Published Papers - YAJIMA Setsuko

Quantitative Evaluation of Aggregation Behaviors of Thiomalic-acid-modified Silver Nanoparticles in Water by Photothermal Microscopy with Multiwavelength Excitation

Yoshio NAKAHARA, Jun MIYAZAKI, Aoi HIRONO, Takashi IENAGA, Setsuko YAJIMA

BUNSEKI KAGAKU ( Japan Society for Analytical Chemistry )  74 ( 1.2 ) 23 - 28   2025.01  [Refereed]

DOI

Polydopamine-Coated Solid Silica Nanoparticles Encapsulating IR-783 Dyes: Synthesis and NIR Fluorescent Cell Imaging

Yoshio Nakahara, Haruki Nakabayashi, Jun Miyazaki, Mitsuru Watanabe, Toshiyuki Tamai, Setsuko Yajima

ACS Omega ( American Chemical Society (ACS) )  9 ( 18 ) 19932 - 19939   2024.04  [Refereed]

DOI

Properties of surface layers of polyethylene naphthalate substrates modified by ultraviolet light irradiation for their electroless deposition

Toshiyuki Tamai, Mitsuru Watanabe, Rie Kakehashi, Yoshio Nakahara, Setsuko Yajima

Colloid and Polymer Science   302 ( 3 ) 433 - 448   2024.03  [Refereed]

　View Summary

The properties of thin surface layers of polymer substrates should be investigated and controlled for their application in electroless deposition. In this paper, polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) substrates were modified by plasma treatment, ultraviolet (UV)/ozone treatment, or UV (254 nm) irradiation. The chemical and physical properties of the modified layer were studied by measuring contact angle and zeta potential, field-emission scanning electron microscope (FE-SEM) imaging, and infrared spectroscopy. The condition of the surface modification affected oxygenation of the polymer chains. The oxygenation formed hydrophilic surface functional groups and relatively polar low-molecular-weight fragments resulting from the scission of the polymer chains. The surface functional groups and the fragments governed the properties of the modified layer. Adhesive metal films were electrolessly deposited on the thinner modified layer having the hydrophilic functional groups. In contrast, the thicker modified layer containing the fragments decreased the adhesion of the metal films. For example, UV/ozone treatment of the PEN substrate formed the thicker modified layer, on which no adhesive metal films were deposited. These findings illustrate that optimizing the condition of the surface modification thoroughly is feasible to form the modified layer having the chemical and physical properties appropriate for depositing adhesive metal films.

DOI

Quantitative Discrimination of Silver and Gold Nanoparticles Immobilized in Transparent Plastic Film by Photothermal Microscopy with Multiwavelength Excitation

Yoshio Nakahara, Jun Miyazaki, Aoi Hirono, Takashi Ienaga, Setsuko Yajima

Chemistry Letters   52 ( 2 ) 113 - 115   2023.02  [Refereed]

DOI

イオンセンサーの応答機構の解明を目指したオルガノゲルのイオン選択的構造変化の観測

矢嶋 摂子, 増永 啓康, 佐々木 園 （Part： Lead author,　Corresponding author )

SPring-8/SACLA利用研究成果集   10 ( 6 ) 485 - 487   2022.12  [Refereed]

Influencing foam properties of aqueous bis(2-ethylhexyl)sulfosuccinate solutions by addition of polypropylene-glycol-modified and amino-modified silica nanoparticles

Keita Aono, Hiroya Shiba, Furitsu Suzuki, Yoshihiro Yomogida, Motomitsu Hasumi, Shinpei Kado, Yoshio Nakahara, Setsuko Yajima

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS ( ELSEVIER )  655   2022.12  [Refereed]

　View Summary

The effect of silica nanoparticle (SiO2NP) addition on the air-water interfacial rheology and foam properties was investigated in aqueous solutions of bis(2-ethylhexyl)sulfosuccinate (AOT), an anionic surfactant. Two types of SiO2NPs were prepared: polypropylene-glycol-modified SiO2NPs (PPG-SiO2NPs) and amino-modified SiO2NPs (NH2-SiO2NPs). The addition of SiO2NPs stabilized the foam in the aqueous AOT solution in all cases, but the effect on the air-water interfacial behavior differed depending on the SiO2NP type. Adsorption of NH2-SiO2NPs to the air-water interface improved the air-water interfacial dilational viscoelasticity (E), enhancing foam stability. Although PPG-SiO2NPs did not adsorb to the air-water interface, the movement of AOT molecules to the air -water interface was partially suppressed by hydrophobic interaction with PPG-SiO2NPs in the bulk aqueous solution. This event limited the decrease in E, thereby stabilizing the foam.

DOI

Room-temperature coalescence of Pd nanoparticles with sacrificial templates and sintering agents, and their catalytic activities in the Suzuki coupling reaction.

Soichiro Okada, Yoshio Nakahara, Mitsuru Watanabe, Toshiyuki Tamai, Yasuyuki Kobayashi, Setsuko Yajima

RSC Advances   12   14535 - 14543   2022.05  [Refereed]

DOI

Synthesis of Silica Nanoparticles with Physical Encapsulation of Near-Infrared Fluorescent Dyes and Their Tannic Acid Coating

Yoshio Nakahara, Yukiho Nakajima, Soichiro Okada, Jun Miyazaki, Setsuko Yajima

ACS Omega ( American Chemical Society (ACS) )  6 ( 27 ) 17651 - 17659   2021.07  [Refereed]

DOI

Room-Temperature Coalescence of Tri-n-Octylphosphine-Oxide-Capped Cu-Ag Core-Shell Nanoparticles: Effect of Sintering Agent and/or Reducing Agent

Soichiro Okada, Yoshio Nakahara, Mitsuru Watanabe, Toshiyuki Tamai, Yasuyuki Kobayashi, Setsuko Yajima

Bulletin of the Chemical Society of Japan   64 ( 5 ) 1616 - 1624   2021.05  [Refereed]

　View Summary

Metal nanoparticle pastes are useful for nanoinks to form fine conductive patterns in printed electronics. This study reports a novel method for room-temperature coalescence of Cu-Ag core-shell nanoparticles (Cu@Ag NPs), which are expected to have the properties of both migration and oxidation resistance originating from Cu and Ag, respectively. First, oleylamine/oleic-acid capped Cu@Ag NPs were synthesized by the galvanic replacement method. Second, the ligand exchange reaction to tri-n-octylphosphine oxide (TOPO) was carried out on the surface of Cu@Ag NPs. Finally, TOPOcapped Cu@Ag NPs were dipped into methanol containing a sintering agent and/or a reducing agent. When HCl was added as a sintering agent to methanol, the crystallite size of Cu@Ag NPs significantly increased. Furthermore, the almost complete removal of organic compounds and suppression of significant oxidation of Ag and Cu were observed. In consideration of these results, a Cu/Ag conductive thin film was prepared from TOPO-capped Cu Ag NPs by dipping into methanol containing HCl at room temperature under air atmosphere. Electrical resistivity of the obtained Cu/Ag thin film was (5.1 « 1.7).

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Foam Destabilization Effect of Sodium Bis(2-ethylhexyl)sulfosuccinate on Sodium Alkylsulfate Aqueous Solutions Based on Its Fast Surface Tension Gradient Relaxation

Keita Aono, Furitsu Suzuki, Yoshihiro Yomogida, Motomitsu Hasumi, Shinpei Kado, Yoshio Nakahara, Setsuko Yajima （Part： Corresponding author )

Bulletin of the Chemical Society of Japan ( The Chemical Society of Japan )  94 ( 2 ) 542 - 548   2021.02  [Refereed]

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Effects of Polypropylene Glycol at Very Low Concentrations on Rheological Properties at the Air–Water Interface and Foam Stability of Sodium Bis(2-ethylhexyl)sulfosuccinate Aqueous Solutions

Keita Aono, Furitsu Suzuki, Yoshihiro Yomogida, Motomitsu Hasumi, Shinpei Kado, Yoshio Nakahara, Setsuko Yajima （Part： Corresponding author )

Langmuir ( American Chemical Society (ACS) )  36 ( 34 ) 10043 - 10050   2020.09  [Refereed]

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Relationship between air-water interfacial dilational viscoelasticity and foam property in aqueous solutions of sodium alkylsulfates with different hydrocarbon chains

Keita Aono, Furitsu Suzuki, Yoshihiro Yomogida, Tetsuya Okano, Shinpei Kado, Yoshio Nakahara, Setsuko Yajima （Part： Corresponding author )

Journal of Dispersion Science and Technology ( Informa UK Limited )    1 - 7   2020.02  [Refereed]

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Preparation of Ag2Se QDs with excellent aqueous dispersion stability by orgainc coating with aqueous ATRP

Yoshio Nakahara, Yuki Kunitsu, Nobuhiko Ozaki, Mutsuo Tanaka, Setsuko Yajima

POLYMER BULLETIN ( Springer Science and Business Media LLC )  76 ( 9 ) 4753 - 4768   2019.09  [Refereed]

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Surface modification of polyethylene naphthalate substrates by ultraviolet light-irradiation and assembling multilayers and their application in electroless deposition: The chemical and physical properties of the stratified structure

T. Tamai, M. Watanabe, Y. Kobayashi, J. Kobata, Y. Nakahara, S. Yajima

Colloids and Surfaces A: Physicochemical and Engineering Aspects   575   230 - 236   2019.08  [Refereed]

　View Summary

© 2019 Elsevier B.V. Electroless metal deposition on polymer surface is useful for fabricating metallic patterns. The surfaces of polyethylene naphthalate (PEN) substrates were modified by ultraviolet (UV) light -irradiation and layer-by-layer assembly of polyelectrolyte multilayer thin films, and then nickel and copper films were electrolessly deposited on the substrate surfaces to form the stratified structure, PEN-substrate/multilayer/metal-film. The chemical and physical properties of the modified layer in the substrate surfaces were studied by X-ray photoelectron spectroscopy, nanoindentation test, and measuring contact angle. The properties of the UV-irradiated surface layer depended on the condition of surface modification and affected the adhesion of the deposited metal film. Adhesive nickel films were deposited on the UV (254 nm)-irradiated PEN substrates that have thin modified layers compatible with the multilayers. In contrast, no adhesive nickel films were deposited on the substrate surfaces having thicker and fragile modified layers. These contrasting results are originated from the oxygenation and crosslinking of the polymer chains in the substrate surface layers, and reactive species formed by the UV irradiation induce the oxygenation and crosslinking. The properties of the modified substrate-surface play an important role for depositing adhesive metal films.

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Crystallite Size Increase of Silver Nanoparticles by Ligand Exchange and Subsequent Washing Process with Antisolvent

Okada Soichiro, Nakahara Yoshio, Watanabe Mitsuru, Tamai Toshiyuki, Yajima Setsuko

JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY   19 ( 8 ) 4565 - 4570   2019.08  [Refereed]

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Room-Temperature Sintering of Tri-n-Octylphosphine-Oxide-Capped Silver Nanoparticle Paste by Dipping into an Organic Solvent Containing a Sintering Agent

Okada Soichiro, Nakahara Yoshio, Watanabe Mitsuru, Tamai Toshiyuki, Kobayashi Yasuyuki, Yajima Setsuko

JOURNAL OF PHYSICAL CHEMISTRY C ( American Chemical Society (ACS) )  123 ( 23 ) 14118 - 14125   2019.06  [Refereed]

DOI

A tetraester derivative of fluorescent calix[4]arene bearing a proton-ionizable moiety for highly sensitive extraction-fluorometric determination of sodium ion

Yoshio Nakahara, Yuta Furuno, Hitoshi Iwamoto, Setsuko Yajima, Keiichi Kimura

Supramolecular Chemistry ( Informa UK Limited )  30 ( 8 ) 697 - 705   2018.08  [Refereed]

DOI

Near-Infrared Dye Immobilized in Porous Silica Layer on Gold Nanorod and Its Fluorescence Enhancement by Strengthened Electromagnetic Field Based on Surface Plasmon Resonance

Yoshio Nakahara, Ryoko Takeda, Toshiyuki Tamai, Setsuko Yajima, Keiichi Kimura

Plasmonics ( Springer New York LLC )  13 ( 2 ) 645 - 652   2018.04  [Refereed]

　View Summary

We report immobilizing Nile Blue A, which is a cationic fluorescent dye emitting in the near-infrared region, in the porous silica layer on gold nanorod and its fluorescence enhancement by strengthened electromagnetic field based on surface plasmon resonance. The effect of the spacer corresponding to the silica layer on the metal-enhanced fluorescence effect is also discussed in detail. Hollow silica nanorod was in advance prepared, and then the silica layer was partly etched to increase the porosity for the improvement of the mass transfer. Subsequently, gold nanorod was fabricated in the restricted space of hollow silica nanorod. Finally, Nile Blue A was physically immobilized in the porous silica layer on gold nanorod through electrostatic interactions. The fluorescence enhancement of Nile Blue A based on surface plasmon resonance was semi-quantified by comparative experiments using hollow silica nanorod, which is exactly the same structure except for gold as silica-coated gold nanorod. Since our results demonstrated that the porosity degree of the silica layer significantly affected the fluorescence enhancement of Nile Blue A, it is hopeful that our design concept, distinct from the conventional one, can lay a foundation for further development of near-infrared fluorescence nanomaterials.

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Effect of Protective Agents on Silver Nanoparticle Preparation by Vacuum Evaporation on Running Hydrocarbon Solution

Ienaga Takashi, Nakahara Yoshio, Yajima Setsuko, Kimura Keiichi

JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY   18 ( 4 ) 2547 - 2554   2018.04  [Refereed]

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Comparison of Physical Adsorption Strength of Protective Agents via Ligand Exchange of Silver Nanoparticles Prepared by Vacuum Evaporation on Running Oil Substrate (vol 90, pg 1251, 2017)

Ienaga Takashi, Okada Soichiro, Nakahara Yoshio, Watanabe Mitsuru, Tamai Toshiyuki, Yajima Setsuko, Kimura Keiichi

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   91 ( 3 ) 506   2018.03  [Refereed]

DOI

Erratum: Comparison of physical adsorption strength of protective agents via ligand exchange of silver nanoparticles prepared by vacuum evaporation on running oil substrate (Bulletin of the Chemical Society of Japan (2017) 90 (1251) DOI: 10.1246/bcsj.20170189)

Takashi Ienaga, Soichiro Okada, Yoshio Nakahara, Mitsuru Watanabe, Toshiyuki Tamai, Setsuko Yajima, Keiichi Kimura

Bulletin of the Chemical Society of Japan ( Chemical Society of Japan )  90 ( 11 ) 1251 - 1258   2018  [Refereed]

　View Summary

We compared adsorption strength of protective agents via ligand exchange of silver nanoparticles synthesized by the improved vacuum evaporation on running oil substrate (VEROS) method. This comparison concerns physical adsorption of protective agents on the surface of silver nanoparticles instead of chemisorption. Clean surfaces of silver nanoparticles synthesized by the improved VEROS method were suitable for this investigation. All the experiments in this study were designed so that as far as possible protective agents did not ionize. Thus, oleic acid capped silver nanoparticles were synthesized by the improved VEROS method. Next, octanoic acid, n-octylamine and oleic acid were used as additive protective agents in ligand exchanges. The ligand exchange is also closely related to physical adsorption strength of protective agents on the surface of metal nanoparticles. Oleic acid on the surface of silver nanoparticles was exchanged by octanoic acid and vice versa under the same experimental conditions. On the other hand, oleic acid on the silver surface was not exchanged by n-octylamine. These results were remarkably different from those reported in general chemical synthetic methods but they were well consistent with our previous study on performance of protective agents in the synthesis of silver nanoparticles with the improved VEROS method.

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Development of Ion Sensors Based on Polysilsesquioxane Modified Chemically with Crown Ether Derivatives in View of in vivo Analyses

Setsuko Yajima, Masato Kishi, Keiichi Kimura （Part： Lead author,　Corresponding author )

BUNSEKI KAGAKU ( JAPAN SOC ANALYTICAL CHEMISTRY )  66 ( 6 ) 431 - 436   2017.06  [Refereed]

　View Summary

We used polysilsesquioxanes (PSQ), which are inorganic-organic composites, as ion-sensing membrane materials of ion sensors. In this study, PSQ-bearing methyl and vinyl groups at a ratio of 4 : 1 were modified chemically with crown ether derivatives. The membranes were formed from solutions of these compounds on the gates of ion-sensitive field-effect transistors, and used as ion-sensing membranes. The ion-sensor properties of these membranes were investigated at 25 degrees C. Ion-sensing membranes based on these PSQ responded to K+. In the case of PSQ chemically immobilized with 18-crown-6, the Nernstian response for K+ activity changes was obtained, and the K+ selectivity of the membrane was similar to that of the conventional 18-crown-6 derivative based ion-sensing membranes. In addition, the adsorption of fibrinogen on PSQ derivatives were highly suppressed; it was therefore suggested that the membranes based on PSQ showed good biocompatibility.

Surface modification of PEN and PET substrates by plasma treatment and layer-by-layer assembly of polyelectrolyte multilayer thin films and their application in electroless deposition

T. Tamai, M. Watanabe, Y. Kobayashi, Y. Nakahara, S. Yajima

RSC ADVANCES ( ROYAL SOC CHEMISTRY )  7 ( 53 ) 33155 - 33161   2017  [Refereed]

　View Summary

The surfaces of the polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) substrates were modified by plasma treatment and then layer-by-layer (LbL) assembly of polyelectrolyte multilayer thin films from two oppositely charged polyelectrolytes. Negatively or positively charged palladium complex ions bound to oppositely charged multilayer surfaces and were reduced to form palladium nanoparticles and then a nickel film was electrolessly deposited on the substrate surfaces. The multilayers on PEN and PET substrate surfaces are suitable for supporting palladium nanoparticle catalysts and their properties can be controlled by the conditions of LbL assembly.

DOI

生体試料のイオン定量のためのオリゴエチレングリコール誘導体化学修飾ゾル-ゲル感応膜の開発

石垣 裕真, 矢嶋 摂子, 田中 睦生, 木村 恵一

日本分析化学会講演要旨集 ( (公社)日本分析化学会 )  64年会   213 - 213   2015.08

Sol-gel transition of organogels observed by terahertz spectroscopy

Hiromichi Hoshina, Atsumi Ozaki, Yusuke Itagaki, Setsuko Yajima, Hal Suzuki, Shinya Ishii, Misaki Ishida, Tetsuji Uchiyama, Keiichi Kimura, Chiko Otani

CHEMICAL PHYSICS LETTERS ( ELSEVIER SCIENCE BV )  608   173 - 176   2014.07

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Terahertz (THz) absorption spectra of organogels consisting of (1R,2R)-1,2-bis(dodecanoylamino) cyclohexane/2-nitrophenyl octyl ether (RR-BDC/NPOE) and RR-BDC/n-dodecane were measured by Fourier-transform far-infrared (FT-FIR) spectroscopy. The vibrational peaks of the gels were observed at the same frequencies as those of the pure gelator, suggesting that the intermolecular structure around the N-H center dot center dot center dot O=C hydrogen bond is maintained in the gel phase. Temperature-dependent spectroscopy showed a drastic spectral change at the sol-gel transition temperature, in which the vibrational peak at 3.5 THz disappears and a new peak appears at 2.9 THz. The change in THz vibrational frequency is indicative of the structural collapse of the hydrogen-bonded fibrous architecture in the sol phase. (C) 2014 Elsevier B.V. All rights reserved.

DOI

アミド基を有する低分子ゲル化剤を用いるイオンセンサーの性能評価とゲル化膜の分光学的検討

尾崎 温美, 高見 健人, 矢嶋 摂子, 保科 宏道, 鈴木 晴, 石井 伸弥, 大谷 知行, 木村 恵一

日本分析化学会講演要旨集 ( (公社)日本分析化学会 )  62年会   167 - 167   2013.08

Sol-Gel Transition of Supramolecular Gels Observed by Terahertz SpectroscopyA

Hiromichi Hoshina, Atsumi Ozaki, Yusuke Itagaki, Setsuko Yajima, Hal Suzuki, Shinya Ishii, Misaki Ishida, Tetsuji Uchiyama, Keiichi Kimura, Chiko Otani

2013 38TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) ( IEEE )    2013

　View Summary

Terahertz (THz) absorption spectra of supramolecular gels ((1R,2R)-1,2-bis(dodecanoylamino)cyclohexane / 2-nitrophenyl octyl ether) were measured by Fourier transform far-infrared spectroscopy (FT-FIR). The spectra were measured by changing concentration and temperature of gels. The absorption intensities of the peaks around 8.6 THz show drastic change at the sol-gel transition temperature.

Chloride Ion Sensor Based on Sol-Gel-Derived Membranes Modified Chemically with Porphyrin-Manganese(III) Complexes

Setsuko Yajima, Hiromasa Ishigaki, Yusuke Hori, Rei Takeaki, Keiichi Kimura

BUNSEKI KAGAKU ( JAPAN SOC ANALYTICAL CHEMISTRY )  61 ( 3 ) 207 - 212   2012.03  [Refereed]

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Porphyrin-manganese(III) complexes were used as Cl--selective ionophores for sol-gel derived membranes encapsulating and binding covalently them. The ion-sensing membrane encapsulating the ionophore showed hardly any EMF response to Cl--activity changes, probably because the ionophore was not uniformly dispersed in the sol-gel-derived membranes. On the other hand, the ion-sensing membrane binding covalently the ionophore, in which the ionophore was dispersed in the membranes uniformly, showed near-Nernstian responses to Cl--activity changes. The sol-gel-derived membranes were relatively Cl--selective over interfering hydrophobic anions, as compared with the case of the membranes containing only a cationic additive. The Cl--selective electrode is, therefore, promising for applications to clinical analysis in the future.

Remarkable potassium selectivity of ion sensors based on supramolecular gel membranes made from low-molecular-weight gelators without any ionophore

Setsuko Yajima, Kento Takami, Ryosuke Ooue, Keiichi Kimura

ANALYST ( ROYAL SOC CHEMISTRY )  136 ( 24 ) 5131 - 5133   2011  [Refereed]

　View Summary

Supramolecular gels formed by low-molecular-weight gelators bearing diamide groups were used as ion-sensing membranes for the first time. Even though no special ionophore was added to the membranes, excellent ion selectivities for K(+) over alkali metal ions were realized with the sensor systems.

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Drastic selectivity reversal on crown-ether based ion-sensing membranes made of ordered mesoporous silica and conventional sol-gel derived one

Setsuko Yajima, Takahito Nakajima, Mariko Higashi, Keiichi Kimura

Chemical Communications   46 ( 11 ) 1914 - 1916   2010

　View Summary

A crown-ether based ion sensor, in which ordered mesoporous silica was used as a membrane material, was fabricated for the first time, and drastic selectivity reversal was attained in comparison with conventional sol-gel derived membrane based on the same crown ether. © The Royal Society of Chemistry 2010.

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Neutral carrier-type Ca2+sensors based on sol-gel-derived membranes incorporating diether-amide derivatives

Setsuko Yajima, Sachie Uchida, Yusuke Hori, Keiichi Kimura

SUPRAMOLECULAR CHEMISTRY ( TAYLOR & FRANCIS LTD )  22 ( 7-8 ) 420 - 424   2010

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We have synthesised Ca2+-selective neutral carriers for sol-gel-derived membranes encapsulating and covalently binding them. These ion-sensing membranes showed excellent EMF responses to Ca2+ activity changes with very short response times. Especially, the membranes covalently binding the neutral carriers did not deteriorate for at least 2 months. These sol-gel-derived membranes were selective for Ca2+ over Na+ and K+. The Ca2+-selective electrode is, therefore, promising for applications to clinical analysis in future.

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Selectivity enhancement in neutral-carrier-type ion sensors based on a liquid-crystalline polymer

Shusuke Osaki, Setsuko Yajima, Keiichi Kimura

ANALYST ( ROYAL SOC CHEMISTRY )  134 ( 7 ) 1472 - 1476   2009

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A liquid-crystalline polymer was applied to a neutral-carrier-type ion sensor as a membrane material for enhancement of ion selectivity. An ion-sensitive field-effect transistor (ISFET) based on the membranes containing the polymer showed high sensitivity and selectivity for K(+) by adding a low-molecular-weight liquid crystal as the plasticizer. The ion-sensor properties of the ISFETs based on the membranes containing a liquid-crystalline polymer were similar to those of the corresponding ion-selective electrodes (ISEs) based on the same polymer. The ion sensor with a liquid-crystalline polymer was more durable than that without any liquid-crystalline polymer. The use of liquid-crystalline polymer as the membrane material improves not only the ion-sensor properties but also the durability.

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Addition effect of ionic liquid to neutral-carrier-type lithium-ion sensing membranes

Ryosuke Ooue, Syusukc Oosaki, Setsuko Yajima, Keiichi Kimura

BUNSEKI KAGAKU ( JAPAN SOC ANALYTICAL CHEMISTRY )  57 ( 8 ) 619 - 624   2008.08  [Refereed]

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Plasticized poly(vinyl chloride) membranes containing an ionic liquid as the membrane solvent were prepared, and the ion-sensor properties of the ISEs were studied. When the ratio of ionic liquids to NPOE was less than 1, the ISEs showed near-Nernstian responses. However, as the ratio became higher than 1, the slope of the EMF responses became smaller. The selectivity for lithium ion was enhanced by the addition of ionic liquid into the membranes, when a polyether-amide derivative was used as the neutral carrier (lithium ionophore).

Addition effect of ionic liquid to neutral-carrier-type lithium-ion sensing membranes

Ryosuke Ooue, Syusuke Oosaki, Setsuko Yajima, Keiichi Kimura

Bunseki Kagaku   57 ( 8 ) 619 - 624   2008

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Plasticized poly(vinyl chloride) membranes containing an ionic liquid as the membrane solvent were prepared, and the ion-sensor properties of the ISEs were studied. When the ratio of ionic liquids to NPOE was less than 1, the ISEs showed near-Nernstian responses. However, as the ratio became higher than 1, the slope of the EMF responses became smaller. The selectivity for lithium ion was enhanced by the addition of ionic liquid into the membranes, when a polyetheramide derivative was used as the neutral carrier (lithium ionophore). © 2008 The Japan Society for Analytical Chemistry.

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Strong molecular aggregation of neutral carriers bearing perfluoroalkyl chains in liquid-crystalline ion-sensor membranes

Shusuke Oosaki, Setsuko Yajima, Keiichi Kimura

Analytical Sciences   23 ( 8 ) 963 - 967   2007.08

　View Summary

A liquid-crystalline benzocrown ether, 4′-[(4″-1,1,2,2- tetrahydroperfluorooctyloxy)biphenyloxycarbonyl]benzo-15-crown-5, was used as a neutral carrier of ion-selective electrodes (ISEs) to elucidate the effect of highly ordered assembling of the neutral carrier on the sensor properties through fluorophilic interactions. The properties for the membrane and the resulting ISEs based on a benzocrown ether bearing a perfluoroalkyl chain were compared with those based on the corresponding crown ether bearing an alkyl chain. Atomic force microscopy and fluorescence measurements suggested that the neutral carrier bearing a perfluoroalkyl chain formed highly aggregational states in the membranes of ISEs. 2007 © The Japan Society for Analytical Chemistry.

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Silver-ion redox sensing based on colloid formation by gallate ester derivatives

S Yajima, Y Iwane, E Nomura, H Taniguchi, K Kimura

ANALYTICA CHIMICA ACTA ( ELSEVIER SCIENCE BV )  556 ( 1 ) 189 - 194   2006.01

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Plasmon absorption of silver colloid, which was formed by reduction of silver ion with compounds bearing gallate ester groups in ethanol, was observed by absorption spectroscopy. The time-dependent absorption of silver colloid was found, which shows that the silver colloid is unstable and easy to aggregate. It seemed that a calixarene derivative bearing two gallate ester groups was the most suitable for determining silver ion. In order to prevent the silver colloid aggregation, poly(N-vinylpyrrolidone) (PVP) was added into the solution at a constant time after the preparation of sample solutions. In the calibration graph, the absorbance increased with increasing silver ion concentration, especially in the concentration range of 2.00 x 10(-6) to 1.00 x 10(-5) M. It is possible to determine silver ion concentrations using this method. (c) 2005 Elsevier B.V. All rights reserved.

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Observation of Blood Protein Adsorption on Biocompatible Ion-sensing Membrane Materials by Quartz Crystal Microbalance

S. Yajima, M. Shiraya, K. Kimura

Chemia Analityczna (Chemical Analysis)   51   939 - 947   2006

Metal colloid formation by calix[4]arene gallate ester for silver-ion determination

Y Iwane, S Yajima, E Nomura, H Taniguchi, K Kimura

BUNSEKI KAGAKU ( JAPAN SOC ANALYTICAL CHEMISTRY )  54 ( 6 ) 527 - 531   2005.06  [Refereed]

　View Summary

The surface plasmon absorption of silver colloid, which was formed by the reduction of silver ion with a calixarene derivative bearing a gallate ester group in ethanol, was observed by absorption spectroscopy. The time-dependent absorption of silver colloid was found, which shows that the silver colloid is unstable and easy to aggregate. In order to prevent the silver colloid aggregation, poly (N-vinylpirrolidone) (PVP) was added into the solution at a constant time after preparing of sample solutions. The addition of PVP was effective for the stabilization of silver colloid, and the absorbance change with time was depressed. In the calibration graph, the absorbance increased with increasing silver-ion concentration, especially in the concentration range of 2.00 x 10(-6)similar to 1.00 X 10(-5) M. It is feasible to determine silver-ion concentrations using this method.

Metal colloid formation by calix[4]arene gallate ester for silver-ion determination

Yoshie Iwane, Setsuko Yajima, Eisaku Nomura, Hisaji Taniguchi, Keiichi Kimura

Bunseki Kagaku   54 ( 6 ) 527 - 531   2005.06

　View Summary

The surface plasmon absorption of silver colloid, which was formed by the reduction of silver ion with a calixarene derivative bearing a gallate ester group in ethanol, was observed by absorption spectroscopy. The time-dependent absorption of silver colloid was found, which shows that the silver colloid is unstable and easy to aggregate. In order to prevent the silver colloid aggregation, poly(N-vinylpirrolidone) (PVP) was added into the solution at a constant time after preparing of sample solutions. The addition of PVP was effective for the stabilization of silver colloid, and the absorbance change with time was depressed. In the calibration graph, the absorbance increased with increasing silver-ion concentration, especially in the concentration range of 2.00 × 10-6-1.00 × 10-5 M. It is feasible to determine silver-ion concentrations using this method. © 2005 The Japan Society for Analytical Chemistry.

DOI

Photocontrol of ion-sensor performances in neutral-carrier-type ion sensors based on liquid-crystalline membranes

S Oosaki, H Hayasaki, Y Sakurai, S Yajima, K Kimura

CHEMICAL COMMUNICATIONS ( ROYAL SOC CHEMISTRY )  ( 41 ) 5226 - 5227   2005  [Refereed]

　View Summary

Neutral-carrier-type ion-selective electrodes based on liquid-crystalline ion-sensing membranes containing an azobenzene derivative as the photosensitive chromophore show remarkable changes in their ion selectivity on photoirradiation, which is induced by the phase transition of the membranes.

DOI

ニュートラルキャリヤ型イオンセンサー

矢嶋摂子, 木村恵一

ぶんせき   ( 6 ) 308 - 313   2005

Properties of dendritic and cyclic thiourea derivatives as neutral carriers for anion sensors

Sachie Uchida, Yuichiro Komatsu, Hitomi Satoh, Setsuko Yajima, Keiichi Kimura, Yoshito Tobe, Shin-Ichi Sasaki, Masaaki Mizuno, Yohei Watanabe, Keiji Hirose

Bunseki Kagaku   53 ( 9 ) 943 - 952   2004.09  [Refereed]

　View Summary

We desinged seven neutral carriers for hydrophilic anion sensors: four compounds containing one thiourea group and dendritic benzyl ether derivatives, two compounds containing three or four thiourea groups, and a cyclic compound containing three thiourea groups. The association constants with dihydrogen phosphate ion for these thiourea derivatives were determined in organic solvents. The compounds exhibited high association constants with dihydrogen phosphate ion. When these compounds were used as neutral carriers of ion-selective electrodes (ISEs) for phosphate ion, the slopes of the EMF responses were very small in all cases. The ISEs showed better EMF responses for sulfate ion than for phosphate ion. Especially in the case that dendritic and cyclic derivatives containing three thiourea groups were used as neutral carriers, the ISEs exhibited excellent EMF responses for sulfate ion and anion selectivities.

DOI

Neutral-carrier-type potassium ion-selective electrodes based on polymer-supported liquid-crystal membranes for practical use

S Oosaki, Y Kawai, S Yajima, K Kimura

ANALYTICAL SCIENCES ( JAPAN SOC ANALYTICAL CHEMISTRY )  20 ( 8 ) 1165 - 1169   2004.08  [Refereed]

　View Summary

Polymer-supported liquid-crystal membranes have been designed for neutral-carrier-type potassium ion-selective electrodes, aiming for practical applications of high-performance liquid-crystalline membrane ion sensors. Two types of polymer-supported liquid-crystal membranes were tested for their usefulness; one is microporous poly(tetra fluoroethylene) (PTFE) membranes impregnated by thermotropic liquid-crystalline compounds, and another is poly(methyl methacrylate) (PMMA) membrane dispersing the same liquid-crystalline compounds. Both of the polymer-supported liquid-crystal membranes containing a liquid-crystalline benzo-15-crown-5 neutral carrier as well as a lipophilic anion excluder work well as ion-sensing membranes for potassium ion-selective electrodes, the ion selectivities of which can be switched by the measurement temperatures. Specifically, PTFE-impregnated liquid-crystal membranes are better than the PMMA-dispersed ones in the sensitivity and selectivity of the resulting ion electrodes. A potassium ion assay in blood sera has proved that neutral-carrier-type ion-selective electrodes based on the polymer-supported liquid-crystal membranes are reliable for practical uses.

Silver ion sensing using π-coordinate aromatic neutral carriers for soft metal ions

Norio Yoshioka, Setsuko Yajima, Keiichi Kimura

Bunseki Kagaku   52 ( 9 ) 689 - 694   2003.09

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We have been studying neutral carriers of ion-selective electrodes (ISEs) for soft metal ions, and have reported that π-coordinate calixarene derivatives are useful for detecting soft metal ions selectively. In this study, in order to investigate what structures are essentially needed for detecting soft metal ions, several π-coordinate aromatic compounds were chosen as neutral carriers of ISEs, and the ion sensor properties were examined. An 1H-NMR study showed that t-butylcalix[4]arene tetra(allyl ether) and [2.2.2]-paracyclophane interact with silver ions power-fully, and that only t-butylcalix[4]arene interacts with thallium ions. Therefore, ISEs based on [2.2.2]-paracyclophane exhibited excellent silver ion sensor properties.

DOI

Silver ion sensing using pi-coordinate aromatic neutral carriers for soft metal ions

N Yoshioka, S Yajima, K Kimura

BUNSEKI KAGAKU ( JAPAN SOC ANALYTICAL CHEMISTRY )  52 ( 9 ) 689 - 694   2003.09  [Refereed]

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We have been studying neutral carriers of ion-selective electrodes (ISEs) for soft metal ions, and have reported that pi-coordinate calixarene derivatives are useful for detecting soft metal ions selectively. In this study, in order to investigate what structures are essentially needed for detecting soft metal ions, several pi-coordinate aromatic compounds were chosen as neutral carriers of ISEs, and the ion sensor properties were examined. An H-1-NMR study showed that t-butylcalix[4]arene tetra(allyl ether) and [2.2.2]-paracyclophane interact with silver ions powerfully, and that only t-butylcalix[4]arene interacts with thallium ions. Therefore, ISEs based on [2.2.2]-paracyclophane exhibited excellent silver ion sensor properties.

Soft metal ion-selective electrodes based on pi-coordinate calixarene derivatives

S Yajima, N Yoshioka, M Tanaka, K Kimura

ELECTROANALYSIS ( WILEY-V C H VERLAG GMBH )  15 ( 15-16 ) 1319 - 1326   2003.09

　View Summary

Calix[4]arene derivatives incorporating omega-unsaturated alkenyl groups or saturated alkyl groups and their monomeric analogues were used as a-coordinate neutral carriers for ion-selective electrodes (ISEs) of soft metals [silver and thallium(I)] ions. The EMF responses were excellent for most of the ISEs, among which there was no significant difference in the response. The ion selectivities of the ISEs depend on the structure of neutral carriers employed. H-1 NMR study explains the difference in the ion selectivity. In the metal-ion complexation by the pi-coordinate calixarene derivatives, thallium ion is likely to interact with the calixarene skeleton, while silver ion tends to interact with both of the calixarene skeleton and the omega-unsaturated alkenyl groups.

DOI

Dependence of ion selectivity on ordered orientation of neutral carriers in ion-sensing membranes based on thermotropic liquid crystals

K Kimura, Y Kawai, S Oosaki, S Yajima, Y Yoshioka, Y Sakurai

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  74 ( 21 ) 5544 - 5549   2002.11  [Refereed]

　View Summary

Thermotropic liquid-crystalline compounds were applied as membrane materials (membrane solvent and neutral carrier) for neutral carrier-type ion sensors to investigate how the ordered arrangement of neutral carriers affects the property of the resulting ion sensors. Nematic, smectic, and cholesteric liquid-crystalline compounds were used as the membrane solvents and crown ether derivatives with a molecular structure similar to the liquid-crystalline solvent as the K+ neutral carriers. Polarized IR spectroscopy and X-ray diffraction experiments confirmed that the highly ordered arrangement of membrane components was retained in the liquid-crystal-based ion-sensing membranes containing a neutral carrier and a lipophilic salt. The ordered arrangement of neutral carriers in the liquid-crystalline membranes enhanced the ion selectivity significantly, probably due to the efficient cooperation of two adjacent crown ether moieties in the highly ordered and aggregated state.

DOI

Ion-sensor property and blood compatibility of neutral-carrier-type poly(vinyl chloride) membranes coated by phosphorylcholine polymers

S Yajima, Y Sonoyama, K Suzuki, K Kimura

ANALYTICA CHIMICA ACTA ( ELSEVIER SCIENCE BV )  463 ( 1 ) 31 - 37   2002.07

　View Summary

Ion-selective membranes (ion-selective electrodes) were coated by biocompatible polymers, which are copolymers of methacryloyloxyethyl phosphorylcholine and an alkyl methacrylate, in order to develop blood compatible ion-selective electrodes. The sensor properties and biocompatibility of the ion-sensors were investigated using two types of alkyl methacrylates with different molecular weights. When the concentration of polymer solution for coating was relatively low, the ISEs showed good sensor properties, which lasted for at least 6 months. When the concentration of polymer solution for coating was relatively high, the coated ion-sensing membranes also showed good biocompatibility, which lasted for about a month. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI

Synthesis and photochromism of spirobenzopyrans and spirobenzothiapyran derivatives bearing monoazathiacrown ethers and noncyclic analogues in the presence of metal ions

M Tanaka, T Ikeda, Q Xu, H Ando, Y Shibutani, M Nakamura, H Sakamoto, S Yajima, K Kimura

JOURNAL OF ORGANIC CHEMISTRY ( AMER CHEMICAL SOC )  67 ( 7 ) 2223 - 2227   2002.04  [Refereed]

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Spirobenzopyrans bearing monoazathiacrown ethers and noncyclic analogues were synthesized, and their ion-responsive photochromism depending on the dual metal ion interaction with the crown ether and the phenolate anion moieties was examined using alkali and alkaline-earth metal ions, Ag+, Tl+, Pb2+, Hg2+, and Zn2+. The prepared spirobenzopyrans showed a selective binding ability to Mg2+ and Ag+ with negative and positive photochromism, respectively. Among the metal ions, only Ag+ facilitated photoisomerization to the corresponding merocyanine form. Depending on the ring size of the monoazathiacrown ether moieties, soft metal ions such as Hg2+ and Ag+ showed significant shifts in the UV-vis absorption spectra, while hard metal ions such as Mg2+, Zn2+, and Pb2+ did not afford any meaningful shift. This result reflects that the monoazathiacrown ether and phenolate anion moieties prefer soft and hard metal ions, respectively. Therefore, the Mg2+ and Ag+ selectivities are mainly derived from the phenolate anion and monoazathiacrown ether moieties, respectively. On the other hand, a spirobenzothiapyran bearing 3,9-dithia-6-monoazaundecane showed a remarkable selectivity to Ag+.

DOI

Decisive factors in the photoisomerization behavior of crowned spirobenzopyrans: Metal ion interaction with crown ether and phenolate anion moieties

Abdussalam M. A. Salhin, Mutsuo Tanaka, Kenji Kamada, Hisanori Ando, Tomokazu Ikeda, Yasuhiko Shibutani, Setsuko Yajima, Makoto Nakamura, Keiichi Kimura

European Journal of Organic Chemistry ( Wiley-VCH Verlag )  ( 4 ) 655 - 662   2002  [Refereed]

　View Summary

The influence of metal ion interaction with crowned spirobenzopyrans on the photoisomerization behavior was investigated through the use of various solvents, crowned spirobenzopyrans, and metal ions. Studies on the photoisomerization behavior of crowned spirobenzopyrans in various solvents revealed that solvation of the phenolate anion moiety in the merocyanine form induced photoisomerization back to the spiropyran form, giving rise to negative photochromism. Metal ion interaction with the phenolate anion moiety similarly caused photoisomerization back to the spiropyran form, while that with the crown ether moiety just produced a polar environment and its influence on photoisomerization behavior was dependent on the affinity of the metal ion captured by the crown ether moiety for the phenolate anion. Therefore, photochromic switching of crowned spirobenzopyrans between positive and negative to control the metal ion interaction with the phenolate anion moiety through the crown ether moiety is possible. This finding suggests a molecular design method for crowned spirobenzopyrans showing desired ion-responsive photochromism.

DOI

Sol-gel modification of pH electrode glass membranes for sensing anions and metal ions

K Kimura, S Yajima, H Takase, M Yokoyama, Y Sakurai

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  73 ( 7 ) 1605 - 1609   2001.04  [Refereed]

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To obtain glass membrane electrodes selective for anions and metal ions, pH electrode glass membranes were modified by a sol-gel method using a quaternary ammonium salt and a bis(crown ether). A chloride ionsensing glass membrane was designed, in which a pH electrode glass membrane was modified chemically by an alkoxysilyl quaternary ammonium chloride. X-ray photoelectron spectroscopy confirmed the chemical bonding of the quaternary ammonium moiety to the starting glass surface, which afforded the first example of glass-based "anion"-sensing membranes. A neutral carrier-type sodium ion-selective glass membrane was also fabricated which encapsulates a bis(12-crown-4) derivative in its sol-gel-derived surface. Both sol-gel-modified anion and metal ion-selective glass electrodes exhibited high sensitivity to their ion activity changes. The present sol-gel modification paves the way for designing glass-based ion sensors with tailor-made ion selectivities toward anions as well as cations.

Liquid crystal effect on neutral-carrier-type ion-sensing membranes

K Kimura, Y Kawai, S Yajima, Y Sakurai

CHEMICAL COMMUNICATIONS ( ROYAL SOC CHEMISTRY )  ( 14 ) 1302 - 1303   2001  [Refereed]

　View Summary

Liquid crystallinity of membrane solvent and neutral carriers for potentiometric ion sensors affects the orientation of neutral carrier molecules in the ion-sensing membranes, thus bringing about significant changes in the ion selectivity for the membrane electrodes.

Silver ion-selective electrodes using pi-coordinate calix[4]arene derivatives as soft neutral carriers

K Kimura, S Yajima, K Tatsumi, M Yokoyama, M Oue

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  72 ( 21 ) 5290 - 5294   2000.11

　View Summary

Calix[4]arene derivatives incorporating pi -coordinate substituents such as allyl, benzyl, and propargyl groups were designed as soft neutral carriers for silver ion sensors. Most of all, tert-butylcalix[4]arene tetra(allyl ether) is an excellent neutral carrier for plasticized poly(vinyl chloride)membrane sih er ion-selective electrodes. The ion sensors showed high silver ion selectivity over alkali metal ions and also good selectivity against other soft metal ions such as lead and mercury(II) ions. The electrode potential response was as rapid as that for neutral-carrier-type alkali metal ion electrodes due to the soft interaction between pi -coordinate substituents and silver ion, which was elucidated by H-1 NMR spectroscopy.

DOI

Potentiometric ion sensors with neutral-carrier-type ion-sensing membranes coated by biocompatible phosphorylcholine polymers

S Yajima, K Suzuki, K Kimura

ANALYTICAL SCIENCES ( JAPAN SOC ANALYTICAL CHEMISTRY )  16 ( 9 ) 899 - 900   2000.09

DOI

Recent Trend in Ion-Sensing Research (Review)

Setsuko Yajima, Keiichi Kimura

Bunseki Kagaku ( Japan Society for Analytical Chemistry )  49 ( 5 ) 279 - 296   2000

　View Summary

Ion sensors include electrochemical sensors to detect analyte ions electrochemically, i.e., mem- brane-potential sensors, such as ion-selective electrodes
voltammetric sensors, such as chemically-modified electrodes
and optical sensors to detect them spectrophotometrically, i.e., optodes or optrodes. There has been much information reported so far on ion sensors from two types of research, viz., the development of new sensors and basic studies about the response mechanism of ion sensors. The present review is concernd mainly with research topics of our intered, which include potentiometric anion sensors based on new neutral carriers and metal complexes. biocompatible ion sensors for the continuous detection of analyte ions in biological samples, and optodes for detecting electrically neutral molecules.

DOI

Supported sol-gel-derived membranes for neutral carrier-type ion-selective electrodes

K Kimura, S Yajima, K Okamoto, M Yokoyama

JOURNAL OF MATERIALS CHEMISTRY ( ROYAL SOC CHEMISTRY )  10 ( 8 ) 1819 - 1824   2000  [Refereed]

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For neutral carrier-type ion-selective electrodes, several sol-gel-derived membranes were designed which encapsulate valinomycin and bis(crown ether) derivatives as the neutral carriers. Relatively large size ion-sensing membranes based on sol-gel-derived glass were successfully fabricated by using membrane filters and sintered glass filters as the membrane supports. Potassium and sodium ion-selective electrodes, at the tip of which sol-gel-derived membranes containing a neutral carrier and a poly(tetrafluoroethylene) membrane filter were incorporated, exhibit high electrode performance in their sensitivity, selectivity, and response time. The supported sol-gel-derived membranes were also modified chemically by alkoxysilylated bis(crown ether) derivatives and were tested for their usefulness as sensing membranes of ion-selective electrodes.

Metal-ion stabilization of photoinduced open colored isomer in crowned spirobenzothiapyran

M Tanaka, K Kamada, H Ando, T Kitagaki, Y Shibutani, S Yajima, H Sakamoto, K Kimura

CHEMICAL COMMUNICATIONS ( ROYAL SOC CHEMISTRY )  ( 16 ) 1453 - 1454   1999.08  [Refereed]

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A spirobenzothiapyran derivative bearing a monoaza-12-crown-4 moiety affords significant thermal stability enhancement in the UV light induced colored merocyanine form of its photochromic moiety by metal-ion complexation of its crown ether moiety, although the complexation hardly induces the isomerization without photoirradiation.

Anion-sensitive field-effect transistors based on sol-gel-derived membranes incorporating quaternary ammonium salts

K Kimura, H Takase, S Yajima, M Yokoyama

ANALYST ( ROYAL SOC CHEMISTRY )  124 ( 4 ) 517 - 520   1999.04

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Quaternary alkylammonium chlorides were encapsulated or bonded covalently to sol-gel-derived membranes made of mixtures of two alkoxysilanes so as to obtain sensing membranes for anion-sensitive field-effect transistors. Both types of anion sensors responded to chloride-ion activity changes with high sensitivity. The anion-sensing membranes modified chemically by an alkoxysilyl derivative of quatenary ammonium salt are superior to those simply encapsulating an ammonium salt in their durability and protein-adsorption properties. The anion sensors are applicable to chloride-ion assay in serum samples.

DOI

Cation complexation, isomerization, and photoresponsive ionic conduction of a crown ether derivative carrying two spirobenzopyran units

K Kimura, T Teranishi, M Yokoyama, S Yajima, S Miyake, H Sakamoto, M Tanaka

JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2 ( ROYAL SOC CHEMISTRY )  ( 2 ) 199 - 204   1999.02  [Refereed]

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Cation complexation and subsequent isomerization of a diaza-18-crown-6 derivative possessing two spirobenzopyran units, crowned bis(spirobenzopyran), were investigated in solution and compared with those of its corresponding derivative incorporating only one spirobenzopyran unit. Complexation of multivalent metal ions, especially Ca2+ and La3+, by crowned bis(spirobenzopyran) enhanced the isomerization of the spirobenzopyran moiety to the corresponding merocyanine form due to the effective intramolecular interaction between a crown-complexed cation and two phenolate anions in the cation complexes of the merocyanine form. Significant photoinduced switching of ionic conductivity was realized in composite films containing crowned bis(spirobenzopyran) and a calcium salt.

Variation of thermodynamic parameters in the adduct formation of beta-diketonato chelates with 1,10-phenanthroline across the lanthanoid series

S Yajima, Y Hasegawa

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN )  71 ( 12 ) 2825 - 2829   1998.12

　View Summary

The enthalpy change in the adduct formation of tris[1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato]lanthanoids (LnA(3)) with 1,10-phenanthroline (phen) as well as the formation constant of the adduct has been determined in chloroform across the lanthanoid series at 298 K by calorimetric titration and solvent-extraction techniques. The enthalpy change in the first adduct formation changes remarkably from light lanthanoids (endothermic) to heavy ones (exothermic), while the entropy change decreases largely from the middle to the heavy lanthanoids along with a small change from light to the middle of the series. Such a trend has been explained on the basis of the difference in the dehydration from lanthanoid(III) chelates and in the strength of the new bonding of chelates formed between tris(beta-diketonato) lanthanoid(III) and phen across the lanthanoid series.

DOI

Neutral carrier-type ion sensors based on sol-gel-derived membranes incorporating a bis(crown ether) derivative by covalent bonding

K Kimura, T Sunagawa, S Yajima, S Miyake, M Yokoyama

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  70 ( 20 ) 4309 - 4313   1998.10

　View Summary

Sol-gel-derived membranes incorporating crown ether neutral carriers by covalent bonding have been designed for durable, nontoxic neutral carrier-type ion sensors by sol-gel processing using tetraethoxysilane, diethoxydimethylsilane, and their corresponding alkoxysilylated neutral carriers. A tetraphenylborate anion was also bound chemically to the neutral carrier-type sol-gel-derived membranes for suppressing anion interference and membrane impedance. Ion-sensitive field effect transistors (ISFETs) based on the sol-gel-derived membranes modified chemically by crown ether derivatives, such as 16-crown-5 and bis(12-crown-4) derivatives, showed high performance, high sensitivity in wide cation activity ranges, short response time, and high electrode durability. Specifically, high ion selectivities of practical use in biological systems were attained in the sodium ISFETs based on the chemically modified bis(12-crown-4), which has been successfully applied to sodium assay in blood sera.

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Co-ion interference for ion selective electrodes based on charged and neutral ionophores: A comparison

P Buhlmann, S Amemiya, S Yajima, Y Umezawa

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  70 ( 20 ) 4291 - 4303   1998.10

　View Summary

Interferences from co-ions, i.e., ions with a charge sign opposite to that of the measured ion, limit the upper detection limit of ion-selective electrodes (ISEs) based on electrically neutral or charged ionophores. A theoretical description based on phase boundary equilibria is used here to predict the co-ion interference (Donnan failure) of both types of ISEs quantitatively and to compare the extent of co-ion interference in these two cases. It is shown that, for practically relevant ionophore-site ratios, Donnan failure for ISEs based on electrically charged and neutral ionophore occurs at very similar co-ion concentrations if the charged and the neutral ionophores form complexes of equal stabilities and stoichiometries. With the exception of the selective complexation of the primary ion and charged ionophores, association of two or more ions such as between ionic sites and complexes has only a limited effect on co-ion interference. If relevant at all, ion pairing is predicted to affect upper detection limits more unfavorably in the case of neutral than in the case of charged ionophore-based ISEs. Experimental determination of co-ion interference for ISEs with five different charged and two electrically neutral H+ ionophores shows that co-ion interference increases as the stability of the H+ complexes increases and confirms that co-ion interferences for charged and neutral ionophore-based ISEs indeed occur to an equal extent if their H+ complexes have the same stabilities. These results corroborate the high potentiality of charged ionophore-based ISEs.

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Calix[4]arene derivative bearing pi-coordinate substituents as neutral carrier for silver ion sensors

K Kimura, K Tatsumi, S Yajima, S Miyake, H Sakamoto, M Yokoyama

CHEMISTRY LETTERS ( CHEMICAL SOC JAPAN )  ( 8 ) 833 - 834   1998.08

　View Summary

Calix[4]arene tetra(allyl ether) 1 was applied as a neutral carrier of silver ion sensors, which exhibited an excellent silver ion selectivity against sodium ion, while calix[4]arene tetra(allyl ester) 2 possesses only poor silver ion selectivity with severe sodium ion interference.

DOI

Complexation of tris(beta-diketonato)lanthanoids with monodentate and bidentate Lewis bases in chloroform

Y Hasegawa, A Hirasawa, S Yajima

JOURNAL OF ALLOYS AND COMPOUNDS ( ELSEVIER SCIENCE SA )  275   859 - 862   1998.07

　View Summary

The enthalpy change and the equilibrium constants for the formation of adducts of tris(1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedionato)lanthanoids (LnA(3)) with triphenylphosphine oxide (TPPO) and 1,10-phenanthroline (phen) in chloroform across the lanthanoid series have been determined by calorimetric titration and solvent extraction techniques. The formation constants with phen increase from the light to the middle lanthanoids, and the constants do not change from the middle to the heavy lanthanoids, while the constants of the second adducts with TPPO (LnA(3)/TPPO = 1:2) decrease with increasing atomic number, although those of the first (1:1) adducts do not change much. The enthalpy change in adduct formation with phen changes remarkably from endothermic to exothermic from light to heavy lanthanoids, while the enthalpy changes with TPPO do not vary much across the series. This suggests that, in adduct formation with phen, the match between the N-N distance in phen and the size of the lanthanoids(III), as well as dehydration from LnA(3), is a significant factor in determining the stability order of the adducts, while the degree of dehydration is significant for adduct formation with TPPO. (C) 1998 Published by Elsevier Science S.A.

DOI

Syntheses and structures of trinuclear molybdenum cluster complexes [Mo3S4Cl4(C5H5N)(5)] and [Mo3S4Cl3(C5H5N)(6)]I

J Mizutani, S Yajima, H Imoto, T Saito

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN )  71 ( 3 ) 631 - 636   1998.03

　View Summary

A trinuclear molybdenum chloro sulfide cluster complex [Mo3S4Cl4(C5H5N)(5)] (1) was synthesized by the excision of a nonmolecular cluster compound Mo3S7Cl4 with triphenylphosphine and pyridine. Three molybdenum atoms and four sulfur atoms form an incomplete cubane-type cluster core, which is coordinated by four chloro and five pyridine ligands. By the reaction of 1 with I-2 in pyridine, [Mo3S4Cl3(C5H5N)(6)]I (2) was synthesized. Three mu-S in the cluster cation and the iodine anion have short contacts, within the sum of the van der Waals radii of sulfur and iodine.

DOI

Donnan exclusion failure of neutral ionophore-based ion-selective electrodes studied by optical second-harmonic generation

S Yajima, K Tohda, P Buhlmann, Y Umezawa

ANALYTICAL CHEMISTRY ( AMER CHEMICAL SOC )  69 ( 10 ) 1919 - 1924   1997.05

　View Summary

Optical second harmonic generation (SHG) at the liquid-liquid interfaces of ionophore-free and neutral ionophore-incorporated membranes has been measured in the presence and absence of ionic sites in order to better understand the influence of ionic sites on the potentiometric responses of liquid membrane ion-selective electrodes. Quick and lasting EMF and SHG responses were observed upon increasing the primary ion activity in aqueous solutions in contact with membranes with ionic sites. For membranes without ionic sites, transient EMF responses due to extraction of primary ion salts occurred. They were accompanied by very similar transient changes in the SHG intensity. No EMF and SHG responses to the primary ion activity were, however, observed for site-free membranes in equilibrium with the aqueous phase, The extent of charge separation at the interfaces of such membranes, as observed by SHG from primary ions or primary ion complexes, does not depend on the primary ion activity in the aqueous phase. This explains why membranes free of ionic sites do not exhibit EMF responses and confirms that ionic sites are a necessity for counterion-independent primary ion responses of potentiometric sensors based on neutral carriers.

DOI

Ion-transfer polarographic study of the distribution of alkali and alkaline-earth metal complexes with 3m-crown-m ether derivatives (m=6,8) between water and nitrobenzene phases

Y Kudo, T Miyakawa, Y Takeda, H Matsuda, S Yajima

JOURNAL OF INCLUSION PHENOMENA AND MOLECULAR RECOGNITION IN CHEMISTRY ( KLUWER ACADEMIC PUBL )  26 ( 4 ) 331 - 341   1996

　View Summary

Stability constants (beta(1)(NB)) of the 1 : 1 cationic complexes of Li+, Na+, K+, Ca2+, Sr2+ and Ba2+ with benzo-18-crown-6 (B18C6), Ca2+ and Sr2+ with 18C6 and dibenzo-18C6 and Li+, Na+, Ca2+, Sr2+ and Ba2+ with dibenzo-24-crown-8 in a nitrobenzene (NB) solution saturated with water (w) were determined at 25 degrees C by ion-transfer polarography. From these values, distribution constants (K-D,K-ML) Of the 18C6-derivative complex cations between the w- and NB-phases were evaluated using the thermodynamic relation: K-D,K-ML = K beta(1)(NB) where K (mol dm(-3)) is an overall equilibrium constant of the processes related to the complexation in the w-phase. The data on the distribution of the 18C6-derivative complex cations between the two phases and the complexation in the NB-phase were examined on the basis of an increase in the number of water molecules hydrated to the species relevant to these processes. The 18C6 derivatives showed higher solubilities in the NB-phase than in the w-phase by complexing with the univalent-metal ions, while, for the divalent-metal ions, the derivatives showed lower solubilities in the NB-phase.

DOI

EMF RESPONSE OF NEUTRAL-CARRIER BASED ION-SENSITIVE FIELD-EFFECT TRANSISTORS WITH MEMBRANES FREE OF IONIC SITES

P BUHLMANN, S YAJIMA, K TOHDA, Y UMEZAWA

ELECTROCHIMICA ACTA ( PERGAMON-ELSEVIER SCIENCE LTD )  40 ( 18 ) 3021 - 3027   1995.12

　View Summary

Response characteristics of field effect transistors covered by membranes containing neutral carriers and an organic liquid but neither a polymer nor ionic sites were determined. The commercially available 2-nitrophenyl octyl ether and dioctyl sebacate, both frequently used plasticizers for poly(vinyl chloride) ISE membranes, had impurity concentrations large enough to lead to small emf responses. Upon removal of these impurities by HPLC, no emf responses were detectable any more, which seems to be due to a negligibly small permselective uptake of primary ions into the membrane and not the high impedance of the membrane bulk. The use of membranes of the more polar nitrobenzene and 2-fluoro-2'-nitrodiphenyl ether resulted in small but transient emf responses. The absence of ionic sites led however to the failure of permselectivity and resulted in co-extraction even of the highly hydrophilic chloride ions. Liquid membranes containing neutral carriers but no ionic sites are thus not only unsuitable for ISEs due to their high impedance, but also because it is very likely that either the failure of permselectivity occurs or the concentration of primary ions permselectivity entering the membrane is too small to determine the phase boundary potential.

DOI

STABILITIES IN WATER OF 1/1 LARIAT 16-CROWN-5 COMPLEXES WITH METAL-IONS - TRANSFER ACTIVITY-COEFFICIENTS FROM PROTIC TO APROTIC-SOLVENTS OF 1/1 COMPLEXES OF LARIAT AND SUBSTITUTED 16-CROWN-5 DERIVATIVES WITH METAL-IONS

Y TAKEDA, T KIMURA, S OCHIAI, S YAJIMA, Y KUDO, M OUCHI, T HAKUSHI

JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS ( ROYAL SOC CHEMISTRY )  91 ( 22 ) 4079 - 4082   1995.11

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Stability constants (K-ML) of 1:1 complexes of 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L16C5) with metal ions have been determined in water at 25 degrees C by conductometry and potentiometry with ion-selective electrodes. The selectivity order of L16C5 to monovalent and bivalent metal ions are Ag+ > Na+ > Tl+ > K+ and Sr2+ > Ba2+ > Pb2+, respectively. The selectivity is not altered by the side chains. The stability of the L16C5-metal ion complex in water is much lower than might be expected on the basis of the solvation power of water for the metal ion (i.e. the relative solubility of the metal ion). Transfer activity coefficients (gamma) of L16C5-Na+ and -K+ complexes from water to acetonitrile, propylene carbonate and methanol [(s) gamma(H2O)(ML(+))] were calculated from the (s) gamma(H2O)(L16C5) and K-ML values determined in this study and the literature values; s, M(+) and L denote a solvent, a monovalent metal ion, and a crown ether, respectively. (s) gamma(H2O)(ML(+)) of L16C5 is larger than (s) gamma(H2O)(L16C5) and the corresponding (s) gamma(H2O)(M(+)) values. The unexpectedly low stabilities of the L16C5-Na+ and -K+ complexes in water are due to strong hydrogen bonding between the uncomplexed L16C5 and water.

DOI

STUDIES ON THE PHASE BOUNDARIES AND THE SIGNIFICANCE OF IONIC SITES OF LIQUID MEMBRANE ION-SELECTIVE ELECTRODES

P BUHLMANN, S YAJIMA, K TOHDA, K UMEZAWA, S NISHIZAWA, Y UMEZAWA

ELECTROANALYSIS ( VCH PUBLISHERS INC )  7 ( 9 ) 811 - 816   1995.09

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Attenuated total reflectance infrared spectroscopy (ATR-IR) has been used to study the cation permselectivity of liquid-membrane ion-selective electrodes (ISEs). All spectroscopic evidence was found to agree with the interpretation of permselectivity as being due to complete exclusion of counter-ions from the boundary phase. Compared to ATR-IR, optical second harmonic generation (SHG) has an even more pronounced surface sensitivity. It has been demonstrated to be a promising new technique for the study of ISE response mechanisms, as it allows one to observe the actual phase boundary. On the other hand, further potentiometric evidence for the influence of ionic sites on the emf response was found, both by a study of membranes free of ionic sites as well as by the investigation of leaching processes at poly(vinyl chloride) membranes. Finally, the use of a photoresponsive crown ether ionophore allowed the determination of emf response characteristics in relation to the ionophore concentration without any changes in the membrane composition.

DOI

SYNTHESIS OF AN EQUILATERAL TRIANGULAR MOLYBDENUM CLUSTER COMPLEX [MO3(MU-3-S)2(MU-S)3(PME3)6] WITH 8 CLUSTER VALENCE-ELECTRONS

K TSUGE, S YAJIMA, H IMOTO, T SAITO

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY ( AMER CHEMICAL SOC )  114 ( 20 ) 7910 - 7912   1992.09

DOI