Reinvestigation of the M(II) (M = Ni, Co)/tetrathiafulvalenetetracarboxylate system using high-throughput methods: isolation of a molecular complex and its single-crystal-to-single-crystal transformation to a two-dimensional coordination polymer

A high-throughput methodology combined with X-ray powder diffraction measurements was used to investigate the reactivity of the TetraThiaFulvalene TetraCarboxylic acid ((TTF-TC)H(4)) with divalent metals (M = Ni, Co) under various reaction conditions (stoichiometry, pH, temperature). Two new crystalline phases were identified and then studied by single crystal X-ray diffraction. Whereas the first one appears to be a simple salt, the second one, formulated {[M(H(2)O)(4)](2)(TTF-TC)}·4H(2)O, is built of 2:1 M:TTF-TC molecular complexes and labeled MIL-136(Ni, Co) (MIL stands for Materials Institute Lavoisier). The combination of thermogravimetric analysis and thermodiffraction studies reveals that MIL-136(Ni) exhibits a complex dehydration behavior. Indeed, a partial dehydration/rehydration process led to the single-crystal-to-single-crystal transformation of the molecular compound in a two-dimensional coordination polymer formulated {[Ni(2)(H(2)O)(5)(TTF-TC)]}·H(2)O (MIL-136'(Ni)). Magnetic and redox properties of MIL-136(Ni, Co) were investigated. Magnetic measurements indicate that all the magnetic coupling, intra- and intermolecular, are very weak; thus, the magnetic data of MIL-136(Ni, Co) have been interpreted in term of single-ion spin orbit coupling. Solid state cyclic voltammetry of MIL-136(Ni, Co) presents three reversible waves which were assigned to the redox activity of the TTF core and the metallic cations. In contrast to solids based on TTF linkers and alkaline ions, the MIL-136(Ni, Co) complexes do not act as excellent positive electrode materials for Li batteries, but present two reversible electron oxidation of the TTF core. These observations were tentatively related to the strength of the metal-carboxylate bond.     

A periodic DFT study of water and ammonia adsorption on anatase TiO2 (001) slab

Water and ammonia adsorption mechanisms on anatase TiO₂ (001) slab surface are investigated by means of periodic DFT approach. Molecular and dissociative adsorption energies for water are calculated to be ? 15 kcal/mol and ? 32 kcal/mol, respectively. Similarly, molecular and dissociative adsorption energies of ammonia on the same surface are found as ? 25 kcal/mol and ? 20 kcal/mol. A reverse result in this order is reached for the previous case of ONIOM cluster study (? 23 kcal/mol and ? 37 kcal/mol, respectively). The vibration frequency values are computed for the optimized geometries of adsorbed water and ammonia molecules on anatase TiO₂ (001) slab surface and compared with the values reported in the literature.     

Selective partial hydrogenation of hydroxy aromatic derivatives with palladium nanoparticles supported on hydrophilic carbon

Selective hydrogenation of phenol to cyclohexanol in the aqueous phase was achieved using a new catalytic system based on palladium particles supported on hydrophilic carbon prepared by one-pot hydrothermal carbonisation.     

TiO2 embedded hydrothermally synthesized carbon composite as interlayer for lithium-sulfur batteries

Journal of Solid State Electrochemistry - Lithium-sulfur battery chemistry is one of the best alternatives to meet the demand of future electric vehicles providing high theoretical capacity and...     

Synthesis and catalytic study of open metal site metal–organic frameworks of Cu3(BTC)2 microbelts in selective organic sulfide oxidation

The synthesis of open metal site metal–organic frameworks of Cu₃(BTC)₂ with microbelt morphology and a study of the catalytic oxidation of organic sulfides are reported. This CuBTC was found to be an efficient, selective and waste‐free green heterogeneous co‐catalyst for the green H₂O₂ catalytic oxidation of sulfides. The catalyst can be isolated from the reaction mixture and reused at least five times. Copyright © 2016 John Wiley & Sons, Ltd.     

Li–S batteries: effect of uniaxial compression on the electrical conductivity and electrochemical performance of graphene aerogel cathodes

Journal of Solid State Electrochemistry - Porous cathodes are preferred to be used in lithium-sulfur (Li–S) batteries for better impregnation of the active material. On the other hand, the...     

Space-time algebra for the generalization of gravitational field equations

The Maxwell–Proca-like field equations of gravitolectromagnetism are formulated using space-time algebra (STA). The gravitational wave equation with massive gravitons and gravitomagnetic monopoles has been derived in terms of this algebra. Using space-time algebra, the most generalized form of gravitoelectromagnetic Klein–Gordon equation has been obtained. Finally, the analogy in formulation between massive gravitational theory and electromagnetism has been discussed.     

An ONIOM and DFT study of water and ammonia adsorption on anatase TiO2 (001) cluster

Density functional theory (DFT) calculations at ONIOM DFT B3LYP/ 6‐31G**‐MD/UFF level are employed to study molecular and dissociative water and ammonia adsorption on anatase TiO₂ (001) surface represented by partially relaxed Ti₂₀O₃₅ ONIOM cluster. DFT calculations indicate that water molecule is dissociated on anatase TiO₂ (001) surface by a nonactivated process with an exothermic relative energy difference of 58.12 kcal/mol. Dissociation of ammonia molecule on the same surface is energetically more favorable than molecular adsorption of ammonia (?37.17 kcal/mol vs. ?23.28 kcal/mol). The vibration frequency values also are computed for the optimized geometries of adsorbed water and ammonia molecules on anatase TiO₂ (001) surface. The computed adsorption energy and vibration frequency values are comparable with the values reported in the literature. Finally, several thermodynamical properties (ΔH°, ΔS°, and ΔG°) are calculated for temperatures corresponding to the experimental studies. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011