UV-visible Data Research Articles

Co-doping of Fe2O3 nanoparticles with Y and Zr by green synthesis

The study aims to co-dope nanoparticles of iron oxide with yttrium and zirconium by one-pot green synthesis method using freshly plucked Simarouba Glauca (Paradise tree) leaf extract. The focus is on the effect of co-doping and also the effect of different annealing durations such as 2–4 h at a constant temperature of 600 °C. The nanoparticles were characterized using various techniques, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Ultraviolet-visible Spectroscopy (UV–vis), Raman Spectroscopy, and Fourier Transform Infrared Spectroscopy (FT-IR). Antibacterial tests on Gram-positive and Gram-negative bacteria were performed to determine the bactericidal activity of the samples. The particle size was calculated to be around 55.95 nm through Bright Field-TEM (BF-TEM) images. XRD data confirms doping and indicates the formation of haematite phase with crystallite size increasing from 1.94 to 41.17 nm on increasing annealing duration and the phase was confirmed through HR-TEM data. Bandgap calculated through UV–vis data shows a decrease from 2.13 to 2.09 eV. Annealing duration had a notable effect on the crystallinity of the samples and their bandgap, but had no impact on their antibacterial properties. A unique result was observed in the degradation of methylene blue, where the reduced form of methylene blue undergoes a reversible change to reproduce methylene blue after a certain period. Liquid Chromatography Mass Spectrometry (LC-MS) was used to identify the intermediates and the products formed on catalysis. The result was a simultaneous reduction, oxidation and demethylation, as all three corresponding intermediates were formed.

Effect of Mg doping at Fe/Cr site on magnetic and optical properties of Gd2FeCrO6 double perovskite

The influence of Mg doping on structural, magnetic and optical characteristics of Gd2FeCrO6, Gd2Fe0.75Mg0.25CrO6 and Gd2FeCr0.75Mg0.25O6 double perovskites has been systematically investigated. The monoclinic crystal structure with the P21/n space group is confirmed by powder X-ray diffraction data. From the scanning electron microscopy graphs, we noticed few nearly spherical and dumbbell-shaped grains for all compounds with an average grain size of about 76 - 85 nm. The magnetic studies demonstrated the presence of a weak ferromagnetic transition with antiferromagnetic background at low temperatures for all the samples. A decrement in the transition temperature of Gd2FeCrO6 (TC = 8.14 K) is observed on Mg doping, which is due to the smaller ionic radii of Mg at the Fe/Cr site in Gd2Fe0.75Mg0.25CrO6 and Gd2FeCr0.75Mg0.25O6 double perovskites. By analyzing the UV–visible spectroscopic absorption data, direct band gaps around 3 eV are concluded for pure and Mg doped Gd2FeCrO6 double perovskites, validating their application in wastewater photocatalysis.

Development of iron oxide nanoparticles using egg peel (brown) extract as a useful tool for removing the MB dye

The development of iron oxide nanoparticles (IO-NPs) (Fe3O4 and γ-Fe2O3) synthesized from ferric chloride (FeCl3) with egg peel extract by the hydrothermal method at different temperatures for the removal of methylene blue dye (MB) (Fe3O4 and γ-Fe2O3) NPs were diagnosed using (XRD) analysis, (FE-SEM) analysis, (TEM) images, (VSM) instrument, (UV–Vis) spectra, and (FTIR) spectroscopy. XRD measurements explained a crystallinity size of about 15 nm and a face center cubic structure (FCC) for Fe3O4 synthesized from egg peel (brown) extract at 200 °C, while for γ-Fe2O3 NPs prepared using egg peel (brown) extract at 400 °C, the crystal peak structure referred to a cubic structure (maghemite). The average grain size of Fe3O4 NPs was 18.61 to 27.91 nm; however, it was 31.25 to 125.5 nm for γ-Fe2O3 NPs, according to FESEM. Average grain size and the morphology of Fe3O4 and γ-Fe2O3 NPs were (14.7 nm to 26.1 nm) and the spherical structure was determined by the TEM images. The saturation magnetization (Ms) values were 8.12 emu/g and 9.39 emu/g, respectively, for Fe3O4 and γ-Fe2O3 NPs measured with the VSM device. The UV–visible data indicated a blue shift to the band energy gap of 4.1 eV for Fe3O4 NPs but 2.5 eV for γ-Fe2O3 NPs. The absorption band for Fe3O4 NPs is robust at 681 cm−1 at 200 °C, whereas it gets weaker at 650 cm−1 for γ-Fe2O3 NPs at 400 °C, according to FTIR. A photocatalytic activity value explained (Fe3O4 and γ-Fe2O3) NPs affected the MB dye's removal. A results referred to the synthesized Fe3O4 (magnétite) synthesized at 200 °C showed a higher removal efficiency (95 %) at 40 min than the γ-Fe2O3 (maghemite) at 400 °C, for which, after 65 min, the removal efficacy was 90 %.

Effect of Calcination Temperature and Substitution of Erbium on Structural and Optical Properties of Nickel Zinc Ferrite Nanoparticles

A single composition of erbium-doped nickel zinc ferrite Ni0.5Zn0.5Fe1.95Er0.05O4 is synthesized by the sol-gel autocombustion process. The prepared composition was divided into five equal parts. One of the parts was an as-prepared sample, and remaining four other parts were calcinated at 600, 700, 800, and 900 ∘C to investigate the variation in structural and optical properties with the calcination temperature. The structural characterization was performed using XRD and SEM. Optical properties were analyzed using FTIR and UV-Visible spectral data. XRD patterns confirm the spinel cubic crystal structure and the Fd3m space group. The crystallite size was minimum for the as-prepared sample (17.9452 nm), and the crystallite size was maximum for the sample calcinated at 900 ∘C (29.8481 nm). SEM images revealed the grain size in the interval from 55.38 nm to 177.73 nm, and certain nanotubes were formed in the sample calcinated at 800 ∘C. Optical energy band gap was observed in the interval from 5.556 eV to 3.969 eV. All these testifies to the variations in structural and optical properties of Ni0.5Zn0.5Fe1.95Er0.05O4 with the calcination temperature.

Annealing-induced characterization of sputtered V2O5 thin films and Ag/V2O5/p-Si heterojunctions

V2O5 thin films were deposited on glass and p-type silicon substrates by radio frequency (RF) sputtering of a single V2O5 target. Half of the samples were annealed at 500 °C at room ambient for an hour. The morphological, structural, and optical properties of the thin films were analyzed by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–Vis data. The results showed that while the as-grown V2O5 thin films had smooth surfaces with an amorph phase, annealed films had rougher surfaces with grains in the polycrystalline phase. It is also reported that the band gap of V2O5 thin films decreased from 2.47 to 2.37 eV. Furthermore, the electrical properties of Ag/V2O5/p-Si junctions were analyzed by current-voltage (I–V) measurements. It was presented that both Ag/V2O5/p-Si structures with as-grown and annealed V2O5 thin films had exciting rectifying behaviors. It was observed that while the barrier heights of the rectifying junctions were nearly the same, the ideality factor and series resistance values of the Ag/V2O5/p-Si device fabricated by annealed V2O5 thin film were higher than the device with as grown V2O5 thin film. Finally, the photoelectrical properties of both samples were analyzed by I–V under various light intensities. It was seen that both Ag/V2O5/p-Si devices had exciting photosensing behavior. While the increase in reverse bias current values with the increase in light intensity was observed for both devices, it was seen that the device obtained by as-grown thin film had much more sensitivity to light.

Synthesis, Computational and Antimicrobial Study of 2-(2-Hydrazinyl)thiazole Derivatives

In the present investigation, we report a combined computational and experimental study of eight thiazole derivatives (4a-4h) obtained from 3,4-dihydronaphthalen-1(2H)-one. A green chemistry protocol comprising PEG-400 and sulfamic acid was employed for the synthesis of eight diverse thiazole derivatives from 3,4-dihydronaphthalen-1(2H)-one, thiosemicarbazide and various phenacyl bromides. The synthetic strategy provides benefits like short reaction time, high yield, and non-chromatographic purification. The compounds were structurally confirmed on the basis of IR, 1HNMR and 13C NMR. The obtained thiazole derivatives were studied using the density functional theory (DFT) method employing B3LYP/6-311G(d,p) level of theory for optimization and Time-Dependent DFT (TD-DFT) approach for examining electronic energies and UV-Vis characteristics. Various computational parameters like bond length, bond angles, HOMO, LUMO, MESP, Mulliken charges, and global descriptors are obtained and discussed. The UV-Vis study the in gas phase and DMSO solvent was investigated to obtain various insights such as absorption energies oscillator strength, configurations and transitions of examined thiazole derivatives. The effect of polar solvent has augmented the absorption wavelength of all studied thiazole derivatives. The experimental and simulated UV-Vis data correlate with each other prompting the effectiveness of the computed method. The scaled and experimental wavenumbers provided the appropriate assignment of various vibrational signals. The antibacterial study was performed against E. coli, P. aeruginosa, and S. aureus which demonstrated the strong antibacterial potential against S. aureus. The antifungal study against C. albicans revealed that these compounds are poor antifungal agents. The DPPH and OH radical assays were used to establish the % radical scavenger effects and results showed that these derivatives are good antioxidant agents. The % hemolytic activity of the tested compounds showed that all compounds fall within the acceptable toxicity limit. Importantly in slico ADME and toxicity prediction studies of these compounds highlighted good ADME profile with no hepatotoxicity, immunotoxicity and cytotoxicity.

Alkaloid diversity expansion of a talent fungus Penicillium raistrichii through OSMAC-based cultivation.

Alkaloidal natural products are attractive for their broad spectrum of pharmaceutical bioactivities. In the present work, the highly productive saline soil derived fungus, Penicillium raistrichii, was subjected to the strategy of OSMAC (one strain many compounds) with changes of cultivation status. Then, the work-flow led to the expansion of the alkaloid chemical diversity and subsequently induced the accumulation of four undescribed alkaloids, named raistrimides A-D (1-4), including three β-carbolines (1-3), one 2-quinolinone (4), and one new natural product, 2-quinolinone (5), along with five known alkaloid chemicals (6-10). A set of NMR techniques including 1H, 13C, HSQC and HMBC, along with other spectroscopic data of UV-Vis, IR and HRESIMS, were introduced to assign the plain structures of compounds 1-10. The absolute configuration of 1-3 were elucidated by means of X-ray crystallography or spectroscopic analyses on optical rotation values and experimental electronic circular dichroism (ECD) data. In addition, it was the first report on the confirmation of structures of 6, 7 and 9 by X-ray crystallography data. The micro-broth dilution method was applied to evaluate antimicrobial effect of all compounds towards Staphylococcus aureus, Escherichia coli, and Candida albicans. The results indicated compounds 1, 3 and 4 to be bioactive, which may be potential for further development of anti-antimicrobial agents. The finding in this work implied that OSMAC strategy was a powerful and effective tool for promotion of new chemical entities from P. raistrichii.

Entropy-driven charge-transfer complexation yields thermally activated delayed fluorescence and highly efficient OLEDs.

Exciplex-forming systems that display thermally activated delayed fluorescence are widely used for fabricating organic light-emitting diodes. However, their further development can be hindered through a lack of structural and thermodynamic characterization. Here we report the generation of inclusion complexes between a cage-like, macrocyclic, electron-accepting host (A) and various N-methyl-indolocarbazole-based electron-donating guests (D), which exhibit exciplex-like thermally activated delayed fluorescence via a through-space electron-transfer process. The D/A cocrystals are fully resolved by X-ray analyses, and UV-visible titration data show their formation to be an endothermic and entropy-driven process. Moreover, their emission can be fine-tuned through the molecular orbitals of the donor. Organic light-emitting diodes were fabricated using one of the D/A systems, and the maximum external quantum efficiency measured was 15.2%. An external quantum efficiency of 10.3% was maintained under a luminance of 1,000 cd m-2. The results show the potential of adopting inclusion complexation to better understand the relationships between the structure, formation thermodynamics and properties of exciplexes.

Preparation and Characterization of Aceclofenac Complexes of First Row Transition Metals Mn(II), Co((II), Ni(II), Cu(II), and Zn(II)

A number of complex compounds of aceclofenac with different first-row transition metal ions like Co(II), Mn(II), Ni(II), Cu(II), and Zn (II) were synthesized in an aqueous medium and characterized on the basis of their UV-Visible, FTIR spectra, elemental (C, H, N) analyses, and metal estimation data. Thermogravimetric analysis (TGA) was also done. Conductivity measurement and magnetic susceptibility measurement were also done to have information about the electrolytic behavior of the compounds and oxidation states of the central metal atoms respectively.
 Dhaka Univ. J. Sci. 71(2): 153-159, 2023 (July)

Poly(bis(2,2′-bipyridine) hydroxy Copper(II) iodide modified glassy carbon electrode for electrochemical determination of chloroquine in pharmaceuticals and biological samples

A new electrochemical sensor, poly(bis(2,2′-bipyridine)hydroxycopper(II) iodide modified glassy carbon electrode (poly([Cu(Bip)2OH]I)/GCE), was prepared by electropolymerization of bis(2,2′-bipyridine)chlorocopper(II) iodide ([Cu(Bip)2Cl]I) on glassy carbon electrode (GCE) for voltammetric determination of chloroquine (CQ). The synthesized complex (bis(2,2′-bipyridine)chlorocopper(II) iodide) was characterized using UV–Vis, CHN elemental analysis, atomic absorption spectroscopy (AAS), electrolytic conductivity, melting point and Fourier transform infrared spectroscopy (FT-IR) were used to characterize and confirm the synthesis of the desired complex (bis(2,2′-bipyridine)chlorocopper(II) iodide). The Uv-Vis, FTIR and electrochemical data of the synthesized polymer supports the replacement of chloro ligand by hydroxyl ligand during electropolymerization of the monomer in aqueous solution. The fabricated electrode (poly([Cu(Bip)2OH]I)/GCE) was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The voltammetric behavior of CQ was examined using CV and square wave voltammetry (SWV). Compared to the bare GCE, poly(Bip)/GCE, and Cu/GCE, the current signal of CQ was significantly enhanced at poly([Cu(Bip)2OH]I)/GCE, which demonstrates excellent electrocatalytic behavior of poly([Cu(Bip)2OH]I)/GCE towards electrochemical oxidation of CQ. Under the optimum experimental conditions, the SWV current signal of poly([Cu(Bip)2OH]I)/GCE offered linearity on the concentration range of CQ between 0.5 and 250 μM with LOD and LOQ values of 4.22 ×10−2 and 1.4 × 10−1 μM, respectively. In the presence of possible interfering substances including glucose, paracetamol, adenine and guanine, the voltammetric determination of CQ was also considered, and their interventions were found to be insignificant, which evidenced the selectivity of the introduced electrode. The analytical application of the established sensor was successfully applied in the determination of CQ in pharmaceuticals, milk, serum, and urine samples. The detected amount of CQ in the tablet samples was in the range between 100.5 and 110.2% with RSD of 1.5 and 1.87%, respectively. The spiked recovery results in pharmaceuticals, milk, serum, and urine biological samples were in the range of 100.5 to 110.2%, 97.13 to 98.12, 103.7 to 103.6% and 95.50 to 97.05%, respectively. These results confirm that the developed method exhibits high applicability for electrochemical determination of CQ in various real samples.

Oxidation of Polycyclic Aromatic Hydrocarbons with Mono-Oxygen Donors Catalysed by Triaryl-Manganese(III) Corroles

Abstract: The oxidation of polycyclic aromatic hydrocarbons (PAH) with mono-oxygen donors such as iodosylbenzene, hydrogen peroxide and tert-butyl hydroperoxide in the presence of selected 5,10,15-triarylmanganese( III) corroles as catalysts were examined under different reaction conditions. The effect of reaction conditions on triaryl-manganese(III) corroles catalysts and oxidants is discussed. It was observed that in a solvent system consisting of a mixture of dichloromethane and acetonitrile, the oxidation of anthracene with tertbutyl hydroperoxide catalysed by tri(aryl)manganese(III)corroles worked better than with hydrogen peroxide or iodosylbenzene as the oxidants. The oxidation of anthracene with hydroxo-manganese(IV)corroles was also examined in organic solvents under mild conditions. UV-Vis and other spectroscopic data were used to determine the oxidative mechanism for the oxidation of anthracene and other polycyclic aromatic hydrocarbons with mono-oxygen donors catalysed by triaryl-manganese(III)corroles.

Investigation of the effect of dye sensitized solar cell efficiency of donor and anchor groups in phthalocyanine compounds

In order to obtain higher power conversion performance in dye-sensitized solar cells, phthalocyanine compounds (ZnPc-1 and ZnPc-2) containing electron donor methoxy groups and aldehyde groups as anchors were synthesized in this study. The photovoltaic and electrochemical properties of these compounds were studied and their applicability as photosensitizers in DSSCs was investigated. The photovoltaic cell efficiencies (PCE) of the devices were in the range of 0.43–0.76 % under simulated AM 1.5 solar irradiation of 100 mW/cm2. Considering the photovoltaic performance of the produced DSSC devices, the anchor group and the chelate effect, it was observed that the efficiency increased, respectively, ZnPc-1 < ZnPc-2. The highest PCE value of 0.76 % was obtained with asymmetric ZnPc-2 based DSSC under. It has been explained that methoxy groups are electron donors and contribute to intramolecular electron mobility and that better electron transfer with single aldehyde anchor increases cell efficiency. In addition, the increase in the number of methoxy groups with known donor properties on the molecule also contributed to the increase in cell efficiency by increasing electron transfer. All compounds synthesized were characterized using FTIR, UV-vis and MS spectroscopic data.

A selective NH3 gas sensor based on (Ag2O)1-x(SnO2)x nanocomposites thin films at various operating temperatures

تم استخدام تقنية ترسيب الليزر النبضي (PLD) للتحضير الأغشية الرقيقة (Ag2O)1-x(SnO2)x النانوية المركبة بنسب مختلفة من x=(0, 0.2,0.4) من النسب الوزنية المرسبة على قواعد زجاجية. تم تلدين الأفلام بعد ذلك في الهواء لمدة ساعتين عند 300 درجة مئوية. تم تأكيد تشكيل المركب (Ag2O)1-x(SnO2)x من خلال تحقيق حيود الأشعة السينية(XRD). وفقًا للفحص المجهري الإلكتروني الماسح (FESEM) ، كانت جزيئات (Ag2O)1-x(SnO2)x التي تم إنشاؤها كروية الشكل. تم أستخدم تحليل مطياف تشتت الاشعة السينية (EDX) لتأكيد العناصر الموجودة في الأفلام المركبة.اظهر تحليل القوة الذرية المجهري (AFM) أن الأفلام الناتجة لها حجم حبيبي بين 37.68 -49.57 نانومتر وخشونة متوسط الجذر التربيعي (RMS ) من 4.92 إلى 8.22 نانومتر. تحتوي الأفلام المحضرة على فجوة طاقة مباشرة بين 2.06 و 3.36 الكترون فولت ، وفقاً لبيانات لبيانات المطياف المرئي للأشعة فوق البنفسجية (UV-Vis) . تم اختبار الأفلام لاستشعار NH3 تحت درجات حرارة تشغيل مختلفة. الاختلافات الملحوظة في مقاومة الغشاء الرقيق لاستجابة استشعار الغاز تدل على الموصلية من النوع n او النوع p عند الغازالمختزل ، تزداد مقاومة أفلام (Ag2O)1-x(SnO2)x عندما تكون x=0, 0.2wt ، مما يشير إلى أن الأفلام من النوع p ، ومع ذلك ، فإن الفيلم الرقيق يعرض السلوك العكسي عندما x = 0.4wt ، مما يشير إلى أنه من النوع n بالإضافة إلى ذلك ، أظهرت جميع الأفلام التي تم إنتاجها حساسية لغاز NH3 بتركيز 95 جزء في المليون. يمتلك الغشاء الرقيق Ag2O حساسية بنسبة 50.5٪ عند درجة حرارة تشغيل 200 درجة مئوية مع أوقات استجابة واسترداد تبلغ 22.5 و 39.6 ثانية على التوالي.علاوة على ذلك أظهرت الأغشية الرقيقة المركبة حساسية أكبرمن الأغشية الرقيقة المصنوعة من أوكسيد الفضة النقي.

Enhancing Structural, Optical, and Thermal Properties of PVA/PEO by Incorporating CrBr2

Films of the PVA/PEO polymer blend incorporated by CrBr2 were prepared using the casting method. Several characterization tools were used to study the PVA/PEO CrBr2 samples. Adding CrBr2 to the PVA/PEO significantly affects the structure, optical and thermal behaviour of the samples. The X-ray diffraction peaks suggest that the pure PEO/PVA blend is semi-crystalline. Still, the presence of CrBr2 reduces the intensity of these peaks, indicating interactions between the polymer blend and filler. The appearance of the main peaks of CrBr2 confirms that the complexation between the PVA/PEO and CrBr2 leads to decreased crystallinity and increased amorphous phase. The UV-Visible data indicate that adding CrBr2 reduces the energy band gap transitions due to the presence of defects and increasing disorder in the samples, creating localized energy states that can lead to energy level overlaps and a reduction of the energy gap. The DSC thermograms show that adding CrBr2 results in higher glass transition and melting temperatures, indicating improved thermal properties and enhanced thermal stability due to intermolecular interactions between CrBr2 and the PVA/PEO blend. The Coats-Redfern method was used to estimate ΔS*, ΔH*, and ΔG* in TGA measurements. These thermal parameters suggest that the presence of CrBr2 affects the thermal degradation mechanism. The values of ΔS*, ΔH*, and ΔG* decrease irregularly with increasing CrBr2, indicating that adding CrBr2 alters the thermal degradation mechanism of the PVA/PEO blend. The dielectric constant and the dielectric loss of the samples decrease with frequency No relaxation peaks observed in the dielectric curves indicate non-Debye behavior.

Exploring promising photovoltaic properties of dithiophene-based non-fullerene chromophores for efficient organic solar cells: A DFT approach

Currently, non-fullerene-based acceptors in organic solar cells (OSCs) have gained significant attention of researchers owing to their particular characteristics. Herein, new W-shaped dithiophene based acceptor chromophores (D1-D8) possessing A-π-D-π-A configuration were fabricated via end group structural tailoring by utilizing promising acceptors groups. To probe the effect of end group manipulation on the optoelectronic properties of entitled chromophores, density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were accommodated at B3LYP/6–311 G(d,p) functional. Frontier molecular orbitals (FMOs) findings revealed that the derivatives (D1-D8) exhibited narrow band gap (1.191–2.110 eV) than that of reference chromophore (R=2.380 eV) due to efficient acceptor moieties. UV–Vis data collected in chloroform solvent revealed that λmax values of D1-D8 were existed in visible region (738.6–692.5 nm). Moreover, D2 and D4 proves to be the best chromophores exhibiting least band gap of 1.191 and 2.000 eV and broad absorption spectrum i.e., 738.573 and 735.986 nm, respectively. Among all the designed compounds, D2, D3, D4 and D6 manifested higher open circuit voltage values. Theoretical analysis disclosed that all the designed molecules exhibited almost comparable results with each other. Nevertheless, D2 and D4 provided significant findings and can be utilized as best candidate for use in optoelectronic devices.

Interaction between the transferrin protein and plutonium (and thorium), what's new?

Transferrin (Tf) is a glycoprotein that transports iron from the serum to the various organs. Several studies have highlighted that Tf can interact withmetals other thanFe(III), including actinides that are chemical and radiological toxics.We propose here to report on the behavior of Th(IV) and Pu(IV) in comparison with Fe(III) upon Tf complexation. We considered UV-Vis and IR data of the M2Tf complex (M = Fe, Th, Pu) and combined experimental EXAFS data with MD models. EXAFS data of the first M-O coordination sphere are consistent with the MD model considering 1 synergistic carbonate. Further EXAFS data analysis strongly suggests that contamination by Th/Pu colloids seems to occur upon Tf complexation, but it seems limited. SAXS data have also been recorded for all complexes and also after the addition of DFOB in the medium. The Rg values are very close for apoTf, ThTf and PuTf, but slightly larger than for holoTf. Data suggest that the structure of the protein is more ellipsoidal than spherical, with a flattened oblate form. From this data, the following order of conformation size might be considered : holoTf < M2Tf (M = Th, Pu) < apoTf < M2Tf-DFOB (M = Fe, Th, Pu).

Magneto-Optical Properties of Ni0.4Cu0.3Zn0.3Gd0.125Fe1.875O4 Nano Ferrite for Application of Soft Magnetic Material

Abstract: Ni0.4Cu0.3Zn0.3Gd0.125Fe1.875O4 spinel ferrite powder is successfully synthesized using sol-gel auto combustion technique. The structural, optical and magnetic properties investigated by using X-ray Diffractometer, FTIR Spectrometer, Scanning Electron Microscope and Vibrating Sample Magnetometer (VSM). XRD analysis confirmed that formation of Nano crystalline cubic spinel structure of the sample. The crystallite size of synthesized nanoparticles is about 29.45nm. The IR study support the confirmation spinel structure of Ni0.4Cu0.3Zn0.3Gd0.125Fe1.875O4 sample. Band gap energy Eg obtained using UV-Visible absorption data is about 2.4238 eV. The magnetic properties have been studied from VSM data shows that

Kinetics of Flavonoid Degradation and Controlled Release from Functionalized Magnetic Nanoparticles.

Flavonoids are naturally occurring antioxidants that have been shown to protect cell membranes from oxidative stress and have a potential use in photodynamic cancer treatment. However, they degrade at physiological pH values, which is often neglected in drug release studies. Kinetic study of flavonoid oxidation can help to understand the mechanism of degradation and to correctly analyze flavonoid release data. Additionally, the incorporation of flavonoids into magnetic nanocarriers can be utilized to mitigate degradation and overcome their low solubility, while the release can be controlled using magnetic fields (MFs). An approach that combines alternating least squares (ALS) and multilinear regression to consider flavonoid autoxidation in release studies is presented. This approach can be used in general cases to account for the degradation of unstable drugs released from nanoparticles. The oxidation of quercetin, myricetin (MCE), and myricitrin (MCI) was studied in PBS buffer (pH = 7.4) using UV-vis spectrophotometry. ALS was used to determine the kinetic profiles and characteristic spectra, which were used to analyze UV-vis data of release from functionalized magnetic nanoparticles (MNPs). MNPs were selected for their unique magnetic properties, which can be exploited for both targeted drug delivery and control over the drug release. MNPs were prepared and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, superconducting quantum interference device magnetometer, and electrophoretic mobility measurements. Autoxidation of all three flavonoids follows a two-step first-order kinetic model. MCE showed the fastest degradation, while the oxidation of MCI was the slowest. The flavonoids were successfully loaded into the prepared MNPs, and the drug release was described by the first-order and Korsmeyer-Peppas models. External MFs were utilized to control the release mechanism and the cumulative mass of the flavonoids released.

Amphiphilic Fluorinated Unimer Micelles as Nanocarriers of Fluorescent Probes for Bioimaging.

The unique self-assembly properties of unimer micelles are exploited for the preparation of fluorescent nanocarriers embedding hydrophobic fluorophores. Unimer micelles are constituted by a (meth)acrylate copolymer with oligoethyleneglycol and perflurohexylethyl side chains (PEGMA90-co-FA10) in which the hydrophilic and hydrophobic comonomers are statistically distributed along the polymeric backbone. Thanks to hydrophobic interactions in water, the amphiphilic copolymer forms small nanoparticles (<10 nm), with tunable properties and functionality. An easy procedure for the encapsulation of a small hydrophobic molecule (C153 fluorophore) within unimer micelles is presented. UV-vis, fluorescence, and fluorescence anisotropy spectroscopic experimental data demonstrate that the fluorophore is effectively embedded in the nanocarriers. Moreover, the nanocarrier positively contributes to preserve the good emissive properties of the fluorophore in water. The efficacy of the dye-loaded nanocarrier as a fluorescent probe is tested in two-photon imaging of thick ex vivo porcine scleral tissue.

SYNTHESISAND ANTIMICROBIAL STUDIES OF SCHIFF BASE DERIVED FROM2-THENOYLTRIFLUOROACETONE AND 4-AMINOANTIPYRINEAND ITSCo(II), Fe(III), Ni(II) AND Cu(II) COMPLEXES

A new ligand, 3-[2-(1, 5-dimethyl-3-oxo-2-phenyl-2, 3-dihydro-1H-pyrazol-4-yl) hydrazinylidene]-2-thenoyltrifluoroacetone (HPDP) was prepared by diazotization of 4-aminoantipyrine and coupling of the obtained diazonium salt with 2-thenoyltrifluoroacetone. It’s Co(II), Fe(III), Cu(II), Ni(II) complexes were synthesized by refluxing the ligand(HPDP) with the metal chlorides in absolute ethanol for 6 hrs. Obtained compounds were characterized by means of melting point, conductivity, elemental analysis UV-Visible, FT-IR, 1H and 1 3C NMR.The molar conductivity values indicated that,[Fe(PDP)(H2O)Cl2], [Co(PDP)Cl2(OH2)], [Cu(HPDP)Cl2], [Ni(PDP)Cl2(OH2)] complexes were electrolytes when compared with CuSO4 and KCl salts respectively. The chloride analysis determination revealed the presence of chloride ions inside the coordination sphere of all the complexes. The Uv-Vis, IR, 1H and 13CNMR data of the complexes suggest square-planar geometry around Co (II), Cu (II), Ni (II) and octahedral geometry around Fe (III) ions. The ligand is tridentate and the complexes crystalized as M (HPDP). The ligand coordinated through the carbonyl oxygens and nitrogen atom of the azomethine –C=N group. The antimicrobial screening of the ligand and complexes with B.subtilis, E.coli, and P.mirabilis,S. aureus, S. intermediusS. typhi and S. pneumoniae showed more activities for the complexes than the ligand in comparison with standard drugs (Ampicillin and Ciprofloxacin), this implies that the synthesized compounds have potency for possible use as antbacterial agents against resistant strains.