β-Cyclodextrin derivatives hybrid Fe3O4 magnetic nanoparticles as the drug delivery for ketoprofen

β-Cyclodextrin (β-CD) and its derivatives carboxymethyl-β-CD (CM-β-CD) and 2,6-dimethyl-β-CD (DM-β-CD) modified magnetic nanoparticles (CD-MNPs) were synthesized via layer-by-layer method. CDs grafted onto Fe₃O₄ MNPs were demonstrated by transmission electron microscopy, Fourier transform infrared and Zeta potential. Magnetic properties of CM-β-CD-MNPs, DM-β-CD-MNPs and β-CD-MNPs were characterized by vibrating sample magnetometer and the magnetic saturation values were 47, 46 and 44 emu g^?1, respectively. CD-MNPs as drug carriers were investigated by inclusion behavior and in vitro release using ketoprofen (KP) as a model drug. The maximum adsorption quantities of CM-β-CD-MNPs, DM-β-CD-MNPs and β-CD-MNPs for KP were 37.03, 7.63 and 25.12 mg g^?1, respectively, and the loading behaviors followed the Langmuir adsorption isotherm model with monolayer adsorption. The release profiles of KP released from KP-loaded CD-MNPs were rapid in initial 60 min and then gradually tend to level off, the release efficiency order was CM-β-CD-MNPs > β-CD-MNPs > DM-β-CD-MNPs, which was consistent with the order of inclusion capability. Therefore, the CD-MNPs were promising candidates for drug delivery.     

A combined electrochemical and DFT study of the lattice strain effect on the surface reactivity of Pd

We report a combined study of electrochemical experiments and ab initio calculations on tuning the surface reactivity of Pd via a compressive lattice strain achieved by employing nanoparticles of Pd-Cu alloys with a Pd-rich surface.Surface oxygen-containing species were used as the probing molecule for revealing the surface reactivity.Both density functional theory (DFT) calculations and experiments showed linear relationships,with very close slopes,between the adsorption strength of OH_(ads) and the Pd lattice constant.Not only is this work a successful realization of controllable modulation in the surface reactivity,but it also provides valuable information for the rational design of Pd-based catalysts for fuel cell applications.     

Synergistic cocatalytic effect of MoO3 and creatinine on Cu–Fenton reactions for efficient decomposition of H2O2

The key scientific problems with conventional Fenton reactions are the acidic pH dependence and low ROS production due to inefficient decomposition of H₂O₂. Although Cu–Fenton reactions can break the pH limitation, there is still an urgent need to improve the overall reaction efficiency, and thus broaden its applicability. Herein, we describe a synergistic strategy by introducing MoO₃ cocatalyst and creatinine (Cr) assistant to enhance the efficiency of Cu–Fenton reactions at near-neutral pH. In this strategy, Cu²⁺ interacts with Cr to form a complex (CuCr₂), which is then mainly linked to MoO₃ via the Cu²⁺ binding site (CuCr₂/MoO₃). Experimental and theoretical calculation results manifest that the CuCr₂/MoO₃ exhibits an excellent cocatalytic activity, which significantly facilitates the rate-limiting step of Cu–Fenton reactions, and enables the efficient decomposition of H₂O₂ for the generation of three reactive oxygen species (ROS, ?OH, ¹O₂, ?O₂^?). More significantly, this cocatalytic system with high oxidation activity can be applied for the detection of Cu²⁺ and ROS-based chemodynamic therapy (CDT), as well as sterilization of Escherichia coli. This study represents a new breakthrough in improving the efficiency of Fenton-based reactions with a facile and promising strategy, and drives great progress in practicality.     

One-pot synthesis of 2H-indazolo[2,1-b]phthalazine-triones via nano γ-Al2O3/BF3/Fe3O4 as an efficient catalyst and theoretical DFT study on them

Experimental and computational studies were carried out for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones using γ-Al₂O₃/BF₃/Fe₃O₄ as a nanocatalyst in optimized and solvent-free conditions. The most significant features of the existing protocol are easy preparation of the catalyst, short reaction times, environmentally benign, and milder reaction conditions. The analysis data were reported using the experimental results of this investigation, such as: H-NMR, FT-IR (Fourier-transform infrared spectroscopy), X-ray diffraction, vibrating-sample magnetometer, Thermal gravimetric analysis (TG-DTG), nitrogen adsorption isotherm, Field Emission Scanning Electron Microscopy, and Transmission electron microscopy images of nanocatalyst. In this study, 2H-indazolo[2,1-b]phthalazine-triones have also been theoretically investigated using DFT-B3LYP/6-31G method. Also, some of the physical chemistry properties have examined for conformers of products, which there was good agreement between the computational results and obtained experimental for the products.     

Experimental investigation of the effect of an external magnetic field on the thermal conductivity and viscosity of Fe3O4–glycerol

Journal of Thermal Analysis and Calorimetry - Thermophysical properties, such as thermal conductivity and viscosity, of magnetic nanofluids (MNFs) can be enhanced by applying external magnetic...     

Per atom muon capture ratios and effects of molecular structure on muon capture by γ-Fe2O3 and Fe3O4

Journal of Radioanalytical and Nuclear Chemistry - An elemental analysis method utilizing muons has been demonstrated to be effective for non-destructive and quantitative analysis of precious bulk...     

Effect of Fe2O3 as an accelerator on the reaction mechanism of Al–TiO2 nanothermite system

Thermite reactions between aluminum and metal oxides could lead to the formation of intermetallic matrix composites used in high-temperature industrial applications. Thermite reaction in Al–TiO₂ system needs a considerable amount of energy to take place by mechanochemical or by the combustion synthesis (CS) method due to the low amount of reaction enthalpy in Al–TiO₂ system. In this study, Fe₂O₃ was chosen as a accelerator for this system, to generate a high amount of heat which could be released between Fe₂O₃ and Al, leading to a more convenient reaction between Al and TiO₂ in the CS process. The results of XRD, SEM, and DSC analyses indicated that both the mechanical activation of Al–TiO₂ system in a high-energy ball mill and the Fe₂O₃ addition led to considerable effects of reduction in the reaction temperature and increase in the reaction intensity in Al–TiO₂ nanothermite system. Finally, it was shown that Fe₃Al intermetallic compounds as well as γ-AlTi and alumina phases in the final products were formed after the CS of the milled powders.     

A combined experimental and model analysis on the effect of pH and O2(aq) on γ-radiolytically produced H2 and H2O2

The effects of pH and dissolved O₂ on the γ-radiolysis of water were studied at an absorbed dose rate of 2.5 Gy s⁻¹. Argon- or air-saturated water with no headspace was irradiated and the aqueous samples were analyzed for molecular radiolysis products (H₂ and H₂O₂) as a function of irradiation time. The experimental results were compared with computer simulation results using a comprehensive water-radiolysis kinetic model, consisting of the primary radiolysis production, subsequent reactions and related acid–base equilibria. Both the experimental and computer model results were discussed based on the steady-state kinetic analysis of smaller reaction sets consisting of key production and removal reactions. While the main production path for a water decomposition product is the primary radiolysis, the main removal path varies. For H₂O₂ the main removal path is the reactions with e_aq⁻ and OH, whereas for H₂ it is the reaction with OH. As a result, the presence of a dissolved species, or a change in chemical environment, affects the concentrations of H₂O₂ and H₂ through interaction with radicals e_aq⁻ and OH. Over a wide range of conditions, there exist quantitative but simple relationships between the radical and the molecular product concentrations. The experimental and model analyses show that dissolved oxygen increases the steady-state concentrations of H₂O₂ and H₂ by reacting with OH and e_aq^–, and the impact of oxygen is more noticeable at pH below 8. The steady-state concentrations of water decomposition products are nearly independent of pH in the range 5–8. However, raising pH above the pKa value of the acid–base equilibrium of H (⇆e_aq⁻+H⁺) significantly increases [H₂O₂] and [H₂] at the expenses of [OH] and [e_aq^–]. At pH >10, the radiolytical production of O₂ becomes significant, but at a finite rate. This considerably increases the time for the irradiated system to reach a steady state, and is responsible for different impacts on [H₂O₂] and [H₂] due to radically produced O₂, compared to impacts due to initially dissolved O₂. Model sensitivity analysis has shown that at higher pHs (pH >10) transient species such as O₂⁻ and O₃⁻ play a major role in determining the steady-state concentration of molecular products H₂ and H₂O₂. Further validation of the water radiolysis model, particularly at higher pHs, is also discussed.     

Effects of oxygen vacancy on the electrochemical properties of γ-V2O5 as cathode material for lithium-ion batteries: a first-principle study

Generating oxygen vacancies is an effective way to improve the lithium-ion storage performance of V₂O₅. However, the mechanism has not been theoretically investigated. In this study, first-principle calculations were performed to study the effect of oxygen vacancy on electrochemical properties of γ-V₂O₅ as cathode material for lithium-ion batteries. γ-V₂O₅ with oxygen vacancy mole fraction of 1.67% shows an open circuit voltage about 0.1 V lower than that of the perfect γ-V₂O₅. Oxygen vacancies generates gap states, which is beneficial to the electronic conductivity of γ-V₂O₅ and γ-LiV₂O₅. In addition, the activation energies for lithium-ion diffusion along [010] in both γ-V₂O₅ and γ-LiV₂O₅ are increased by oxygen vacancy, which might lead to the decrease of diffusion coefficient. Our results will provide guidance for further improving the lithium-ion storage performance of γ-V₂O₅.

     

Thermal decomposition study of HAuCl4·3H2O and AgNO3 as precursors for plasmonic metal nanoparticles

Thermal decomposition of HAuCl₄·3H₂O and AgNO₃, as precursors for Au and Ag nanoparticles, respectively, was monitored by coupled TG–DTA with TG/EGA–FTIR and EGA–MS techniques in a flowing 80 %Ar + 20 %O₂ and Ar atmospheres in the temperature range of 30–600 °C. The intermediate and final products of thermal decomposition were analysed by ex situ XRD and FTIR techniques. The thermal degradation of HAuCl₄·3H₂O starts immediately after melting at 75 °C and takes place in three steps in the temperature range of 75–320 °C with total mass loss of 49.4 and 49.7 % in artificial air and Ar atmospheres, respectively. EGA by MS and FTIR revealed a simultaneous release of H₂O and HCl in the temperature range of 75–235 °C. EGA by MS revealed a release of Cl₂ at around 225 °C and in the interval of 250–320 °C. According to the XRD analysis, the main solid product in the end of the first decomposition step at 190 °C is AuCl₃; in the end of the second decomposition step at 240 °C is AuCl and the final product at 320 °C is Au. The thermal decomposition of AgNO₃ takes place in a single step in the temperature range of 360–515 °C with a total mass loss of 39.0 and 37.8 % in flowing artificial air and Ar atmospheres, respectively. According to EGA–MS and EGA–FTIR the main evolved gases are NO₂, NO and O₂. The final product of the thermal decomposition at 600 °C is Ag irrespective of the atmosphere.     

Preparation of γ-Fe2O3/SiO2-capsule composites capable of using as drug delivery and magnetic targeting system from hydrophobic iron acetylacetonate and hydrophilic SiO2-capsule

Series of nanocomposites with γ-Fe₂O₃ supported on SiO₂-capsules were prepared by adsorption of hydrophobic iron acetylacetonate on the hydrophilic surface of SiO₂-capsules in the evaporation process of the solvent and then calcination the complex at 450 °C. The adsorption and calcination conditions were studied and the resultant nanaoparticles were characterized by XRD, XRF and TEM in detail. The results indicated that γ-Fe₂O₃ loaded discontinuously but uniformly on the surface of SiO₂-capsules at appropriate content. The specific surface area characterization and doxorubicin hydrochloride release shown although the surface area of the target composites decreased slightly, the nanoparticles still had large potential using as drug delivery and magnetic targeting system.     

Fe3O4 Nanoparticles as an Efficient and Magnetically Recoverable Catalyst for Friedel–Crafts Acylation Reaction in Solvent-Free Conditions

Application of Fe₃O₄ nanoparticles (NPs) as a robust, very efficient, and magnetically recoverable catalyst was investigated in Friedel–Crafts acylation (FCA) of ferrocene and aromatic compounds. This reaction was performed with acid chlorides in solvent-free conditions at room temperature. The catalyst was easily separated by an external magnetic field from the reaction mixture. The separated catalyst was recycled for several consecutive runs without appreciable loss of its catalytic activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Fe3O4 Nanoparticles as an Efficient and Magnetically Recoverable Catalyst for the Synthesis of α,β-Unsaturated Heterocyclic and Cyclic Ketones under Solvent-Free Conditions

An efficient and green procedure has been developed for the synthesis of monoarylidenes of cyclic and heterocyclic ketones. The reaction was carried out under solvent-free conditions in the presence of a catalytic amount of nanosized magnetite (Fe₃O₄). The catalyst was easily removed by using an external magnet. The structures of the products were deduced from their ¹H NMR, ¹³C NMR, and infrared spectroscopy and mass spectrometry.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resource(s): Full experimental and spectral details.]     

Combined use of β-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics—A study of the synergistic effect

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l -alanine tert butyl ester lactate (l -AlaC₄Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).     

In situ coarsening study of inverse micelle-prepared Pt nanoparticles supported on γ-Al2O3: pretreatment and environmental effects

The thermal stability of inverse micelle prepared Pt nanoparticles (NPs) supported on nanocrystalline γ-Al(2)O(3) was monitored in situ under different chemical environments (H(2), O(2), H(2)O) via extended X-ray absorption fine-structure spectroscopy (EXAFS) and ex situ via scanning transmission electron microscopy (STEM). Drastic differences in the stability of identically synthesized NP samples were observed upon exposure to two different pre-treatments. In particular, exposure to O(2) at 400 °C before high temperature annealing in H(2) (800 °C) was found to result in the stabilization of the inverse micelle prepared Pt NPs, reaching a maximum overall size after moderate coarsening of ～1 nm. Interestingly, when an analogous sample was pre-treated in H(2) at ～400 °C, a final size of ～5 nm was reached at 800 °C. The beneficial role of oxygen in the stabilization of small Pt NPs was also observed in situ during annealing treatments in O(2) at 450 °C for several hours. In particular, while NPs of 0.5 ± 0.1 nm initial average size did not display any significant sintering (0.6 ± 0.2 nm final size), an analogous thermal treatment in hydrogen leads to NP coarsening (1.2 ± 0.3 nm). The same sample pre-dosed and annealed in an atmosphere containing water only displayed moderate sintering (0.8 ± 0.3 nm). Our data suggest that PtO(x) species, possibly modifying the NP/support interface, play a role in the stabilization of small Pt NPs. Our study reveals the enhanced thermal stability of inverse micelle prepared Pt NPs and the importance of the sample pre-treatment and annealing environment in the minimization of undesired sintering processes affecting the catalytic performance of nanosized particles.     

L-Tyrosine-Pd complex supported on Fe3O4 magnetic nanoparticles: A new catalyst for C–C coupling and Synthesis of sulfides

In the present work, Fe₃O₄@L-Tyrosine-Pd heterogeneous nanocatalyst was prepared by a simple and inexpensive procedure. The prepared nanocatalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM), Transmission electron microscopy)TEM(, X-ray mapping, thermal gravimetric analysis (TGA), N₂ adsorption and desorption (BET) and vibrating sample magnetometer (VSM) techniques. Besides, it was employed as an efficent catalyst for C-C cross coupling and S-arylation reactions under green conditions. The optimized conditions for these reactions are described. The heterogeneous catalyst can be easily separated by applying a simple magnet and can also be reused in several consecutive runs without appreciable change in its catalytic activity.     

Decoration of β-CD-ZrO on Fe3O4 magnetic nanoparticles as a magnetically,recoverable and reusable catalyst for the synthesis of 2,3-dihydro-1H-perimidines

Research on Chemical Intermediates - This study focuses on covalent grafting of ZrO to β-CD to prepare an organic–inorganic hybrid material. The synthesised product was successfully...     

B2O3/Al2O3 as an Efficient and Recyclable Catalyst for the Synthesis of β-Amino Alcohols under Solvent-Free Conditions

A convenient and efficient procedure for the solvent-free synthesis of β-amino alcohols has been achieved via B₂O₃/Al₂O₃-promoted highly regioselective ring opening of epoxides with aromatic amines in good to excellent yields at room temperature. Additionally, the catalyst can be recycled without affecting the catalytic property.     

Investigation of controlled release properties and anticancer effect of folic acid conjugated magnetic core–shell nanoparticles as a dual responsive drug delivery system on A-549 and A-431 cancer cell lines

Research on Chemical Intermediates - Epirubicin loaded on magnetite-coated calcium ferrite conjugated folic acid (Fe3O4@CaFe2O4-FA@EPI) was synthesized and characterized using various techniques...