Titania-coated monolithic silica as separation medium for high performance liquid chromatography of phosphorus-containing compounds

A method of preparing titania-coated monolithic silica stationary phase has been developed to achieve liquid chromatographic separation of phosphorus-containing compounds, which have recently been attracting increasing attention in biochemical research. The titania-coated silica columns exhibited efficient separation with low pressure drop, which is a typical feature of monolithic structures, and also possessed phospho-selectivity, which is a unique property of the titania surface. The material characteristics of titania-coated monolithic silica were examined, and then resin-clad columns were applied to the HPLC analysis of phosphorylated compounds. Highly efficient separation of phosphorylated substances indicated that the novel titania-coated monolithic silica column will find applications as a useful tool in the field of biochemistry, especially in post-genomic analyses.     

Deep‐level characterization of emissive interface states in Alq3‐based OLEDs

We have succesfully investigated emissive interface states in fabricated indium‐tin‐oxide (ITO)/N,N′‐di‐1‐naphthyl‐N,N′‐diphenyl‐1,1′‐biphenyl‐4,4′diamine (α‐NPD)/tris(8‐hydroxyquinoline) aluminum (Alq₃)/LiF/Al organic light‐emitting diodes (OLEDs) by a modified deep‐level optical spectroscopy (DLOS) technique. In the vicinity of the α‐NPD/Alq₃ emissive interface, a discrete trap level was found to be located at ～1.77 eV below the conduction band of Alq₃, in addition to band‐to‐band transitions of carriers from α‐NPD to Alq₃. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Tectonic pumping: earthquake-induced chemical flux detected in situ by a submarine cable experiment in Sagami Bay,Japan

We successfully deployed an in situ automatic chemical analyzer sensitive to manganese (Mn) in seawater for a period of 81 days for the first time on the deep seafloor of Sagami Bay along a convergent plate boundary south of Japan. The in situ Mn analyzer (GAMOS-IV) was connected to a submarine cable as a means to supply power and to relay real time data. During the observation period from April 5 till June 25, 2006, the amount of measured Mn was seen to increase abruptly up to 10 times that of the background level only on April 21, probably triggered by a M5.8 earthquake which occurred ∼7 km south-southwest of the observation site. This study demonstrates the suitability of submarine cables for the long-term geochemical monitoring of deep sea environments.     

MMIC LNA based novel composite-channel Al0.3Ga0.7N/Al0.05Ga0.95N/GaN HEMTs

A microwave monolithic integrated circuit （MMIC） C-band low noise amplifier （LNA） using 1 μm-gate composite-channel Al0.3Ga0.7N/Al0.05Ga0.95N/GaN high electron mobility transistors （CC-HEMTs） has been designed, fabricated and characterized. The material structure and special channel of CC-HEMT were given and analysed. The MMIC LNA with CC-HEMT showed a noise figure of 2.4 dB, an associated gain of 12.3 dB, an input return loss of -6 dB and an output return loss of -16 dB at 6GHz. The IIP3 of the LNA is 13 dBm at 6 GHz. The LNA with 1 μm ×100 μm device showed very high-dynamic range with decent gain and noise figure.[第一段]     

Radical-assisted metalorganic chemical vapor deposition of ZnSe

Radical-assisted metalorganic chemical vapor deposition (MOCVD) of ZnSe has been performed by using diethylzinc (DEZn) and diethylselenide (DESe) as a source and azo-t-butane ((t-C₄H₉)₂N₂)and nitrogen trifluoride (NF₃) as co-reactants. The growth rate was significantly increased in the measured temperature range of 623 to 723 K.     

One-pot synthesis of 2,3-disubstituted benzofurans from 2-chlorophenols using palladium–dihydroxyterphenylphosphine catalyst

2,3-Disubstituted benzofurans possessing 2-hydroxyphenyl moiety at the C-3 position were synthesized from readily available 2-chlorophenols and terminal alkynes by hydroxy-directed ortho-Sonogashira coupling and subsequent oxypalladation/reductive elimination, using Pd-dihydroxyterphenylphosphine catalyst. The catalyst accelerates not only the Sonogashira coupling but also the introduction of 2-hydroxyphenyl group at the C-3 position of benzofuran.     

Direct enolization chemistry of 7-azaindoline amides: A case study of bis(tetrahydrophosphole)-type ligands

7-Azaindoline amides are particularly useful in direct enolization chemistry due to their facilitated enolization in soft Lewis acid/Brønsted base cooperative catalysis. The Cu(I) complex of (R,R)-Ph-BPE, a bis(tetrahydrophosphole)-type chiral bisphosphine ligand, exhibits consistently high catalytic performance and stereoselectivity irrespective of the nature of the α-substituent of the amides. Unexpectedly, however, alkyl-substituted bis(tetrahydrophosphole)-type ligands have substantially inferior catalytic performance. Evaluation of the optimized structures of Cu(I)/amide and Cu(I)/enolate complexes provided clues to dissecting the diverted reaction outcomes.     

Controlled Sol–Gel Transitions of a Thermoresponsive Polymer in a Photoswitchable Azobenzene Ionic Liquid as a Molecular Trigger

Producing ionic liquids (ILs) that function as molecular trigger for macroscopic change is a challenging issue. Photoisomerization of an azobenzene IL at the molecular level evokes a macroscopic response (light‐controlled mechanical sol–gel transitions) for ABA triblock copolymer solutions. The A endblocks, poly(2‐phenylethyl methacrylate), show a lower critical solution temperature in the IL mixture containing azobenzene, while the B midblock, poly(methyl methacrylate), is compatible with the mixture. In a concentrated polymer solution, different gelation temperatures were observed in it under dark and UV conditions. Light‐controlled sol–gel transitions were achieved by a photoresponsive solubility change of the A endblocks upon photoisomerization of the azobenzene IL. Therefore, an azobenzene IL as a molecular switch can tune the self‐assembly of a thermoresponsive polymer, leading to macroscopic light‐controlled sol–gel transitions.     

Quaternary β2,2‐Amino Acids: Catalytic Asymmetric Synthesis and Incorporation into Peptides by Fmoc‐Based Solid‐Phase Peptide Synthesis

β‐Amino acid incorporation has emerged as a promising approach to enhance the stability of parent peptides and to improve their biological activity. Owing to the lack of reliable access to β^2,2‐amino acids in a setting suitable for peptide synthesis, most contemporary research efforts focus on the use of β³‐ and certain β^2,3‐amino acids. Herein, we report the catalytic asymmetric synthesis of β^2,2‐amino acids and their incorporation into peptides by Fmoc‐based solid‐phase peptide synthesis (Fmoc‐SPPS). A quaternary carbon center was constructed by the palladium‐catalyzed decarboxylative allylation of 4‐substituted isoxazolidin‐5‐ones. The N?O bond in the products not only acts as a traceless protecting group for β‐amino acids but also undergoes amide formation with α‐ketoacids derived from Fmoc‐protected α‐amino acids, thus providing expeditious access to α‐β^2,2‐dipeptides ready for Fmoc‐SPPS.     

Oxidation reaction of [Ni(1,4,7-triazacyclononane)(2)](2+) by [Fe(o-phenanthroline)(3)](3+) in aqueous acidic solution at elevated pressures: determination of the activation and reaction volumes for the Ni(iii)/(ii) couple

The reaction volume corresponding to the self-exchange process of the [Ni(tacn)(2)](3+/2+) couple was determined in aqueous acidic solution. Theoretical equations on the basis of the Mean Spherical Approximation were proposed for the estimation of reaction volumes for M(n+/(n- 1)+) couples in solution, and the calculated reaction volumes were compared with the experimentally estimated values. The activation volume for the [Ni(tacn)(2)](3+/2+) couple was determined in the acidic condition from the cross reaction of [Ni(tacn)(2)](2+) and [Fe(o-phen)(3)](3+) at elevated pressures. The agreement of the experimentally estimated activation volume for the [Ni(tacn)(2)](3+/2+) couple, -8.2 +/- 2.4 cm(3) mol(-1), with the theoretically calculated value, -7.5 cm(3) mol(-1), within the allowed uncertainty (+/-1 cm(3) mol(-1)) indicates that the electron self-exchange reaction of this redox couple obeys the Marcusian behavior in aqueous acidic solution.