X-ray absorption spectroscopic study on the electronic structure of Li(1)(-)(x)()CoPO(4) electrodes as 4.8 V positive electrodes for rechargeable lithium ion batteries

Changes in the electronic structure of olivine Li(1-x)CoPO(4), 4.8 V positive electrode material for lithium ion batteries, were investigated using the X-ray absorption spectroscopy (XAS) technique. The threshold energy in the Co K-edge increased with electrochemical Li removal, indicating the oxidation of cobalt ions due to charge compensation. Moreover, P and O K-edge XAS showed a slight shift in threshold energy with Li removal. Although it is generally believed that the electrons of PO(4) polyanion do not contribute to the oxidation process, present experimental results indicate changes in the electronic structure around PO(4) units. Such results would be interpreted by the idea of the hybridization effect between the Co 3d and O 2p orbitals and of the polarization effect introduced by Li ions.     

Patterning of DNA nanostructures on silicon surface by electron beam lithography of self-assembled monolayer

Nanoscale patterns of modified oligonucleotides are produced on octadecyltrimethoxysilane self-assembled monolayers at a silicon surface by electron beam lithography. DNA structures with feature sizes of the order of 250 nm were detected by epi-fluorescence microscopy.     

Scale-up study of high osmotic pressure chromatography for separation of poly(epsilon-caprolactone)

Methods to prepare fractions of poly(epsilon-caprolactone) with a narrow molecular mass distribution in large quantities have been examined using high osmotic pressure chromatography under the theta condition. Effects of column dimension and coupling columns in series on the separation resolution were studied. We found that use of a thicker column can improve the resolution if adverse effects of viscous fingering are avoided. We also demonstrated that coupling the columns results in a better separation if the second column does not adsorb high-molecular-mass components purified in the first column.     

Surface modification of silicon with single ion irradiation

In order to solve the issues in Si nanoelectronics such as fluctuation in the device functions and poor reliability of devices due to relative increase in mass transport in nm size structures and to yield novel functions by rather taking advantage of the nm size, we need to understand the phenomena peculiar to nm size structures. Based on the fact that a practical method to fabricate nm structures in terms of throughput, process time, and cost is to combine modification of solid surfaces with energetic particles (especially with single ions) and subsequent chemical processing in solutions, we describe single ion irradiation effects as a tool to modify solid surfaces in nm scale, a method for nm scale in-situ observation of solid surfaces, and some examples of the acquired knowledge.     

Characteristic reactions of group 9 transition metal compounds in organic synthesis

Group 9 metal compounds in organic synthesis have two characteristic reactions. The first occurs because the group 9 metals have a high affinity to carbon–carbon or carbon–nitrogen π‐bonds. The first type of characteristic reactions in these group 9 metal compounds includes Pauson–Khand reactions, the Pauson–Khand‐type reactions ([2 + 2 + 1] cyclization), the other cyclizations and coupling reactions. The second occurs because the group 9 metals have a high affinity to carbonyl groups. The second type of characteristic reactions includes carbonylations such as hydroformylations, the carbonylations of methanol, amidocarbonylations and other carbonylations. The first characteristic reactions are applied for the synthesis of fine chemicals such as pharmaceuticals and agrochemicals. However, the second characteristic reactions are utilized not only for fine chemicals but also for important bulk commodity chemicals such as aldehydes, carboxylic acids and alcohols. Copyright © 2009 John Wiley & Sons, Ltd.     

Rod-like liquid crystals of organic transition metal complexes. I. Reversible transformation between blue smectogen and red nematogen

Two novel types of transition-metal-containing liquid crystals, bis(p-n-koxydithiobenzoato)nickel(II) (abbreviated as (C_nO-DTB)₂Ni), and (p-n-alkoxydithiobenzoato)(p-n-alkoxyperthiobenzoato)nickel(II) (abbreviated as (C_nO-DTB)(C_nO-PTB)Ni), were synthesized. It was found that the (C_nO-DTB)₂Ni complex for n = 8 has smectic H and C mesophases, and that the (C_nO-DTB)₂Ni complexes for n = 4 and 8 easily transform into the corresponding monoperthio complexes, _nO-PTB)Ni, by heating at temperatures between 230°C and 285°C. It was confirmed that the transformation originates from an intermolecular reaction between the (C_nO-DTB)₂Ni complexes at high temperatures, and that the origin of the extra sulphurs in the resulting (C_nO-DTB)(C_nO-PTB)Ni complexes is the neighbouring (C_nO-DTB)₂Ni complexes. Interestingly, each of the (C_nO-DTB)(C_nO-PTB)Ni complexes (n = 4 and 8), has nematic mesophase and exhibits a unique double melting behaviour via the nematic phase, which is the first example in liquid crystals. The reversible transformation between the blue smectic rod-like (C_nO-DTB)₂Ni complex and the red nematic Λ-like (C_nO-DTB)(C_nO-PTB)Ni complex is possible.     

Zeta Functions of Graph Coverings

We give a decomposition formula for the zeta function of a group covering of a graph.     

Efficient and enantioselective total syntheses of heliannuols A and K

The second-generation enantioselective synthesis of heliannuol A and the first enantioselective total synthesis of heliannuol K (via two routes) have both been accomplished efficiently; (heliannuol A, nine steps and 25% yield; heliannuol K, seven steps and 47% yield). Highlights of our synthetic strategy include a substrate-controlled chirality transfer in the Lewis acid mediated Claisen rearrangement of the allyl aryl ether for the key construction of a tertiary stereogenic center at the benzylic position followed by, for heliannuol A, ring-closing metathesis, diastereoselective epoxidation, and regioselective cleavage of the epoxide; and for heliannuol K, ring-closing metathesis and conjugate reduction of the eight-membered enone.