Certain invariant spaces of bounded measurable functions on a sphere

Positivity - In their 1976 paper, Nagel and Rudin characterize the closed unitarily and Möbius invariant spaces of continuous and $$L^p$$ -functions on a sphere, for $$1\le p<\infty $$...     

Synthesis, characterization, and controlled aggregation of biotemplated polystyrene nanodisks

Cross-linked polystyrene nanodisks were prepared by controlled polymerization of styrene and divinylbenzene in the interior of bicelles, discoidal lipid aggregates. Aggregation behavior of polymer nanodisks was studied in water, organic solvents, and solid phase. Nanodisks form stable dispersions in aqueous solutions of surfactants, such as sodium dodecyl sulfate (SDS). Varying SDS/nanodisk ratio allowed us to control the size of nanodisk aggregates. Nanodisks are readily solubilized in nonpolar organic solvents, such as toluene and carbon tetrachloride, to yield stable monodisperse suspensions. These findings open opportunities for creating nanodisk-based nanocomposite materials. Stable nanodisk suspension in toluene enabled small angle neutron scattering (SANS) measurements. SANS data confirmed the nanodisk diameter and allowed accurate measurement of nanodisk thickness (19.5 ± 1.0 Å). In solid phase, nanodisks aggregate in sub-micron platelets.     

Synthesis and Electronic Properties of Novel 5,7-Diazapentacene Derivatives

A route to the synthesis of novel 5,7-diazapentacenes and some preliminary studies on their properties is reported. A single crystal X-ray diffraction study of the dihexyl derivative showed it had formed a dimer during the analysis. The materials possess lower lying frontier orbitals than pentacene and may have potential applications in organic electronic devices. This synthetic method may be applicable to the synthesis of other azaacenes.     

Catalytic Hydrocyanation of Activated Terminal Alkynes

A universal, practical and scalable organocatalytic hydrocyanation manifold to provide β-substituted acrylonitriles bearing an electron-withdrawing functionality has been implemented. The catalytic manifold operates under the reactivity generation principle “a good nucleophile generates a strong base”, and it uses 1,4-diazabicyclo[2.2.2]octane (DABCO) as the catalyst, activated terminal alkynes as substrates and acetone cyanohydrin as the cyanide source. The acrylonitriles obtained as E,Z mixtures are straightforwardly resolved by simple flash chromatography delivering the pure isomers in preparative amounts.     

Characterization and Monitoring of Porous Media with Electrical Imaging: A Review

Transport in Porous Media - Electrical geophysical imaging is a widely used noninvasive technology for visualizing porous media at scales larger than individual pores. Originally developed for...     

Energy transfer from a polymer host to a europium complex in light-emitting diodes

Energy transfer leading to electroluminescence of a lanthanide complex, Eu(Fod)₃MK (Fod=heptafluoro-dimethyl-octanedionate, MK=4, 4′-bis(N,N-dimethylaminobenzophenone) doped into PVK host is investigated. The optical properties of pure Eu(Fod)₃MK and its doping in PVK show that the PVK host can efficiently transfer energy to europium ions through a co-ligand of MK due to good spectrally overlap. Light-emitting diodes (LED) consisting of PVK doped with 1-5 wt% of Eu(Fod)₃MK also demonstrates this energy transfer. Organolanthanide complexes doped into a wide-gap conducting polymers would lead to efficient and pure red organic LEDs to solve the full colour conjugated polymer displays.     

An ab initio molecular dynamics study of ionic conductivity in hexagonal lithium lanthanum titanate oxide La0.5Li0.5TiO3

To date, the fastest lithium ion-conducting solid electrolytes known are the perovskite-type ABO₃ oxide, with A = Li, La and B = Ti, lithium lanthanum titanate (LLTO) Li_3x La_{( 2 \mathord}

Nitrous Oxide as a Hydrogen Acceptor for the Dehydrogenative Coupling of Alcohols

The oxidation of alcohols with N₂O as the hydrogen acceptor was achieved with low catalyst loadings of a rhodium complex that features a cooperative bis(olefin)amido ligand under mild conditions. Two different methods enable the formation of either the corresponding carboxylic acid or the ester. N₂ and water are the only by‐products. Mechanistic studies supported by DFT calculations suggest that the oxygen atom of N₂O is transferred to the metal center by insertion into the Rh?H bond of a rhodium amino hydride species, generating a rhodium hydroxy complex as a key intermediate.     

Combined experimental and computational study of W(II), Ru(II), Pt(IV) and Cu(I) amine and amido complexes using 15N NMR spectroscopy

Using 2D proton-coupled gHSQC pulse sequences in addition to 1D ¹⁵N NMR experiments of ¹⁵N labeled systems, ¹⁵N NMR chemical shifts of a range of transition metal amido and amine complexes were determined. Tungsten(II), ruthenium(II), platinum(IV) and copper(I) complexes with aniline and their anilido variants were studied and compared to free aniline, lithium anilido and anilinium tetrafluoroborate. Upon coordination of aniline to transition metals, upfield chemical shifts of 20–60 ppm were observed. Deprotonation of the amine complexes to form amido complexes resulted in downfield chemical shifts of 40–60 ppm for all of the complexes except for the tungsten d⁴ system. For the tungsten(II) complexes, the cationic aniline complex displayed a downfield shift of approximately 56 ppm relative to the neutral anilido complex. The change in chemical shift for amine to amido conversion is proposed to depend on the ability of the amido ligand to π-bond with the metal center, which influences the magnitude of the paramagnetic screening term.