Shohei Tanaka, Kenta Adachi
Phosphorus, Sulfur, and Silicon and the Related Elements, 2022, 1-9, 848-856
DOI:10.1080/10426507.2022.2046573

Shohei Tanaka, Mina Imamura, Kenta Adachi
J. Sol-Gel Sci. Technol., 2022, 102 , 322-334
DOI:10.1007/s10971-002-05773-5

Koki Isoyama, Seiji Tani, Suzuko Yamazaki
Colloids and Surfaces A, 2022, 635, 128060
DOI:10.1016/j.colsurfa.2021.128060

Suzuko Yamazaki, Masanari Kutoh, Yukari Yamazaki, Nanami Yamamoto, and Mamoru Fujitsuka
ACS Omega, 2021, 6 , 31557-31565
DOI:10.1021/acsomega.1c04003

Suzuko Yamazaki, Kotoe Sonoda, Kiyotaka Maruoka, Yukari Yamazaki, Hiroshi Naragino, Kensuke Honda, Toshihiro Murafuji, Michinori Sumimoto
J. Photochem. Photobiol. A: Chem., 2021, 421, 113543
DOI:10.1016/j.jphotochem.2021.113543

Keigo Tashiro,Toshihiro Murafuji, Michinori Sumimoto, Mamoru Fujitsuka, Suzuko Yamazaki
New J. Chem., 2020, 44 , 13824-13833
DOI:10.1039/d0nj02829k

Suzuko Yamazaki, Koki Isoyama, Dai Shimizu
Optical Materials 106 (2020) 109929
DOI:10.1016/j.optmat.2020.109929

Suzuko Yamazaki, Keisuke Kozasa, Koshiro Okimura, Kensuke Honda
RSC Adv., 2020, 10, 4193-41402
DOI:10.1039/dr0ra07567a

Kenji Hori, Aki Hasegawa, Noriaki Okimoto, Suzuko Yamazaki
Journal of Computer Aided Chemistry, Vol.20, 50-55 (2019)
DOI:10.2751/jcac.20.50

Yukari Yamazaki, Mamoru Fujitsuka, Suzuko Yamazaki
ACS Appl. Nano Mater. 2019, 2, 9, 5890-5899
DOI: 10.1021/acsanm.9b01334

S. Tanaka, K. Adachi
DOI:10.1016/j.mtcomm.2019.100584

K. Tashiro, S. Yamazaki
Colloids and Surfaces A, 2019, 580, 123741
DOI : 10.1016/j.colsurfa.2019.123741

K. Tashiro, T. Tanimura, S. Yamazaki
J. Photochem. Photobiol. A: Chem., 2019, 377, 228–235.
DOI : 10.1016/j.jphotochem.2019.03.037

<2018>

K. Adachi, N. Tsuru
Bunseki Kagaku, 2018, 67, 719-726.
DOI : 10.2116/bunsekikagaku.67.719

Y. Yamazaki, K. Azami, R. Katoh, S. Yamazaki
ACS Appl. Nano Mater., 2018, 1, 5927-5935.
DOI : 10.1021/acsanm.8b01617

N. Nishiyama, K. Kozasa, T. Okajima, M. Fujitsuka, T. Majima, S. Yamazaki
Catal. Sci. Technol., 2018, 8, 4726-4733.
DOI : 10.1039/c8cy01411f

S. Yamazaki, D. Shimizu, S. Tani, K. Honda, M, Sumimoto, K, Komaguchi
ACS Appl. Mater. Interfaces, 2018, 10, 19889-19896.
DOI : 10.1021/acsami.8b04875

K. Adachi, Y. Ura, N. Kanetada
J. Porphyrins Phthalocyanines, 2018, 22, 658-669.
DOI : 10.1142/S1088424618500372

<2017>

N. Nishiyama, S. Yamazaki
ACS Omega., 2017, 2, 9033-9039.
DOI : 10.1021/acsomega.7b01393

A. Yamamoto, K. Adachi
Bunseki Kagaku., 2017, 9, 639-646.
DOI : 10.2116/bunsekikagaku.66.639

T. Seyama, T. Tanimura, K. Tashiro, S. Yamazaki
Res. Chem. Intermed., 2017, 43, 5025-5039.
DOI : 10.1007/s11164-017-3051-z

<2016>

N. Nishiyama, K. Kozasa, S. Yamazaki
Appl. Catal. A: General, 2016, 527, 109-115.
DOI : 10.1016/j.apcata.2016.09.001

K. Adachi, M. Tokushige, K. Omata, S. Yamazaki, Y. Iwadate
ACS Appl. Mater. Interfaces, 2016, 8, 14019-14028.
DOI : 10.1021/acsami.6b04115

Y. Nishimoto, Y. Hasegawa, K. Adachi, S. Yamazaki
RSC Adv., 2016, 6, 46994-47000.
DOI : 10.1039/c6ra06151f

Abstract: The effect of physicochemical properties such as specific surface area, crystalline phase, crystallite size, and crystallinity of TiO2 on photocatalytic water oxidation was investigated. Two types of polycrystalline TiO2 samples which have different physicochemical properties were prepared by a sol–gel method. The photocatalytic activities of the TiO2 samples for water oxidation were evaluated by the O2 evolution rate from an aqueous silver nitrate solution under ultraviolet light irradiation. Comparison of the two types of TiO2 samples revealed that the specific surface area and crystalline phase were not related to the O2 evolution rate. In contrast, a linear relationship between the crystallite sizes and the O2 evolution rates was observed for most of the TiO2 samples. Crystal face selective Pt and PbO2 depositions on the TiO2 samples were observed by photocatalytic reduction of PtCl62− and oxidation of Pb2+ ions, respectively, indicating that the oxidation and reduction sites are separated on the surface. An increase in the crystallite size of the TiO2 promotes a spatial separation of the redox sites and suppresses the electron–hole recombination, leading to the enhancement of the photocatalytic activity.

<2015>

S. Yamazaki, H. Ishida, D. Shimizu, K. Adachi
ACS Appl. Mater. Interfaces, 2015, 7, 26326–26332.
DOI : 10.1021/acsami.5b09310

K. Adachi, S. Toyomura, Y. Miyakuni, S. Yamazaki, K. Honda, T. Hirano
Polym. Adv. Technol., 2015, 26, 597-605.
DOI : 10.1002/pat.3491

N. Nishiyama, Y. Fujiwara, K. Adachi, K. Inumaru, S. Yamazaki
Appl. Catal. B-Environ., 2015, 176-177, 347-353.
DOI : 10.1016/j.apcatb.2015.04.015

<2014>

K. Adachi, K. Watanabe, S. Yamazaki
Ind. Eng. Chem. Res., 2014, 53, 13046-13057.
DOI : 10.1021/ie5018817

Abstract: The surface interactions between xanthene (XN) dyes, including rhodamine B, rhodamine 3B, rhodamine 19, rhodamine 6G, rhodamine 110, and rhodamine 123, and tungsten(VI) oxide (WO3) colloid particles were investigated. These XN dyes were strongly adsorbed as monolayer onto the WO3 surface via the electrostatic interaction between their peripheral cationic amino-substituents and negatively surface-charged WO3 colloid particles, and most of ones adsorbed eventually formed the stable π-stacked dimers. The geometry of dimers formed on the WO3 colloid surface is discussed on the molecular exciton theory framework. Cationic XN dyes formed the approximately ideal face-to-face H-dimers on the WO3 colloid surface, whereas zwitterionic ones had a higher tendency to form the oblique J-dimers. Additionally, we have experimentally demonstrated the possibility of pH-induced switching between H- and J-aggregation modes of the XN dye's dimers formed on the WO3 colloid surface. The findings lead to a better understanding of organic dye's adsorption/aggregation behaviors on the metal oxide surface.

<2013>

N. Kanetada, C. Matsumura, S. Yamazaki, K. Adachi
ACS Appl. Mater. Interfaces, 2013, 5, 12991–12999.
DOI : 10.1021/am403751t

Abstract: The adsorption and aggregation behaviors of the cationic porphyrin derivatives such as 5,10,15,20-tetrakis(4-pyridyl)porphyrin [TPyP], 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin [TMPyP], 5,10,15,20-tetrakis(N-ethyl-4-pyridyl)porphyrin [TEPyP], and 5,10,15,20-tetrakis(N-n-propyl-4-pyridyl)porphyrin [TPPyP] (hereafter called "TPyP derivatives") in the tungsten(VI) oxide (WO3) colloid aqueous solution at weak acidic pH were studied by UV–vis spectroscopy. The TPyP derivatives were strongly adsorbed as monolayer onto the WO3 surface via the electrostatic interaction between their peripheral cationic substituents and negatively surface-charged WO3 colloid particles, and most of the ones adsorbed eventually formed J-type dimers aligned in the head-to-tail fashion. These different dimerization states were effectively analyzed by the change of ratios among the intensities of exciton split Soret bands (H- and J-bands). Judging from the exciton coupling theory and adsorption measurements, we concluded that the J-dimer geometry of the TPyP derivatives adsorbed on the WO3 colloid particle surface is strongly dependent on the presence and difference of peripheral substituents. The results described here indicate a new and promising way of designing surface supramolecular structures combination of two principles, the self-association of organic dyes, and the steric repulsive interaction between the peripheral substituents and the inorganic semiconductor surfaces.

S. Tanaka, K. Adachi, S. Yamazaki
Analyst, 2013, 138, 2536-2539. (selected "Back Cover")
DOI : 10.1039/c3an36650b

Abstract: The enhanced photochromic behaviors of the L-phenylalanine (Phe)/tungsten(VI) oxide (WO3) colloid binary aqueous solution have been investigated by means of UV-vis absorption spectrometry. The phenomena provided a potential use of the WO3 nanoparticles as a colorimetric probe for sensitive “label-free” detection of amino acid compounds.

S. Yamazaki, T. Yamate, K. Adachi
Appl. Catal. A-Gen., 2013, 454, 30-36.
DOI : 10.1016/j.apcata.2012.12.038

Abstract: Photocatalysis of a transparent aqueous WO3 sol was investigated for the color-fading of Orange II. Dependence of the degradation rate of Orange II on pH and ionic strength of the WO3 sol was explained in terms of the electrostatic interaction between Orange II and the WO3 colloid particles. The degradation rate follows the first-order kinetics with respect to the concentration of Orange II. It was demonstrated that the photogenerated electron in WO3 reduced O2 effectively since the photochromism of the WO3 sol observed under nitrogen atmosphere did not occur under air-saturated condition. The photocatalytic activity of WO3 was lower than that of TiO2 by a factor of 0.5 and was enhanced by mixing with the TiO2 sol. The best photocatalytic performance for the degradation of Orange II was obtained by using the mixed sol with WO3:TiO2 molar ratio of 1:2. Similar enhancement in the photocatalytic activity was confirmed for the degradation of 4-chlorophenol.

<2012>

T. Seyama, K. Adachi, S. Yamazaki
J. Photochem. Photobiol. A Chem, 2012, 249, 15-20.
DOI : 10.1016/j.jphotochem.2012.09.001

Abstract: Kinetic studies on the photocatalytic degradation of trichloroethylene (TCE) were performed in TiO2 or WO3 aqueous sol which consisted of anatase nanocrystalline TiO2 of ca. 3.9 nm or WO3 spherical particles of ca. 17.6 nm, respectively. Photocatalytic activity of TiO2 colloid is higher than that of WO3 by a factor of 2.1. Kinetic analyses for both sols give a similar rate law containing γ value which represents a ratio of the reaction rate of the photogenerated electrons with O2 against the total disappearance rate of the photogenerated electrons. Reaction temperature did not affect the TiO2 photocatalysis whereas higher temperature increased the oxidation rate of TCE in the WO3 sol. Such a difference in the temperature effect was explained in terms of the γ values. The photocatalytic degradation of TCE was enhanced by mixing the WO3 and the TiO2 sol and the best performance was obtained by using the mixed sol with WO3:TiO2 molar ratio of 1:2. In the mixed sol, the similar temperature dependence as in the WO3 sol was obtained. Reaction mechanism and the rate law are proposed to account for the obtained kinetic data.

K. Adachi, S. Tanaka, S. Yamazaki, H. Takechi, S. Tsukahara, H. Watarai
New J. Chem., 2012, 36, 2167-2170 (selected "Inside Front Cover")
DOI : 10.1039/c2nj40415j

Abstract: In the methylene blue (MB)/phenylalanine (Phe)/tungsten(VI) oxide (WO3) colloid ternary aqueous solution, the MB H-aggregates, which could recognize the chirality of D- and L-Phe, were formed and investigated by means of UV-Vis absorption and CD spectroscopy. These results demonstrate a chirality transfer and amplification from only the pre-adsorbed Phe molecules to MB aggregates formed on the WO3 colloid surface via non-covalent interactions.

S. Yamazaki, Y. Fujiwara, S. Yabuno, K. Adachi, K. Honda
Appl. Catal. B-Environ., 2012, 121-122, 148-153
DOI : 10.1016/j.apcatb.2012.03.026

Abstract: Porous platinum-ion-doped TiO2 (Pt-TiO2) with BET surface area higher than 200 m2 g-1 was prepared by using water as solvent and conducting dialysis in a sol-gel method and demonstrated to have superior photocatalytic activity for the photodegradation of 4-chlorophenol (4-CP) under both ultraviolet and visible light (VL) irradiation. During dialysis, 76.5% of Cl was removed and mesopores were formed in Pt-TiO2. Measurements of pore-size distribution indicated a peak at ca. 3 nm after the calcination of Pt-TiO2 at 200C. Optimal conditions to prepare Pt-TiO2 acting under VL were 0.5 at.% as the Pt-doping content and 200C as the calcination temperature in the range of 200-500C. Kinetic studies were performed to clarify the effect of the amount of Pt-TiO2, initial concentration of 4-CP, intensity and wavelength of the incident light, pH and temperature on the reaction rate and to obtain the rate law under VL irradiation. Formation of benzoquinone and hydroquinone as intermediates was observed. They were further photodegraded on Pt-TiO2 and 90.7% of 4-CP was completely mineralized at the VL irradiation of 390 min.

K. Adachi, T. Mita, S. Tanaka, K. Honda, S. Yamazaki, M. Nakayama, T. Goto, H. Watarai
RSC Adv., 2012, 2, 2128-2136
DOI : 10.1039/c2ra00217e

Abstract: The nanostructured tungsten(VI) oxide (WO3)/cellulose derivatives (cellulose (CE) and triacetyl cellulose (TACE)) hybrid films were prepared by a solution-dipping adsorption process, and their structure and optical properties have been investigated. Various techniques, including adsorption isotherm, transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), in situ UV-Vis absorption, and in situ total internal reflection Raman spectroscopy, were used for the characterization of the WO3/CE and WO3/TACE hybrid materials. Under UV irradiation, the photochromism (colorless → blue) was confirmed from the WO3/CE hybrid film, although no coloration of the WO3/TACE hybrid film was observed. This distinct difference in the coloration suggested that the interfacial interaction between hydroxyl groups present on the surface of the CE substrate and WO3 nanoparticles via hydrogen bonding plays a major role in the enhancement of photochromism in the WO3/CE hybrid system. Moreover, the joint evidence in in situ UV-Vis absorption and in situ total internal reflection Raman studies clearly revealed that the photogenerated coloration is related to a partial reduction of W6+ cations into W5+ cations in the WO3/CE hybrid film. The findings in this study have great implications for the development of the novel green-functional inorganic/organic hybrid materials in optical devices.

<2011>

S. Yamazaki, T. Yamate, K. Adachi
Colloids and Surfaces A: Physicochem. Eng. Aspects., 2011, 392, 163-170
DOI : 10.1016/j.colsurfa.2011.09.050

Abstract: Photochromism of a WO3 aqueous sol has been investigated in a nitrogen atmosphere under controlled temperature. Effects of ageing of the WO3 sols, concentrations of WO3 sols or Cl− ion and temperature on the coloring rate were examined. The coloring rate was the first-order with respect of the WO3 concentration. The coloring process was accelerated by an addition of TiO2 aqueous sols. Spectral changes were measured using the mixing sol with various molar ratios (γ) of WO3 and TiO2. The absorption spectra changed from those having the single peak at 775 nm to those with two peaks at 640 and 980 nm. Such spectral transformation was ascribed to the structural change of the WO3 nanoclusters, depending on the γ value and the concentration of Cl− ion.

K. Adachi, K. Honda, S. Yamazaki, T. Hirano, H. Kurokawa, A. Wakabayashi, P.H. Kasai, K. Nakamae, H. Iwabuki, K. Murakami
Polym. Eng. Sci., 2011, 51, 632-640
DOI : 10.1002/pen.21856

Abstract: The vinyltrimethoxysilane-grafted ethylene-propylene copolymer/trifunctional methoxysilane (EPR-g-VTMS/RTMS) composites were prepared via in situ silica sol-gel reactions. Five trifunctional methoxysilane compounds (n-hexyltrimethoxysilane, n-decyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-octadecyltrimethoxysilane, and phenyltrimethoxysilane) have been selected for this study. The water-cross-linked EPR-g-VTMS/RTMS composites were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy, gel content, solid-state 29Si CP/MAS NMR, wide-angle x-ray scattering, tensile strength, and field emission scanning electron microscopy measurements. The type of RTMS additive has a substantial influence on the nature of siloxane band networks and eventually the mechanical tensile properties. This finding suggests that the interaction and/or entanglement between the EPR-g-VTMS matrix and the substituent of the RTMS additives are crucial for the modifying mechanical properties. Moreover, for the water-cross-linked EPR-g-VTMS/CnTMS (n = 6, 10, 14, and 18) composites, the joint evidence provided by attenuated total reflectance-Fourier transform infrared spectroscopy, 29Si CP/MAS NMR, and wide-angle x-ray scattering results suggested the formation of ladder-type poly(n-alkyl silsesquioxane)s and the presence of the highly ordered structure with a thickness equal to the length of two n-alkyl groups in all-trans conformation.

S. Yamazaki, K. Ichikawa, A. Saeki, T. Tanimura, K. Adachi
J. Phys. Chem. A, 2010, 114, 5092-5098
DOI : 10.1021/jp911842t

Abstract: The photocatalytic degradation of chlorinated ethanes was studied in a tubular photoreactor packed with TiO2 pellets prepared by sol-gel method. The steady-state condition was not obtained, but the deterioration in the photocatalytic activity was observed during the irradiation. Effects of mole fractions of water vapor, O2, and C2H5Cl or C2H4Cl2 and reaction temperature on the photodegradation of C2H5Cl or C2H4Cl2 were examined, and these data were compared with those obtained by the photodegradation of chlorinated ethylenes. On the basis of the products detected with and without oxygen in the reactant's gas stream, we proposed the degradation mechanism. Measurement of diffuse reflectance infrared Fourier transform spectroscopy of pyridine adsorbed on the catalysts showed that decrease in the conversion for the photodegradation of C2H5Cl was attributable to the formation of Brønsted acid sites. Comparison of the data obtained with the TiO2 and the sulfated TiO2 (SO42-/TiO2) pellets indicated that the photodegradation of C2H5Cl was suppressed by the presence of the Brønsted sites, but that of trichloroethylene was not affected. Such a difference is attributable to the adsorption process of these reactants on the acid sites on the catalyst surface.

K. Adachi, T. Mita, T. Yamate, S. Yamazaki, H. Takechi, H. Watarai
Langmuir, 2010, 26, 117-125
DOI : 10.1021/la902174s

Abstract: The monomer−aggregate equilibrium of four phenothiazine (PN) dyes, containing thionine (TH), methylene blue (MB), new methylene blue (NMB), and 1,9-dimethylmethylene blue (DMB), in the tungsten(VI) oxide (WO3) nanocolloid solution has been investigated by means of UV−vis spectroscopy. Addition of PN dye into the WO3 nanocolloid solution brought about significant changes in the absorption spectrum, suggesting the formation of H-type (face-to-face fashion) trimer on the WO3 nanocolloid surface. The adsorptivity of PN dyes onto the WO3 nanocolloid surface was diminished by the raising the ionic strength, indicating the evidence of the electrostatic interaction between cationic PN dye and negatively charged WO3 nanocolloids. The detail analysis of each spectral data provided insight into the effect of molecular structure of PN dyes on the adsorption and aggregation behaviors on the WO3 nanocolloid surface. Moreover, in situ measurement of PN dye aggregation using the centrifugal liquid membrane (CLM) technique revealed that the aggregation of PN dyes on the WO3 nanocolloid surface proceeded in a two-step three-stage (monomer → dimer → trimer) formation. The aggregation mechanism of PN dyes on the WO3 nanocolloid surface was discussed on the basis of Kasha’s exciton theory.

S. Yamazaki, M. Sugihara, E. Yasunaga, T. Shimooka, K. Adachi
J. Photochem. Photobiol, A: Chem., 2010, 209, 74-78
DOI : 10.1016/j.jphotochem.2009.11.002

Abstract: Cu-deposited TiO2 films were prepared by photoreduction of Cu(II) in the presence of sodium formate. With the initial Cu(II) concentrations more than 100 mg L-1, induction periods were observed before the transmittance decreased. Scanning electron microscopy indicated that Cu particles of 2.6 ± 0.5 μm were deposited isolatedly with much open space in the induction periods. The films prepared by changing the irradiation time within the induction periods showed a higher photocatalytic activity than a pure TiO2 for the degradation of methylene blue under the reaction condition without purging air.

K. Adachi, T. Hirano, P.H. Kasai, K. Nakamae, H. Iwabuki, K. Murakami
Polym. Int., 2010, 59, 510-516
DOI : 10.1002/pi.2729

Abstract: In situ silica sol–gel-derived organic–inorganic hybrid materials, which comprise a vinyltrimethoxysilane-grafted ethylene–propylene copolymer (EPR-g-VTMS) and n-hexyltrimethoxysilane (HTMS), were successfully prepared in the presence of an organic acid and base catalyst. Benzenesulfonic acid and aniline were selected as the organic acid and base catalyst, respectively, to examine the progress and effect of progressive changes in the silane water-crosslinking reaction of EPR-g-VTMS/HTMS composites. The water-crosslinked EPR-g-VTMS/HTMS composites were characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, gel content, solid-state 29Si cross-polarization/magic-angle spinning NMR, wide-angle X-ray scattering, tensile strength and field-emission scanning electron microscopy measurements. These results revealed that the type of catalyst has a substantial influence on the nature of siloxane bonds and eventually the physical tensile properties of the water-crosslinked EPR-g-VTMS/HTMS composites, which can be explained mainly from knowledge of the traditional acid- and base-catalyzed silica sol–gel reaction. Moreover, an in-depth analysis of the aniline-catalyzed composites indicated the formation of ladder-type poly(n-hexylsilsesquioxane)s and the presence of a highly ordered structure with a thickness equal to the length of two n-hexyl groups in all-trans conformation. We demonstrate potential for the future design of highly ordered silicate-based organic–inorganic hybrid nanocomposites.

安達健太
財団法人 近畿地方発明センター 研究助成成果報告書, 2010, 47-53.

<2009>

S. Ikeda, H. Kobayashi, Y. Ikoma, T. Harada, S. Yamazaki, M. Matsumura
Appl. Catal. A: Gen., 2009, 369, 113-118
DOI : 10.1016/j.apcata.2009.09.008

Abstract: TiO2 particles encapsulated in hollow silica shells with controlled shell thicknesses were fabricated. Compared to naked TiO2 without coverage by a hollow silica shell, all of these composites showed low levels of photocatalytic activity for gas-phase decomposition of acetone into CO2. The activities over these composites tended to decrease with increase in thickness of the lateral silica shell. These results can be explained by a decrease in the diffusion of acetone with increase in thickness of the silica shell, leading to hampering of supply of the substrate to the surfaces of core TiO2 particles. In contrast, for the overall photodecomposition of gaseous 2-propanol into CO2, the presence of the lateral silica shell was found to be beneficial, i.e., the composite induced a high level of activity compared to the activity of naked TiO2. The enhancement of activity for this reaction was likely to be due to condensation of the intermediate product of acetone in the void spaces, leading to an increase in the collision probability between acetone and the surface of the TiO2 core.

S. Yamazaki, H. Abe, T. Tanimura, Y. Yamasaki, K. Kanaori, K. Tajima
Res. Chem. Intermed., 2009, 35, 91-101
DOI : 10.1007/s11164-008-0001-9

Abstract: The thermal treatment of TiO2 pellets prepared by the sol–gel method decreased the photocatalytic activity. The activity divided by the specific surface area of the pellets for the complete mineralization of ethylene or chloroform was maximized at the firing temperature of 400°C. For the photocatalytic degradation of trichloroethylene (TCE), most of them were converted to chlorinated by-products, such as dichloroacetic acid, chloroform, and phosgene, and the stoichiometric ratio of [CO2]formed/[TCE]degraded showed a maximal value at 400°C. The electron spin resonance (ESR) spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) in the flow injection system indicated that firing at 400°C gave the highest signal intensity of DMPO–OH adducts. These findings indicated that the OH radical was produced most effectively on the TiO2 fired at 400°C, which would be related to the content of anatase and rutile. Concerning the formation of chlorinated by-products from TCE, more dichloroacetic acid (DCAA) were detected and less CHCl3 and COCl2 were formed at lower firing temperatures, suggesting that the branching ratio of chloroethoxy radicals to the formation of DCAA or CHCl3 and COCl2 by C–C bond scission depended on the firing temperature.

S. Tani, H. Yamaki, A. Sumiyoshi, Y. Suzuki, S. Hasegawa, S. Yamazaki, J. Kawamata
J. Nanosci. Nanotechnol., 2009, 9, 658-661
DOI : 10.1166/jnn.2009.J081

Abstract: The interaction of three photoactive organic dyes, Rhodamine B, Rhodamine 6G and a stilbazolium derivative 4’-dimethylamino-N-methyl-4-stilbazolium with synthetic sodium-saponite has been examined by UV-visible absorption spectroscopy. In all cases, bathochromic shifts and the reduction of peak absorbance for the dyes were observed in the absorption spectra at a low dye concentration (25% adsorption of the cation exchange capacity (CEC) of the clay), although the shape and the width of their absorption bands were similar to those in aqueous solution. This absorption behavior indicates that the organic dye molecules adsorbed onto the surface of the negatively charged clay particles and the adsorbed molecules were well dispersed. The photodegradation of the organic dyes in aqueous solution and in the clay suspension has been also examined by the irradiation of a laser beam at a wavelength of 532 nm. We have found that the hybridization of the organic dyes with the exfoliated clay particles largely enhanced a photodegradation. The clay particles acted as a catalyst even at a high concentration such as ∼300% of CEC.

K. Adachi, T. Hirano
J. Sol-Gel Sci. Tech., 2009, 49, 186-195
DOI : 10.1007/s10971-008-1857-2

Abstract: Catalytic effects of Bronsted acid on the early kinetics of water-crosslinking reaction in the vinyltrimethoxysilane-grafted ethylene–propylene copolymer (EPR-g-VTMS) system were investigated by means of an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) technique and gel fraction measurements. Four sulfonic acids with different substituent, including methanesulfonic acid (C1SO3H), 1-propanesulfonic acid (C3SO3H), 1-pentanesulfonic acid (C5SO3H), and dodecylbenzenesulfonic acid (C12PhSO3H), were selected to examine the progress and effect of progressive changes in the silane water-crosslinked network structure in comparison with a primary amine (n-octadecylamine, Lewis base). From the kinetic analysis using Arrhenius equation, we found that the frequency factors for both hydrolysis (ATR-FTIR) and condensation step (gel content) of EPR-g-VTMS decreased in the order of C1SO3H > C3SO3H > C5SO3H > C12PhSO3H, while the activation energy values for each reaction did not differ significantly. These relationships can be explained mainly on the basis of the diffusion factors of the sulfonic acids in EPR-g-VTMS system. Moreover, the stress–strain curve comparison between water-crosslinked EPR-g-VTMS samples containing sulfonic acid and amine compound clearly indicated the difference in their tensile properties as a result of the catalyst variation; the use of sulfonic acid as water-crosslinking catalyst eventually achieves to the soft and tough water-crosslinked EPR-g-VTMS, while the hard and strong one was produced using amine catalyst. Not only the catalytic activity but also the type of the catalyst has eventually significant effects upon the physical properties of the water-crosslinked EPR-g-VTMS.

山崎鈴子
財団法人 池谷科学技術振興財団 年報, 2009, 20, 166.

<2008>

S. Yamazaki, T. Mori, T. Katou, A. Saeki, M. Sugihara, T. Tanimura
J. Photochem. Photobiol.A: Chem., 2008, 199, 330-335
DOI : 10.1016/j.jphotochem.2008.06.017

Abstract: Photocatalytic degradation of 4-(tert-octyl)phenol (4-OP) has been investigated by recirculating the aqueous solution through a packed bed reactor with TiO2. The first-order rate constant k for the degradation of 4-OP was evaluated to be 5.40×10−3 min−1 and an activation energy of 18.6 kJ mol−1 was obtained. The rate constant k was not dependent of the flowrate but a decrease in total organic carbon (TOC) became smaller as the flowrate increased. Under the illumination for 6 hrs at the flowrate of 28.5 ml min−1, 83.2% of 4-OP was degraded but 60.7% of the initial TOC was remained. Measurements of LC/MS using electrospray ionization revealed the formation of byproducts having molecular weights of 136, 178, 192, 220 and 222. Possible candidates for these byproducts were proposed. The degradation rate of 4-OP was remarkably accelerated by addition of K2S2O8: 4-OP was completely disappeared under irradiation of 4 or 2 hrs, respectively, in the presence of 4×10−3 or 2×10−2 mol dm−3 K2S2O8. In the latter case, the TOC decreased to 34.6% by continuing the irradiation even after 4-OP was disappeared. In the presence of S2O82−, 4-OP was degraded without TiO2, which is attributable to the reaction by SO4− radicals. We demonstrated that the UV/TiO2/S2O82− system was more appropriate than the UV/S2O82− for decontamination of 4-OP in water.

S.Yamazaki, N. Nakamura
J. Photochem. Photobiol. A:Chem., 2008, 193, 65-71
DOI : 10.1016/j.jphotochem.2007.06.008

Abstract: Photocatalysis of a transparent aqueous sol, which was prepared by peptizing titanium tetraisopropoxide in nitric acid for 7 days followed by dialysis was examined for the color-fading of methylene blue (MB) and Orange II and for the degradation of 4-chlorophenol (4-CP). Measurements of XRD patterns of the powders obtained by drying the sol indicated the formation of anatase. Under argon-bubbling, MB was degraded via the formation of colorless leuco form and the color of the sol returned to original by bubbling air in the dark. Reaction rates for oxidative degradation of MB under air-bubbling showed maximum at the 0.013 mol-Ti dm−3 in the sol and at pH 4.2. Reaction rates for color-fading of Orange II were higher by a factor of 6.8 than that of MB. The dependence of rates on the concentrations of MB or Orange II in the sol was discussed with the rate law. For the degradation of 4-CP in the sol under the irradiation for 6 hrs, 92.7% of 4-CP was completely dechlorinated and 69.5% of the initial TOC was decreased.

H. Takechi, K. Adachi, H. Monjushiro, H. Watarai
Langmuir, 2008, 24, 4722-4728
DOI : 10.1021/la7027862

Abstract: The apparent circular dichroism (CD) and the linear dichroism (LD) spectra of the aggregates of achiral zinc(II)-5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (ZnTPyP), formed at the toluene/water interface in a centrifugal liquid membrane (CLM) cell, were investigated by comparison with the microscopic CD and LD spectra of a single interfacial aggregate of ZnTPyP about 100 μm in length, measured by a microscope−spectropolarimeter. The interfacial ZnTPyP aggregate showed two types of flat trapezoidal shapes, one had a seedlike core at an edge (type I) and another a needlelike core at an edge (type II). The microscopic CD and LD spectra were observed by varying the angle between the parallel axis of the trapezoidal aggregate and the perpendicular axis of a polarized light for LD. The plot of the CD intensity against the LD intensity for a single aggregate, observed at a given wavelength, showed a rotated elliptical shape with a long axis through the origin, when the orientation angle was changed. From these results, it was concluded that the apparent CD spectra observed by the CLM-CD method were mainly due to the large linear dichroism of the aggregate. Both type I and type II structures showed two transition dipole moments, parallel and perpendicular to the long axis of the structure, but suggesting a more developed J-aggregate in type II structure. AFM measurements showed that the interfacial ZnTPyP aggregate had a multilayer structure, in which the unit monolayer thickness was 1.58±0.23 nm. Finally, the orientation angle of the interfacial aggregate in the CLM cell was estimated as 41°−44° to the rotating axis of the cell.

K. Adachi, T. Hirano
Ind. Eng. Chem. Res., 2008, 47, 1812-1819
DOI : 10.1021/ie0708069

Abstract: Catalytic effects on the water-cross-linking process (hydrolysis and condensation) of vinyltrimethoxysilane-grafted ethylene−propylene copolymer (EPR-g-VTMS) were investigated for several amine compounds (primary, secondary, and tertiary). Silane water-cross-linking kinetics and curability of EPR-g-VTMS samples containing each specific amine were analyzed by the ATR-FTIR technique and gel-fraction method using xylene as an eluent. The primary amine showed the strongest catalytic effect, followed by the secondary one. The tertiary amine, meanwhile, showed little catalytic effect. Moreover, the amine compound with a small substituent had a much faster initial rate of the silane water-cross-linking reaction than the one with a large substituent. In order to gain visual insights into the hydrolysis and condensation of an alkoxysilane in the presence of the amine compound, the plausible reaction intermediates were examined using a semiempirical molecular orbital method (AM1 level) for each case. The novel possible catalytic mechanism for the amine compounds in the EPR-g-VTMS system is proposed on the basis of these results and the knowledge of traditional silicate sol−gel reactions.

K. Adachi, T. Hirano
Eur. Polym. J., 2008, 44, 542-549
DOI : 10.1016/j.eurpolymj.2007.11.033

Abstract: Catalytic efficiencies of seven divalent metal acetylacetonate complexes [M(acac)2; M = Cd(II), Co(II), Cu(II), Fe(II), Ni(II), Pb(II), and Zn(II)] with respect to the water-crosslinking kinetics of vinyltrimethoxysilane-grafted ethylene-propylene copolymer (EPR-g-VTMS) were investigated to examine the effects of progressive changes in metal ion using ATR–FTIR spectroscopy. The hydrolysis activation energies of EPR-g-VTMS follows the order: No catalyst ≈ Ni(acac)2 > Co(acac)2 > Fe(acac)2 ≈ Zn(acac)2 > Cd(acac)2 ≈ Cu(acac)2 > Pb(acac)2. Interestingly, the kinetics results revealed that the plots of hydrolysis activation energies of EPR-g-VTMS containing M(acac)2 complexes and Eigen's water exchange constants for corresponding metal ions showed a excellent linear relationship, suggesting that the reaction pathway for the silane water-crosslinking with hydrous M(acac)2 complex in EPR-g-VTMS system may be similar to that for water exchange of the metal ion in an aqueous system. Based on the knowledge of traditional kinetics studies by Eigen and Wilkins and hybrid sol–gel chemistry, the plausible catalytic mechanism for M(acac)2 complexes in EPR-g-VTMS system was proposed.

<2007>

S. Yamazaki, N. Yamabe, N. Nagano, A. Fukuda
J. Photochem. Photobiol. A: Chem., 2007, 185, 150-155
DOI : 10.1016/j.jphotochem.2006.05.024

Abstract: 1,4-Dioxane in hexane as a solvent was adsorbed on TiO2 due to an electrostatic interaction. The porous TiO2 pellets (SG) prepared by sol–gel method were superior adsorbent to ST-B21 and Degussa P-25. Effects of firing temperature of the pellets and the initial concentrations of 1,4-dioxane on the adsorption percents were examined. Photocatalytic degradation of aqueous 1,4-dioxane gave 1,2-ethanediol diformate and formic acid as intermediates. Analysis of total organic carbon indicated that 1,4-dioxane was mineralized effectively in the following order: P-25 > ST-B21 > SG. The photocatalytic degradation of 1,4-dioxane adsorbed on the TiO2 pellets in air showed that ST-B21 had a higher activity than SG. These facts indicate that SG pellet acts as a good adsorbent because of its high specific surface area but the internal region of the pores is not illuminated and acts only as a support.

矢野潤, 中村紀幸, 山崎鈴子, 一森勇人, 尾崎信一, 岡野　寛
工学教育, 2007, 55, 37-42
DOI : 10.4307/jsee.55.2_37

Abstract: Few general chemistry textbooks of high schools, colleges and universities introduce the corrosion of iron into the oxidation-reduction (redox) section, although the corrosion is very popular phenomena for students. Besides, no description appears about conductive polymers as anti-corrosion materials. The corrosion is a redox reaction proceeding through the local cell mechanism : the iron oxidation half-cell reaction at the local anode and the reduction of oxygen at the local cathode. To prepare a teaching tool for understanding of the mechanism, the visualization of the corrosion was attempted using phenolphthalein and potassium hexacyanoferrate (III) as color couplers for the anodic and cathodic products : Fe2+ and OH-. The local anode and cathode were obviously shown as gradual blue and red coloration when commercial nails were soaked in 4% NaCl aqueous solution containing phenolphthalein and potassium hexacyanoferrate (III) . On the other hand, no coloration occurred for the nail covered with a conductive polymer polyaniline. To know the anti-corrosion mechanism, the open-circuit potential of the nail was measured. The fact that the potential was kept at the potential range where iron was passivated implied that polyaniline acted as an in-situ oxidant. The visualization was experimentally performed at an actual chemistry class and the utility value was estimated. As a result, the visualization is expected to be a useful teaching tool for the corrosion and the understanding of the role of polyaniline as the anti-corrosion material.

K. Adachi, T. Hirano, K. Fukuda, K. Nakamae
Macromol. React. Eng., 2007, 1, 313-320
DOI : 10.1002/mren.200600044

Abstract: The hydrolysis and overall water-crosslinking kinetics of vinyltrimethoxysilane-grafted ethylene–propylene copolymer (EPR-g-VTMS) containing boron trifluoride monoethylamine complex (BF3–MEA), boron trifluoride methanol complex (BF3–MeOH), or di-n-butyltin(II) dilaurate (DBTL) as a silane-crosslinking catalyst was followed by ATR-FT-IR and measuring the gel fraction, respectively. Kinetics results by ATR-FT-IR technique showed that using BF3–MEA provided much lower activation energy for the hydrolysis reactions than that of DBTL; however, BF3–MeOH had little catalytic effect on both the hydrolysis and overall water-crosslink reaction of EPR-g-VTMS. We propose that the actual catalytic effect of ethylamine molecule dissociated from BF3–MEA results in the displacement of Si-OCH3 groups via an SN2-Si mechanism.

<2006>

K. Adachi, K. Chayama, H. Watarai
Chirality, 2006, 18, 599-608.
DOI : 10.1002/chir.20293

Abstract: The Pd(II)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP)-mediated chiral assembly of thioether-derivatised phthalocyanatomagnesium(II) compounds (MgPc(SR)8, SR is benzylthio (SBz) or benzhydrylthio (Bh)) was formed in toluene and at the toluene/water interface, and investigated by means of UV-Vis absorption and circular dichroism (CD) spectroscopy combined with the centrifugal liquid-membrane (CLM) devise. Interfacial tension measurements indicated that, in the presence of PdSO4 in the aqueous phase, BINAP ligand adsorbed as a monolayer forming Pd(II)BINAP2+ complex at the toluene/water interface. UV-Vis absorption spectrum of MgPc(SR)8 in the Q-band region was blue-shifted in toluene upon addition of [Pd(II)BINAP]Cl2, but red-shifted at the toluene/water interface when Pd(II)BINAP2+ was formed at the interface. These results suggested that MgPc(SR)8-Pd(II)BINAP complex formed H-aggregate (face-to-face type) in toluene solution and J-aggregate (end-to-end type) at the toluene/water interface, respectively. Moreover, the specific bisignate CD spectral pattern in both systems indicated that the aggregates of MgPc(SR)8-Pd(II)BINAP complexes were chirally twisted, well controlled by the chirality of BINAP ligand. Very interestingly, the morphology of MgPc(SBz)8-Pd(II)BINAP and MgPc(SBh)8-Pd(II)BINAP aggregates formed at the toluene/water interface were significantly different as the rodlike and the ribbonlike crystalline structure, respectively, as observed by a scanning electron microscopy (SEM). On the basis of these experimental results, we proposed schematic molecular models of the chiral aggregates of MgPc(SR)8-Pd(II)BINAP complexes and demonstrated the specific role of the toluene/water interface.

K. Adachi, H. Watarai
Anal. Chem., 2006, 78, 6840-6846
DOI : 10.1021/ac060720+

Abstract: Subphthalocyaninatoboron(III) was applied for the first time as a novel marker-tag of testosterone (Subpc-test) for the binding analysis with human serum albumin (HSA) at a liquid/liquid interface. The binding interaction of Subpc-test with HSA at the n-hexane/water interface was studied by UV−visible absorption and circular dichroism (CD) spectroscopy combined with a centrifugal liquid membrane cell at different pHs of aqueous solutions. Complementary studies by a high-speed stirring experiment and an interfacial tension measurement were also performed to characterize the interfacial adsorptivity of Subpc-test and HSA molecules, respectively. The n-hexane solution of Subpc-test showed no optical chirality, but the contact with the aqueous solution of HSA induced its optical chirality, clearly suggesting the formation of Subpc-test/HSA complexes at the n-hexane/water interface. Furthermore, pH profiles of CD signals showed that the interaction between Subpc-test and HSA was very sensitive to the neutral-to-base transition (N−B transition). Interfacial formation of the Subpc-test/HSA complex was studied in the presence of the site-selective ligand, furosemide (site I) or cefaclor (site II). The experimental results suggested that Subpc-test is bound to site I of the HSA molecule at the n-hexane/water interface. This technique using subphthalocyanine as a tag molecule and the liquid/liquid interface as a two-dimensional nanoreaction field will be useful for the evaluation of the interaction between drugs or hormones and proteins.

K. Adachi, H. Watarai
Chem. Eur. J., 2006, 12, 4249-4260.
DOI : 10.1002/chem.200501330

Abstract: Several subphthalocyanine derivatives that contain an alkoxo substituent as an axial ligand (RO-Subpc, R = 9-anthracenemethyl, benzyl, phenyl, 3,5-dimethylbenzyl, 3,5-dimethylphenyl, 4-methylbenzyl, and 4-methylphenyl) were synthesized. The formation of inclusion complexes of RO-Subpc with β-CD in DMSO and at the toluene/water interface was investigated by UV/Vis absorption spectroscopy, induced circular dichroism (ICD), and nuclear magnetic resonance (NMR) measurements. Interfacial tension measurements suggested that β-CD adsorbed as a monolayer at the toluene/water interface and probably orientated towards the toluene phase with its primary face. The 1:1 composition of β-CD⋅RO-Subpc inclusion complexes was confirmed in DMSO and at the toluene/water interface for BzO-Subpc, PhO-Subpc, MeBzO-Subpc, and MePhO-Subpc. A 2:1 inclusion complex of AnO-Subpc formed in DMSO. The observed ICD spectra of β-CD⋅RO-Subpc inclusion complexes are discussed with respect to molecular modeling and the simulation based on Tinoco–Kirkwood theory. Interestingly, the ICD spectra of β-CD⋅BzO-Subpc and β-CD⋅MeBzO-Subpc inclusion complexes exhibited a negative sign in DMSO and a positive sign at the toluene/water interface. This reversal of the ICD sign strongly suggests a difference in the structure of the inclusion complexes: β-CD at the interface formed the inclusion complex with its primary face, whereas the secondary face of β-CD bound favorably to RO-Subpc in DMSO.

K. Adachi, H. Watarai
New J. Chem., 2006, 30, 343-348.
DOI : 10.1039/b517657c

Abstract: Formation of the Pd(II)-induced thioether-derivatised subphthalocyanine Subpc(SR)6 (R = Et (ethyl) or Bz (benzyl)) aggregate at the toluene/glycerol interface was investigated by means of a new in situ spectrophotometric method using two-phase Couette flow (TPCF). The shear-forced orientation of the aggregate of Subpc(SR)6–Pd(II) complexes formed at the toluene/glycerol interface was studied by their linear dichroism (LD) spectra. The H-aggregate of the Subpc(SEt)6–Pd(II) complex gave no LD signal, but the J-aggregate of the Subpc(SBz)6–Pd(II) complex clearly afforded LD spectra at a wide range of rotation speeds, suggesting a longer J-aggregate structure in the Subpc(SBz)6–Pd(II) system. The relaxation kinetics of the shear-forced orientation of the Pd(II)–Subpc(SBz)6 aggregate were observed after stopping the rotation and analysing using a multi-exponential decay equation. By increasing the Subpc(SBz)6 concentration in toluene, the fast relaxation fraction of 6.6–7.5 seconds decreased and the slow relaxation fraction of 292–322 seconds increased. The results obtained in this study demonstrate that the TPCF method is useful for studying the size distribution of aggregates formed at liquid/liquid interfaces.

K. Adachi, K. Chayama, and H. Watarai
Langmuir, 2006, 22, 1630-1639
DOI : 10.1021/la0526131

Abstract: A chiral thioether-substituted phthalocyanine ((2,3,9,10,16,17,23,24-octakis-1-phenylethylthio- phthalocyaninato) magnesium(II) [MgPc(SEtPh)8]) has been synthesized, which can be bound by soft-metal ions such as palladium(II) ion. Aggregates formed from MgPc(SEtPh)8 and Pd(II) in toluene and at the toluene/water interface were characterized by means of UV−vis absorption and circular dichroism (CD) spectrometries using centrifugal liquid−membrane (CLM) cell. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) and scanning electron microscope (SEM) were used as complementary techniques. The toluene solution of MgPc(SEtPh)8 had no optical chirality. However, the addition of PdCl2 into the toluene solution of MgPc(SEtPh)8 induced optical chirality, which indicated the formation of a twisted H-type dimer (face-to-face fashion) of MgPc(SEtPh)8 bound by four PdCl2 in the bulk toluene solution. On the other hand, in the toluene/water interface, helical J-aggregate (head-to-tail fashion) of MgPc(SEtPh)8 bound by PdCl2 was formed, in which one J-aggregate unit contained five 1:2 complexes of MgPc(SEtPh)8−Pd(II) on average. On the basis of the experimental results and the exciton theory for optical chirality, a possible mechanism for the chiral aggregation of MgPc(SEtPh)8−Pd(II) complexes at the interface was proposed. In the present study, we demonstrated a novel strategy for the design of helical phthalocyanine aggregates using the liquid/liquid interface as a template.

<2005>

T. Tanimura, A. Yoshida, S. Yamazaki
Appl. Catal. B: Env., 2005, 61, 346-351
DOI : 10.1016/j.apcatb.2005.05.015

Abstract: Photocatalytic degradation of trichloroethylene (TCE) was investigated using a tubular photoreactor packed with TiO2 powders prepared by sol–gel techniques. Powders of the following metals: Cr, Fe, Ni, Cu and Pt, or Ca(OH)2 were uniformly mixed with the TiO2 powders and then their effect on the formation of COCl2, CHCl3, and CHCl2COCl as by-products was examined. Concentrations of COCl2 and CHCl3 were determined in a product gas stream by GC/MS while CHCl2COCl accumulated on the catalyst surface. When the catalysts were immersed in water after TCE photodegradation, the formation of Cl- and CHCl2COO− ions was confirmed by ion-chromatography. Of the chemicals tested, only Cu and Ca(OH)2 inhibited the formation of the chlorinated by-products. With increasing Cu and Ca(OH)2 content, TCE conversion decreased while the stoichiometric ratio ([CO2]formed/[TCE]degraded) increased. Concentrations of COCl2, CHCl3, and CHCl2COCl decreased with increasing Cu and Ca(OH)2 content. Especially, the formation of COCl2 was remarkably suppressed with Ca(OH)2.

S. Yamazaki, A. Yoshida, H. Abe
J. Photochem. Photobiol. A:Chem., 2005, 169, 191-196
DOI : 10.1016/j.jphotochem.2004.06.018

Abstract: The photocatalytic degradation of chloroform was studied in a tubular photoreactor packed with TiO2 pellets prepared by sol–gel method. Concentrations of chloroform and CO2 in the gas stream and Cl− ion which was dissolved from the pellets into water after the photodegradation experiments were detected quantitatively. Chloroform was completely mineralized to CO2 and HCl but the conversion decreased drastically with an increase in the irradiation time. Such a decrease in the catalytic activity was attributable to the accumulation of Cl− on the TiO2 surface and was recovered by washing the pellets with water. The presence of Cu and Ca(OH)2 increased the concentration of Cl− accumulated on the surface. The deterioration of the catalytic activity was suppressed with Ca(OH)2 whereas no appreciable effect was observed with Cu. The TiO2 prepared by sol–gel method exhibited a higher catalytic activity than commercially available Degussa P-25.

K. Adachi, H. Watarai
J. Mater. Chem., 2005, 15, 4701-4710 (selected "Hot Articles")
DOI : 10.1039/b509009a

Abstract: The interfacial aggregation of three thioether-substituted phthalocyanine–magnesium(II) complexes, MgPc(SR)8, of (2,3,9,10,16,17,23,24-octakis-ethylthiophthalocyaninato)magnesium(II), [MgPc(SEt)8], (2,3,9,10,16,17,23,24-octakis-benzylthiophthalocyaninato)magnesium(II), [MgPc(SBz)8], and (2,3,9,10,16,17,23,24-octakis-benzhydrylthiophthalocyaninato)magnesium(II), [MgPc(SBh)8] were investigated in the toluene/water system by means of a centrifugal liquid membrane (CLM) method. Aggregation of MgPc(SR)8 molecules at the interface was significantly promoted by the complexation with soft metal ions such as Pd(II) and Hg(II) added to the aqueous phase. The interfacial adsorption of MgPc(SEt)8 was caused even in the absence of Pd(II) by the formation of a co-facial H-dimer, but the presence of Pd(II) promoted H-dimer aggregation at the interface. In the cases of MgPc(SBz)8 and MgPc(SBh)8, there was observed no significant self-aggregation, but in the presence of Pd(II), the interfacial aggregation of Pd(II) complexes of MgPc(SBz)8 and MgPc(SBh)8 proceeded remarkably. It was suggested that MgPc(SBz)8–Pd(II) and MgPc(SBh)8–Pd(II) could not form H-aggregates, because of the steric hindrance of benzyl or bezhydryl group, but they formed J-aggregates. Furthermore, MALDI-TOF/MS spectra indicated that oligomers of MgPc(SBz)8–Pd(II) complex were formed at the liquid/liquid interface. The present study demonstrated the first example of Pd(II)-induced interfacial aggregation of phthalocyanine derivatives at the liquid/liquid interface, and suggested the possibility of controlling the aggregate structure between H- and J-aggregates by the size of peripheral substitute groups.

K. Adachi, K. Chayama, H. Watarai
Soft Matter, 2005, 1, 292-302 (selected "Hot Articles")
DOI : 10.1039/b508648e

Abstract: Novel chloro-subphthalocyaninatoboron(III) (Subpc) derivatives with six thioether at the 2 and 3 positions of peripheral benzene (Subpc(SR)6) such as chloro-[2,3,9,10,16,17-hexakis-ethylthio-subphthalocyaninato] boron(III) (Subpc(SEt)6) and chloro-[2,3,9,10,16,17-hexakis-benzylthio-subphthalocyaninato] boron(III) (Subpc(SBz)6) were synthesized. The interfacial adsorption of Subpc and Subpc(SR)6, and the interfacial aggregation of Subpc(SR)6–Pd(II) complexes in the toluene–water system have been investigated by means of high-speed stirring (HSS) spectrometry, centrifugal liquid-membrane (CLM) spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Characteristically orientated structures of Subpc(SR)6 molecules and the aggregates of Subpc(SR)6–Pd(II) complexes at the toluene–water interface have been suggested depending on the structures of Et and Bz at the periphery. The interfacial aggregation was observed only in the presence of palladium(II), in which one aggregate unit contained at least seven 1 : 2 complexes of Subpc(SR)6–Pd(II). Interestingly, the absorption spectra of the interfacial aggregates of Subpc(SEt)6–Pd(II) and Subpc(SBz)6–Pd(II) complexes were very similar to the previously reported spectra of μ-oxo dimer and binuclear molecule of subphthalocyanine, respectively, suggesting the formation of “face-to-face” or H-aggregate for Subpc(SEt)6–Pd(II) and “head-to-tail” or J-aggregate for Subpc(SBz)6–Pd(II), respectively, at the toluene–water interface.

<2004>

S. Yamazaki, T. Tanimura, A. Yoshida, K. Hori
J. Phys. Chem. A. 2004, 108, 5183-5188
DOI : 10.1021/jp0311310

Abstract: The photoassisted catalytic degradation of chloroethylene was studied in a tubular photoreactor packed with TiO2 pellets prepared by a sol−gel method. The experiments were performed in a noncirculating mode. Kinetic data and the reaction products were compared with those for the photodegradation of ethylene, trichloroethylene, and tetrachloroethylene. The theoretical calculations at the MP4/6-31G**//B3LYP/6-31G** level indicated that the addition of OH radicals to chlorinated ethylenes is more exothermic than that of Cl radicals by 14.6−29.5 kcal mol-1. Examination of Cl mass balance indicated that the concentration of Cl- collected from the TiO2 surface was higher than that from the product gas stream. When the photodegradation of ethylene was performed on the TiO2 pellets which had been used for that of TCE or which were pretreated with HCl, the formation of chloroacetaldehyde was confirmed by the GC/MS. We proposed that during the photodegradation of the chlorinated ethylenes, the Cl-, as one of the reaction products, accumulated and was oxidized to Cl radical on the TiO2 surface, which might be due to the oxidation by OH radical. Then, the Cl radical reacted with chlorinated ethylenes, leading to the formation of undesirable chlorinated byproducts.

J. Yano, K. Noguchi, S. Yamasaki, S. Yamazaki
Electrochem., 2004, 72, 304-309
DOI : 10.1119/1.2746365

J. Yano, K. Noguchi, S. Yamasaki, S. Yamazaki　
Electrochem. Commun., 2004, 6, 110-114
DOI : 10.1016/j.elecom.2003.10.026

Abstract: An aramid resin, poly(p-phenylene terephtalamide) (PPTA) was precoated on an ITO electrode as a stable matrix film. Iridium oxide could be electrodeposited on the electrode because the PPTA film was permeable to dissolved species. Although the cyclic voltammogram (CV) pattern of the PPTA–iridium oxide film was almost the same as that of the original iridium oxide film, the color change differed a little. In the oxidized state, the PPTA–iridium oxide film showed greenish blue. The XPS-biding energy of Ir 4f5/2 and Ir 4f7/2 electrons was shifted to about 2 eV higher energy. The maximum absorption wavelength of the original iridium oxide film was about 650 nm, while that of the PPTA–iridium oxide film was about 600 nm. The color change was probably due to donating of the lone pair electrons of PPTA to the indium. The electrodeposition of Au on the PPTA–iridium oxide film was carried out. The obtained PPTA–iridium oxide–Au film showed quite different electrochromic properties. New redox current peaks appeared in the CV of the film. The film was colored vermilion in the reduced state and greenish blue in the oxidized state. The XPS-biding energy of Ir 4f5/2 and Ir 4f7/2 electrons was shifted to about 2 eV lower energy, implying that the electrodeposition of Au transformed the electronic state and structure structure of iridium oxide, suggesting the formation of a -Au-Cl-Ir- binuclear Cl-bridged complex.

K. Adachi, H. Watarai
Bull. Chem. Soc. Jpn., 2004, 77, 2011-2020
DOI : 10.1246/bcsj.77.2011

Abstract: Three novel phthalocyaninatomagnesium(II) derivatives with eight peripheral thioethers (MgPc(SR)8) such as (2,3,9,10,16,17,23,24-octakis-ethylthiophthalocyaninato)magnesium(II) (MgPc(SEt)8), (2,3,9,10,16,17,23,24-octakis-benzylthiophthalocyaninato)magnesium(II) (MgPc(SBz)8), and (2,3,9,10,16,17,23,24-octakis-benzhydrylthiophthalocyaninato)magnesium(II) (MgPc(SBh)8) were synthesized. The interfacial adsorption and aggregation behavior of the three derivatives in a toluene/water system were examined by means of a high-speed stirring (HSS) method and a centrifugal liquid membrane (CLM) method. The interfacial adsorption constant of each MgPc(SR)8 derivative at the toluene/water interface was determined by the HSS measurement. Only in the case of MgPc(SEt)8, the formation of the trimer was observed at the interface. Moreover, the CLM measurements showed that the interfacial aggregate of MgPc(SEt)8 had a new broad band (613 nm) at the blue flank of the Q band (702 nm) of MgPc(SEt)8 monomer, which might be ascribed to H-aggregate. Extended double-dipole (EDD) model calculations suggested a cofacially stacked arrangement of MgPc(SEt)8 molecules in the trimer. The interfacial spectral change indicated that the aggregation of MgPc(SEt)8 at the toluene/water interface proceeded in a two-step, three-stage (monomer → dimer → trimer) formation.

安達健太
MATERIAL STAGE., 2017, 17, 49-52
Web content :

山崎鈴子
光化学, 2015, 46, 66-73

Abstract: Degradation of various pollutants by photocatalysis has been widely studied over the last 30 years. Titanium dioxide is still the widely used photocatalyst for environmental remediation because there is no satisfactory alternative. Sol-gel method is efficient for tailoring nanostructure materials with high specific surface area without the need for using expensive equipment. We have developed a synthetic method to prepare porous TiO2 with BET surface area higher than 200 m2 g-1 by using water as solvent and conducting dialysis in the sol-gel method. Recently, many attempts have been devoted to enhance the photocatalytic activity of TiO2 by extending its spectral response to visible light and/or suppressing the recombination of the photogenerated hole and electron. In this review, the preparation of metal-ion-doped TiO2 working under visible light by conducting dialysis in the sol-gel method and enhancement of the photocatalytic activity obtained by mixing TiO2 and WO3 sol are prepared.

H. Watarai, K. Adachi
Anal. Bioanal. Chem., 2009, 395, 1033-1046
DOI : 10.1007/s00216-009-3012-5

Abstract: Some new experimental methods for measuring the optical chirality of molecular aggregates formed at liquid–liquid interfaces have been reviewed. Chirality measurements of interfacial aggregates are highly important not only in analytical spectroscopy but also in biochemistry and surface nanochemistry. Among these methods, a centrifugal liquid membrane method was shown to be a highly versatile method for measuring the optical chirality of the liquid–liquid interface when used in combination with a commercially available circular dichroism (CD) spectropolarimeter, provided that the interfacial aggregate exhibited a large molar absorptivity. Therefore, porphyrin and phthalocyanine were used as chromophoric probes of the chirality of itself or guest molecules at the interface. A microscopic CD method was also demonstrated for the measurement of a small region of a film or a sheet sample. In addition, second-harmonic generation and Raman scattering methods were reviewed as promising methods for detecting interfacial optical molecules and measuring bond distortions of chiral molecules, respectively.

安達健太
ぶんせき（トピックス）, 2009(5), 261-262.

山崎鈴子
ぶんせき（話題欄）, 2007(5), 247-248

山崎鈴子
オプトニューズ, 2006, 2（通巻152号）, 48-50.

安達健太, 渡會仁
表面, 2006, 44, 39-59.

山崎鈴子
化学と工業, 2004, 57, 929‐930.

河野誠，安達健太
特開2017-015159 (JP 2017-015159)

安達健太，山崎鈴子，豊村祥子
特開2015-234907 (JP 2015-234907)

山崎鈴子, 安達健太, 石田裕貴
特開2014-062218 (JP 2014062218)

概要： フォトクロミズムを示す複合膜であって、成膜性、暗下での透明性に優れ、且つ、光照射により高い遮光性を示す調光フィルム等として利用できる複合膜を提供する。複合膜は、遷移金属酸化物、水溶性高分子化合物、及びヒドロキシ基を有する水溶性化合物（ただし、前記水溶性高分子化合物を除く）を含有する。遷移金属酸化物としては、酸化タングステンが好ましく、水溶性高分子化合物としてはメチルセルロース等のアルキルセルロースが好ましく、ヒドロキシ基を有する水溶性化合物としては、エチレングリコールやグリセリン等のアルコール類や、シュウ酸やグリコール酸等の有機酸類が好ましい。本発明の複合膜は、紫外線の照射によって発色するため、調光フィルム、記録媒体、青写真（日光写真）用感光体等として有用である。 Abstract: The title composite membranes contain transition metal oxides (e.g., WO3), water-​solution macromolecules (e.g., alkylcelluloses), and water-​solution compounds (e.g., alcohols., organic acids). The composite membranes are transparent under room light, and develop blue by UV irradation to have light shield 99​%.