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The development of base metal catalysts for industrially important reactions continues to be an important goal of catalysis research. Herein, the effects of pyrolysis temperature on the textural, structural, surface, magnetics properties and catalytic properties of silica-supported nickel nanoparticles (NiNPs) were thoroughly investigated. Mono-dispersed NiNPs encapsulated in graphitic shells were first successfully obtained and were characterized using a variety of methods such as BET surface area measurement, CO-pulse chemisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), and superconducting quantum interference device (SQUID) measurement. The findings showed that all catalysts’ properties were considerably altered with change in pyrolysis temperature. Hydrogenation of diphenylacetylene was then selected as the model reaction for the evaluation of the catalytic performance of the graphitic-shelled NiNPs. After testing, pyrolysis of a nickel at 800 °C (catalyst A) displayed tremendous activity and selectivity to produce >94% of stilbene with selectivities of 99% for the Z-isomer. Keywords: Ni catalyst, Pyrolysis temperature, Magnetic properties, Nanoparticles characterization, Catalytic properties

In this study, we report the synthesis of a new organic–inorganic molecular salt of the clinically used antifungal drug fluconazole, (H2Fluconazole).SnCl6.2H2O. By detailed investigation and analysis of its structural properties, we show that the structure represents a 0D structure built of alternating organic and inorganic zig-zag layers along the crystallographic c-axis and the primary supramolecular synthons in this salt are hydrogen bonding, F···π and halogen bonding interactions. Magnetic measurements reveal the co-existence of weak ferromagnetic behavior at low magnetic field and large diamagnetic contributions, indicating that the synthesized material behaves mainly as a diamagnetic material, with very low magnetic susceptibility and with a band gap energy of 3.6 eV, and the salt is suitable for semiconducting applications. Extensive theoretical study is performed to explain the acceptor donor reactivity of this compound and to predict the Cl-substitution effect by F, Br and I. The energy gap, frontier molecular orbitals (FMOs) and the different chemical reactivity descriptors were evaluated at a high theoretical level. Calculations show that Cl substitution by Br and I generates compounds with more important antioxidant ability and the intramolecular charge transfer linked to the inorganic anion.

In this report, the heating efficiencies of γ-Fe2O3 and hybrid γ-Fe2O3-TiO2 nanoparticles NPs under an alternating magnetic field (AMF) have been investigated to evaluate their feasible use in magnetic hyperthermia. The NPs were synthesized by a modified sol-gel method and characterized by different techniques. X-ray diffraction (XRD), Mössbauer spectroscopy and electron microscopy analyses confirmed the maghemite (γ-Fe2O3) phase, crystallinity, good uniformity and 10 nm core sizes of the as-synthesized composites. SQUID hysteresis loops showed a non-negligible coercive field and remanence suggesting the ferromagnetic behavior of the particles. Heating efficiency measurements showed that both samples display high heating potentials and reached magnetic hyperthermia (42 °C) in relatively short times with shorter time (~3 min) observed for γ-Fe2O3 compared to γ-Fe2O3-TiO2. The specific absorption rate (SAR) values calculated for γ-Fe2O3 (up to 90 W/g) are higher than that for γ-Fe2O3-TiO2 (~40 W/g), confirming better heating efficiency for γ-Fe2O3 NPs. The intrinsic loss power (ILP) values of 1.57 nHm2/kg and 0.64 nHm2/kg obtained for both nanocomposites are in the range reported for commercial ferrofluids (0.2–3.1 nHm2/kg). Finally, the heating mechanism responsible for NP heat dissipation is explained concluding that both Neel and Brownian relaxations are contributing to heat production. Overall, the obtained high heating efficiencies suggest that the fabricated nanocomposites hold a great potential to be utilized in a wide spectrum of applications, particularly in magnetic photothermal hyperthermia treatments.

Fe-doped In2O3 thin films are deposited on sapphire substrates using pulsed laser ablation. The effects of Fe concentration and oxygen partial pressure on the structure, magnetism and transport properties of (In1-xFex)2O3 films are studied systematically. A detailed analysis of the structural properties suggests the substitution of Fe dopant ions with mixture valences and rules out the presence of clusters and secondary phases as the source of ferromagnetism. Systematic investigations of transport properties for (In1-xFex)2O3 films with a wide range of carrier densities reveal that they occur in both metallic and insulating regimes. The insulating films exhibit variable range hopping at low temperatures and show temperature dependent ferromagnetism, which can be explained by bound magnetic polarons mechanism. For the metallic films, the carrier densities play a crucial role in their robust ferromagnetism and the resistivity and magnetization are independent of temperature; the carrier-mediated exchange mechanism has been suggested as responsible for magnetic ordering in these metallic films. Optical absorption and magneto-optic studies of (In1-xFex)2O3 films indicate further differences between metallic and semiconducting films and show significant magnetic circular dichroism below the In2O3 bandedge at room temperature, which also implies intrinsic ferromagnetism. [ABSTRACT FROM AUTHOR]