Facile Preparation of Organometallic Nanorods from Various Ethynyl-Substituted Molecules

A facile method to prepare one-dimensional (1D) organometallic nanomaterials from various ethynyl-substituted molecules is reported. The reactions of 3-chloro-1-ethynylbenzene, p-tBu-phenylacetylene and 4-ethynylbiphenyl with Cu⁺ ions in acetonitrile yield nanorod-shaped copper acetylides (Cu−C≡C−R) crystals. In the case of linear alkynes, namely, propyne, 1-pentyne and 1-hexyne, it was found that using an aqueous ammonia/ethanol mixed solvent instead of acetonitrile is a better approach to obtain 1D nanostructures. This procedure also enables us to prepare functional 1D nanomaterials. We demonstrate the preparation of a paramagnetic nanorod from the organic radical p-ethynylphenyl nitronyl nitroxide, and fluorescent nanorods from 9-ethynylphenanthrene and 2-ethynyl-9,9′-spirobifluorene.     

Nonabelian dark matter with resonant annihilation

Journal of High Energy Physics - This paper shows that the positive-energy and non-renormalization theorems of traditional supersymmetry survive the addition of Lorentz violating interactions. The...     

Novel sequential sigmatropic rearrangements of allylic diols: application to the total synthesis of (-)-kainic acid

Sequential sigmatropic rearrangements (Claisen/Claisen and Claisen/Overman) of enantiopure allylic diols are described. The reactions proceeded in complete diastereoselectivity without protecting group manipulations. The sequential Claisen/Overman rearrangement was successfully applied to the total synthesis of (-)-kainic acid.     

New sign of vacuum ultraviolet driven crystal growth in ternary oxide Zn 3 V 2 O 8 films

Ternary oxide Zn₃V₂O₈ films was successfully formed on glass substrates only by means of vacuum ultraviolet irradiation to the spin-coated metal–organic solutions. From Fourier transform infrared spectroscopy measurements, we confirmed that the crystal growth proceeded at metal–organic bond cleavage under VUV irradiation. The crystalline size of the obtained materials was estimated to be 1.5–2.5 nm. The prepared Zn₃V₂O₈ films clearly showed yellow luminescence, corresponding to a charge transfer transition in the VO₄ tetrahedra.     

Cover Picture: Heterogeneously Hybridized Porous Coordination Polymer Crystals: Fabrication of Heterometallic Core–Shell Single Crystals with an In‐Plane Rotational Epitaxial Relationship (Angew. Chem. Int. Ed. 10/2009)

A porous copper coordination framework grew epitaxially as a single crystal on the surface of a single crystal of a porous zinc coordination framework, as described by S. Kitagawa and co‐workers in their Communication on page 1766 ff. The picture shows the structural relationship between the copper and zinc frameworks, which has been unveiled by synchrotron surface X‐ray diffraction measurements; in‐plane rotational epitaxial growth compensates for the different lattice constants of the two crystals.

     

A direct method for the separation and quantification of bile acid acyl glycosides by high-performance liquid chromatography with an evaporative light scattering detector

A direct method for the separation and quantification of a series of bile acid acyl glycosides using high-performance liquid chromatography coupled to an evaporative light scattering detector (HPLC-ELSD) is described. Complete separation of each of 15 bile acid acyl 24-alpha-glucosides and their 24-beta-anomers and 24-beta-galactosides was achieved by the stepwise gradient elution mode on a C18 column using a mixture of acetonitrile-methanol (8:2, v/v) and 1% aqueous acetic acid as the mobile phase. 24-beta-Galactosides were always eluted faster than the corresponding 24-beta-glucosides, which eluted after the corresponding 24-alpha-anomers. Calibration curves of different 24-beta-galactosides were linear over a range of 0.2-40 nmol of injected amount and the detection limits (S/N > 3) were from 0.08 to 0.1 nmol. The present HPLC-ELSD method may provide an insight into the separation and quantification of the biologically interesting neutral bile acids.     

Thermal decomposition reactions of n‐alkylated 2‐aminobiphenyls to carbazole and phenanthridine

Thermal cyclization reactions were examined by passing vapors of N‐alkylated 2‐aminobiphenyls 1a‐c and 2 over calcium oxide at 450‐600°C under nitrogen carrier gas. The reactions yielded 9‐methylcarbazole 3 , carbazole 4 , phenanthridine 5 and phenanthrene 6. The major product for the reactions of 1a, 1b and 2 was phenanthridine 5 while that of 1c was carbazole 4.     

Interfacial polarization phenomena in organic molecular films

Electrostatic phenomena occurring at the interface between metal/organic and organic/organic materials are discussed from the viewpoint of dielectrics physics. Focusing on two important origins of surface polarization phenomena, orientational ordering of polar molecules and displacement of excess charges at the interface, surface polarization phenomena of organic thin films are discussed. To define the orientational order of polar molecules, orientational order parameters are introduced, and surface polarization due to the alignment of dipoles is expressed. The generation of Maxwell displacement current (MDC) and optical second harmonic generation (SHG) that are specific for surface organic monomolecular films are discussed, and some experimental evidence are shown. As an extension of the concept of surface Fermi level introduced to discuss the electrostatic phenomena due to electron transfer at the interface between metal-organic insulators, the surface Fermi level is extended to the discussion on the electrostatic phenomena of organic semiconductor materials on metals. In this paper, some experimental evidence of surface polarization originating from polar molecules and displacement of excess charges are shown. After that, with consideration of these surface phenomena, single electron tunneling of organic films are briefly discussed in association with surface polarization phenomena.     

MassBank: a public repository for sharing mass spectral data for life sciences

MassBank is the first public repository of mass spectra of small chemical compounds for life sciences (<3000 Da). The database contains 605 electron‐ionization mass spectrometry(EI‐MS), 137 fast atom bombardment MS and 9276 electrospray ionization (ESI)‐MSⁿ data of 2337 authentic compounds of metabolites, 11 545 EI‐MS and 834 other‐MS data of 10 286 volatile natural and synthetic compounds, and 3045 ESI‐MS² data of 679 synthetic drugs contributed by 16 research groups (January 2010). ESI‐MS² data were analyzed under nonstandardized, independent experimental conditions. MassBank is a distributed database. Each research group provides data from its own MassBank data servers distributed on the Internet. MassBank users can access either all of the MassBank data or a subset of the data by specifying one or more experimental conditions. In a spectral search to retrieve mass spectra similar to a query mass spectrum, the similarity score is calculated by a weighted cosine correlation in which weighting exponents on peak intensity and the mass‐to‐charge ratio are optimized to the ESI‐MS² data. MassBank also provides a merged spectrum for each compound prepared by merging the analyzed ESI‐MS² data on an identical compound under different collision‐induced dissociation conditions. Data merging has significantly improved the precision of the identification of a chemical compound by 21–23% at a similarity score of 0.6. Thus, MassBank is useful for the identification of chemical compounds and the publication of experimental data. Copyright © 2010 John Wiley & Sons, Ltd.