lignin sulfation with sulfamic acid is dioxane and, in the presence of a catalyst, urea. Although the sulfated lignins obtained using the reaction in dimethyl sulfoxide and diglyme have the maximum sulfur contents (11.2% and 9.9%, respectively), these products are difficult to isolate and purify, which complicates the use of these solvents. Sulfated lignin obtained in the dioxane medium has a high (10.1%) sulfur content and is easy to isolate and purify. The incorporation of sulfate groups into the lignin structure has been confirmed by the infrared and nuclear magnetic resonance spectroscopy investigations. In the infrared spectra of sulfated lignin, characteristic absorption bands at 800–860 and 1260–1200 cm−1 appear. The dominant substitution of aliphatic hydroxyl groups has been confirmed by the nuclear magnetic resonance spectroscopy study. It has been found that, during the modification and purification of lignin, the latter is fractionated, which results in the redistribution of molecular weights toward the high molecular-weight region, as well as the removal of some low-molecular-weight components, which is reflected in a decrease in the number of signals in the nuclear magnetic resonance spectra.

Physicochemical compatibility studies of triclosan and flurbiprofen with excipients of pharmaceutical formulation using binary, ternary, and multi-combination approach

BackgroundThe aim of the study was to evaluate the suitability of triclosan (TCS) and flurbiprofen (FLB) with poly-ε-caprolactone (PCL), chitosan (CS), and Kolliphor® P188 (KP) for possible application in the design of nano-formulations.ResultsDifferential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) revealed the physical characteristics of the various sample compositions without any apparent interaction. The Fourier transform infrared spectroscopy (FTIR)’s spectra of the physical mixtures showed their characteristic absorption bands with broadening and overlapping of bands in some instances, but no appearance of new bands was observed.ConclusionThe study revealed the physical form stability of the evaluated components after the storage period and lack of definite pharmaceutical incompatibility between them. Thus, the selected drugs and excipients could be used for the development of pharmaceutical nano-formulations.

Synthesis, crystal structure and vibrational properties of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide

Derivatives of imidazo[1,2-a]pyridine, a type of fused heterocyclic substance, play major roles in the chemical fields and are confirmed to be the core fragments of various drug molecules. In this study, the title compound was designed and synthesized from the coupling reaction of N-(8-iodoimidazo[1,2-a]pyridin-6-yl)acetamide and 1-(tert-butyl)-3-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)urea. The crystals of the title compound were obtained by solvent evaporation at room temperature. The structure of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide was demonstrated by 1H NMR, 13C NMR, FT-IR and single crystal X-ray diffraction studies. Additionally, theoretical calculations, based on the density functional method B3LYP at the 6-311+G(d, p) level, were performed on the title compound, and the molecular structure optimized using DFT was consistent with the results obtained using X-ray diffraction. In addition, hydrogen bonding, intramolecular π–π stacking and the Van der Waals forces significantly stabilized of N-(8-(3-(3-(tert-butyl)ureido)phenyl)imidazo[1,2-a]pyridin-6-yl)acetamide, as shown in the packing diagram. Moreover, the vibrations of the title compound were reliably assigned on the basis of characteristic vibrational absorption bands. Finally, frontier molecular orbital (FMO) was employed to verify the charge transfer interaction involving the electron acceptor and electron donor groups.

Fabrication and Characterization of GO-Fe3O4/PSF Membrane with Phase Inversion Method

Polysulfones are hydrophobic which can reduce membrane permeability. Permeability can be increased through the application of hydrophilic materials such as GO-Fe3O4 to the polysulfone membrane so that the membrane is hydrophilic. The riset purpose to determine the effect of the percentage weight of different material compositions on the hydrophilicity properties of the polysulfone membrane. Membrane fabrication is carried out using the phase inversion method where the polymer solution is molded in a place and immersed in a coagulation bath containing non-solvent. This solvent exchange causes the polymer to form a solid matrix and become a membrane. The results showed that GO particles were successfully doped with Fe3O4 material shown by XRD analysis at a peak of 35.61˚ with a magnetite phase, while FTIR analysis showed that there was an absorption band characteristic of Fe-O streching vibrations. The results of the contact angle test on the GO-Fe3O4/PSF membrane 0.75 wt per cent were around 73.17˚ which showed the smallest hydrophobic value and the membrane surface morphology had an average pore size of 333.61 nm so that the addition of GO-Fe3O4 composites could increase membrane hydrophilicity.

Magnetically retrievable nanoscale nickel ferrites: An active photocatalyst for toxic dye removal applications

Nickel ferrite (NiFe2O4) nanoparticles were synthesized through the sol-gel auto-combustion method using urea and glycine as mixed fuel. The prepared nanoparticles were investigated for their structural, optical, and magnetic characterizations. Rietveld refined X-ray diffraction (XRD) patterns revealed the development of single-phase cubic spinel. The crystallite size was calculated by using Modified Scherrer's method and the W-H plot was found in the order of 26.6 nm and 25.4 respectively which are nearly the same. The infrared spectrum showed the typical characteristic absorption bands in the range of 400 cm-1 to 600 cm-1 belonging to cubic spinel structure. Scanning electron microscopy images showed the spherical nature of the nanoparticles along with agglomeration to some extent. As per the optical study, the prepared nanoparticles have an optical bandgap of 2.59 eV. The magnetic properties were studied through the M − H hysteresis curve showing superparamagnetic nature, the value of saturation magnetization (Ms), coercivity (Hc) was observed 46.20 emu/gm, and 383.2 Oe respectively. The photocatalytic activity of nickel ferrite was studied based on the degradation of methylene blue (MB) dye as a model compound, where the result showed that prepared nanoparticles possessed a good photocatalytic activity against dye degradation. Up to four times catalyst exhibits nearly the same reutilization.

Retraction Notice: Synthesis and study the crystal structure of polycrystalline a novel type phase in Zn- Pb- Zr intermetallic alloy by ab initio method via powder XRD system

Zn- Pb- Zr ternary intermetallic phases were synthesized by high-temperature solid-state synthesis. Structural characterization was performed by means of powder X-ray diffraction and energy dispersive X-ray analysis. X-ray powder diffraction coupled with Rietveld refinement reveals the sample’s phase purity we have prepared. Thermal behavior analysis shows Zn0.61 Pb0.91 Zr0.138 is very stable, it doesn’t decomposition until heated up to 998 °C. UV-visible absorption and diffuse reflection spectrum feature characteristic absorption bands of d-electron transition and main group metallic alloy given an optical band gap value of 3.65 eV. Magnetic susceptibilities measurement gives significant anti- ferromagnetic interactions between magnetic centers. The results further encourage the prospects of ternary Zn-Pb-Zr alloy anodes to utilize in real energy storage applications The photo degradation experiment were performed to evaluate photocatalytic activities of Zn0.61 Pb0.91 Zr0.138 .The Rietveld refinement parameters are a=8.731(A),b=8.734(A),c=5.929(A), GOF=1.214,Rwp=31.21,Rp=21.321 having hexagonal crystal system with primitive . P 63/m c m space group.

Synthesis and Characterization of Caprolactam- based Ionic Liquids as Green Solvents

Aims: To synthesize and characterize six caprolactam-based ionic liquids (CPILs) by combination of caprolactam with different organic and inorganic Brønsted acids that can be utilized for lipid extraction from microalgae.
 Study design: Experimental design include quantitative and qualitative.
 Place and duration of study: The study was done at Department of Chemistry & Biochemistry, School of Sciences and Aerospace Studies, Moi University (Kenya) between November 2020 and May 2021.
 Methodology: Six CPILs were prepared through a simple neutralization reaction between Caprolactam and Brønsted acids such as Hydrochloric acid (HCl), Methane sulphonic acid (CH3SO3H), Trifluoromethanesulphonic acid (CF3SO3H), Acetic acid (CH3CO2H), Trifluoroacetic acid (CF3CO2H), and Sulfuric acid (H2SO4). The first three acids were used in the synthesis of CPILs for the first time. The chemical structures of the synthesized CPILs were characterized by Fourier transform infrared and Raman spectroscopy. The densities and viscosities were measured at 20 oC using the weight (pycnometer) and capillary viscometer (Oswald) methods, respectively.
 Results: All the CPILs were insoluble in hexane and had high miscibility with water and methanol. Fourier transform infrared and Raman spectra of the CPILs were compared with that of free Caprolactam. The characteristic absorption bands of the synthesized compounds showed a big shift in position and/or intensity (compared to caprolactam), indicating the formation of the CPILs. The results showed that both the density and viscosity increased with the molecular weight of the anion - except in Caprolactamium hydrogen sulphate (CPSA)- which could be due to the strong interactions between the cation and anion resulting from the dimerization between hydrogen sulphate anions. 
 Conclusion: The hydrophilic nature of the CPILs indicated by high miscibility with polar solvents (water and methanol) indicates that they are suitable for the dissolution of cellulose of microalgae cell wall and thus could result in high lipid extraction efficiency. Further studies should therefore utilize the synthesized CPILs in lipid extraction from microalgae.

Simple Method to Produce Carbon from Cassava Peel by Calcination for Future Application

Abstract- and economic material. One of the benefit things is the processing of organic waste to produce carbon. This study has decomposed waste of cassava peel to yield carbon through calcinations. The process of carbonization has been conducted at temperature of thermal decomposition of cassava peel applying TGA and the carbon yield characterized by FTIR and XRD. The FTIR spectra indicates that the carbon yield from calcinations of cassava peel at various temperatures of thermal decomposition still containing some functional groups of organic compounds showed by its characteristic absorption bands. The characteristic FTIR absorption bands become more distinguishable from the spectra of unmanageable cassava peel due to increasing calcination temperatures. The pattern of X-Ray diffraction of carbon samples yielded from calcinations showed amorphous phase of carbon with several crystalline peaks of graphite at C(001), C(102), and C(112) planes.

Preparation and luminescence properties of ZnWO4 :Eu3+ ,Tb3+ phosphors.

A series of ZnWO4 :Eu3+ ,Tb3+ phosphors was prepared using a co-precipitation method at room temperature. The structures and luminescence properties of the materials were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and UV-vis light, differential thermal analysis-thermogravimetric analysis, fluorescence spectra and the calculated Commission Internationale de l'Éclairage (CIE) coordinates. The results showed that the material had a monoclinic structure and the P2/c group was determined using XRD. FTIR spectroscopy confirmed the existence of W-O, Zn-O bonds, and Zn-O-W groups in WO6 and ZnO6 octahedra. In the excitation spectrum, there was an overlap of the broad band charge transfer bands belonging to O2- →W6+ and O2- →Eu3+ or O2- →Tb3+ transitions in the range 200-325 nm, and excitation bands between 350 and 500 nm belonged to the characteristic absorption bands for Eu3+ and Tb3+ . Therefore, the phosphor can be used as a single component tunable phosphor in light-emitting diodes.

Evaluation of conductivity of nanostructured polyaniline/cellulose nanocrystals (PANI/CNC) obtained via in situ polymerization

Cellulose nanocrystals (CNC) have a wide range of applications due to the high aspect ratio, crystallinity and mechanical properties in addition to being renewable and biodegradable. Polyaniline (PANI) is a conductive polymer that has attracted extensive attention due to low density and high electrical conductivity. However, polyaniline in the bulk form has some limitations in terms of use because of its chemical nature as a consequence of secondary hydrogen bonds that reduces conformability and mechanical strength. Aiming at the applicability of polyaniline as films or gels, this work combines two types of materials: cellulose nanocrystals (CNC) and polyaniline through an in situ polymerization of PANI in CNC suspensions to create a nanostructured material. Thermal stability (TGA), particle size (Zeta-sizer), physical and chemical characteristics (FTIR, UV-vis), the process of polymerization (Voc) as well as conductivity was evaluated according to the different PANI/CNC ratios (R = 0.05, 0.1, 0.2, 0.3 and 0.4). Results show that particle size, thermal stability and time of polymerization increase with CNC concentration, indicating that cellulose nanostructure works as a backbone to PANI deposition. FTIR and UV-vis show the evolution of the main characteristics absorption bands around 1220 cm−1 , 1487 cm−1 and 1594 cm−1 (IR) and 381∼391 nm, respectively while the PANI/CNC ratios increase. Otherwise, conductivity values of the nanostructured PANI/CNC with the higher content of PANI is 8.9 × 10−1 S/cm−1 compared to 3.63 S/cm−1 to neat polyaniline, showing to be a great alternative of nanostructured material.