Introduction of antimony triiodide (SbI3) as a new and efficient catalyst for synthesis of polyfunctionalized piperidines

Research on Chemical Intermediates - In the present work, an efficient and convenient one-pot multi-component reaction is reported for the synthesis of highly diversified piperidines by tandem...     

Single-Step Synthesis of SiO<Subscript>2</Subscript>–TiO<Subscript>2</Subscript> Hydrophobic Core–Shell Nanocomposite by Hydrothermal Method

The objective of this work is the synthesis and characterization of an appropriate hydrophobic nanoparticle as a collector for flotation of hematit in Gol-E-Gohar Iron Mine Iran. In this investigation, SiO₂–TiO₂ nanocomposites have been successfully synthesized by hydrothermal process. The morphology, structure, and composition of the as-synthesized nanostructures have been investigated by scanning electron microscopy and transmission electron microscopy. The ability of SiO₂–TiO₂ nanocomposite to facilitate the froth flotation of pyrite was correlated to the hydrophobicity of the nanoparticles. Furthermore, the efficiency of the mineral flotation process was evaluated in terms of final recovery and grade of S in Gol-e Gohar Iron Ore Complex, Sirjan, Iran.     

Synthesis and reactivity of cyclopentadienyl iron complexes containing ferrocenyl selenolates

New homo-trimetallic complexes of general formula?1,1??-fc[SeFeCp(CO)₂]₂ (fc?=?Fe(??⁵-C₅H₄)₂) are accessible in high yield by the reaction of 1,1??-fc(SeLi)₂, which is generated from 1,1??-fc(SeSiMe₃)₂ and n-BuLi, with two equivalents of CpFe(CO)₂I. Photolytic CO-substitution reactions of the organoiron diselenolate with bis-phosphines at ?50?°C using 1:2 (metal/ligand) molar ratio afforded 1,1??-fc(SeFeCp(P^P)₂. All these complexes were characterized by physicochemical and spectroscopic methods.     

Ellipsometric configurations using a phase retarder and a rotating polarizer and analyzer at any speed ratio

In this paper,we propose an ellipsometer using a phase retarder and rotating polarizer and analyzer at a speed ratio 1:N.Different ellipsometric configurations are presented by assuming N = 1,2,and 3.Moreover,two values of the offset angle of the retarder are considered for each ellipsometric configuration.The Mueller formalism is employed to extract the Stokes parameters,from which the intensity received by the detector is obtained.The optical properties of c-Si are calculated using all configurations.A comparison between different configurations is carried out considering the effect of the noise on the results and the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients.It is found that the alignment of the phase retarder has a crucial impact on the results and the ellipsometric configuration with speed ratio 1:1 is preferred over the other configurations.     

Green and diasteroselective oxidative cyclization of bisnaphthols to spirans

Hydrogen peroxide/MoO₃, as an efficient and clean oxidizing system was used to afford diasteroselective oxidative cyclization of bisnaphthols to spirans in ethanol at 60 °C with high yields. Bisnaphthols were prepared by the reaction of a series of aldehydes and 2-naphthol in the presence of a catalytic amount of H₃[P(Mo₃O₁₀)₄].nH₂O (HPa) in refluxing dichloromethane.