C/C composite anodes for long-life lithium-ion batteries

The research of anodic materials which could improve the performance and reduce the cost of graphite-based materials in lithium-ion batteries leads to a considerable effort for creating novel carbons. In this work, special attention has been paid to investigating the possibility of improving the electrochemical behavior of graphite anode by application of composite materials with carbon materials coming from agro-wastes. For that, different carbons coming from agro-wastes have been synthesized and characterized in order to study the effect of their properties on the electrochemical performance of C/C composites with graphite. It has been established that introduction of hard carbon obtained from olive stones into the active mass of anode based on graphite allows one to increase the reversible capacity up to 405 mAh g^?1 for the total mass of graphite/carbon content of electrode, and also to improve stability of characteristics during cycling. We suggested that such a binary carbon mixture (graphite and hard carbon) would be a better choice for development of the anode for lithium-ion battery.     

Intercalation of 1-Alkanol Binary Mixtures into the Layered Structure of Vanadyl Phosphate

Mixed intercalates VOPO4.C2H5 OH.C4 H9OH, VOPO4.C3H7 OH.C5H11OH, VOPO4.C3H7 OH.C6H13OH and VOPO4.C4H9 OH.C6H13OH have been prepared by reaction of polycrystalline vanadyl phosphate dihydrate with liquid mixtures of the 1-alkanols in a microwave field. The same mixed layer-type complexes were also obtained as intermediary products of exchange reactions consisting in substitution of one alkanol bound in the solid intercalate by another alkanol introduced in the form of vapour. The composition of products has been determined, and the basal spacing of all the mixed layer-type complexes prepared has been found by diffraction. A structural principle is suggested which governs the depositing of two kinds of 1-alkanol molecules (differing in the lengths of their aliphatic chains) while acting as guests in the layered structure of vanadyl phosphate.     

Understanding sulfone behavior in palladium-catalyzed domino reactions with aryl iodides

Unlike traditionally used acyclic 1,2-disubstituted alkenes, the reaction of alpha,beta-unsaturated phenyl sulfones with aryl iodides under Heck reaction conditions takes place mainly by means of a four-component domino process, involving one unit of the alkene and three units of the aryl iodide, affording substituted 9-phenylsulfonyl-9,10-dihydrophenanthrenes. We report here the results of a computational study on the mechanism of this domino arylation reaction. Based on these results we can explain why vinyl sulfones, unlike other electron-deficient alkenes such as enones, preferentially follow this domino pathway instead of the usual Heck pathway. The key step is a C-H activation process in which a five-membered palladacycle is formed. The greater ability of vinyl sulfones, relative to enones, to reach the transition state that leads to the formation of the initial palladacycle makes the difference.     

Doping of TiO2–GO and TiO2–rGO with Noble Metals: Synthesis,Characterization and Photocatalytic Performance for Azo Dye Discoloration

The nanocomposites of titania coupled with graphene oxide (GO) and reduced graphene oxide (rGO), respectively, were prepared by homogeneous hydrolysis with urea. Graphene was obtained by effect of high‐intensity cavitation field on natural graphite in the presence of strong aprotic solvents in pressurized ultrasonic reactor. The morphology of TiO₂–GO and TiO₂–rGO composites was assessed by scanning electron microscopy and atomic force microscopy. The nitrogen adsorption–desorption was used for determination of surface area (BET) and porosity. Raman and IR spectroscopy were used for qualitative analysis and diffuse reflectance spectroscopy was employed to estimate band‐gap energies. Further enhancement of the photocatalytic activity was attained by codoping of composites with noble metals—Au, Pd and Pt. The photocatalytic activity of TiO₂–GO and TiO₂–rGO were assessed by photocatalytic decomposition of Orange II dye in an aqueous slurry under UV and visible light irradiation. The photocatalytic activity of noble metals codoped samples was determined with decomposition of Reactive Black 5 azo dye.     

Every finite lattice can be embedded in a finite partition lattice

Conclusions There are many questions, which arise in connection with the theorem presented. In general, we would like to know more about the class of embeddings of a given lattice in the lattices of all equivalences over finite sets. Some of these problems are studied in [4]. In this paper, an embedding is called normal, if it preserves 0 and 1. Using regraphs, our result can be easily improved as follows: THEOREM.For every lattice L, there exists a positive integer n ₀,such that for every n≥n ₀,there is a normal embedding π: L→Eq(A), where |A|=n. Embedding satisfying special properties are shown in Lemma 3.2 and Basic Lemma 6.2. We hope that our method of regraph powers will produce other interesting results. There is also a question about the effectiveness of finding an embedding of a given lattice. In particular, the proof presented here cannot be directly used to solve the following. Problem. Can the dual of Eq(4) be embedded into Eq(2¹⁰⁰⁰)? Presented by G. Gr?tzer.     

Mechanistic Insight into the Facilitation of β‐Lactam Fragmentation through Metal Assistance

The mechanism of OsH₆(PiPr₃)₂‐mediated fragmentation of a 4‐(2 pyridyl)‐2‐azetidinone has been investigated by DFT calculations. The addition of the C4?H bond of the substrate to OsH₂(PiPr₃)₂ allows the active participation of an osmium lone pair in the B‐type β‐lactam fragmentation process. This new mechanism makes the N1?C4/C2?C3 fragmentation of the lactamic core thermally accessible through a stepwise process.     

Antimycobacterial 3-phenyl-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dithiones substituted on phenyl and benzoxazine moiety in position 6

A series of forty-five derivatives of 3-phenyl-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and forty-five derivatives of 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dithiones was synthesised. The compounds exhibited in-vitro activity against Mycobacterium tuberculosis, M. kansasii (two strains), and M. avium. The most active derivatives were more active than isonicotinhydrazide (INH). The quantitative relationships between the structure and antimycobacterial activity were calculated. The activity against M. tuberculosis increased with the lipophilicity of the substituents.     

The effect of solvent accessible surface on Hammett‐type dependencies of infinite dilution 29Si and 13C NMR shifts in ring substituted silylated phenols dissolved in chloroform and acetone

Infinite dilution ²⁹Si and ¹³C NMR chemical shifts were determined from concentration dependencies of the shifts in dilute chloroform and acetone solutions of para substituted O‐silylated phenols, 4‐R‐C₆H₄‐O‐SiR′₂R″ (R = Me, MeO, H, F, Cl, NMe₂, NH₂, and CF₃), where the silyl part included groups of different sizes: dimethylsilyl (R′ = Me, R″ = H), trimethylsilyl (R′ = R″ = Me), tert‐butyldimethylsilyl (R′ = Me, R″ = CMe₃), and tert‐butyldiphenylsilyl (R′ = C₆H₅, R″ = CMe₃). Dependencies of silicon and C‐1 carbon chemical shifts on Hammett substituent constants are discussed. It is shown that the substituent sensitivity of these chemical shifts is reduced by association with chloroform, the reduction being proportional to the solvent accessible surface of the oxygen atom in the Si‐O‐C link. Copyright © 2012 John Wiley & Sons, Ltd.