A Reusable Unsupported Rhenium Nanocrystalline Catalyst for Acceptorless Dehydrogenation of Alcohols through γ‐C–H Activation

Rhenium nanocrystalline particles (Re NPs), of 2 nm size, were prepared from NH₄ReO₄ under mild conditions in neat alcohol. The unsupported Re NPs convert secondary and benzylic alcohols to ketones and aldehydes, respectively, through catalytic acceptorless dehydrogenation (AD). The oxidant‐ and acceptor‐free neat dehydrogenation of alcohols to obtain dihydrogen gas is a green and atom‐economical process for making carbonyl compounds. Secondary aliphatic alcohols give quantitative conversion and yield. Transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), Re K‐edge X‐ray absorption near‐edge structure (XANES), and X‐ray absorption fine structure (EXAFS) data confirmed the characterization of the Re NPs as metallic rhenium with surface oxidation to rhenium(IV) oxide (ReO₂). Isotope labeling experiments revealed a novel γ‐CH activation mechanism for AD of alcohols.     

Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications

A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H₂Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO₄⁻) in the presence of triphenylphosphine led to oxidative decomposition of the H₂Pcs, giving their respective phthalonitriles. Conversely, treatment of H₂Pcs with ReO₄⁻ employing sodium metabisulfite yielded the desired Re^VO−Pc complex. Finally, reaction of H₂Pcs with ReO₄⁻ and NaBH₄ as reducing agent led to the formation of rhenium oxide (Re_xO_y) nanoparticles (NPs). The NP synthesis was optimised, and the Re_xO_y NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant Re_xO_y−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.     

Photoelectron spectroscopy (XPS) and thermogravimetry (TG) of pure and supported rhenium oxides 1. Pure rhenium compounds

To investigate the interaction of rhenium with several supports, a preliminary study on pure rhenium compounds has been carried out in order to achieve a better understanding of their surface chemical properties. To this end X-ray photoelectron spectroscopy (XPS) and thermogravimetry (TG) methods have been applied. The results show that metallic rhenium, ReO₂ and ReO₃ are covered with Re(VII). By heating in H₂, NH₄ReO₄ and rhenium oxides are reduced to metallic rhenium in different temperature ranges. In the case of Re₂O₇ a spillover effect has been found when platinum is present. For ReO₃ and ReO₂ a morphological model has been described on the basis of combined XPS, TG and surface area measurements. The binding energy values of the different rhenium oxidation states have been assessed and their variation with the oxidation number briefly discussed.     

Cu2SnSe3-Ag纳米复合物的合成及其热电性质研究

采用Schlenk line技术,通过一种简单的硒源热注射的方法合成了Cu_2SnSe_3(CTSe)纳米晶,同时采用胶体法得到了单分散性极好的、粒径为4nm左右的Ag纳米颗粒(Ag NPs),之后通过简单的滴加法向CTSe纳米晶基质中掺入了特定比例的Ag NPs,得到CTSe-Ag纳米复合物。通过X射线粉末衍射、透射电镜、高分辨透射电镜、红外光谱和热重分析等表征了样品的组成、结构和形貌。同时对合成样品的热电性质进行了研究,相关的测试结果表明,以CTSe为基体掺杂AgNPs的样品中,CTSe-1(mol)%Ag具有最佳的热电优值(ZT=0.23,655K),相较纯相CTSe(ZT=0.18,655K)提高了27%。     

Structural and optical properties of novel CdSe nanoparticles produced via a facile synthetic route: Studies on the effects of cadmium sources

We report on the successful synthesis of CdSe nanoparticles (NPs) via a facile aqueous approach. Investigation on the effects of various cadmium sources in the precursor solution on the CdSe NPs is discussed. The structural and morphological properties characterized by the X-ray diffraction (XRD) and scanning electron microscope (SEM) displayed good features of the as-prepared CdSe NPs. The XRD pattern displayed a pure zinc blende crystal structure for all samples, with the most crystalline sample observed for CdSe NPs prepared using anhydrous cadmium chloride. The estimated crystallite sizes were below 6 nm for all the CdSe NPs samples. Mixed shapes of spherical and nanorods of varying sizes were observed from the SEM images for the as-prepared NPs prepared using different cadmium sources. The optical studies conducted by photo-spectroscopy pointed out the CdSe NPs prepared using anhydrous cadmium chloride gave the best optical properties. The emission wavelengths were in the range 565 to 574 nm while the optical band gaps were in the range 2.94 to 3.23 eV for all the as-prepared CdSe NPs samples. All the samples, however, displayed quantum confinement effects giving room for further fabrication and engineering to suit specific applications in the biological field. The obtained results demonstrated that aqueous phase synthetic route employed in this study could be successfully adopted for production of high-quality CdSe NPs because of its facile and inexpensive nature.     

Growth phase diagram and X-ray excited luminescence properties of NaLuF4:Tb3+ nanoparticles

X-rays are energy sources exhibiting extended penetration depths, and they have attracted increasing attention in industry and for clinical application. With the rapid development of nanomaterials and X-ray excited luminescent nanoparticles (XLNPs), new modalities for bioimaging and cancer therapy have been developed, such as X-ray luminescent computed tomography (XLCT) and X-ray excited photodynamic therapy (X-PDT). To meet the requirements of biomedical applications, XLNPs must exhibit high luminescence intensities, appropriate size distributions (less than100 nm) and negligible cytotoxicity. Due to the optical properties associated with f-electrons, rear earth (RE) elements are highly suitable for creating XLNPs. NaREF₄ nanoparticles (NPs) have been shown to be suitable hosts with high luminescence intensities, controllable sizes, and biocompatibility for X-ray-based biomedical applications. Syntheses of NaLuF₄ NPs doped with rare earth elements for upconversion applications have been systematically studied. However, for X-ray excited applications, the doping levels of the NPs must be totally different, which greatly affects the morphologies and sizes of the NaLuF₄ NPs. Thus, in this paper, nucleation, phase transitions, morphologies and sizes, and luminescence properties of Tb³⁺-doped NaLuF₄ NPs were systematically studied. OA-capped NaLuF₄:Tb³⁺ NPs were synthesized via coprecipitation processes with different reaction temperatures and reaction times to study the nucleation mechanism systematically, and the morphologies, size distributions and crystal phases were characterized with TEM and XRD. The morphologies, size distributions and crystal phases of these NPs were seriously influenced by the reaction temperature and reaction time. At 295 ℃, the NP sizes increased with prolonged reaction time, and the crystalline phase was a mixture of cubic and hexagonal phases. At 300 ℃ and 310 ℃, the pure hexagonal phase was obtained after 20 min and 35 min reaction times, respectively. The luminescence strengths of these NPs were associated with the particle sizes, crystalline phases, and Tb³⁺ doping levels. Stronger luminescence was achieved with larger particle sizes and purer hexagonal crystal phases. In addition, the 15 % doping level for Tb³⁺ provided the maximum luminescence intensity. The present work provides insights into the mechanism of NaLuF₄:Tb³⁺ nanocrystal growth.     

Green synthesis and characterization of Fe doped ZnO nanoparticles and their interaction with bovine serum albumin

Herein we report an eco-friendly and cost efficient synthesis of Fe doped ZnO (TPFZO) nanoparticles using the extract of Thespesia polpulanea flowers as a stabilizing agent. The synthesized NPs have been characterized by XRD, FT-IR, UV-DRS, SEM, EDAX and TEM studies. The synthesized NPs were found to have the crystallite size in the range of 30–60 ​nm. The calculated band gap energies for ZO and TPFZO nanoparticles were 3.00 ​eV and 1.97 ​eV respectively. The size distribution of the ZO and TPFZO obtained from TEM were observed to be lying in the range 50–120 ​nm and 4–22 ​nm respectively. The interaction of TPFZO NPs with bovine serum albumin (BSA) has been studied using fluorescence and absorption titration methods. The results indicated that the nanoparticles quenched the BSA fluorescence at 340 ​nm via static quenching mode having a bimolecular quenching rate constant value of 6.21 ​× ​10¹³ Lmol⁻¹s⁻¹.     

Effect of Pluronic P103 Concentration on the Simple Synthesis of Ag and Au Nanoparticles and Their Application in Anatase-TiO2 Decoration for Its Use in Photocatalysis

Silver and gold nanoparticles were synthesized under environmentally-friendly reaction conditions by using a biodegradable copolymer and water as a solvent. The triblock copolymer Pluronic P103 was utilized as a stabilizing agent or soft template to produce Ag and Au nanoparticles (NPs) of different sizes. Moreover, in the synthesis of Au NPs, the polymer acted as a reducing agent, decreasing the number of reagents used and consequently the residues produced, hence, rendering the procedure less complicated. It was observed that as the concentration of the polymer increased, the size of the metallic NPs augmented as well. However, AgNPs and AuNPs prepared with 1 and 10 wt% Pluronic P103, respectively, showed a significant decrease in particle size due to the presence of polymeric soft templates. The hybrid materials (metal/polymer) were characterized by UV-Vis spectroscopy, DLS, and TEM. The pre-synthesized nanoparticles were employed to decorate anatase-TiO₂, and the composites were characterized by DRS, XRD, BET surface area measurements, the TEM technique with the EDS spectrum, and XPS spectroscopy to demonstrate NPs superficial incorporation. Finally, methylene blue was used as a probe molecule to evidence the effect of NPs decoration in its photocatalytic degradation. The results showed that the presence of the NPs positively affected methylene blue degradation, achieving 96% and 97% removal by utilizing TAg0.1 and TAu10, respectively, in comparison to bare anatase-TiO₂ (77%).     

Anticancer and antibacterial potential of Rhus punjabensis and CuO nanoparticles

Abstract

The present study reports ecofriendly synthesis of CuO nanoparticles (NPs) using an extract of Rhus punjabensis as a reducing agent. NPs structural and composition analysis are evaluated by X-rays diffraction (XRD), Fourier transform infrared, Energy dispersive spectroscopy, Scanning electron microscopy, Transmission electron microscopy, and Thermal analysis. The NPs have pure single phase monoclinic geometry with spherical structure and high stability toward heat and with average particle size of about 36.6 and 31.27?nm calculated by XRD and SEM, respectively. NPs are tested for antibacterial, protein kinase (PK) inhibition, SRB cytotoxic, and NF-κB activities. Antibacterial activity is observed against B. subtilis and E. coli. Significant PK and SRB cytotoxic activity is observed with some NF-κB inhibition. NPs IC₅₀ values against HL-60 and PC-3 prostate cancer cells are 1.82?±?1.22 and 19.25?±?1.55?μg/mL. The results encourage further studies for antibacterial and anticancer drug development of NPs using animal models.     

激光CVD法合成SiC-Si3N4复合纳米颗粒

用激光化学蒸汽沉积(CVD)法合成了SiC-Si₃N₄复合纳米颗粒,并用X射线衍射(XRD),透射电子显微镜(TEM)和电子自旋共振磁力计(ESR)分析了试料的晶体结构,颗粒形状以及悬空键的状况。合成的试料粒度分布集中,平均粒径为32nm,颗粒由直径为5～30nm的单晶或多晶组成。试料纯度高,颗粒为近似球形,十分适合于粉体的加工和烧结。另外试料有很高的热稳定性,在加热的过程中的变化首先是悬空键减少,然后是相分解和颗粒长大。     

A green chemical route for the synthesis of Mn3O4 nanoparticles

A novel environmental friendly, room temperature route using an ionic liquid 1-n-butyl-3-methylimidazolium hydroxide ([BMIM]OH) for the synthesis of Mn₃O₄ nanoparticles is presented. The product was characterized using Fourier transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. Phase purity was confirmed by XRD, and X-ray line profile fitting determined a crystallite size of 42 ± 11 nm. TEM analysis revealed various morphologies. EPR measurements have indicated the existence of long-range interactions, due to the wide range of particle sizes and morphologies observed.      

Sol-gel preparation and spectroscopic study of the pyrophanite MnTiO<Subscript>3</Subscript> nanoparticles

The nanosized xerogel of titanium dioxide (TiO₂) and manganese oxides (MnO₂, Mn₂O₃, Mn₃O₄) was prepared by the sol-gel method using manganese chloride (MnCl₂·4H₂O) and titanium isopropoxide (Ti(O-iPr)₄) as precursors in cetyltrimethylammonium bromide (CTAB)/ ethanol/H₂O/HCl micelle solutions, following the calcinations of the produced powders at difference temperatures. The nanostructure and phase composition of these nanoparticles were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The spectroscopic characterizations of these nanoparticles were also done with UV-Vis spectroscopy and laser Raman spectroscopy (LRS). XRD patterns show that the pyrophanite MnTiO₃ phase was formed at the calcinations temperature of 900°C. The TEM images show that the nanoparticles are almost spherical or slight ellipose and the sizes are 50 nm on average. The UV-Vis spectra show that the nanosized MnTiO₃ have significant absorption bands in the visible region. There are new absorption peaks of MnTiO₃ nanoparticles in LRS compared with the pure TiO₂ powder.     

Research article green synthesis of zirconium oxide nanoparticles (ZrO2NPs) using Helianthus annuus seed and their antimicrobial effects

Monoclinic Zirconia (ZrO₂NPs) nanoparticles were successfully prepared by non-toxic and low-cost production using green synthesis analysis from the methanolic extract of Helianthus annuus (sunflower) seeds as the reducing agent. Mechanism of the chemical reaction has shown the reduction and which confirmed the formation of nanoparticles via chemical bonding in the IR spectrum at 502-498 ​cm^-1 ZrO₂ nanoparticles were characterized as sharp peak at 275 ​nm in the UV-Vis spectrum with 3.7eV in photon energy bandgap, it confirms the monoclinic crystal structure, as well as x-ray diffractometry, reveals zirconia crystallite is 40.59 ​nm. The internal morphology of crystal structure is exhibited by Scanning Electron Microscopy (SEM), and Transmission Electron Microscope (TEM). The stability of nanoparticles is represented in terms of zeta potential (-9.32 ​mV) and particle size distribution (~331 ​nm). Biosynthesized ZrO₂NPs were indicated as superior antimicrobial activity for biomedical applications.     

Bi6Fe1.9Co0.1Ti3O18纳米片负载Au尺寸对其可见光光催化性能的影响

我们通过一种简单的化学方法制备了具有可见光催化性能的Bi₆Fe_1.9Co_0.1Ti₃O₁₈/Au（BFCTO/Au）纳米复合材料。结果表明,通过负载不同颗粒大小的Au纳米颗粒（~23 nm、~36 nm、~55 nm和~80 nm）,BFCTO的可见光光催化性能明显增强,其中负载粒径为~23 nm的Au纳米颗粒的BFCTO/Au-1样品的可见光光催化效率最高。     

Single-phase α-Cr2O3 nanoparticles’ green synthesis using Callistemon viminalis’ red flower extract

This contribution reports for the first time on the synthesis and the main physical properties of single-phase pure α-Cr₂O₃ nanoparticles synthesized by a facile, rapid and eco-friendly process using Callistemon viminalis flower's extract as an effective oxidizing/reducing agent. These crystalline nanoparticles exhibit a cubic-like platelet shape with sharp edges with an average particle diagonal size of ～92.2?nm. The room temperature physical properties of these pure highly crystalline Eskolaite α-Cr₂O₃ nanoparticles were carried out using complementary techniques such as high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), XRD, FTIR-ATR, Raman and XPS.     

Regulation of the PI3K/AKT/mTOR signaling pathway with synthesized bismuth oxide nanoparticles from Ginger (Zingiber officinale) extract: Mitigating the proliferation of colorectal cancer cells

In order to overcome the limitations of conventional therapeutic systems in the treatment of cancer, nanoparticles (NPs) have been rapidly produced and developed as a separate treatment method for control of cancer. Synthesis of nanoparticles using plant-based materials (green synthesis), due to the easy and cost-effective synthesis, production of non-toxic, sustainable and environmentally friendly products, can be considered the most appropriate method for preparation of NPs. In this study, after synthesis of Bi₂O₃ NPs using Ginger (Zingiber officinale) root (rhizome) extract, the synthesized NPs were characterized and their potential application as selective anticancer agents against HCT116 colorectal cancer cells was evaluated through regulation of PI3K/AKT/mTOR signaling pathway, whereas the human kidney (HK-2) cells were used as normal cells. FTIR analysis showed a band at 673 cm^?1 attributed to Bi-O vibration with a fingerprint region at 1291 cm^?1 demonstrating the attachment of the organic molecules to the synthesized Bi₂O₃ NPs. UV–visible study showed a λ_max of around 268 nm, whereas XRD analysis showed eight clear peaks, demonetizing the crystalline phase of synthesized Bi₂O₃ NPs. TEM analysis showed that spherical-shaped Bi₂O₃ NPs have a size range of 20–50 nm with a man size of around 35 nm. Finally, DLS analysis determined that Bi₂O₃ NPs have a hydrodynamic size of about 71.19 nm (PDI of 0.179) and a zeta potential value of ?44.39 mV, revealing the good colloidal stability of NPs. Cellular assays (MTT, LDH, flow cytometry, and RT-qPCR) showed that synthesized Bi₂O₃ NPs selectively induced anticancer effects against HCT116 colorectal cancer cells through membrane leakage, generation of ROS, induction of apoptosis via dysregulation of Bax, Bcl-2 and caspase-3 at mRNA level mediated via regulation of PI3K/AKT/mTOR signaling pathway. In conclusion, it may be suggested that the presence study could provide useful information for the potential anticancer effects mediated by synthesized Bi₂O₃ NPs in vitro, although further studies, including in vivo studies and clinical trials, are needed to support our findings.     

Synthesis and characterization of poly(3-thiophenyl acetic acid) (P3TAA)-BaFe12O19 nanocomposite

We have presented a method for the fabrication of poly(3-thiophenyl acetic acid) (P3TAA)-BaFe₁₂O₁₉ nanocomposites by the in situ polymerization of P3TAA in the presence of synthesized BaFe₁₂O₁₉ nanoparticles. The nanoparticles and the nanocomposite were analyzed by XRD, FTIR, TGA, TEM, VSM and conductivity techniques for structural and physicochemical characteristics. Crystallographic analysis revealed the phase as hexaferrite and X-ray line profile fitting yielded a crystallite size of 32 nm. The particles, observed by TEM, exhibit irregular shapes and sizes between 100 and 500 nm, revealing polycrystalline character when compared with the crystallite size from XRD. FTIR and TGA analysis results show that P3TAA is conjugated to the particle surface via a carboxylate group and that the composite has a polymer content of ∼10%. Magnetic hysteresis curves do not saturate at high fields, which is a characteristic feature of fine particle systems with grain sizes smaller than 1 μm. Conductivity measurements showed a semiconductor character of the nanocomposite.     

Sunlight Photocatalytic Performance of ZnO Nanoparticles Synthesized by Green Chemistry Using Different Botanical Extracts and Zinc Acetate as a Precursor

In this work, the assessment of Azadirachta indica, Tagetes erecta, Chrysanthemum morifolium, and Lentinula edodes extracts as catalysts for the green synthesis of zinc oxide nanoparticles (ZnO NPs) was performed. The photocatalytic properties of ZnO NPs were investigated by the photodegradation of methylene blue (MB) dye under sunlight irradiation. UV-visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Thermogravimetric (TGA), and Brunauer-Emmett-Teller analysis (BET) were used for the characterization of samples. The XRD results indicate that all synthesized nanoparticles have a hexagonal wurtzite crystalline structure, which was confirmed by TEM. Further, TEM analysis proved the formation of spherical and hemispherical nanoparticles of ZnO with a size in the range of 14–32 nm, which were found in aggregate shape; such a size was well below the size of the particles synthesized with no extract (~43 nm). ZnO NPs produced with Tagetes erecta and Lentinula edodes showed the best photocatalytic activity, matching with the maximum adsorbed MB molecules (45.41 and 58.73%, respectively). MB was completely degraded in 45 min using Tagetes erecta and 120 min using Lentinula edodes when subjected to solar irradiation.     

Biosynthesis of zinc oxide nanoparticles using Euphorbia milii leaf constituents: Characterization and improved photocatalytic degradation of methylene blue dye under natural sunlight

A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m²/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm³/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm^?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications.     

Microwave synthesis and phase transitions in nanoscale BiFeO<Subscript>3</Subscript>

Nanosized multiferroic BiFeO₃ powders were synthesized by a microwave combustion method. The average crystallite sizes of the samples stay at a same level with the ratio of fuel glycine 0.5 ≤ G/N ≤ 1.5 and it increases significantly with G/N = 2.0. An inhomogeneity of amorphous and microcrystallites is observed directly by HRTEM. A ferromagnetic hysteresis loop with a saturation magnetization (M _S) of ~0.09 μ _B /Fe has been observed at room temperature in the sample with a crystallite size of 53 nm, whereas other powders with much smaller crystallite size (~20 nm) will not saturate even at 20 kOe. These magnetic behaviors were ascribed to a combination of the magnetic enhancement effect of a decreased crystallite size and superparamagnetic mechanism.