We developed two new types of organic-inorganic hybrid coatings using sol-gel technology. They have excellent durability such as weather resistance, soil resistance, heat resistance, scratch resistance etc. Many applications such as super weather resistant paint for exterior walls, heat resistant paint, binder for textiles or non-woven fabrics etc. have been achieved.
Organically modified polysiloxane was polymerized by hydrolysis and condensation of alkoxyalkylsilane in the presence of colloidal silica or colloidal alumina. We successfully improved the pot life of coatings based on organic synthesis. We also studied the structure of polysiloxanes using NMR.
The organic-inorganic hybrid polymer was prepared by using polyacrylate having alko xysilyl groups, alkoxyalkylsilane and Al-compound as an effective catalyst. The structure of the hybrid was assumed by using GPC analysis, DMTA analysis and SEM. This hybrid could be formed as a thick (>100μm), uniform, transparent and flexible film by coating. This film can be cured at wide range of temperature (room temp ≈200°C) using a special catalyst. It has been applied as super weather resistant paint as well as for other uses.

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When a viologen-linked Mn (III) porphyrin complex as well as a mixed system of Mn (III) porphyrin and hexylviologen were used as a catalyst for a monooxygenation reaction of cyclohexene in an airequilibrated dichloromethane suspension containing insoluble zinc powder as a reductant and benzoiC anhydride as a cleaving reagent of dioxygen O-O bond, cyclohexene oxide (epoxide) was obtained as a single oxidation product of cyclohexene. Cyclic voltammetry was carried out to clarify the role of the molecular dioxygen, hexylviologen, 1-methyl-imidazole (III/II) and benzoic anhydride for the redox characteristics of the Mn porphyrin, and to explain this catalytic mechanism. It was consequently proved that the coordination of 1-MeIm to Mn porphyrins let to vary the redox potential of its couple and also the coordination of 1-MeIm to Mn (II) porphyrin interfered with that of the molecular dioxygen to its porphyrin, and hexylviologen acted as a mediator of electron transfer from zinc powder to Mn (II) porphyrin-O₂ adduct. Therefore, the amount of the produced epoxide varied complexly with concentration of 1-MeIm added in this catalytic system. The larger amount of epoxide was obtained in the mixed system using the Mn porphyrin that has more positive redox potential, because the reduction of the Mn porphyrin occurred more easily.

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Four crystalline forms of strontium sulfite were synthesized by a metasilicate gel-growth method. We found from inspection of the crystals growth that the strontium sulfite crystals with each form were produced through the two processes of shape transformations and discussed that the processes of shape transformations were changed by the ionic product ( [Sr²⁺] [SO₃^2-] ) in the gel. To start with, spherulite of strontium sulfite was formed in the gel for all the conditions. The spherulite was not changed on the condition of [Sr²⁺] [SO₃^2-] = 70.5 × 10^-6-8.06 × 10^-6 mol² dm^-6 in the gel. Then, the spherulite was transformed into the ellipsoidal form by way of the poly-spherulite on the condition of [Sr²⁺] [SO₃^2-] =5.72 × 10^-6-0.87 × 10^-6 mol² dm^-6 in the gel. In addition, the spherulite was transfo rmed into the spindle form of single crystal by way of the growth of the center of poly-spherulite on the condition of [Sr²⁺] [SO₃^2-] = 0.63 × 10^-6-0.32 × 10^-6 mol² dm^-6 in the gel.

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Well-formed transparent crystals of CaNb₂O₆ were grown from an Na₂Mo₂O₇ flux by the slow cooling method. The crystal growth was conducted by heating mixtures of solute and flux at 1100 °C for 10 h and subsequent cooling to 500 °C at a rate of 5 °Ch^-1. Colorless to pale brown CaNb₂O₆ crystals were obtained from high-temperature solutions containing 9-25 mol% solute. The crystal sizes depended on the solute content. The largest crystal of 20 mm long and 2.2 mm wide was obtained from the solution with 12 mol% solute. The form of the grown crystals was a twelve-sided prism bounded by the {100}, {010}, {110}, {310} and {111} faces. The aspect ratios were in the range of 2.5 to 6.8. The lattice parameters were a=15.025±0.003 Å, b=5.732±0.002 Å and c=5.230±0.002 Å. The density was 4.76 ± 0.02 g cm^-3. The CaMoO₄ and Na₂Nb₄O₁₁ crystals were produced as by-products in most runs. The crystals of CaNb₂O₆, C aMoO₄ and Na₂Nb₄O₁₁ crystallized in this order from the high-temperature solution containing 12 mol% solute.

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An α-cyclodextrin-based three-fold symmetric tripodal ferrichrome mimic containing three MeN (OH) COCH₂CH₂CONH side chains was designed and synthesized. The chirality of its com plex with Fe³⁺ ion was examined in various solvents such as water, methanol, and acetonitrile by using circular dichroism spectroscopy. The chirality varied remarkably with changing solvents. A mechanism involving hydrogen-bonding with solvent, which determines the chirality, was proposed.

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A copper (I) chloride-pyridine complex supported on silica gel was prepared by mixing porous silica gel beads with an acetonitrile solution containing the complex composed of copper (I) chloride (CuCl) and pyridine under nitrogen, followed by removal of liquid phase under reduced pressure. The resulting silica gel, 5.8 g, contained 4.39 mmol of CuCl and 4.08 mmol of pyridine. It rapidly adsorbed carbon monoxide (CO) at 30 °C under 1.0 atm of CO, and the equilibrium amount of adsorbed CO was 3.29mmol (80.6% against containing pyridine). The adsorbed CO was rapidly desorbed by maintaining it at 70 °C under 1.0 atm or at 30 °C under 0.4 mmHg. The adsorption-desorption cycle was repeated without any deterioration. The equilibrium amount of adsorbed CO (3.29 mmol) was 5.5 times that of adsorbed carbon dioxide (0.60 mmol), and 36.6 times that of adsorbed methane (0.09 mmol) at 30 °C under 1.0 atm. The reversible and selective adsorption of CO was attributed to formation of molar ratio 1: 1: 1 CuCl-pyridine-CO complex from CO molecule and molar ratio 1: 1 CuCl-pyridine complex supported on silica gel. When the adsorbent contacted with oxygen, the CO adsorbing ability decreased. The adsorbing ability was completely recovered by maintaining the adsorbent at 120 °C under 1.0 atm of hydrogen for 48 h.

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Photochemical formation of hydroxyl radical (OH radical) was studied using rain (n=22) and dew (n=9) waters collected during June to September, 1997 in Higashi-Hiroshima city, Hiroshima pre fecture. The mean photochemical formation rates of OH radical for rain and dew waters were 0.36μMh^-1and 0.83μMh^-1 (1 M=1 mol dm^-3), respectively, at noon, clear sky conditions in Higashi-Hiroshima city (34 degree north) on May 01. Photoformation of OH radical was detected in all the samples studied, except for one rain water, and the OH radical formation kinetics appeared to be linear. Effect of filtration (0.45, um glass fiber filter) was studied to elucidate the formation mechanisms of OH radical. Comparison between filtered and unfiltered samples indicated that the particles (>0.45μm) present in rain and dew waters caused small change (less than 22%) in OH radical photoformation. Furthermore, OH radical formation rates from nitrate (NO₃^-) and nitrite (NO₂^-) ion photolyses were estimated, based on the photolysis rate constants (J_NO3-=2.43×10^-7s^-1 : J_NO2-=2.8×10^-5s^-1 : J_HNO2=3.30×10^-4s^-1), nitrate and nitrite ion concentrations, and pK_a of nitrous acid in those samples. The estimated OH radical formation rates from nitrate ion photolysis accounted for only small percentage of OH radical observed in rain and dew waters. Nitrous acid photolysis accounted for majority of OH radical formed in dew waters (mean =99.3%), while on the average 11.2% of OH radical was from nitrous acid photolysis in rain waters. For rain waters, it was speculated that major sources of OH radical were reaction between reduced iron (Fe (II)) and hydrogen peroxide (HOOH), “Fenton's reaction” and photoformation from dissolved organic compounds.

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In Pd catalysts for automobile exhaust, the effect of oxygen storage component (OSC) on NO_x conversion after thermal aging has been studied, characterizing structure, oxidate state, O₂ storage capacity and NO_x adsorption property.
After aging, the hi gher O₂ storage capacity was achieved and NO_x conversion was improved by addition of Zr to CeO₂. From the various characterizations, it was considered that there were cubic and tetragonal structure in (Ce, Zr) O₂, and that tetragonal one enhanced the O₂ storage-release ability. As a result, even in O₂ perturbated atmosphere like automotive exhaust, using (Ce, Zr) O₂ as OSC, O₂ on active site might spillover to OSC and active site keep reductive state, so NO might absorb and converse to N₂.

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Antibacterial characteristics of zinc oxide (ZnO) powders heated at different temperatures against Escherichia coli and Staphylococcus aureus were determined by the conductance method. The values of the minimal inhibitory concentrations (MIC) of the ZnO powders increased with an increase in heating temperature. The variation of MIC against E. coli was larger than that against S. aureus. It was suggested that the difference in the sensitivity between S. aureus and E. coli was due to the action of hydrogen peroxide generated from the ZnO powders.

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Chitosan was crosslinked with glutaraldehyde in lactic acid, and the insoluble polymer obtained was examined for its ability to bind the acid dyes, C. I. Acid Orange 7 and Methyl Orange, in buffered solutions at pH's 5 and 7. The intrinsic and first binding constants and the number of binding sites for the binding of C. I. Acid Orange 7 by crosslinked chitosan were measured. Also the thermodynamicparameters accompanied by the binding were calculated. The first binding constant of C. I. Acid Orange 7 for crosslinked chitosan was larger than that for partially deacetylated chitin used as a control sample. This is mainly attributed to the difference of the number of binding sites between these two substrates. The binding ability of crosslinked chitosan for Methyl Orange was also larger than those of bovine serum albumin and poly (N-vinylpyrrolidone) showing large binding abilities for small molecules. The amount of C. I. Acid Orange 7 or Methyl Orange bound by chitosan was markedly lower than that of crosslinked chitosan in pH's 5 and 7, respectively. It is obvious that the affinity for the acid dyes is greatly increased by crosslinking through the entropy effect.

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