Chemistry Letters

Highlight Review

Heterolytic Dissociation of C–H Bond of Methane over Ag⁺-exchanged Zeolites and Conversion of Methane into Higher Hydrocarbons in the Presence of Ethene or Benzene

Toshihide Baba, Koji Inazu

2006 Volume 35 Issue 2 Pages 142-147
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.142

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The heterolytic dissociation of CH₄ over silver cationic clusters (Ag_n⁺) in Ag⁺-exchanged zeolites leads to the formation of silver hydride (Ag_n–H) and methyl cations, which then reacts with C₂H₄ to form C₃H₆. This process provides methane conversion of 13.2% at 673 K to afford higher hydrocarbons, such as toluene. Under these reaction conditions, H–ZSM-5 only catalyzes ethene conversion to higher hydrocarbons, such as butenes, and no methane conversion occurs. The reaction of CH₄ with benzene also proceeds to form toluene and xylenes over Ag–ZSM-5 at 673 K. Zeolites prepared by exchange with other metal cations, including In and Ga, also activate CH₄ in the presence of C₂H₄. Using ¹³C-labeled methane (¹³CH₄) as a tracer, propene is shown to be a primary product for the ethene reaction based on the observation of a significant proportion of singly ¹³C-labeled propene (¹³CC₂H₆). In–ZSM-5 catalyzes the formation of not only propene, but also benzene and toluene. ¹³C label atoms are not found in the benzene thus produced, indicating that benzene originates entirely from C₂H₄. However, the occurrence of singly ¹³C-labeled toluene (¹³CC₆H₈) implies that toluene is formed by the reaction of benzene with ¹³CH₄. The alternative reaction path, involving ¹³CC₆H₈ formation by reaction of propene with n-butenes generated by ethene dimerization, can be refuted by confirmation of the toluene origin through direct reaction of ¹³CH₄ with benzene.

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Chiral Symmetry Breaking in Chiral Crystallization and Soai Autocatalytic Reaction

Ilya D. Gridnev

2006 Volume 35 Issue 2 Pages 148-153
Published: 2006
Released: December 28, 2005

DOIhttps://doi.org/10.1246/cl.2006.148

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Complete chiral crystallization and absolute chiral synthesis are both fascinating phenomena shedding light on the possible origins of homochirality in nature and opening perspectives for efficient preparations of optically pure materials. Originally these two phenomena have been considered mechanistically quite different belonging to the hetero- and homogeneous systems, respectively. However, the results of the active research in both fields undertaken in the last few years suggest that there may be a much closer likeness of the most important mechanistic features of these two phenomena. In the present review, we bring together the latest data on the complete chiral crystallization and absolute chiral synthesis including our own data on the mechanism and spontaneous break of chirality in the Soai asymmetric autocatalysis.

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Letter

Syntheses and Characterization of Palladium(II) Complexes with Tridentate N-Heterocyclic Carbene Ligands Containing Aryloxy Groups and Their Application to Heck Reaction

Takeyoshi Yagyu, Shoko Oya, Masunobu Maeda, Koichiro Jitsukawa

2006 Volume 35 Issue 2 Pages 154-155
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.154

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Two palladium(II) complexes with tridentate N-heterocyclic carbene ligands containing aryloxy groups were prepared and characterized by X-ray crystallographic method. They showed good performance for Heck reaction.

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Anomalous ¹³C NMR Chemical Shifts of High-spin Saddle Shaped Manganese(III) Octaethyltetraphenylporphyrin Complexes

Akira Ikezaki, Mikio Nakamura, Ru-Jen Cheng

2006 Volume 35 Issue 2 Pages 156-157
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.156

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NMR spectra of highly saddled Mn(III) porphyrinates such as Mn(OETPP)(CD₃OD)₂⁺ have been measured. The extraordinarily upfield shifted meso-¹³C signals, which reach as much as −492 ppm at 298 K, are ascribed to the d_x²−y²–a_2u, d_xy–a_1u, and d_π–3e_g interactions, the former two of which occur only when the porphyrin ring is saddled.

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An Efficient Energy Transfer Found in Triphenylene/Hexaazatriphenylene System with Electronic Complimentarity and Structural Similarity

Tsutomu Ishi-i, Hiroshi Tashiro, Rempei Kuwahara, Shuntaro Mataka, Tos ...

2006 Volume 35 Issue 2 Pages 158-159
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.158

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In a donor–acceptor system with structural similarity and electronic complimentarity, an efficient energy transfer was observed from energy-donor triphenylenes to energy-acceptor hexaazatriphenylenes in a film state.

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Effect of Fluorine Substituent on the Chitinase-catalyzed Polymerization of Sugar Oxazoline Derivatives

Akira Makino, Junji Sakamoto, Masashi Ohmae, Shiro Kobayashi

2006 Volume 35 Issue 2 Pages 160-161
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.160

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6-Deoxy-6-fluoro sugar oxazoline derivatives were synthesized and evaluated their polymerizabilities with the catalysis of chitinase. The polymerizability of an N-acetyl-6-deoxy-6-fluoroglucosamine oxazoline was lower than that of non-fluorinated N-acetylglucosamine oxazoline, only providing the ring-opened hydrolyzate. The disaccharide oxazoline derivative of N,N′-diacetyl-6′-deoxy-6′-fluorochitobiose exhibited lower polymerizability with the enzyme compared to that of the non-fluorinated N,N′-diacetylchitobiose oxazoline, providing the corresponding fluorinated chitin derivative in good yields within 4 h. These results suggest that the fluorine atom-incorporation reduced the reactivity of the oxazolines.

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Synthesis of Single-crystal BaMo₂O₇ Nanowire Bundles: A General, Low-temperature Hydrothermal Approach to 1D Molybdenum Oxide-based Nanostructures

Peng Gao, Yi Xie, Lina Ye, Ying Chen, Zhen Li

2006 Volume 35 Issue 2 Pages 162-163
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.162

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Multicomponent BaMo₂O₇ single-crystalline nanowire bundles were synthesized by a hydrothermal crystallization process under mild conditions using cheap and simple bulky oxide and fluoride as precursors. This new strategy has been extended to prepare other 1D molybdenum oxide-based nanomaterials including alkaline earth metal molybdate compounds (such as BaMo₃O₁₀), transition-metal molybdate compounds (e.g., CdMoO₄, PbMoO₄, Ag₆Mo₁₀O₃₃, etc.) and metal molybdenum oxide fluoride compounds (e.g., Ba₂MoO₃F₄). Our experiments have also proved that this facile hydrothermal route is a general method for the synthesis of various multicomponent nanomaterials (such as tungstate, chromate, phosphate compounds).

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Repetitive Two-step Method for Oligoarene Synthesis through Rapid Cross-coupling of Hydroxyphenylboronic Acids and Anhydrides

Shunpei Ishikawa, Kei Manabe

2006 Volume 35 Issue 2 Pages 164-165
Published: 2006
Released: December 27, 2005

DOIhttps://doi.org/10.1246/cl.2006.164

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A two-step Suzuki–Miyaura coupling–triflation procedure, which features the use of hydroxyphenylboronic acids or anhydrides in the palladium-catalyzed cross-coupling step, has been developed for the synthesis of oligoarenes.

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Practical One-step Synthesis of Symmetrical Liquid Crystalline Dialkyloligothiophenes for Molecular Electronic Applications

Julie Leroy, Jeremy Levin, Sergey Sergeyev, Yves Geerts

2006 Volume 35 Issue 2 Pages 166-167
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.166

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This communication describes extremely simple one-step synthesis of α,α′-dialkyloligothiophenes by the lithiation/alkylation of the corresponding commercially available oligothiophenes. Use of t-BuOK to enhance the reactivity of lithiated oligothiophene species towards alkyl halides is crucially important.

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Synthesis and Characterization of Cyclopentadienone-annelated Hexadehydrodibenzo[12]annulene

Tsumoru Morimoto, Shuji Nagano, Daishi Yokoyama, Masutaka Shinmen, Kiy ...

2006 Volume 35 Issue 2 Pages 168-169
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.168

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Hexadehydrodibenzo[12]annulene annelated by a cyclopentadienone moiety was synthesized. On the basis of the theoretical calculations and experimental NMR and IR spectra, it was shown to be weakly aromatic owing to the contribution of the diatropic [15]annulenone resonance structure.

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Ordered CoSb₃ Nanowire Arrays Synthesized by Electrodeposition

Lijie Chen, Haining Hu, Yangxian Li, Guifeng Chen, Shuyun Yu, Guanghen ...

2006 Volume 35 Issue 2 Pages 170-171
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.170

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Highly ordered CoSb₃ nanowire arrays have been fabricated successfully by direct current electrodeposition from aqueous solution into the pores of a porous anodic aluminum oxide (AAO) template. Extensive characterization of the as-synthesized sample has been performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDS). The analysis indicates that the CoSb₃ nanowires are single crystals with highly preferential orientation and the atomic ratio of Co to Sb is very close to 1:3.

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Design of Chiral Macrocyclic Complexes Based on trans-Chelation of n:n Metal–Bidentate P,N- or N,N-Ligands

Manabu Hatano, Takafumi Asai, Kazuaki Ishihara

2006 Volume 35 Issue 2 Pages 172-173
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.172

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Chiral self-assembled macrocyclic Pd(II) and Cu(II) complexes with trans-chelation of n:n metal–bidentate P,N- and N,N-ligands have been designed toward the possibility of asymmetric Diels–Alder catalysis.

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Platelike Crystal Growth of Zn–Al Layered Double Hydroxide by Hot Water Treatment of Sol–Gel Derived Al₂O₃–ZnO Films on Glass Substrate

Naoko Yamaguchi, Tomohiko Nakamura, Kiyoharu Tadanaga, Atsunori Matsud ...

2006 Volume 35 Issue 2 Pages 174-175
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.174

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We have successfully immobilized Zn–Al layered double hydroxide (LDH) directly on glass substrates through the sol–gel method with hot water treatment. Al₂O₃–ZnO thin films were originally prepared on glass substrates by the sol–gel method with a heat treatment at 400 °C for 30 min, and then the films were immersed in distilled water at 100 °C for 15 min to form nanocrystalline Zn–Al LDH with hexagonal structure.

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Asymmetric Addition of Alkynylzinc Reagents to Nitrones Utilizing Tartaric Acid Ester as a Chiral Auxiliary

Weilin Wei, Masato Kobayashi, Yutaka Ukaji, Katsuhiko Inomata

2006 Volume 35 Issue 2 Pages 176-177
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.176

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The asymmetric addition of alkynylzinc reagents, prepared in situ from dialkylzinc and 1-alkynes, to nitrones was achieved by utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary to afford the corresponding optically active (R)-α-substituted propargylic N-hydroxylamines. By the addition of product-like N-hydroxylamine, unprecedented enhancement of enantioselectivity was observed to afford the N-hydroxylamines up to 95% ee.

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Solution Phase Synthesis of Hollow SnO₂ Nanospheres at Room Temperature

Qinghui Cao, Yongqian Gao, Xiangying Chen, Li Mu, Weichao Yu, Yitai Qi ...

2006 Volume 35 Issue 2 Pages 178-179
Published: 2006
Released: January 07, 2006

DOIhttps://doi.org/10.1246/cl.2006.178

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Hollow SnO₂ nanospheres with diameters ranging from 100–120 nm have been synthesized via a room-temperature wet-chemical route. A possible formation mechanism of the hollow SnO₂ nanospheres is briefly discussed.

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In situ Polymerization of Liquid Crystalline Monomers within Photoaligned Mesoporous Silica Thin Film

Haruhiko Fukumoto, Shusaku Nagano, Takahiro Seki

2006 Volume 35 Issue 2 Pages 180-181
Published: 2006
Released: February 05, 2006

DOIhttps://doi.org/10.1246/cl.2006.180

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Photopolymerization of liquid crystalline monomers was achieved within photoaligned mesoporous silica film. After resolving the template of silica networks, bundles of nanofibers containing polymer chains with a narrow molecular weight distribution were obtained.

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Hexa-, Hepta-, and Octacyclic Ladder Polysilanes

Soichiro Kyushin, Yoshinori Ueta, Ryoji Tanaka, Hideyuki Matsumoto

2006 Volume 35 Issue 2 Pages 182-183
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.182

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Hexa-, hepta-, and octacyclic ladder polysilanes (5–7) were synthesized, and their structures were determined by X-ray crystallography. These compounds have the double helix structure consisting of two linear polysilane chains. In the UV–visible spectra, the lowest energy absorption maxima of 5–7 shift bathochromically as the number of cyclotetrasilane rings progressively increases.

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Cation–π-driven Fluorescence Signalling of Ammonium Cations by Naphthyl-substituted Zn₁₀S₁₆ and Cd₁₀S₁₆ Clusters

Katsuaki Konishi, Takayuki Hiratani

2006 Volume 35 Issue 2 Pages 184-185
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.184

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Zn₁₀S₁₆ and Cd₁₀S₁₆ clusters bearing twelve naphthalene units on the surface showed characteristic blue emission in response to the cation–π-mediated intercalative binding of quaternary ammonium cations that allows the formation of ground-state naphthalene aggregates.

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Linear Relationship between Activity of a New Ru-catalyst and Acidity of Substituted Benzoic Acids in the Dimerization of Acrylonitrile

Kohichi Kashiwagi, Ryoji Sugise, Toshihiro Shimakawa, Tunao Matuura, M ...

2006 Volume 35 Issue 2 Pages 186-187
Published: 2006
Released: February 05, 2006

DOIhttps://doi.org/10.1246/cl.2006.186

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A new type of catalyst system using ruthenium and carboxylic acid is useful for the tail-to-tail dimerization of acrylonitrile, proceeding without the formation of undesired by-product propionitrile. Carboxylic acids having pK_a 3.5–5 are suitable as co-catalysts for the dimerization of acrylonitrile. The relationship between the logarithm of the relative rate in the dimer formation and the pK_a of m- and p-substituted benzoic acids (Brønsted plot) was linear (R² = 0.946) with a slope of −0.199. The role of the carboxylic acids can be considered to be effective protonation in the protonolysis of the carbon–ruthenium bond of an intermediate Ru complex.

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Stereoselective Hydrogenation of Tetralin to cis-Decalin over a Carbon-supported Rhodium Catalyst in Supercritical Carbon Dioxide Solvent

Norihito Hiyoshi, Eiichi Mine, Chandrashekhar V. Rode, Osamu Sato, Mas ...

2006 Volume 35 Issue 2 Pages 188-189
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.188

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cis-Decalin was selectively obtained with high cis/trans ratio (83%) over a carbon-supported rhodium catalyst at 333 K under 6 MPa of hydrogen and 15 MPa of carbon dioxide.

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An Efficient Synthesis of Helical Mesoporous Silica Nanorods

Qinghong Zhang, Fei Lü, Changli Li, Ye Wang, Huilin Wan

2006 Volume 35 Issue 2 Pages 190-191
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.190

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Helical mesoporous silica nanorods have been synthesized with high efficiency by the addition of 1-alkanol or 1-aminoalkane with proper carbon chain length (C₄–C₈) as a cosurfactant of cetyltrimethylammonium bromide (CTAB) during the synthesis of MCM-41 in a dilute synthesis gel containing CTAB, tetraethyl orthosilicate, ammonium hydroxide, and water.

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Fabrication of Ordered Nanostructures in Ta Films Using 2D Array of Ferritin Molecules as Template

Hideki Masuda, Yoshitaka Matsui, Tetsuya Miwa, Mitsutaka Nagae, Miyuki ...

2006 Volume 35 Issue 2 Pages 192-193
Published: 2006
Released: February 05, 2006

DOIhttps://doi.org/10.1246/cl.2006.192

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Metal (Ta) films with ordered structures of nanometer-scale dimensions were fabricated by replicating the structure of a 2D array of ferritin molecules as a template. The deposition of a Ta layer onto a 2D array of ferritin molecules using ion-beam sputtering and subsequent removal of the ferritin molecules generated Ta films with an ordered array of concave with a 13 nm interval. The uniformity and chemical stability of Ta formed by ion-beam sputtering contributed to the precise replication of the fine structures of the 2D array of ferritin molecules.

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(Inorganic Nanofiber/Enzyme) Hybrid Hydrogel: Preparation, Characterization, and Enzymatic Activity of Imogolite/Pepsin Conjugate

Nozomi Inoue, Hideyuki Otsuka, Shin-Ichiro Wada, Atsushi Takahara

2006 Volume 35 Issue 2 Pages 194-195
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.194

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The hybrid hydrogel composed of tubular aluminosilicate nanofiber, “imogolite,” and pepsin was prepared in a simple manner. We confirmed the formation of a network structure of imogolite in hydrogel by FE-SEM observations. Pepsin immobilized onto imogolite showed enzymatic activity after repeated reactions.

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Prediction of the Octanol/Water Partition Coefficients of Petroporphyrin Model Compounds

Satsuki Asami, Koichi Saitoh

2006 Volume 35 Issue 2 Pages 196-197
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.196

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The octanol/water partition coefficients (P_OW) were predicted for five vanadium(IV)–porphyrin complexes which were taken as model compounds of petroporphyrin. The correlation between the reversed-phase liquid chromatographic retention factor and the P_OW observed for standards was applied to the prediction. The log P_OW values estimated for the metalloporphyrins range from 5.8 (for 5,10,15,20-tetramethylporphine complex) to 10.1 (for 2,3,7,8,12,13,17,18-octaethylporphine complex).

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Palladium Catalyzed Conjugate 1,4-Addition of Organoboronic Acids to α,β-Unsaturated Ketones

Tetsuya Yamamoto, Michiko Iizuka, Tetsuo Ohta, Yoshihiko Ito

2006 Volume 35 Issue 2 Pages 198-199
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.198

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1,4-Addition of arylboronic acids to α,β-unsaturated ketones was smoothly catalyzed by palladium(0) phosphine complexes with chloroform in the presence of base. It is remarked that the palladium(0) complexes have no catalytic activity in the absence of chloroform. The reaction proceeded without β-hydride elimination.

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Kabob-like Carbon Nanotube Hybrids

Yuyang Liu, Ronghua Wang, Wei Chen, Xianqiong Chen, Zhigang Hu, Xiaoyi ...

2006 Volume 35 Issue 2 Pages 200-201
Published: 2006
Released: January 14, 2006

DOIhttps://doi.org/10.1246/cl.2006.200

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Inspired by the formation of stalagmite in nature, calcium carbonate nanoparticles (CaCO₃) have been successfully generated along multiwalled carbon nanotubes (MWNTs) backbones periodically via a very simple wet chemical route, thus forming the kabob-like MWNTs–CaCO₃ hybrids. These MWNTs–CaCO₃ hybrids are expected to have many potential applications in biomaterials and polymer reinforcement.

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Solid Synthesis of Cs_xH_3−xPW₁₂O₄₀ Salts and Their Catalytic Activity for the Isomerization of n-Butane

Yan Zou, Bin Yue, Bin Zhang, Heyong He

2006 Volume 35 Issue 2 Pages 202-203
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.202

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Cs_xH_3−xPW₁₂O₄₀ salts prepared by a simple solid-synthesis method show good catalytic activity in n-butane isomerization as those analogues prepared by traditional liquid-preparation method.

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Development of Ordered Calcium Carbonate Microarrays from Polymorph Specific Planar Films

Akiko Kotachi, Hiroaki Imai

2006 Volume 35 Issue 2 Pages 204-205
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.204

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Ordered microarrays of rectangular calcite, platy vaterite and spicular aragonite were selectively obtained through overgrowth from planar films prepared with polymeric species. We successfully visualized the polymorphs of the calcium carbonate films using the overgrowth technique.

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Liposomal Sorting onto Substrate through Ion Recognition by Gemini Peptide Lipids

Masashi Otsuki, Yoshihiro Sasaki, Shintaro Iwamoto, Jun-ichi Kikuchi

2006 Volume 35 Issue 2 Pages 206-207
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.206

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Selective liposomal assembling in aqueous solution was achieved by ion-recognizable gemini peptide lipids as an inducer. The methodology was extended to liposomal sorting on a substrate covered with a supported bilayer membrane, which was confirmed by means of fluorescence and atomic force microscopy, fluorescence spectroscopy, and quarts crystal microbalance measurements.

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Two-parameter Analysis of Solvent Effects on Selectivity in Chemical Reactions: Information of Polarity and Activation Volume at the Transition State in Organic and Enzymatic Reactions

Chunlei Lin, Yoshikazu Hiraga, Katsuo Ohkata

2006 Volume 35 Issue 2 Pages 208-209
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.208

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The solvent effects on stereoselectivity in the Diels–Alder reaction of cyclopentadiene, the [2 + 2]photodimerization of 2-cyclopentenone, and the enzymatic asymmetrization of prochiral 1,3-propanediols were analyzed by two-parameter treatment using both the dielectric constant and the solubility parameter to show a good linear relationship.

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Protic, Imidazolium Ionic Liquids as Media for (Z)- to (E)-Alkene Isomerization

Ewa Janus, Marek Lozynski, Juliusz Pernak

2006 Volume 35 Issue 2 Pages 210-211
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.210

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The quantitative isomerization of (Z)- to (E)-alkene in protic, imidazolium ionic liquids is demonstrated. The isomerization parameters were determined. The mechanism on the addition of the protic imidazolium species to carbon–carbon double bond is presented.

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Rotaxane Synthesized by End-capping via Hydroruthenation of Axle Terminal Acetylene and Its Derivation to η³-Allylruthenium Complex-containing Rotaxane

Hisahiro Sasabe, Nobuhiro Kihara, Kazuhiko Mizuno, Akiya Ogawa, Toshik ...

2006 Volume 35 Issue 2 Pages 212-213
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.212

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The hydroruthenation of pseudorotaxane 1·DB24C8 having an alkyne moiety at the axle terminal with RuHCl(CO)(PPh₃)₃ gave [2]rotaxane 2 with an alkenylruthenium complex moiety in a good yield. The carbometalation of allenes with 2 resulted in the formation of the corresponding [2]rotaxanes 3 with η³-allylruthenium complex moieties in good yields.

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Fabrication of Gold Nanosheet and Nanowire by Oxygen Plasma Induced Fusion of Densely Arrayed Nanoparticles

Shin-ya Onoue, Junhui He, Toyoki Kunitake

2006 Volume 35 Issue 2 Pages 214-215
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.214

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Densely assembled gold nanoparticles were treated by low temperature oxygen plasma to undergo complete fusion due to removal of organic protecting groups. Nanosheet and nanowire of gold with thicknesses of less than 10 nm were formed at room temperature without oxidation. Their sizes reached more than several hundred nanometers, demonstrating the effectiveness of the current method to fabricate nanoscopic architectures of mesoscopic sizes.

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Production of CO_x-free Hydrogen by Alkali Enhanced Hydrothermal Catalytic Reforming of Biomass-derived Alcohols

Yunpeng Xu, Zhijian Tian, Guodong Wen, Zhusheng Xu, Wei Qu, Liwu Lin

2006 Volume 35 Issue 2 Pages 216-217
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.216

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CO_x-free hydrogen could be produced by hydrothermal catalytic reforming process when Ca(OH)₂ was added into the reaction, and biomass-derived alcohols were used as the reactants.

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Fabrication of a Novel Microfluidic Device Incorporating 2-D Array of Microbeads

Thomas Gumpenberger, Tadatake Sato, Ryozo Kurosaki, Aiko Narazaki, Yos ...

2006 Volume 35 Issue 2 Pages 218-219
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.218

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A novel microfluidic device incorporating a two-dimensional array of microbeads with 10 μm diameter was fabricated. Surface-modified microbeads to be used as detectors were arranged into microstructures prepared at the surface of a silica glass plate by laser-micromachining and sealed with a polydimethylsiloxane (PDMS) plate to form microchannels. The capturing reaction of surface amino groups with fluorescein isothiocyanate (FITC) supplied via microchannels was examined.

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Syntheses, Structures, and Properties of the First Stable 1,1′-Bis(diphosphenyl)ferrocenes

Noriyoshi Nagahora, Takahiro Sasamori, Norihiro Tokitoh

2006 Volume 35 Issue 2 Pages 220-221
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.220

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Kinetically stabilized 1,1′-bis(diphosphenyl)ferrocenes have been synthesized by taking advantage of extremely bulky substituents, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt) and 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt) groups, and fully characterized by the spectroscopic and X-ray crystallographic analyses. The electrochemical behavior showed well-defined two reversible one-electron reduction couples.

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Bulk Synthesis of Poly(tert-butyl methacrylate) Long Macromonomer with Narrow Distribution by Atom Transfer Radical Polymerization and Nucleophilic Substitution

Wei Yang, Tatsuo Kaneko, Xiao-Ya Liu, Ming-Qing Chen, Mitsuru Akashi

2006 Volume 35 Issue 2 Pages 222-223
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.222

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Poly(tert-butyl methacrylate) macrointermediates (PtBMA-Br) with a bromine atom end group were synthesized in the presence of the single ligand N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) by atom transfer radical polymerization (ATRP) in bulk. A macromonomer was successfully prepared by the nucleophilic substitution of the chain end to attain a high efficiency of C=C incorporation (89–92%; ¹H NMR). The macromonomer molecular weight was controlled to result in a high molecular weight (11000) with a narrow distribution of 1.20.

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EXAFS Studies about the Sorption of Cadmium Ions on Montmorillonite

Rieko Takamatsu, Kiyotaka Asakura, Wang-Jae Chun, Tsuyoshi Miyazaki, M ...

2006 Volume 35 Issue 2 Pages 224-225
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.224

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We investigated local structures around cadmium (Cd) sorbed on montmorillonite at various pH values by EXAFS (extend X-ray absorption fine structure). We found two sorption types, an outer-sphere complex and a surface precipitate. The outer-sphere complex was mainly formed at a lower pH which had an identical structure to aqueous Cd²⁺, while the surface precipitate was found at high pH which had a one-layer Cd₅(OH)₈(NO₃)₂(H₂O)₂-like structure.

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Ultrasound-promoted Highly Chemoselective Reduction of Aromatic Nitro Compounds to the Corresponding N-Arylhydroxylamines Using Zinc and HCOONH₄ in CH₃CN

Qi Xun Shi, Rong Wen Lu, Kun Jin, Zhu Xia Zhang, De Feng Zhao

2006 Volume 35 Issue 2 Pages 226-227
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.226

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N-Arylhydroxylamines were prepared in high yields through chemoselective reduction of the corresponding aromatic nitro compounds under ultrasound (59 kHz) at room temperature using a convenient Zn/HCOONH₄/CH₃CN system. This method was highly efficient, environmentally benign, especially simple and practical.

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Amorphous Carbon-promoted Low-temperature Crystallization of Silica

Akihiro Okabe, Makiko Niki, Takanori Fukushima, Takuzo Aida

2006 Volume 35 Issue 2 Pages 228-229
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.228

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Heating of mesoporous silica hybridized with self-assembled disc-like molecules such as hexabenzocoronene and triphenylene derivatives at ≥900 °C under N₂ resulted in low-temperature crystallization of its amorphous silicate framework into cristobalite, a form of crystalline silica that appears in a much higher temperature range in the phase diagram.

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Photocatalytic Decomposition of Environmentally Persistent Perfluorooctanoic Acid

Jing Chen, Pengyi Zhang, Li Zhang

2006 Volume 35 Issue 2 Pages 230-231
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.230

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Perfluorooctanoic acid was photocatalytically decomposed by using TiO₂/Ni–Cu, and a small bias potential (−0.1 V) applied on TiO₂/Ni–Cu electrode greatly enhanced its decomposition.

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Importance of 3′-Hydroxyl Group of the Nucleosides for the Reactivity of Thymidine Phosphorylase from Escherichia coli

Akihiko Hatano, Aiko Harano, Masayuki Kirihara

2006 Volume 35 Issue 2 Pages 232-233
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.232

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Thymidine phosphorylase in phosphate buffer catalyzed the conversion of thymidine to unnatural nucleosides. The 3′-OH, but not the 5′-OH of ribosyl moiety is necessary to be recognized as a substrate. Thus 3′-deoxythymidine could not convert to 5-fluorouracil-2′,3′-dideoxyribose. However, 5′-deoxythymidine was converted to 5-fluorouracil-2′,5′-dideoxyribose.

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Oxygen Permeability of Surface-modified Poly(dimethylsiloxane) Characterized by Scanning Electrochemical Microscopy

Hitoshi Shiku, Takeshi Saito, Ching-Chou Wu, Tomoyuki Yasukawa, Masaki ...

2006 Volume 35 Issue 2 Pages 234-235
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.234

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Scanning electrochemical microscopy (SECM) was employed to quantitatively characterize the oxygen permeation behaviors of poly(dimethylsiloxane) (PDMS) and surface-modified PDMS. The mass-transfer process of oxygen from the PDMS substrate to the tip electrode is diffusion limited, whereas the oxygen permeability of PDMS subjected to oxygen plasma treatment or albumin adsorption is critically restricted. Our results suggest that the oxygen permeability of PDMS is possibly affected by O₂ plasma irradiation and albumin adsorption at the PDMS surfaces.

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Separation of Americium(III) from Europium(III) by Dioctylammonium Dioctyldithiocarbamate/Nitrobenzene Extraction

Sunao Miyasita, Makoto Yanaga, Isamu Satoh, Hideo Suganuma

2006 Volume 35 Issue 2 Pages 236-237
Published: 2006
Released: January 21, 2006

DOIhttps://doi.org/10.1246/cl.2006.236

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The extraction of Am(III) and Eu(III) from a nitric medium by dioctylammonium dioctyldithiocarbamate (DOA·DODTC)/nitrobenzene was studied. The separation factor of Am(III)/Eu(III) shows a higher value than the highest one hitherto obtained by a cyanex/kerosene extraction. The high selectivity of a functional group of dithiocarbamate will be contributed to the investigation for the separation of Am(III) from trivalent lanthanoids.

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Dehydrative Glycosylation in Water Using a Brønsted Acid–Surfactant-Combined Catalyst

Naohiro Aoyama, Shu Kobayashi

2006 Volume 35 Issue 2 Pages 238-239
Published: 2006
Released: January 25, 2006

DOIhttps://doi.org/10.1246/cl.2006.238

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Brønsted acid–surfactant-combined catalyst, dodecylbenzenesulfonic acid (DBSA), was used in catalytic dehydrative glycosylation reactions in water. 1-Hydroxy sugars, such as O-benzyl-protected furanose and pyranose, reacted with alcohols and a nitrogen nucleophile in the presence of a catalytic amount of DBSA to afford the desired adducts in good yields. Detailed study of the glycosylation of 2-deoxy-D-ribofuranose showed that hydrophobicity of the substrates was important to attain higher yields. Regarding the α/β selectivities, D-ribose and D-mannose derivatives gave the products in high β- and α-selectivities, respectively.

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