Dimolybdenum and ditungsten complexes containing terminal and bridging sulfido ligands [M₂S₂(μ₂–S)₂(S₂CNEt₂)₂] (M = Mo, W) react with a range of noble-metal complexes to afford a series of trinuclear and cubane-type tetranuclear mixed-metal clusters, whereby the core structure of the produced clusters, which is either [M′(μ₂–S)₂M₂(μ₂–S)₂], [M′(μ₃–S)(μ₂–S)₃M₂], or [M′₂M₂(μ₃–S)₄] (M′ = Pd, Pt, Rh, Ir, or Ru), sharply depends upon the choice of the combination M/M′ as well as the nature of the ligands bound to the noble metal incorporated into the cluster. Detailed structures of the new clusters obtained in this study have been determined by the single-crystal X-ray analyses for [Pt(PPh₃)(μ₂–S)₂{W(S₂CNEt₂)}₂(μ₂–S)₂], [{Pd(PPh₃)}₂{Mo(S₂CNEt₂)}₂(μ₃–S)₄], [Ir(PPh₃)₂(μ₃–S)(μ₂–S)₃{W(S₂CNEt₂)}₂(μ₂–Cl)], [{Rh(cod)}₂{MoCl(S₂CNEt₂)}₂(μ₃–S)₄] (cod = 1,5-cyclooctadiene), and [(Cp^*Ru)₂{MoCl(S₂CNEt₂)}₂(μ₃–S)₄] (Cp^* = η⁵–C₅Me₅).

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Studies have been performed on a cast-coated Nafion^® thin film deposited on an interdigitated microarray electrode in order to elucidate its basic characteristics. Conductivity dependence on relative humidity and temperature were clearly observed. Chemical activation process of the Nafion^® film by H₂O₂ and H₂SO₄ aqueous solutions effectively enhanced the AC-conductivity. Heat treatment of the Nafion^®, especially at temperature higher than 200 °C, also decreased the conductivity, which was never recovered by the chemical activation. Interestingly, after cooling in liquid nitrogen, the conductivity was perfectly recovered. Furthermore, DC current-voltage (I-V) curves were measured varying the relative humidity in order to compare with results of the AC-conductivity measurements. Two kinds of processes for water molecules in the film were strongly suggested; one concerns an ionic conduction and the other concerns an electrode reaction. When the film was exposed to methanol saturated nitrogen gas, the I-V profile dramatically changed, which indicates an irreversible change in the cast-coated Nafion^® thin film.

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The electronic absorption spectra of 2-(salicylideneamino)phenol (SAP), 2-(salicylideneamino)aniline (SAA) and 2-(salicylideneamino)benzenethiol (SABT) have been measured in various media. Their polarization spectra have been also obtained by the use of the stretched polymer film technique. From the spectral data in conjunction with ab initio and semiempirical MO calculations, the molecular and electronic structure and the nature of the electronic transitions of the above compounds have been clarified. SAP, SAA and SABT are considered to have twisted molecular structures: the salicylideneamino groups are tilted against the phenyl groups by 29, 37 and 34° for SAP, SAA and SABT, respectively. The first electronic transition (357 nm band) of SAP (SAA, 382 nm or SABT, 352 nm) is polarized along the longer-molecular axis, to which charge transfer transition from 2-hydroxyphenyl(2-aminophenyl or 2-mercaptophenyl) to azomethine group is considerably contributed.

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A series of aryl fluoroalkyl ethers, composed of hydrocarbon components, fluorinated alkyl groups, and ether linkage group has good thermal and oxidative stability and has excellent lubricities due to strong coordination of ether oxygen atoms to metal surfaces. In this study, the antiwear effectiveness of aryl fluoroalkyl ethers was evaluated by Falex wear test.
Aryl fluoroalkyl ethers were miscible with bis(alkylphenyl) ether, silicone oils and polyalkylene glycols, and improved their antiwear properties. Five wt% addition of BisOSBP-A-TFE or BisP-OT-TFE to bis(alkylphenyl) ether reduced the wear to 1/30. Nine wt% addition of β-Naph-(HFP)₃ to dimethyl silicone reduced the wear to 1/35. Nine wt% addition of BisP-AP-TFE to polypropylene glycol reduced the wear to 1/8. All aryl fluoroalkyl ethers evaluated in this study proved to be highly durable against high temperature, even in air.

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We developed and commercialized the biphenyl-type epoxy molding compound at the first time in 1989, which was suitable for surface mount devices. The biphenyl-type epoxy molding compound with low crosslinking density showed higher fracture toughness at high temperature than conventional cresol novolac-type epoxy molding compound. Furthermore, water absorption was reduced by increasing the silica content through the addition of small amount of micro spherical silica that gave good fluidity to the molding compound. As a result, the biphenyl-type epoxy molding compound made a significant improvement on resistance against cracks during re-flow soldering process.
We also developed and commercialized the halogen-free flame retardant epoxy molding compound in 1995. By decreasing content of flammable epoxy matrix resin in the compound and increasing aromatic group content in the epoxy matrix resin, the flame resistance of the epoxy molding compound without either halogenated flame retardant or antimony compound successfully passed the level of UL94, V-0. It also possessed excellent reliability, such as heat resistance, humidity resistance and re-flow soldering resistance, due to its low impurity and low water absorption.

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This paper describes synthesis of new hybrid compound 3 consisting of arbutin (1) and kojic acid (2). The compound was synthesized in four step reactions from 1. At first, phenolic hydroxy group of 1 was protected, and then tosyl group was introduced at position 6, giving rise to the electrophile-type arbutin derivative 5. Then, the nucleophilic substitution of 2 with 5 successfully took place in the presence of DBU in DMF solvent to produce the hybrid compound 6. Finally, the deprotection of the benzyl group was carried out by the catalytic hydrogenation to give the desired compound 3. The analytical data of the compound fully supported the structure of 3.

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Low crystalline porous aggregates of hydroxyapatite (HAp) were prepared with colloidal calcium carbonate and phosphoric acid. Particle size and specific surface area of spherical HAp aggregates were controllable by two-step phosphoration with colloidal calcium carbonate and ammonium dihydrogenphosphate using low crystalline porous aggregates of HAp as seeds. The HAp aggregates after two-step phosphoration showed high crystallinity and thermal stability.

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