Magnetism of fcc/fcc, hcp/hcp twin and fcc/hcp twin-like boundaries in cobalt

The magnetic moments of the fcc/fcc, hcp/hcp twin and fcc/hcp twin-like boundaries in cobalt were investigated by first-principles calculations based on density functional theory. The magnetic moments in fcc/fcc were larger than those of the bulk fcc, while the variations in the magnetic moment were complicated in hcp/hcp and fcc/hcp. The magnetovolume effect on the magnetic moment at the twin(-like) boundaries was investigated in terms of the local average atomic distance and the average deviation from equilibrium; however, the complicated variations in the magnetic moment could not be explained from the magnetovolume effect. Next, the narrowing (or broadening) of the partial density of states (PDOS) width of 3d orbitals, the number of occupied states for the spin-down channel, and the PDOS around the Fermi level were investigated. The entire variation in the magnetic moment at the twin(-like) boundaries could be understood in terms of these factors. Charge transfer occurred in hcp/hcp. In this case, the contributions of 4s and 4p electrons to the variation in the magnetic moment were relatively large.     

Single-crystal-to-single-crystal photocyclization of 4-(2,4,6-triisopropylbenzoyl)benzoic acid in the salt crystal with (S)-phenylethylamine

Ultraviolet irradiation of a salt crystal of 4-(2,4,6-triisopropylbenzoyl)benzoic acid with (S)-phenylethylamine promoted single-crystal-to-single-crystal photocyclization to give an enantiopure (R,R)-cyclopentenol and almost racemic cyclobutenol. The reaction paths were elucidated by X-ray crystallographic analysis of the crystal before and after irradiation.     

Palladium-catalyzed amidation by chemoselective C(sp3)-H activation: concise route to oxindoles using a carbamoyl chloride precursor

Quite select: a new strategy was developed for the synthesis of various oxindoles from carbamoyl chlorides. Under the optimum reaction conditions, with Ad(2)PBu as a ligand, tBuCONHOH as an additive, and a CO atmosphere, selective C(sp(3))-H activation proceeded in the presence of a C(sp(2))-H bond. Ad=adamantyl.     

Shape- and size-controlled synthesis in hard templates: sophisticated chemical reduction for mesoporous monocrystalline platinum nanoparticles

Here we report a novel hard-templating strategy for the synthesis of mesoporous monocrystalline Pt nanoparticles (NPs) with uniform shapes and sizes. Mesoporous Pt NPs were successfully prepared through controlled chemical reduction using ascorbic acid by employing 3D bicontinuous mesoporous silica (KIT-6) and 2D mesoporous silica (SBA-15) as a hard template. The particle size could be controlled by changing the reduction time. Interestingly, the Pt replicas prepared from KIT-6 showed polyhedral morphology. The single crystallinity of the Pt fcc structure coherently extended over the whole particle.     

NO reduction by C3H6 over apatite-type A10(PO4)6(OH)2 (A?=?Ca and Sr)-supported Pt catalysts

A₁₀(PO₄)₆(OH)₂ (A = Ca and Sr)-supported Pt catalysts were prepared and their catalytic activity in NO reduction were investigated. The Sr₁₀(PO₄)₆(OH)₂-supported catalyst had high catalytic activity in the C₃H₆?CNO?CO₂ reaction; the activity was higher than that of the ??-Al₂O₃-supported catalyst at 300 °C. The basicity of the apatite supports would affect the chemical state of Pt on catalyst, resulting in promotion of NO reduction.     

Diethylhydrogensilyl cyclic diethylsilylene derivatives in gas chromatography/mass spectrometry of hydroxylated steroids. III-Fragmentations of 5β-pregnane-17,20,21-triol derivatives

A reaction of N,O-bis-(diethylhydrogensilyl) trifluoroacetamide with 5β-pregnane-17,20,21-triols afforded diethylhydrogensilyl (DEHS) cyclic diethylsilylene (DES) derivatives. 5β-Pregnane-3α,17α,20β,21-tetraol yielded the 3α,21-bis-DEHS-17α,20β-DES compound, whereas the structure of the major product from its 20α isomer was assigned as the 3α,17α-bis-DEHS-20α,21-DES derivative, which would undergo facile isomerization to the unstable 3α,21-bis-DEHS-17α,20α-DES structure under electron ionization. Fragmentations of these DEHS-DES compounds are discussed on the basis of isotope labelling experiments, linked scanning data, and accurate mass measurements.     

Microscopic Elucidation of Solid‐Electrolyte Interphase (SEI) Film Formation via Atomistic Reaction Simulations: Importance of Functional Groups of Electrolyte and Intact Additive Molecules

Secondary batteries such as Li‐ion battery are expected to be utilized as not only ubiquitous electric power sources such as mobile phones but also large‐scale electricity storage devices. Therefore, it is urgent to develop the higher performance secondary batteries. Their lifetime and stability are found to be strongly dependent on the nature of passivation film called solid electrolyte interphase (SEI) film formed on the anode surface in the initial charge‐discharge cycle. However, since it is difficult to directly observe the film formation processes in experiment, its microscopic mechanism is still not found. On the other hand, although the theoretical methods are useful complement to the experiment, some new methodologies are necessary to understand the long‐term processes of SEI film, which is produced as a result of that a lot of chemical reactions proceed simultaneously. Under the circumstances, we have developed Red Moon method that can simulate such complex chemical reaction systems, and were able to analyze for the first time the SEI film formation processes on the anode surface at the atomistic level. Then, we clarified theoretically the microscopic mechanism of the additive effect which is essential to improve the Na‐ion battery performance so as to enhance the SEI film formation. This new microscopic insight must provide an important guiding principle for use in designing the most suitable electrolytes for developing high‐performance secondary batteries.     

Coordination‐Induced Spin‐State Switching of an Aminyl‐Radical‐Bridged Nickel(II) Porphyrin Dimer between Doublet and Sextet States

A bis(Ni^II‐porphyrinyl)aminyl radical with meso‐C₆F₅ groups was prepared as a spin‐delocalized stable aminyl radical with a doublet spin state. Upon addition of pyridine, both Ni^II centers became hexacoordinated by accepting two axial pyridines, which triggered a spin‐state change of the Ni^II centers from diamagnetic (S=0) to paramagnetic (S=1). The resulting high‐spin Ni^II centers interact with the aminyl radical ferromagnetically to give rise to an overall sextet state (S=5/2). Importantly, this coordination‐induced spin‐state switching can be conducted in a reversible manner, in that washing of the high‐spin radical with aqueous hydrochloric acid regenerates the original doublet radical in good yield.