Atomic scale insight into the decomposition of nanocrystalline zinc hydroxynitrate toward ZnO using Mn paramagnetic probes.

Layered zinc hydroxynitrate (ZHN), with the chemical formula Zn (OH) (NO)·2HO, exhibits a range of special properties such as anion-exchange and intercalation capacity, as well as biocompatibility, making it attractive for a large variety of applications in fields from nanotechnology to healthcare and agriculture. In this study nanocrystalline ZHN doped with 1,000 ppm Mn was prepared by two synthesis methods (coprecipitation and solid state reaction) using similar environment-friendly precursors. The complex morpho-structural [X-ray diffraction, scanning and transmission electron microscopy, textural analysis] and spectroscopic [Fourier transform infrared and electron paramagnetic resonance (EPR)] characterization of the two ZHN nanopowders showed similar crystalline structures with Mn ions localized in the nanocrystals volume, but with differences in their morphological and textural characteristics, as well as in the doping efficiency.

Synthesis and Characterization of Hematite-Based Nanocomposites as Promising Catalysts for Indigo Carmine Oxidation.

The hematite-based nanomaterials are involved in several catalytic organic and inorganic processes, including water decontamination from organic pollutants. In order to develop such species, a series of bimetallic hematite-based nanocomposites were obtained by some goethite composites-controlled calcination. Their composition consists of various phases such as α-FeOOH, α-FeO or γ-FeO combined with amorphous (MnO, CoO, NiO, ZnO) or crystalline (CuO) oxides of the second transition ion from the structure.

A new method for obtaining the magnetic shape anisotropy directly from electron tomography images.

A new methodology to obtain magnetic information on magnetic nanoparticle (MNP) systems via electron tomography techniques is reported in this work. The new methodology is implemented in an under-development software package called Magn3t, written in Python and C++. A novel image-filtering technique that reduces the highly undesired diffraction effects in the tomography tilt-series has been also developed in order to increase the reliability of the correlations between morphology and magnetism.

Soft synthesis and characterization of goethite-based nanocomposites as promising cyclooctene oxidation catalysts.

Goethite based nanocomposites with a different composition such as 6FeO(OH)·MnO(OH)·0.5HO (Mn-composite), FeO(OH)·M(OH)·yHO (Co-composite (M: Co, = 12, = 3), Ni-composite (M: Ni, = 7, = 2)) and FeO(OH)·MO·yHO (Cu-composite (M: Cu, = 5.5, = 3), Zn-composite (M: Zn, = 6, = 1.

Facile synthesis of low toxicity iron oxide/TiO nanocomposites with hyperthermic and photo-oxidation properties.

The present study aimed to assess the feasibility of developing low-cost multipurpose iron oxide/TiO nanocomposites (NCs) for use in combined antitumor therapies and water treatment applications. Larger size (≈ 100 nm) iron oxide nanoparticles (IONPs) formed magnetic core-TiO shell structures at high Fe/Ti ratios and solid dispersions of IONPs embedded in TiO matrices when the Fe/Ti ratio was low. When the size of the iron phase was comparable to the size of the crystallized TiO nanoparticles (≈ 10 nm), the obtained nanocomposites consisted of randomly mixed aggregates of TiO and IONPs.

Antiproliferative and antibacterial properties of biocompatible copper(II) complexes bearing chelating N,N-heterocycle ligands and potential mechanisms of action.

In an attempt to propose new applications for the biomedical field, complexes with mixed ligands {[Cu(bpy)(μOClO)]ClO}n (1) and [Cu(phen)(OH)](ClO) (2) (bpy: 2,2'-biyridine; phen and 1,10-phenantroline) were evaluated for their antibacterial and cytotoxicicity features and for the elucidation of some of the mechanisms involved. Complex (2) proved to be a very potent antibacterial agent, exhibing MIC and MBEC values 2 to 54 times lower than those obtained for complex (1) against both susceptible or resistant Gram-positive and Gram-negative strains, in planktonic or biofilm growth state. In exchange, complex (1) exhibited selective cytotoxicity against melanoma tumor cells (B16), proving a promising potential for developing novel anticancer drugs.

Influence of surfactant-tailored Mn-doped ZnO nanoparticles on ROS production and DNA damage induced in murine fibroblast cells.

The present study concerns the in vitro oxidative stress responses of non-malignant murine cells exposed to surfactant-tailored ZnO nanoparticles (NPs) with distinct morphologies and different levels of manganese doping. Two series of Mn-doped ZnO NPs were obtained by coprecipitation synthesis method, in the presence of either polyvinylpyrrolidone (PVP) or sodium hexametaphosphate (SHMTP). The samples were investigated by powder X-ray Diffraction, Transmission Electron Microscopy, Fourier-Transform Infrared and Electron Paramagnetic Resonance spectroscopic methods, and N adsorption-desorption analysis.

Electron paramagnetic resonance and microstructural insights into the thermal behavior of simonkolleite nanoplatelets.

The aim of this paper is the study of the thermal behavior of the simonkolleite Zn5(OH)8Cl2·H2O (ZHC) by electron paramagnetic resonance (EPR) spectroscopy, in particular. It is well known that during heating ZHC undergoes a complex transformation which involves several overlapping stages. However, with reference to the data reported on this subject, it can be concluded that there is still an ongoing debate regarding the intermediate stages of this process.

Tailoring the Dopant Distribution in ZnO:Mn Nanocrystals.

The synthesis of semiconductor nanocrystals with controlled doping is highly challenging, as often a significant part of the doping ions are found segregated at nanocrystals surface, even forming secondary phases, rather than incorporated in the core. We have investigated the dopant distribution dynamics under slight changes in the preparation procedure of nanocrystalline ZnO doped with manganese in low concentration by electron paramagnetic resonance spectroscopy, paying attention to the formation of transient secondary phases and their transformation into doped ZnO. The acidification of the starting solution in the co-precipitation synthesis from nitrate precursors lead to the decrease of the Mn ions concentration in the core of the ZnO nanocrystals and their accumulation in minority phases, until ~79% of the Mn ions were localized in a thin disordered shell of zinc hydroxynitrate (ZHN).

X-ray Crystal Structure, Geometric Isomerism, and Antimicrobial Activity of New Copper(II) Carboxylate Complexes with Imidazole Derivatives.

Five new copper(II) acrylate complexes (acr is the acrylate anion: C₃H₃O₂) with imidazole derivatives (2-methylimidazole/2-MeIm, 5-methylimidazole/5-MeIm, 2-ethylimidazole/2-EtIm) of type: -[Cu(2-RIm)₂(acr)₂]·xH₂O ((): R = ⁻CH₃, x = 2; (): R = ⁻CH₂⁻CH₃, x = 0), -[Cu(2-RIm)₂(acr)₂] ((): R = ⁻CH₃; (): R = ⁻CH₂⁻CH₃) and -[Cu(5-RIm)₂(acr)₂] ((): R = ⁻CH₃) have been prepared and characterized by elemental analysis, Fourier Transform Infrared spectrometry (FTIR), Electron Paramagnetic Resonance (EPR), electronic reflectance spectroscopy, scanning electron microscopy, and mass spectrometry. The single crystal X-ray diffraction study of complexes () and () reveals that the copper(II) ion is located on an inversion center and show elongated octahedral geometry completed by two coplanar bidentate acrylates and two unidentate imidazole derivatives displayed in positions. For complex () the single crystal X-ray diffraction shows that the copper(II) ion is in a distorted octahedral environment which can be easily confused with a trigonal prism completed by two bidentate acrylates and two unidentate imidazole derivatives displayed in positions.