Published papers

The electrochemical analysis of tetracycline was investigated using nickel-implanted boron-doped diamond thin film electrode by cyclic voltammetry and amperometry with a flow injection system. Cyclic voltammetry was used to study the electrochemical oxidation of tetracycline. Comparison experiments were carried out using as-deposited boron-doped diamond thin film electrode (BDD). Nickel-implanted boron-doped diamond thin film electrode (Ni-DIA) provided well-resolved oxidation irreversible cyclic voltammograms. The current signals were higher than those obtained using the as-deposited BDD electrode. Results using nickel-implanted boron-doped diamond thin film electrode in flow injection system coupled with amperometric detection are presented. The optimum potential for tetracycline was 1.55 V versus Ag/AgCl. The linear range of 1.0 to 100 μM and the detection limit of 10 nM were obtained. In addition, the application for drug formulation was also investigated. 2005 © The Japan Society for Analytical Chemistry.

The crystal structures of the title compounds, [Cu(C15H 11N2-O2)2(C14H 15N)2] and [Cu(C15H11N 2O2)2(C14H15N) 2]·2CHCl3, respectively, have been determined. The red disolvate complex affords a square-planar CuN4 coordination environment in which the Cu" atom lies on a centre of symmetry. The blue solvent-free complex affords a distorted square-pyramidal CuN4O coordination environment and adjacent molecules form centrosymmetric dimers. A comparison of the different crystal structures focuses on the role of the solvent molecules in supramolecular assemblies of the copper(II) complexes. © 2005 International Union of Crystallography.

The crystal structure of the title compound, [Mn(C20H 16Br4N2O2)(H2O) 2](ClO4)·2H2O, has been determined. The mononuclear complex affords an elongated octahedral MnN2O 4 coordination geometry with the four donor atoms of the tetradentate chiral Schiff base in the equatorial plane and with two aqua ligands in axial positions with Mn-O = 2.278 (9) and 2.269 (10) Å. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.

The title compound. [Mn2Ni(C20H20N 2O2)2(CN)4(H2O) 2], is the first chiral trinuclear complex having an Mn III-NC-NiII-CN-MnIII unit. A pair of the trans sites of [Ni(CN)4]2- links two MnIII units. The MnIII ion has a pseudo-octahedral coordination geometry with the four donor atoms of the tetradentate chiral Schiff base forming the equatorial plane, and with a bridging cyanide and an aqua ligand at the axial positions. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.

We report here a self-cleaning particle coating with antireflection (AR) properties. The coatings were prepared by (1) depositing SiO2 single-layered particle coatings on polyelectrolyte-modified glass substrates through electrostatic attraction, (2) subsequently depositing another layer of TiO2 nanoparticles through electrostatic attraction, and (3) removing the polymer by calcination at 500 °C. The AR effect of the coatings was studied with transmission spectra collected at normal incidence. The self-cleaning properties of the coatings were studied by the change of the water contact angle on octadodecyldimethylchlorosilane-modified coatings under 1.0 mW cm-2 ultraviolet light. Both the AR and self-cleaning properties of the coatings were dependent on the concentration of colloidal TiO2 solution used in the preparation. However, excellent surface wettability of the coatings for water was obtained, independent of the preparation conditions. The experimental findings are discussed in terms of the special structure of the particle coatings.

Two new 3d-4f cyano-bridged hetero-bimetallic compounds with distinguished two-dimensional honeycomb network structure, {Ln(HP)2(H 2O)3(μ-NC)3Fe(CN)3}n, (Ln=Ce, Nd; HP=4-Hydroxypyridine) were synthesized and crystallographically characterized. A novel photo-induced magnetization phenomenon for {Nd(HP) 2(H2O)3(μ-NC)3Fe(CN) 3}n, was revealed and studied. Furthermore, the correlation between photo-induced magnetization and structure was proposed. © 2004 Elsevier Inc. All rights reserved.

Highly boron-doped diamond (BDD) electrode was used as anode for ozone generation system by electrolysis of acidic solution. We have succeeded to generate ozone by using this BDD electrode with high efficiency compared to traditional lead oxide (PbO2) electrode. Ozone generation by using PbO2 electrode was gradually decreased due to its structural degradation at continous operating. However, electrochemical and physical properties of the BDD electrode were kept its high stability even after long operation time (>3000 hours) in comparison with PbO2 electrode. The stability of BDD electrode for long time operation was due to physical and chemical properties of diamond electrode. It was expected that the use of BDD electrode as an anode would make a positive contribution to the electrochemical ozone generation. © New. Mat. Electrochem. Systems.

Electrochemical oxidation of Mn2+ with and without the presence of Bi3+ was studied using voltammetric and in situ spectro-electrochemical techniques at boron-doped diamond (BDD) electrodes in 1.0 M HClO4. Electrochemical oxidation of only Mn2+ resulted in the formation of mostly MnO2 with MnO4 - produced as a minor product. The MnO2 film formed on the electrode surface, which is an inevitable part of Mn2+ oxidation, shows a blocking effect on the formation of MnO4-, and reduces the overall current efficiency of MnO4- production. Higher Mn2+ concentrations result in less MnO 4- production due to the formation of more MnO 2. The addition of Bi3+ increased the current efficiency of MnO4- production. The Bi3+ is oxidized to Bi(V), which acts as an electrocatalyst in MnO4- production. The Bi(V) oxidizes MnO2, formed on the electrode surface, to MnO4-. This increases the production of MnO 4- by removing the blocking film to provide an active electrode (bare BDD) surface, which is available for further Mn2+ oxidation. © 2004 The Electrochemical Society. All rights reserved.

The thermal and photo-responsibility of the axial semicoordination Cu-O bonds in [Cu(en)2](ClO4)2 (1) (en = ethylenediamine) have been investigated. We discovered a new photoresponsive behavior that was attributed to photoinduced ClO4- cleavage accompanied by compression of the Cu-O bonds using the structural degree of freedom of the semi-coordination bonds.

The crystal structure of bis[(R)-3,5-dichloro-N-(1-phenyl-ethyl) salicylideneaminato- κ2N, O]-copper(II) and bis[(R)-3-ethoxy-N-(1-phenylethyl)salicylideneaminato-κ2N, O] copper(II) was investigated. The complexes adopt a compressed tetrahedral trans-[CuN2O2] coordination geometry. The complexes also differ from one another with respect to the 1-phenylethylamine moieties and the direction of the benzene rings. The structural change was found to be irreversible for both the complexes, though there are no intermolecular hydrogen bonds in the crystals.

X-ray absorption (XAS) and emission (XES) spectroscopy near B K and C K edges have been performed on metallic (∼0.1 at. % B, B-diamond) and semiconducting (∼0.03 at. % B and N, BN-diamond) doped diamond films. Both B K XAS and XES spectra show a metallic partial density of states (PDOS) with the Fermi energy of 185.3 eV, and there is no apparent boron-concentration dependence in contrast to the different electric property. In C K XAS spectrum of B-diamond, the impurity state ascribed to boron is clearly observed near the Fermi level. The Fermi energy is found to be almost same with the top of the valence band of nondoped diamond: EV=283.9 eV. C K XAS of BN-diamond shows both the B-induced shallow level and N-induced deep and broad levels as the in-gap states, in which the shallow level is in good agreement with the activation energy (Ea=0.37 eV) estimated from the temperature dependence of the conductivity; namely, the change in C 2p PDOS of impurity-induced metallization is directly observed. The electric property of this diamond is ascribed mainly to the electronic structure of C 2p near the Fermi level. The observed XES spectra are compared with the discrete variational Xα (DVXα) cluster calculation. The DVXα result supports the strong hybridization between B 2p and C 2p observed in XAS and XES spectra, and suggests that the small amount of boron (≤0.1 at. %) in diamond occupies the substitutional site rather than interstitial site. © 2004 The American Physical Society.

The title compound, (RS)-3,5-dichloro-2-{[(1-phenylethyl)-imino]methyl} phenol, C15H13Cl2NO, was synthesized from racemic 1-phenylethylamine and 3,5-dichlorosalicylaldehyde. The π-conjugate system around the imine group is essentially planar in the phenol-imine tautomer. Intramolecular O⋯N hydrogen-bond and intermolecular C - H⋯π interactions are present in the crystal structure.

The title compound, [Cu(C15H14NO)2], adopts a stepped conformation and displays a square-planar trans-[CuN 2O2] coordination geometry. The asymmetric unit contains two independent half molecules and each Cu atom is located on a center of symmetry. For one molecule, the Cu-N and Cu-O bond distances are 2.013 (2) and 1.893 (2) Å, respectively, while for the other molecule, these distances are 2.008 (2) and 1.896 (2) A. The extended conformation of the phenethylimine pendant groups results in crystal packing formed by weakly aggregated planar molecules. © 2004 International Union of Crystallography Printed in Great Britain -all rights reserved.

The title compound, [Cu(C11H12Cl2NO) 2], has a compressed tetrahedral trans-[CuN2O 2] coordination environment. The absolute configuration is found to be Δ(S,S) for the crystal examined. The Cu-N bond distances are 1.969 (4) and 1.971 (4) Å, while the Cu-O bond distances are 1.886 (3) and 1.892 (3) Å. The ligands, containing optically active (S)-2-butylamine moieties and electron-withdrawing Cl substituents, lead to an umbrella conformation of the overall molecule. On heating to 387 K, a structural phase transition is observed, probably involving a change in coordination geometry. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.

Metal-modified diamond electrodes were fabricated by using ion implantation method for electroanalytical applications. Nickel and copper ion were implanted at a different film of boron-doped diamond (BDD) with a dose of 5×1014 cm-2 for each type of ion. The electrochemical behavior has been studied for glucose oxidation in alkaline media by using cyclic voltammetry and flow injection analysis. Those electrodes exhibited high catalytic activity and excellent electrochemical stability with low background current even after strong ultrasonication in the cleaning process. The results indicate that metal-implanted method could be a promising method for controlling the electrochemical properties of diamond electrodes. © 2004 Elsevier B.V. All rights reserved.

In the title complex, [Cu(C16H11N2O) 2], the CuII atom lies on a center of symmetry within a square-planar trans-N2O2 coordination geometry and adopts a stepped conformation with regard to the bulky Schiff base ligands. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.

In the solid state at room temperature, reversible control of magnetic properties was achieved with photo-illumination of a composite material made up of γ-Fe2O3 nanoparticles encapsulated with n-octylamine and an azobenzene-containing amphiphilic compound (see picture).

A visible light-induced magnetization change of the 3d-4f heterometallic, [Nd(DMF)4(H2O)3(μ-NC)Co(CN) 5]·H2O (DMF=N,N-dimethylformamide), is observed and described. The plots of χMT versus T of the complex showed that the χMT values, after visible light illumination, were enhanced by about 25% as compared to before irradiation in the temperature range of 5-40K. © 2004 Elsevier Inc. All rights reserved.

FeCo Prussian blue analogues, which are known as typical molecule-based magnets, exhibited abrupt conductance switching by applying a high electric field as well as by varying the temperature. The current density versus electric field (J-E) curves of FeCo Prussian blue with Rb cations in interstitial sites shows so-called negative resistance effects at electric fields higher than the threshold voltage. This means that the FeCo Prussian blue analogues are multiproperty materials in the sense that their conducting, magnetic, and optical properties can be reversibly controlled by certain external stimuli. Copyright © 2004 American Chemical Society.

Pt-modified diamond electrodes were fabricated for electroanalytical applications by implantation method with a dose of 5 × 1014 cm-2. The electrochemical behavior has been studied for oxidation of hydrogen peroxide by using cyclic voltammetry in phosphate buffer solution. With very low background current in comparison to that of Pt metal electrode, the electrode exhibited higher signal to background ratio (≈3.8 times) as well as better electrochemical and physical stability.