Phosphides with Zr2Fe12P7-type structure

Twenty-six ternary phosphides Ln₂T₁₂P₇ (Ln = lanthanoid, T = Fe, Co, Ni) were prepared for the first time by reaction of the elemental components in liquid tin or by reaction of the components in evacuated silica tubes. The analysis of their powder patterns indicates their isotypism with Zr₂Fe₁₂P₇. Their lattice constants are reported. Gd₂Ni₁₂As₇ also crystallizes with that structure.     

Intertwined Detection and Recognition Roles of Tetrazine in Synergistic Anion-π and H-bond Based Anion Receptor

The intrinsic properties of tetrazine as a π-anion receptor and as an on/off recognition probe merged with H-bond ability of an urea motif into a single architecture constitutes a new generation of well-defined anion receptors. Complexation properties directly benefit from the dual and synergistic contribution of tetrazine and urea. In this study, we report on the synthesis and assessment of binding properties to anions of diverse geometries. Association constants have been predicted by theoretical calculations and evaluated by multiple and complementary experimental techniques including electrospray-mass tandem spectroscopy, NMR, UV-visible, steady state fluorescence spectroscopies and time resolved fluorescence. These results provide the basis for a better understanding of both the complexation and the anion-dependent quenching mechanism.     

Electrochemical and photochemical approaches for the synthesis of the C28–C38 fragment of okadaic acid

Okadaic acid, a potent and selective inhibitor of Protein Phosphatases 1 and 2A (PP1 and PP2A), is widely used as a probe for various biochemical processes. We describe herein two innovative methods for the synthesis of the terminal C28–C38 fragment of the natural polyether. Suárez photochemical oxidative cyclization and electrochemical oxidation of malonates to their ketals equivalents have been successfully applied for the assembly of the key spiroketal core.     

Towards the total synthesis of Calyculin C: preparation of the C13-C25 spirocyclic core

A stereoselective synthesis of the C₁₃-C₂₅ of Calyculin C is described. Key steps involve the coupling of a terminal acetylene with a thiol ester and subsequent spirocyclisation using a double intramolecular hetero-Michael addition.     

Electrochemical approach to detect the presence of peroxynitrite in aerobic neutral solution

This work describes the conditions of use of bare gold electrode to detect electrochemically the presence of peroxynitrite ONOO^? in phosphate buffer solution at pH 7.1. As ONOO^? is extremely unstable in neutral solution, current–potential curve was reconstructed between ?0.5 and 0.7 V vs SCE by amperometry experiments at rotating disk electrode at different potentials. Comparison of this reconstructed curve with voltammograms of the common interfering species (dopamine, hydrogen peroxide, nitrite, ascorbic acid and glutamate) shows that the presence of ONOO^? can be selectively determined at ?0.1 V vs SCE. This detection occurs through the electrochemical reduction of peroxynitrous acid ONOOH, the conjugated acid of ONOO^?. Detection of ONOO^? produced in situ by the reaction of nitric oxide with superoxide was also achieved.     

Hydrothermal Synthesis of Mo-Based Oxide Catalysts and Selective Oxidation of Alkanes

Mo-V-M(=Al, Ga, Bi, Sb and Te)–O mixed oxide catalysts were synthesized hydrothermally for the first time, characterized structurally, and tested for ethane and propane oxidation after activation by various ways. These catalysts were black solids of rod-shaped (fiber like) crystals, which had a layer structure in the direction of fiber axis and a high dimensional arrangement of metal octahedra in the cross-section plane. These fresh crystalline materials became active for catalytic oxidation of alkanes after heat-treatment at 600 °C and subsequent grinding in order to increase exposed plane of the cross-section. The resulting catalysts were very active for an oxidative dehydrogenation of ethane with 80% of the ethylene selectivity in the reaction temperature range of 300 to 400 °C and also showed about 50% selectivity to acrylic acid in the propane oxidation. Multi-functional character which derived from the high dimensional structure of the catalysts and mechanism of the selective alkane oxidation were discussed.