REDUCTION OF BIS(BROMO(MESITYL)-{2,4,6-TRIS[BIS(TRIMETHYLSILYL)METHYL]- PHENYL}SILYL)BUTADIYNE WITH POTASSIUM GRAPHITE: UNEXPECTED FORMATION OF 2-ALLENYL-1-BENZOSILOLE

The reductive debromination of an very crowded bis(bromodiaryl- silyl)butadiyne 2 was performed with potassium graphite to give the corresponding 2-allenyl-1-benzosilole 3 was isolated as a main product.     

Some Alternating Double Binomial Sums

We consider some new alternating double binomial sums. By using the Lagrange inversion formula, we obtain explicit expressions of the desired results which are related to a third-order linear recursive sequence. Furthermore, their recursive relation and generating functions are obtained.     

Novel hybrids of Cu2+ ternary complexes of salicylidene-amino acid Schiff base with phenanthroline（or bipyridine） intercalated in Mg/Al-NO3-layered double hydroxide

Four Cu²⁺ complexes of salicylidene-amino acid Schiff base with 1,10-phenanthroline（Phen） or 2,2’- bipyridine（Bipy） were successfully intercalated in interlayer galleries of Mg/Al-NO₃-layered double hydroxide（LDH） by the swelling-restored method.The hybrids were characterized by elemental analysis,X-ray diffraction,FT-IR spectra,UV-vis DRS,TG-DTA and SEM observation.Good protection of the complexes by LDH in neutral and weak acidic solutions was revealed by UV spectra,cyclic voltammograms and luminescence spectra.     

Pretilt study of double‐layer alignment film (DLAF)

A novel double‐layer alignment film (DLAF) was developed to obtain greater control of the alignment characteristics of the liquid crystal director. The DLAF consists of a thin fluorinated polymer layer on the top of a rubbed non‐fluorinated, non‐branched polyimide layer (PI 2555). Two types of fluorinated polymer with different chemical structures and wetting behaviour on PI 2555 were chosen, to provide either continuous or discontinuous top layers. The continuous top layer DLAF (DLAF‐1) exhibits an abrupt pretilt transition from planar to homeotropic as the top layer thickness increases. The discontinuous top layer DLAF (DLAF‐2) exhibits a gradual transition where the pretilt correlates with the coverage of fluorinated top layer. These two types of transitions fit with de Gennes' local Frederick's transition and Kwok's inhomogeneous alignment theories, respectively. The abrupt pretilt transition system may be promising for chemical/biosensor applications, whereas the gradual transition system is suitable for pretilt control in LCD devices.     

Modulating Hydroxyl-Rich Interfaces on Nickel–Copper Double Hydroxide Nanotyres to Pre-activate Alkaline Ammonia Oxidation Reactivity

The surface hydroxyl groups of Ni_xCu_1−x(OH)₂ play a crucial role in governing their conversion efficiency into Ni_xCu_1−xO_x(OH)_2−x during the electro-chemical pre-activation process, thus affecting the integral ammonia oxidation reaction (AOR) reactivity. Herein, the rational design of hierarchical porous NiCu double hydroxide nanotyres (NiCu DHTs) was reported for the first time by considering hydroxyl-rich interfaces to promote pre-activation efficiency and intrinsic structural superiority (i.e., annulus, porosity) to accelerate AOR kinetics. A systematic investigation of the structure–function relationship was conducted by manipulating a series of NiCu DHs with tunable intercalations and morphologies. Remarkably, the NiCu DHTs exhibit superior AOR activity (onset potential of 1.31 V with 7.52 mA cm⁻² at 1.5 V) and high ammonia sensitivity (detection limit of 9 μm ), manifesting one of the best non-noble metal AOR electrocatalysts and electro-analytical electrodetectors. This work deepens the understanding of the crucial role of surface hydroxyl groups on determining the catalytic performance in alkaline medium.     

Structure-Directing Roles of Organic Molecules in the Formation of Aluminosilicate and Aluminophosphate Molecular Sieves Revealed by 2D 1H DQ-SQ NMR Spectroscopy

Understanding of crystallization mechanisms of molecular sieves is driven by the broad range of usefulness and unique properties they possess. It is still difficult to obtain information related to the crystallization mechanism of molecular sieves, partly because the materials are generally prepared under hydrothermal conditions and the whole reaction happens in the “black box” autoclave. In this work, 2D ¹H DQ-SQ NMR results clearly demonstrate that it is not only the electrostatic interactions between organic structure-directing agents (OSDAs) and the framework, but also the correlation among OSDAs playing the dominant structural directing roles during the crystallization process. Our fundamental understanding of the crystallization mechanism of molecular sieves could be of great value to design and synthesize new molecular sieves with desirable structural properties.     

Protein dielectrophoresis: Key dielectric parameters and evolving theory

Globular proteins exhibit dielectrophoresis (DEP) responses in experiments where the applied field gradient factor ∇E² appears far too small, according to standard DEP theory, to overcome dispersive forces associated with the thermal energy kT of disorder. To address this a DEP force equation is proposed that replaces a previous empirical relationship between the macroscopic and microscopic forms of the Clausius–Mossotti factor. This equation relates the DEP response of a protein directly to the dielectric increment δε⁺ and decrement δε⁻ that characterize its β-dispersion at radio frequencies, and also indirectly to its intrinsic dipole moment by way of providing a measure of the protein's effective volume. A parameter Γ_pw, taken as a measure of cross-correlated dipole interactions between the protein and its water molecules of hydration, is included in this equation. For 9 of the 12 proteins, for which an evaluation can presently be made, Γ_pw has a value of ≈4600 ± 120. These conclusions follow an analysis of the failure of macroscopic dielectric mixture (effective medium) theories to predict the dielectric properties of solvated proteins. The implication of a polarizability greatly exceeding the intrinsic value for a protein might reflect the formation of relaxor ferroelectric nanodomains in its hydration shell.     

Mechanochemical synthesis of PbS/Ni–Cr layered double hydroxide nanocomposite

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Carbenes,related intermediates,and small-sized cycles: contribution from Professor Nefedov’s laboratory

The review summarizes some of the most prominent results obtained in the laboratory headed by Academician Oleg M. Nefedov at the N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences in the field of chemistry of carbenes, their heavy analogs, and related intermediates, as well as small-sized cycles. Those include elaboration of safe methodology of cyclopropanation using diazomethane, development and extension of synthetic applications of diazoesters and other diazo compounds in the preparation of valuable chemical products, design of functionalized alkynylcyclopropanes on the basis of alkynylcarbene reactions, creation of versatile synthetic approaches to preparation of various practically useful fluoroorganic compounds on the basis of reactions of fluorocarbenes, development of synthetic applications of heavy carbene analogs and synthesis of small-sized heterocycles containing silicon and germanium atoms, analysis of mechanisms of some important reactions of carbenes, their analogs and related intermediates on the basis of physicochemical studies, direct spectroscopic studies of various labile intermediates of chemical reactions.     

“Confinement effects for nano-electrocatalysts for oxygen reduction reaction”

Oxygen reduction reaction (ORR) is one of the most technologically relevant reactions. It occurs at the interface of the electrocatalyst and electrolyte, where oxygen reacts with protons and electrons to produce water. Because the electrocatalyst is dispersed on a high surface area support, morphological confinement becomes critical, as it dictates proton and oxygen transport. Furthermore, confinement is induced by ionomer, ionic liquids (ILs), or molecular additives, and their impact on electrocatalyst reactivity and transport properties is currently not well understood. We present an overview of electrostatics and mass transport–induced confinement and zoom in into ILs and molecular additives and try to unravel how local confinement induced by them impacts ORR.