Selective Reactions with Organoaluminum Compounds

With the aid of selected examples an overview is given of the development trends in highly discriminative reactions using organoaluminum compounds. (1) Isomerization of substituted oxiranes into allyl alcohols has been effected both stereo- and regioselectively by means of a new organoaluminum reagent, diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP); this reaction which provides a new route for the regiospecific transformation of allyl alcohols into 1,3-dienes. (2) A novel nonenzymic heterolysis of allylic phosphates of terpenoids has been effected by organoaluminum compounds and has enabled development of a new method for the selective synthesis of cyclic terpenes. (3) The reductive condensation of α-haloketones with carbonyl compounds in the presence of diethylaluminum chloride and zinc affords β-hydroxy-carbonyl derivatives in good yields with exclusion of undesired self-condensations products.     

Studies on vocal fold injection and changes in pitch associated with alcohol intake

The current study was carried out with particular emphasis on the association between phonetic function tests and alterations in the appearance of the hypopharyngeal and laryngeal mucosa, such as capillary dilatation, edema, and vocal fold injection after alcohol intake. The results demonstrated the occurrence of previously unrecognized pathophysiological changes associated with synchronous phonetic functions in the vocal pathway after alcohol intake. Serum ethanol and aldehyde concentration levels were evaluated hourly for 2.5 h after ingestion of alcohol. When an electronystagmogram showed the typical pattern of alcohol intake, the study was initiated. Occasionally, rhinography was performed on subjects complaining of a stuffy nose after alcohol intake.     

Silver(I) coordination polymers of fluorescent oligo(phenylenevinylene) with pi-pi stackings: luminescence and conductivity

Three luminescent silver(I)-oligo(phenylenevinylene) complexes, [Ag2(bmsb)(ClO4)2] (1), [Ag2(bmsb)(H2O)4](BF4)2 (2), and [Ag2(bdb)(CF3SO3)2] (3) (bmsb = 1, 4-bis(methylstyryl)benzene, bdb = 4,4'-bis(2, 5-dimethylstryryl)biphenyl), have been synthesized and structurally characterized. Complexes 1 and 2 are 2D networks with unique metallocyclophane motifs. Complex 3 affords a 2D zigzag sheet, in which silver triflates form tubelike double chains and bdb molecules act as linkages. Complex 2 exhibits high electric conductivity because of columnar aromatic stackings formed through intra- and intermolecular pi-pi interactions. Complexes 1-3 in the solid state exhibit luminescence, of which excitation and emission maxima are shifted to longer wavelength as compared to those of the corresponding metal-free ligands.     

Adenopeptin, a new apoptosis inducer in transformed cells from Chrysosporium sp.

A new antitumor antibiotic, adenopeptin (1), was isolated from the culture broth of Chrysosporium sp. PF1201. The planar structure, which includes a tridecapeptide and a hexahydropyrrolo[1,2-a]pyrimidinium, was elucidated by mass spectrometric and NMR experiments. Adenopeptin (1) induced apoptotic cell death in cells transformed with the adenovirus oncogenes.     

Dendritic effects on the ordered assembly and the interfacial one-electron oxidation of redox-active dendron-functionalized gold nanoparticles

A higher generation dendron with a long-alkyl chain thiol (DA2-SH) induced the formation of nanoparticles with a small core with quite a narrow size distribution (1.5 +/- 0.1 nm), the self-assembly of one-dimensional arrays of these gold nanoparticles (DA2-Au), and the stabilization for the formation of the radical cation of the phenothiazine of DA2-Au nanoparticles from the interfacial one-electron oxidation of the nanoparticles with NOBF4.     

Synthesis of small palladium nanoparticles stabilized by bisphosphine BINAP bearing an alkyl chain and their palladium nanoparticle-catalyzed carbon-carbon coupling reactions under room-temperature

A new bisphosphine ligand, C8-BINAP, and C8-BINAP-stabilized palladium nanoparticles have been prepared; C8-BINAP was found to be an effective protecting ligand for preparing and stabilizing palladium nanoparticles with very small core size and narrow size distribution and the C8-BINAP-Pd nanoparticles behave as an efficient catalyst for carbon-carbon coupling reactions at room temperature.     

Photoluminescence of SrGa2S4:Sn,Re(=Ce, Gd) phosphors

The photoluminescence (PL) spectra, PL excitation spectra, color coordinates, and X-ray diffraction spectra are reported for SrGa₂S₄:Sn,Re(=Ce and Gd, respectively) phosphors. By mixing SrGa₂S₄:Sn,Ce phosphors with different Ce³⁺ concentrations, white emissions can be obtained under the excitation of a 340-nm UV LED. Emissions in the green to yellow color range can be obtained from SrGa₂S₄:Sn,Gd phosphors. The rare earth ions enhance the green emission band, which peaks at 534 nm, instead of the yellow one. The origin of this enhancement is discussed. The resonant energy transfer rates are estimated in the cases from Ce³⁺ to the green and yellow centers of Sn²⁺ and between the yellow centers and the green centers.