Comparative XPS study between experimentally and naturally weathered pyrites

A comparative study has been carried out between experimentally and naturally weathered pyrites. Both were found to share similar species of weathering products and a similar weathering mechanism. The weathering products could be divided into sulphur-bearing or iron-bearing groups. The sulphur-bearing group was comprised of sulphate, sulphite, thiosulphate, elemental sulphur, polysulphide, and mono-sulphide. The iron-bearing group was comprised of goethite, hematite or magnetite, and iron sulphate. The weathering structural profile was also similar for both types of weathering, being composed of a surficial layer and a transitional layer. The surficial layer was made up of both the sulphur-bearing and the iron-bearing products, while the transitional layer was comprised of goethite, and hematite or magnetite. The inward migration of the weathering interface was stimulated by the diffusion of oxygen and moisture. The oxygen was considered to preferably squeeze the iron to form goethite, and the ferric ions of goethite to have acted as a bridge for electron transfer between the oxygen and bulk S₂²⁻ and Fe²⁺ of pyrite.     

Nondestructive rare earth element imaging of fish teeth from deep‐sea sediments

X‐ray fluorescence computed tomography is an emerging imaging modality that allows for the nondestructive reconstruction of the internal distribution of elements within a sample. The common use of X‐ray excitation energy (up to approximately 20 keV) has necessitated the use of l ‐shell fluorescence for heavy elements. In this study, based on high energy X‐ray at BL13W1 of the Shanghai Synchrotron Radiation Facility, we employed high‐energy excitation for tomographic imaging of the heavy metals (rare earth elements) in fish teeth from deep‐sea sediments on the micrometer scale using K‐shell X‐ray fluorescence. The virtual cross‐sectional distribution of La, Ce, Pm, Pr, Nd, and Sm were obtained, thereby providing a feasible approach for analyzing the enrichment mechanism of rare earth elements. Copyright © 2015 John Wiley & Sons, Ltd.     

One-Pot Synthesis and Fungicidal Activities of Derivatives of Imidazo [2,1-b]-1,3,4-thiadiazol-5(6H)-one

The isothiocyanates 2, obtained from aza-Wittig reactions of vinyliminophosphoranes 1 with CS ₂ , reacted with hydrazine to give 3-amino-2-thioxo-4-imidazolidinones 4. One-pot reactions of 4, aromatic isocyanates, Ph ₃ P, C ₂ Cl ₆ , and Et ₃ N generated imidazo[2,1-b]-1,3,4-thiadiazol-5(6H)-ones 7. Compound 7 exhibited good fungicidal activities, especially against Sclerotinia sclerotiorum de Bary and Botrytis Cinerea Pers.     

Synthesis of some novel 5-substituted benzamido-6-arylamino-pyrazolo[3,4-D]pyrimidin-4-one derivatives for herbicidal activity

Abstract

Sixteen novel 3-methylthio-5-substituted benzamido-6-arylamino-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one derivatives (4a–p) were successfully synthesized from iminophosphoranes, aryl isocyanate, and substituted benzoylhydrazine. The structures of the title compounds were elucidated by FT-IR, ¹H NMR, ¹³C NMR, and HRMS. Herbicidal activity of the compounds 4a–p against Brassica napus (rape), Echinochloa crusgalli (barnyard grass), Cucumis sativus (cucumber), and Triticum aestivum (wheat) were determined. The results showed that 5-(2-chlorobenzamido)-6-phenylamino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H)-one (4c) displayed remarkable inhibition activity against the stalk and root of rape with 100% inhibition rate at the dosages of 10?mg/L and 100?mg/L, and 5-(4-nitrobenzamido)-6-phenylamino-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4 (5H) -one (4d) exhibited excellent activity against the stalk and root of barnyard grass with 100% inhibition rate at the same dosages.