bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of Trifluoroacetonitrile Oxide or -nitrilimines with β-Diketones and β-Keto Esters
Authors: Tanaka Kiyoshi , Kishida Munehisa , Maeno Seiji , Mitsuhashi Keiryo
Published: July 2006

N-Phenyl-C-(trifluoromethyI)nitrilimine cyclized with β-diketones or β-keto esters under alkaline conditions to give the corresponding 3-trifluoromethylpyrazoles with acyl or alkoxycarbonyl group at the 4-position of the ring, respectively. While trifluoroacetonitrile oxide with β-diketones provided the corresponding trifluoromethylisoxazoles, its reactions with β-keto esters gave 4-acyl-5-hydroxy-3-trifluoromethylisoxazoles as well as the expected isoxazoles without the regioselectivity.
Oxidation of Cyclopentene by RuCl3–NaOCl Catalyst
Authors: Orita Hideo , Hayakawa Takashi , Takehira Katsuomi
Published: July 2006

Oxidation of cyclopentene by RuCl3–NaOCl catalyst in an aqueous-organic two phase system was investigated by changing compositions of solvent system and additives to the aqueous solution. Use of acetonitrile as a cosolvent enhanced the reaction rate greatly, and addition of NaOH improved the yield of glutaric acid up to 80%.
S–Alkyl-4-oxothianium Ions for the Synthesis of Cyclopentenones. Acid-Catalyzed Cyclization of Divinyl Ketones
Authors: Matsuyama Haruo , Takei Yuji , Kobayashi Michio
Published: July 2006

A new approach to 2-cyclopentenones via an acidic cyclization of divinyl ketones by the use of S–alkyl-4-oxothianium ions as key compounds is described.
Stereoselective Reduction of Symmetrical Diketones with Biological Methods. Microbial Reduction of cis-2,7-Decalindione
Authors: Chikamatsu Hiroaki , Taniguchi Masatoshi , Kanemitsu Takamasa
Published: July 2006

The pro-S group of two enantiotopic carbonyl groups in cis-2,7-decalindione was preferentially reduced with Rhodotorula rubra to give (−)-(7S,9R,10S)-7-hydroxy-cis-2-decalone of high optical purity.
Tertiary Amine-Catalyzed Acyl Group-Exchange Reactions of N, O-Diacyl-o-aminophenols
Authors: Sakurai Tadamitsu , Yamada Shuichi , Inoue Hiroyasu
Published: July 2006

A kinetic study on the base-catalyzed acyl group-exchange reactions of N,O-diacyl-o-aminophenols was undertaken to show that the formation of the amidate ion should be the rate-determining step in these intramolecular acyl-exchange reactions, and that the electron-withdrawing power of acyl group becomes an important factor to control the relative stabilities of a pair of N,O-diacyl-o-aminophenols.
Dehydrogenation of Ethylbenzene on Potassium-Promoted Iron Oxide Catalyst Containing Magnesium Oxide
Authors: Hirano Takenori
Published: July 2006

Among potassium-promoted iron oxide catalysts containing a minor chromia and a series of alkaline earth oxides, i.e., MgO, CaO, SrO, and BaO, the MgO-containing catalyst showed the best performance with respect to the dehydrogenation activity and the stability even at a steam-toethylbenzene molar ratio (H2O/EB ratio) as low as 6.
Basis Set Dependency of Molecular Electronic Structures
Authors: Ichikawa Hiroshi , Sameshima Keiichiro , Ebisawa Yukiko
Published: July 2006

The total atomic charges as well as the kinetic and potential energies calculated using 22 different basis sets were compared. It was shown that polarization functions must be added to atoms of the first row as well as the hydrogen atom in order to obtain well-balanced wave functions. The STO-NG (N=3, 4, 5, or 6) method, which is considered to give poor wave functions, is shown to give well-balanced wave functions.
Photochemical Reactions of Bromoanthraquinones in Ethanol at Room Temperature Studied by Steady-State Photolysis and Laser Photolysis
Authors: Hamanoue Kumao , Nakayama Toshihiro , Sawada Kazuhide , Yamamoto Yoshiaki , Hirase Susumu , Teranishi Hiroshi
Published: July 2006

Photolyses of α-bromoanthraquinones (1-bromo-, 1,5-dibromo-, and 1,8-dibromoanthraquinones) with 366-nm light in ethanol at room temperature gave rise to the formation of debrominated 9,10-anthracenediol as a final product. This was interpreted in terms of the sequence of the formation of α-bromo-9,10-anthracenediols followed by the photochemical dehydrobromination yielding the corresponding anthraquinones with one less bromine atom than original ones. Photolysis of 2-bromoanthraquinone gave rise to the formation of 2-bromo-9,10-anthracenediol, and no dehydrobromination was observed. Combined with the values of the quantum yields of photoreduction, the results of the laser photolyses revealed that the rate constant for the hydrogen-atom abstraction from ethanol decreased as an increase of the ππ* character of the lowest triplet states of α-bromoanthraquinones.
Nuclear Magnetic Resonance Studies of Copper(I) Complexes of Imidazoles. II. Their Reaction with Ethylene, Phosphite, and Isocyanides
Authors: Kitagawa Susumu , Munakata Megumu
Published: July 2006

The reaction of binary copper(I) complexes of monodentate imidazole(im) with π acceptor ligands (ethylene, triethyl phosphite, p-tolyl isocyanide, and phenyl isocyanide) have been carried out in acetone. The resultant copper(I) complexes have been characterized by 1H and 31P NMR spectroscopy. Ethylene reacts with [Cu(im)2]+ (2) to give [Cu(im)2(C2H4)]+ (2-b), but does not react with [Cu(im)3]+ (3). This shows a clear difference in reactivity between 2 and 3. Phosphite and isocyanides give rise to a substitution reaction for im in 2 and 3, accompanying with addition reaction. Among the copper(I) compounds prepared here, two- and fourcoordinate forms show sharp 1H NMR signals of coordinated im, indicating that they are in the slowexchange regime. This proved that 1H NMR spectroscopy is a useful tool to characterize diamagnetic copper(I)–imidazole complexes in solution.
Splitting Parameters in Ligand Field Absorption Bands of Cobalt(III) Ammine Complexes with Chloro or Aqua Ligands
Authors: Mitsutsuka Yoshihiro , Kondo Ichiji , Nakahara Masayoshi
Published: July 2006

The splitting parameters of ligand field absorption bands for cobalt(III) ammine complexes containing aqua or chloro ligands were investigated by microspectrophotometry. The polarized absorption spectra were measured for these crystals. The spectra obtained were separated into Gaussian components according to a nonlinear least-squares method. The splitting parameters were determined from the locations of the components for the first absorption band.
The Solvent-Extraction Equilibrium of Vanadium(III, IV, V) with Acetylacetone in Nonpolar Solvents
Authors: Imura Hisanori , Suzuki Nobuo
Published: July 2006

The extraction of vanadium(III, IV, V) with 0.01–0.1 mol dm−3 acetylacetone in such nonpolar organic solvents as heptane, benzene, and chloroform has been investigated at pH 1–7 under a nitrogen atmosphere. The extraction constant, the partition coefficient, and the stability constant for the vanadium(III) and vanadium(IV) chelate were determined. Vanadium(V) was found to have been extracted as the vanadium(IV) chelate with reduction.
A Voltammetric Detection System for Measuring the Concentration of Chloride Ions in Fresh Concrete
Authors: Yamada Akifumi , Hodouchi Kazunori , Katoh Koichi , Otsuga Nozomu , Hashida Choichi , Honda Tetsuo
Published: July 2006

A voltammetric detection system for measuring the concentration of chloride ions in fresh concrete has been developed. A comparative determination using the Volhard titration method showed that the voltammetric system works as well in slushy concrete as in an aqueous chloride solution. No interference from the admixture was observed.
Mössbauer and DTA Studies of K2SO4–ZnSO4–Fe2(SO4)3 Glasses
Authors: Nishida Tetsuaki , Takashima Yoshimasa
Published: July 2006

A structural study of ternary sulfate glasses has been performed to elucidate the nature of the chemical bond and the local structure of these glasses. Mössbauer parameters (isomer shift and quadrupole splitting) show drastic decrease with an increase in the K2SO4 content. This is ascribed to the gradual change in the coordination number of iron (Fe3+) from six (Oh) to four (Td) when the K2SO4 content is higher than about 60 mol%. Lattice dynamic information obtained from low-temperature Mössbauer measurements suggests that the chemical bond between the iron and the neighboring oxygen is essentially ionic. All the Mössbauer results for the ternary sulfate glasses suggest that the Fe3+ ions are present at the vacant sites (voids) of the pseudospherical SO42− ions which are considered to be randomly packed to constitute the ionic glasses. Glass transition temperature (Tg) of these sulfate glasses, obtained from DTA measurements, also shows a gradual decrease with increasing K2SO4 content. This result is very similar to the composition dependency of the Mössbauer parameters described above, and suggests that the ionic field strength of the sulfate glasses decreases with increasing K2SO4 content. These experimental results are ascribed to the increased intermolecular bond length between the pseudospherical SO42− units.
Photochemical Reactions of Aryltriethylgermanes and Diethyldiphenylgermane
Authors: Kobayashi Michio , Kobayashi Masanori
Published: July 2006

Aryltriethylgermanes and diethyldiphenylgermane were found to split easily to generate germyl radicals by irradiation with a medium-pressure mercury lamp in hexane or cyclohexane. The germyl free radicals produced reacted with hydrocarbon radicals generated from the solvent by hydrogen abstraction either by recombination or by disproportionation.
Preparation and Thermal Ring Opening of 1-(Methylthio)cyclopropenes
Authors: Yoshida Hiroshi , Sano Hiroe , Kato Makoto , Ogata Tsuyoshi , Matsumoto Kiyoshi
Published: July 2006

The reaction of (methylthio)diphenyl- and methyl(methylthio)phenylcyclopropenium salts with Grignard reagents (methyl, 1-methylethyl, and phenyl) yielded 1-(methylthio)cyclopropenes as major products together with isomeric 3-methylthio-1-cyclopropenes in moderate total yields. Phenyllithium also reacted similarly with the salt to afford cyclopropenes in lower yields. Thermal ring opening of 1-(methylthio)cyclopropenes took place readily at room temperature or on heating at around 80 °C to give indene and/or butadiene derivatives in good yields. Product analysis of the reaction in methanol as well as kinetic studies of one of 1-(methylthio)cyclopropenes gave strong evidence for the intermediacy of vinylcarbene in the ring opening of cyclopropene.
Syntheses, Characterization, and Structures of (Monomethyl Carbonato)–Nickel(II), –Copper(II), and –Cobalt(II) Complexes with Tetraazacycloalkanes Obtained from CO2 Uptake
Authors: Kato Masako , Ito Tasuku
Published: July 2006

A new series of monomethyl carbonato complexes of nickel(II), cobalt(II), and copper(II) containing tetraazacycloalkanes (L) have been synthesized and characterized: Ni(L)(O2COCH3)(ClO4) (L=[14]aneN4 (1); L=[15]aneN4 (2); L=iso-[14]aneN4 (3); L=RSRS-Me4[14]aneN4 (4)), [Ni(RRSS-Me4[14]aneN4)(O2COCH3)2]·HNEt3ClO4 (5), Cu([14]aneN4)(O2COCH3)(ClO4) (6), [Cu(Me4[14]aneN4)(O2COCH3)](ClO4)·CH3OH (7), and Co(L)(O2COCH3)(ClO4) (L=[15]aneN4 (8); L=Me4[14]aneN4 (9)), where [14]aneN4=1,4,8,11-tetraazacyclotetradecane, [15]aneN4=1,4,8,12-tetraazacyclopentadecane, iso-[14]aneN4=1,4,7,11-tetraazacyclotetradecane, Me4[14]aneN4=1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, RSRS-=1RS,4SR,8RS,11SR-, and RRSS-=1RS,4RS,8SR,11SR-. These compounds have been obtained through CO2 uptake reaction in basic methanol from the corresponding four-coordinate complex, [M(L)](ClO4)2. X-Ray structures of three compounds, 4, 5, and 6, have been determined. Compound 4 is a five-coordinate complex with the trigonal bipyramidal geometry (Type II), in which CH3OCO2− is coordinated in a unidentate fashion. Compound 5 is a tetragonally distorted sixcoordinate complex with two unidentate CH3OCO2− at axial sites (Type III). Compound 6 is also a tetragonally distorted six-coordinate complex but the CH3OCO2− ligand bridges two neighboring [Cu([14]aneN4)]2+ to form a linear chain structure (Type I). All the monomethyl carbonato complexes synthesized are classified into these three types on the basis of IR and/or electronic spectral data, supplemented with the X-ray results. Efficiency of the CO2 uptake depends strongly on the coordination structure which is controlled by a combination of metal ion and tetraazacycloalkane. Differences in reactivity among the complexes of various metal ions and factors influencing the efficiency have been discussed in connection with the zinc(II) system which undergoes the most effective CO2 uptake of this type.
Effect of the Structure of Insoluble Pyridinium-Type Polymer on Its Ability to Capture Bacteria in Water
Authors: Kawabata Nariyoshi , Hayashi Takaya , Nishikawa Masaru
Published: July 2006

Effect of the structure of insoluble pyridinium-type polymer on its ability to capture bacteria in water was investigated. Strong ability of the polymer was further confirmed by an equilibrium capture experiment. The ability was quantitatively evaluated by the removal coefficient reported previously based on initial rate of decrease of viable cell counts caused by the presence of the polymer. The coefficient uniformly increased with the content of pyridinium group, and considerably increased when the content of divinylbenzene became smaller. The coefficient also increased with the content of 4-vinylpyridine in the polymer matrix. Based on these observations, presence of pyridinium group was concluded to be essentially important in the affinity of the polymer for bacterial cells. Hydrophilicity and high degree of swelling in water of the polymer matrix appeared to enhance the ability to capture bacteria.
Optical Resolution of erythro-2-Amino-1,2-diphenylethanol by Reciprocal Crystallization of the Diastereomeric Salts with (−)-Mandelic Acid on Alternate Seeding
Authors: Saigo Kazuhiko , Sugiura Izuru , Shida Ikuko , Tachibana Kouzou , Hasegawa Masaki
Published: July 2006

erythro-2-Amino-1,2-diphenylethanol was efficiently resolved into a pair of enantiomers by reciprocal crystallization of the diastereomeric salts with (−)-mandelic acid on alternate seeding.
Resonance Raman Spectra of Red-Shifted Retinal Schiff’s Base
Authors: Sugihara Toshiharu , Kitagawa Teizo
Published: July 2006

We have found that the visible absorption maximum (λmax) of retinal Schiff’s base in fluoro alcohols is considerably red-shifted. The C=N stretching Raman line exhibits a frequency shift in deuterated fluoro alcohols, indicating that the Schiff’s base is protonated. Frequencies of the in-phase C=C stretching Raman lines (νC=C) changed linearly with λmax, and the νC=C vs. λmax correlation coincides with that observed for retinoid proteins.
Tetraoxotetraazaparacyclophanes with Various Alkyl Chains as Hosts for Hydrophobic Compounds
Authors: Kodaka Masato , Fukaya Toshio
Published: July 2006

Tetraoxotetraazaparacyclophanes with short or long alkyl chains and tertiary amino groups were synthesized. It was shown that NN′N″N'″-tetrakis-(3-dimethylaminopropyl)-3,10,21,28-tetraoxo-2,11,20,29-tetra-aza[3.3.3.3]paracyclophane and NN′N″N'″-tetrakis-(5-dirnethylaminopentyl)-3,10,21,28-tetraoxo-2,11,20,29-tetra-aza[3.3.3.3]paracyclophane as well as NN′N″N'″-tetrakis-(10-dimethylaminodecyl)-3,10,21,28-tetraoxo-2,11,20,29-tetra-aza[3.3.3.3]paracyclophane could undergo a complex formation with picrate and 8-anilino-1-naphthalenesulfonic acid, while the dissociation constants for the former cyclophanes were larger than those for the latter cyclophane. The hydrolysis of p-nitrophenyl hexanoate was also studied in the presence of the cyclophanes and azide ion (N3−), but the reaction was not significantly activated.
Selective 2′-O-Methylation of Pyrimidine-Ribonucleosides by Trimethylsulfonium Hydroxide in the Presence of Mg2+ and Ca2+ Ions
Authors: Yamauchi Kiyoshi , Nakagima Toru , Kinoshita Masayoshi
Published: July 2006

Reactions of various ribonucleosides with trimethylsulfonium hydroxide were investigated in the presence of Mg2+ and Ca2+ ions. The 2′-OH groups of pyrimidine-ribonucleosides were methylated selectively.
The Addition of Alcohol to 1,2-Naphthoquinone Promoted by Metal Ions. A Facile Synthesis of 4-Alkoxy-1,2-naphthoquinones
Authors: Takuwa Akio , Soga Osamu , Iwamoto Hidetoshi , Maruyama Kazuhiro
Published: July 2006

In the presence of some metal ions and sodium iodate, 1,2-naphthoquinone (1) readily reacted with methanol to give 4-methoxy- 1,2-naphthoquinone (2a). The activity of the metal ions increased in the following order: Co(II)<Ni(II) << Cu(II)<La(III) << Ce(III). The reaction was remarkably affected by the reaction temperature, reaction time, and molar ratio of the chelating agent. By the use of 1 equivalent of cerium salt to 1, the yield of 2a increased to 81% at 20 °C for 30 min. In higher alcohols, the addition reaction proceeded under similar conditions to give 4-alkoxy-1,2-naphthoquinones (2b–f) in 46–75% yields.
The Enantioselective Hydrogenation of Methyl Levulinate on the Interactive and Noninteractive Sites of Nickel Surfaces with Preadsorbed Asymmetric Compounds
Authors: Yokozeki Michio , Shimokoshi Kazuo , Miyazaki Eizo
Published: July 2006

The gaseous hydrogenation of methyl levulinate on the Ni surface modified with the optically active tartaric, malic and lactic acids was studied. It was found that γ-valerolactone is formed on an unmodified surface, while optically active methyl 4-hydroxypentanoate [MHP] and γ-valelolactone [VL] are formed consecutively on modified surfaces. Using these results and the temperature dependency of the reaction rates, along with previous theoretical results [J. Phys. Chem., 89, 2397 (1985)], it was concluded that, on an Ni surface modified with preadsorbed optically active acids, there are two different and independently operative sites, i.e., noninteractive (nonselective) and interactive (selective) sites which give the enantioselectivity. Further, the fractions of the noninteractive sites in the total amount of active sites were estimated to be about 18 and 13% for TA- and MA-modified surfaces respectively. A similar character of the active sites was found for the enantioselective hydrogenation of methyl acetoacetate [MAA] to methyl 3-hydroxybutyrate [MHB] on TA-modified Ni, where the fraction of noninteractive sites was evaluated to be about 15%.
Effects of Cyclodextrins on the Fluorescence of Diphenyl Phosphate in Aqueous Solution
Authors: Hamai Sanyo
Published: July 2006

The effects of α-, β-, and γ-cyclodextrin (CD) on intramolecular excimer formation between the two phenyl groups of diphenyl phosphate (DP) in aqueous solution were investigated by means of absorption and fluorescence spectra. It was found that DP forms 1 : 1 inclusion compounds with α-, β-, and γ-CDs. In the inclusion compound with α- or β-CD, only one phenyl group of a DP molecule is incorporated in the cavity of a CD molecule. In the case of γ-CD, however, the cavity can accommodate either one or two phenyl groups of a DP molecule. The pH dependence of the equilibrium constant for the formation of the inclusion compound between DP and β-CD has also been examined. Over the pH range from 3.46 to ≈10 the equilibrium constant does not change, whereas for pH values above ≈11 it decreases drastically.
Heterogeneous Hydration of Acrylonitrile over the Metal Oxide Catalysts in Liquid Phase
Authors: Sugiyama Kazuo , Miura Hiroshi , Nakano Yasushi , Sekiwa Hideyuki , Matsuda Tsuneo
Published: July 2006

The liquid-phase hydration of acrylonitrile has been examined over various single metal oxide catalysts at 65 °C. Numerous metal oxides have proved to be active for hydration and have been used to produce three products: acrylamide, ethylene cyanohydrin, and bis(2-cyanoethyl) ether. These oxide catalysts could be divided into two groups with respect to the acrylamide selectivity with 100% or not. A good relationship between the catalytic abilities (activity and selectivity) and the solid acid-base properties of each metal oxide group examined in benzene or in water was observed. Differences in the hydration selectivity to either a C≡N or a C=C bond of acrylonitrile over the catalysts could be explained on the basis of the IR spectra of two adsorbed states of acrylonitrile on the metal oxide surface. It was proved that the liquid-phase hydration of acrylonitrile over the insoluble metal oxide catalysts was an acid-base-catalyzed reaction proceeding on the acidic or basic surface hydroxyl groups.
Polarized Raman and Infrared Spectra of [1H4]- and [2H4]Pyridazines
Authors: Ozono Yoshimi , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi
Published: July 2006

The polarized Raman and infrared spectra of [1H4]- and [2H4]pyridazines were studied. Assignments of the normal vibrations made by previous workers were reexamined on the basis of polarization behavior of the Raman and infrared bands and also through the normal coordinate calculation, and reasonable assignments are presented.
Synergistic Extraction of Copper(II) and Zinc(II) with Tributyl Phosphate and Crown Ether
Authors: Hasegawa Yuko , Miyata Hirofumi , Yoshida Satoshi
Published: July 2006

The solvent extraction of copper(II) and zinc(II) with 12-crown-4 (12C4) or 15-crown-5 (15C5) as picrates into chloroform containing tributyl phosphate (TBP) has been studied. The following conclusions have been reached. i) Even in the presence of TBP which is more basic than crown ether, either copper(II) or zinc(II) is extracted in association with 2 moles of 12C4 or 15C5. ii) The crown ether complex of either copper(II) or zinc(II) forms 1 : 1 : 1 (metal(II): crown ether: TBP) stoichiometric adducts in chloroform. iii) The 12C4 complex of either copper(II) or zinc(II) forms more stable adducts with TBP than the 15C5 complex. iv) The extraction of the metal (II) with 15C5 and TBP is better than that of 12C4 and TBP. v) The copper(II) complex with 12C4 or 15C5 forms more stable TBP adducts than those from zinc(II) complex.
Effects of EDTA Derivatives on the Photoreduction of Methyl Viologen by a Thiacarbocyanine Sensitizer in a Micellar Solution
Authors: Nakagaki Masayuki , Komatsu Hiroaki , Tanaka Hiromi , Handa Tetsurou
Published: July 2006

The photoinduced reduction of Methyl Viologen (MV2+) by ethylenediaminetetraacetate (EDTA), 1,2-propanediamine-N,N,N′,N′-tetraacetate (MeEDTA), and trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetate (CyDTA) was investigated by using 3,3′-dioctadecylthiacarbocyanine (C18–18+) as a sensitizer in a micellar solution of a nonionic surfactant, heptaethylene glycol monododecyl ether. The production rate of reduced Methyl Viologen (MV+·) decreased with the light-irradiation time, while the deceleration increased in the order of: CyDTA<MeEDTA<EDTA. The concentration of the EDTA derivatives at the micellar surface was estimated to be in the order of EDTA<MeEDTA<CyDTA, this difference in the concentration being attributed to such hydrophobic groups as methyl group and cyclohexane ring in the EDTA-derivative molecules. The high concentration of the EDTA derivatives at the surface accelerated the reaction of the sensitizer divalent cation radical (C18–182+·) with the EDTA derivatives, prevented the consumption of MV+· through the back reaction of C18–182+· with MV+·, and facilitated the efficient photoproduction of MV+·. It was demonstrated that the hydrophobic interaction between the EDTA-derivative molecules and the micellar surface is an important factor in determining the efficiency of the photoinduced MV+· production.
Polymerization of Styrene Adsolubilized in Surfactant Adsorbed Bilayer on Pigments
Authors: Meguro Kenjiro , Yabe Toshikazu , Ishioka Sayuri , Kato Kazufumi , Esumi Kunio
Published: July 2006

The polymerization of styrene adsolubilized in a surfactant-adsorbed bilayer formed on the surface of inorganic pigments (iron oxide, titanium dioxide) was attempted in order to modify their surface properties. After the polymerization, the amount of polystyrene formed on the pigments gradually increased with an increase in the amount of styrene adsolubilized. Further, the molecular weight of the polystyrene formed changed with an increase in the amount of styrene. The surface properties of pigments after the polymerization were characterized by FTIR-PAS, turbidity, and zeta potential measurements.
State of Polarization of Light Scattered by Colored Spheroids
Authors: Sano Yoh , Nakagaki Masayuki
Published: July 2006

Using the light-scattering theory of Rayleigh–Gans for spheroids, theoretical expressions were derived for the polarization state of light scattered by randomly oriented small and colored spheroidal particles in the case of linearly polarized incident light with an angle of inclination of ψ to the scattering plane. The azimuth angle ζ of the ellipse of the scattered light did not depend on the axial ratio p and the relative complex refractive index m (=m0−ik0), but was a function of only the scattering angle θ and ψ; also, the ellipticity of the ellipse of the scattered light was always equal to 0 and the scattered light was partially linearly polarized for linearly polarized incident light. The degree of polarization of the scattered light for spheroidal particles, P, defined as the ratio of the polarized component to the intensity of the scattered light, depended strongly on p, m0, k0, and θ together with the angle ψ. This P was found to be smaller than 1. In the case of spherical particles, P was always equal to 1 at any θ; this means that the scattered light was perfectly polarized. It has been concluded that a determination of P as a function of ψ and θ gives good information regarding the shape and the optical constants (m0 and k0) of the colored spheroidal particles.
Studies of Spin-Labeled Sodium Dodecyl Sulfate. II. Effect of Sodium Chloride on ESR Line Width
Authors: Yamaguchi Takeo , Yamauchi Akira , Kimoto Eiji , Kimizuka Hideo
Published: July 2006

The ESR spectra of spin-labeled sodium dodecyl sulfate were examined by changing the concentration, temperature, and ionic strength. The broadening of ESR lines due to a monomer surfactant could be explained in terms of an electron-spin exchange and a monomer-micelle exchange. The spin-exchange rate increased with increasing temperature and decreased with increasing ionic strength, i.e., the spin-exchange frequency was closely related to the viscosity of the medium. On the basis of an analysis of the line width above the critical micelle concentration, it was found that the aggregation number of the micelle of this compound and the monomer-micelle exchange frequency were dependent on the ionic strength.
On the Relationship Between the Chemical Structure and the Carcinogenicity of Polycyclic and Chlorinated Monocyclic Aromatic Compounds as Studied by Means of 13C NMR
Authors: Sakamoto Yohko , Watanabe Shosuke
Published: July 2006

The relationship between chemical structure and carcinogenicity was investigated in thirty-eight polycyclic aromatic compounds and forty-four chlorinated aromatic hydrocarbons by means of 13C NMR. As an “index” serving as a measure of the electronic structure of aromatic compounds, which is closely related to the carcinogenicity, the averaged 13C NMR chemical shift over all the aromatic carbons in the molecule was used. In polycyclic aromatic compounds, the averaged chemical shifts of the carcinogenic compounds are within the range from 127.11 to 127.87 ppm, but those of the noncarcinogenic compounds are not within this range. In chlorinated monocyclic aromatic compounds, the carcinogenic compounds was within the range from 127.76 to 132.64 ppm. Thus, we proposed that the “index” is very useful for the discernment of the carcinogenicity of polycyclic and chlorinated monocyclic aromatic compounds.
Trachit Change of the ZrSiO4 Single Crystal During Crystal Growth Studied by the Na2O·3V2O5 Flux Method
Authors: Ushio Masumi , Sumiyoshi Yoshihiro
Published: July 2006

The appearance and disappearance of the crystal faces of the ZrSiO4 single crystal during crystal growth under the conditions of a growth temperature of 900 °C and a Δt value (temperature difference) of 1 °C have been studied by means of the Na2O·3V2O5 flux method. A spherical seed prepared from a natural zircon single crystal was used. The c{001}, a{100}, and m{110} appeared at the earliest stage, and next appeared r{115}, u{015}, p{111}, e{011}, and q{021} after 20 h of growth time. However, the u-face, r-face, and q-face disappeared after 400 h, and the c-face and a-face began to disappear after 500 h. The final morphology after 1400 h was a firstorder prism and a pyramid consisting of only the m-face and the p-face. It was found that the m-face and the p-face were dominant on a flux-grown ZrSiO4 single crystal, and that this tendency was unchangeable after 2500 h.
Studies on Dissolved Metalloenzymes in Lake Water. II. Seasonal Variations in Phosphatase Activity in Lake Kasumigaura
Authors: Kobayashi Kensei , Hashimoto Shinya , Iwase Koichi , Otsuki Akira , Fujiwara Kitao , Fuwa Keiichiro , Haraguchi Hiroki
Published: July 2006

Alkaline phosphatase activity in Lake Kasumigaura was determined periodically and characterized by highperformance liquid chromatography and isoelectric focusing electrophoresis. There are two peaks in dissolved alkaline phosphatase activity; the bigger one in summer and the smaller one in winter. Molecular weight of ca. 89000 and isoelectric points 5–6 were found for most phosphatases in samples collected during the summer. A considerable part of the winter alkaline phosphatases, however, have much higher molecular weights, and major isoelectric points for these were ca. 4. These alkaline phosphatases were metalloenzymes activated by zinc. The observations above suggest that there are seasonal changes in the dominant microbial species producing dissolved alkaline phosphatase; i.e., blue-green algae, a procaryote, in summer and diatoms and flagellates, eucaryotes, in winter. The peak of alkaline phosphatase activity in lake water was predictive of a following increase in algal species therein.
Metallation of Aliphatic Carbon Atoms. IV. Syntheses and Characterization of the Cyclopalladated Complexes of 2-t-Butylbenzothiazole
Authors: Hiraki Katsuma , Fuchita Yoshio , Nakashima Motoharu , Hiraki Hirofumi
Published: July 2006

2-t-Butylbenzothiazole reacts with palladium(II) acetate in acetic acid to produce the cyclopalladated dimer [{Pd(CH2CMe2–C7H4NS)(μ-MeCO2)}2] (2) (C7H4NS=2-benzothiazolyl). Complex 2 shows temperature-dependent 1H NMR spectra, which have been interpreted on the basis of the inversion motion of the acetato bridges. Metatheses of 2 with lithium chloride and sodium iodide result in the formation of the chloro- and iodo-bridged analogues, [{Pd(CH2CMe2–C7H4NS)(μ-Cl)}2] (3) and [{Pd(CH2CMe2–C7H4NS)(μ-I)}2] (4), respectively, each of which is found to be composed of cis and trans isomers. The 1H NMR spectra of 3 and 4 depend on temperature and are ascribed to rapid exchange between the two isomers. Equimolar amounts of 3 and 4 afford a μ-chloro-μ-iodo binuclear complex, [(C7H4NS–CMe2CH2)Pd(μ-Cl)(μ-I)Pd(CH2CMe2–C7H4NS)]. The reaction of 3 with thallium(I) acetylacetonate [Tl(acac)] produces a mononuclear cyclopalladated complex [Pd(CH2CMe2–C7H4NS)(acac)]. Complexes 2 and 3 react with CO in methanol to give MeO2CCH2CMe2–C7H4NS, the formation of which comfirms also the cyclopalladated structure of 2-t-butylbenzothiazole in 2 and 3.
121Sb Mössbauer and 1H and 13C NMR Spectroscopic Studies of a Series of Organoantimony(V) Compounds, R3SbX2
Authors: Yanaga Makoto , Miura Taichi , Endo Kazutoyo , Nakahara Hiromichi , Takeda Masuo
Published: July 2006

The 121Sb Mössbauer spectroscopic and the 1H and 13C NMR nuclear magnetic resonance studies have been performed for a series of organoantimony(V) compounds: R3SbX2 (R=CH3, C6H5, p-CH3C6H4; X=F, Cl, Br, I). For the trimethylantimony dihalides, the isomer shifts and quadrupole coupling constants of the 121Sb Mössbauer spectra indicated that the withdrawal of the bonding electrons from the antimony atom along Sb–X increased, as the electronegativity of the halogen increased. The chemical shifts of the 1H and 13C NMR spectra showed that the electron population around the methyl group increased with increasing electronegativity of halogen. For phenyl and p-tolyl derivatives, both 121Sb Mössbauer and 13C NMR data showed a trend similar to the methyl compounds. The results suggest that the electron cloud around the antimony atom spreads, with an increase in the electronegativity of the halogen, not only toward the halogen atoms but also toward the plane perpendicular to the bonding direction with the halogen atoms.
The Reaction of cyclo-Triphosphate with Ethanolamines
Authors: Tsuhako Mitsutomo , Sueyoshi Chiyoko , Miyajima Tohru , Ohashi Shigeru , Nariai Hiroyuki , Motooka Itaru
Published: July 2006

The reaction of cyclo-triphosphate(P3m) with mono-(MEA), di-(DEA), or triethanolamine(TEA) in an aqueous solution was investigated under various conditions (mixing ratio of MEA, DEA, or TEA to P3m, pH, temperature, and reaction time). 1) In the pH region of 7–12, P3m reacted with MEA or DEA to yield tri-, di-, and monophosphate derivatives of MEA or DEA. The phosphoric acid ester of MEA or DEA was not formed at all. 2) The reactivities of MEA and DEA to P3m were in the order of MEA>DEA, and TEA did not react with P3m. 3) The reactivity of P3m with MEA or DEA decreased with the decrease in the pH, and no reaction took place under acidic conditions. 4) The maximum yields of triphosphate derivatives of MEA, N-(2-hydroxyethyl)triphosphoramidate(P3-(N)MEA) and of DEA, N-bis(2-hydroxyethyl)triphosphoramidate (P3-(N)DEA), were about 75 and 60% respectively at a molar ratio of 1 : 1, at pH 12, and at room temperature. 5) P3-(N)MEA and P3-(N)DEA easily recyclized to the raw material, P3m, under acidic conditions. 6) The mechanism of the reaction between P3m and MEA or DEA was investigated.
Ring-Opening Reactions of Thiophene Derivatives by the Use of the Birch Reduction
Authors: Kumamoto Takanobu , Hosoya Kumiko , Kanzaki Satoshi , Masuko Kazuhiro , Watanabe Mikio , Shirai Kozo
Published: July 2006

It was found that the Birch reduction of 2-(2-thienyl)alkanoic acid and subsequent alkylation with benzyl bromide resulted in the formation of 2-alkyl-3-benzylthio-3-hexenoic acid selectively. Further, the Birch reduction of a 2,3-dialkylthiophene and subsequent alkylation with benzyl bromide gave a tetrasubstituted olefin which was formed by a selective C–S bond fission between the 1 and 5 positions of the thiophene nuclei. In contrast to these results, the Birch reduction of 3-thiophenecarboxylic acid derivatives and subsequent benzylation gave 2-alkyl-4-benzylthio-3-butenoic acid which was formed by a C–S bond fission between the 1 and 2 positions of the thiophene nuclei.
The Total Synthesis of (±)-Pisiferin
Authors: Matsumoto Takashi , Imai Sachihiko , Yoshinari Takashi , Matsuno Shigeo
Published: July 2006

The conversion of racemic α-cyclocitral into 3-(3-isopropyl-4-methoxyphenethyl)-4,4-dimethyl-2-methylenecyclohexanone (2) was carried out in five steps via 3-(3-isopropyl-4-methoxyphenethyl)-2,4,4-trimethyl-1-cyclohexene. An intramolecular cyclization of 2 with polyphosphoric acid produced the corresponding two tricyclic ketones possessing cis- and trans-A/B ring junctions. Each of these ketones was further converted into 12-mesyloxy-9(10→20)-abeo-abieta-1(10),8,11,13-tetraene in four steps. The mesylate was reduced with lithium aluminium hydride to give (±)-pisiferin.
Spacer-Assisted Catalytic Action of Imidazole-Appended γ-Cyclodextrin
Authors: Ueno Akihiko , Moriwaki Fumio , Osa Tetsuo , Ikeda Tsukasa , Toda Fujio , Hattori Kenjiro
Published: July 2006

Catalytic activity of γ-cyclodextrin bearing an imidazole moiety (1) was compared with that of the corresponding β-cyclodextrin derivative (2) in the hydrolysis of p-nitrophenyl acetate. The catalysts 1 and 2 hydrolyzed the ester 80 and 172 times, respectively, as fast in the complexes as the buffer without any catalyst. The binding of 1 for the ester was 40% weaker than that of 2. When sodium 1-naphthaleneacetate was present in the catalytic systems, the hydrolysis rate was enhanced for 1, but depressed for 2. This rate enhancement of 1 suggests that sodium 1-naphthaleneacetate acts as a spacer which facilitates 1 to bind the substrate by narrowing the large γ-cyclodextrin cavity. The time dependency of p-nitrophenol formation under the conditions of large excess of p-nitrophenyl acetate to 1 or 2 exhibited that the inhibitory effect of the product was remarkable for 2, but negligible for 1.
Mechanism of Carboxylic Acid-Catalyzed Reduction of Substituted Nitrosobenzenes by 1-Benzyl-3,5-bis(1-pyrrolidinylcarbonyl)-1,4-dihydropyridine in Acetonitrile
Authors: Awano Hiroshi , Tagaki Waichiro
Published: July 2006

Mechanism of carboxylic acid-catalyzed reduction of substituted nitrosobenzenes by 1-benzyl-3,5-bis(1-pyrrolidinylcarbonyl)-1,4-dihydropyridine has been studied in acetonitrile at 25 °C. The major product was hydroxylamine when the dihydropyridine was used in excess over nitrosobenzene, while that was azoxybenzene in the reverse case. The observed second-order rate constant k2R are dependent on acid concentration in a first-order manner with the acid-catalyzed third-order rate constant kHR. The Hammett relationship for kHR for substituted nitrosobenzenes gave a ρ=−0.93. The Brönsted plot of log kHR vs. pKa of acids gave a straight line with a slope of −0.34. The deuterium isotope effect for the catalysis by dichloroacetic acid was found to be kHR⁄kDR=2.80. These results indicate that a general acid catalysis by carboxylic acids plays an important role in the reduction of nitrosobenzene by dihydropyridine in acetonitrile.
Conformational Study of Acyclic Alcohols by NMR Spectroscopic Analysis, Molecular Force Field and Ab Initio Calculations
Authors: Abe Kazuhisa , Ito Kohichi , Suezawa Hiroko , Hirota Minoru , Nishio Motohiro
Published: July 2006

Conformations of a series of acyclic alcohols (CH3CH(R)CH(OH)CH3, CH3CH(R)CH(OH)CH(R′)CH3, and CH3CH(R)CH(OH)But) were studied (1) by measuring vicinal H–H coupling constants (3JH–H), (2) by lanthanoid-induced shift (LIS) analysis, (3) by molecular mechanics calculations (MM2), and (4) by ab initio (STO-3G, 4-31G geometry optimization) calculations. In the case of conformationally flexible alcohol as exemplified by 2-butanol and 3-pentanol, population of conformers determined by the LIS method do not agree with those determined by the 3JH–H, MM2, and ab initio methods. The discrepancy comes from the fact that the LIS measurement gives the most stable conformation of the alcohol in the LSR-alcohol complex and not of the free alcohol. In some flexible molecules, the most stable conformer in the complex can be different from that of the free molecule. In general, the conformational equilibrium is shifted by coordination of the shift reagent to the conformer whose alkyl chain stretches opposite to the direction of the coordination site of the shift reagent.
Synthetic Studies on Glycocinnamoylspermidine. II. Synthesis of 4-O-(2-Azido-2-deoxy-d-xylopyranosyl)-2-azido-2-deoxy-d-xylopyranose Derivatives
Authors: Araki Koichi , Kawa Manabu , Saito Yoshihiro , Hashimoto Hironobu , Yoshimura Juji
Published: July 2006

Synthetic intermediates for the aminopentose disaccharide moiety of glycocinnamoylspermidine were synthesized from d-xylose.
Fusogenic Behavior of Single-Walled Vesicles Composed of Synthetic Peptide Lipids
Authors: Murakami Yukito , Kikuchi Jun-ichi , Takaki Toshihiko
Published: July 2006

Fusogenic behavior of the single-walled vesicles formed with mixed or individual synthetic peptide lipids, N+C5Ala2Cn and (SO3−)C5Ala2Cn (n=14,16), was investigated in the presence of various water-soluble polymers or a nonbilayer-forming lipid by means of electron microscopy, differential scanning calorimetry, and turbidity measurements. The following ionic polymers having opposite charges to the net surface charges of the vesicles immediately induced fusion via vesicle aggregation; heparin, chondroitin sulfate C, chondroitin, and potassium salt of poly(vinyl sulfate) for the cationic vesicles, and polybrene for the anionic ones. On the other hand, ionic polymers having electrostatic charges identical with the vesicular surface charges and nonionic ones, such as amylose, poly(vinyl alcohol), polyethylene glycol 20000, and polyethylene glycol 6000, induced neither fusion nor aggregation. A nonbilayer-forming lipid, QC5Ala2C14, incorporated into the N+C5Ala2Cn vesicles induced fusion at kinetic rates much slower than those triggered by the ionic polymers. The observations were discussed with attention to the dehydration effect and the participation of nonbilayer structures in the fusion process.
Synthesis and Complexing Ability of New Type of Macrobicyclic Compounds
Authors: Nakatsuji Yohji , Kikui Takashi , Ikeda Isao , Okahara Mitsuo
Published: July 2006

New types of macrobicyclic compounds were synthesized from monoaza crown ethers bearing two hydroxyl groups and their complexing abilities regarding alkali metal cations were investigated.
Selective Linear Codimerization of Terminal Acetylenes and 1,3-Butadienes Catalyzed by (η4-1,5-Cyclooctadiene)(η6-1,3,5-cyclooctatriene)ruthenium(0)–Trialkylphosphine
Authors: Mitsudo Take-aki , Hori Yoji , Watanabe Yoshihisa
Published: July 2006

The reaction of terminal acetylenes with 1,3-butadienes catalyzed by (η4-1,5-cyclooctadiene)(η6-1,3,5-cyclooctatriene)ruthenium [Ru0(COD)(COT)]–PR3 (R=ethyl, butyl, octyl) in various solvents at 80 °C afforded linear codimers in good to excellent yield with high chemo-, regio-, and stereoselectivities. Reactions of deuterated acetylenes were also examined.
Synthesis and Antitumor Activity of N-Acetylmuramyl-l-alanyl-d-isoglutamine 6-Phosphate and Its Lipophilic Derivatives
Authors: Imoto Masahiro , Kageyama Shigeki , Kusumoto Shoichi , Kohno Morihiro , Matsumoto Kensuke , Hashimoto Shinjiro , Tohgo Akiko , Shiba Tetsuo
Published: July 2006

6-Phosphate of N-acetylmuramyl-l-alanyl-d-isoglutamine and its lipophilic derivatives, i.e., 6-(octadecyl hydrogenphosphate) and 6-(2-docosyltetracosyl hydrogenphosphate) were synthesized after the structural feature of mycobacterial cell walls for the purpose to modify and possibly to enhance the immunostimulating activity of the muramyl dipeptide which is the minimum requisite for the activity. As expected, the latter more lipophilic phosphate showed a high activity in a tumor regression test.
Dual-Mode Transport of Molecular Oxygen through the Membrane of the Poly(octyl methacrylate-co-4-vinylpyridine)(N,N′-disalicylideneethylenediaimine)cobalt(II) Complex
Authors: Nishide Hiroyuki , Ohyanagi Manshi , Kawakami Hiroyoshi , Tsuchida Eishun
Published: July 2006

Molecular oxygen transport through a polymeric membrane was enhanced in the membrane of poly(octyl methacrylate-co-4-vinylpyridine), complexed with (N,N′-disalicylideneethylenediamine)cobalt(II), which forms an oxygen adduct rapidly and reversibly. The cobalt complex in the membrane effectively acted as a fixed carrier on oxygen permeation. The oxygen-binding parameters determined spectroscopically were adequate to analyze the dual-mode transport model.
Kinetics and Mechanism of Acid-Catalyzed Oxidation of Substituted Toluenes by Pyridinium Fluorochromate
Authors: Bhattacharjee Bharati , Bhattacharjee Manabendra Nath , Bhattacharjee Mitra , Bhattacharjee Apurba Krishna
Published: July 2006

The kinetics of oxidation of substituted toluenes by pyridinium fluorochromate(VI) (PFC), C5H5N\overset+HCrO3F−, in aqueous acetic acid, in the presence of perchloric acid, have been studied. The main products are the corresponding aldehydes. While each of the oxidation is first order with respect to the oxidant, the rate is almost independent of the substrate concentration. The reactions depend on the first power of the concentration of acid. A kinetic isotope effect, kH⁄kD=5.4 at 30 °C, was observed. Electron-releasing groups were found to moderately facilitate the reaction, whereas the electron-withdrawing groups were found to have a retardation effect. Correlation with σ value yielded a ρ value of −2.0. The reaction does not induce polymerization of acrylonitrile. The effects of temperature and solvent compositions were studied and activation parameters evaluated. These and related data suggest that the initial reaction involves hydrogen abstraction forming an intermediate which subsequently produces the corresponding aldehyde.
Vibrational Spectrum of 2-Aminopyrazine
Authors: Kalkar Arun Kumar , Ars Comakshi C
Published: July 2006

Infrared and polarized laser Raman spectra in the solid phase and in the solution phase in different solvents have been obtained within the spectral region between 4000 and 200 cm−1 and analyzed for the purpose of vibrational assignments. The impact of intermolecular hydrogen bonding on amino group frequencies has been discussed in length. The fundamentals arising out of aromatic nucleus in particular various assignments are consistent with predicted spectral changes due to the presence of strong electron-activating amino group resulting in considerable perturbation of the vibrational levels of “parent” molecule pyrazine.
Interaction of Dithiophosphinates of Cobalt and Nickel with Pyridine-Type Donors
Authors: Mukherjee Rabindra Nath , Shankar Sanganabatla , Mascarenhas Denis Louis
Published: July 2006

The relative isotropic 1H NMR shifts of several pyridine-type base adducts of M(2,4-Me2dtpi)2 [where M=Co, Ni and 2,4-Me2dtpi=bis(2,4-dimethylphenyl)dithiophosphinate] were measured. The opposite signs of ring and methyl proton resonance shifts in α- and γ-picoline complexes of nickel indicate that both σ- and π-mechanisms are operative. In the cobalt cases all proton resonances are shifted down-field suggesting a negative dipolar contribution in addition to contact interaction. The magnetic and electronic spectral studies on these compounds are consistent with either MS4N or MS4N2 chromophores.
Kinetics of the Iron(II) Reduction of Glycinatobis(malonato)-, trans-Bis(malonato)bis(pyridine)-, Nitrilotriacetato(malonato)-, and Nitrilotriacetato(oxalato)cobaltates(III)
Authors: Viswanathan Ramakrishnan , Vijayaraghavan Venkatapuram Ramanujam
Published: July 2006

The kinetics of the iron(II) reduction of glycinatobis(malonato)-, trans-bis(malonato)bis(pyridine), nitrilotriacetato(malonato)-, and nitrilotriacetato(oxalato)cobaltates(III) have been studied in aqueous perchlorate medium at I=1.0 mol dm−3 (LiClO4) and 30 °C in the [H+] range 0.01–0.90 mol dm−3. The reductions are found to be second order. The reduction of [Co(gly)(mal)2]2− and [Co(py)2(mal)2]− is accelerated by H+, while the reduction of [Co(nta)(mal)]2− and [Co(nta)(ox)]2− is independent of [H+] in the range 0.1<[H+]<0.9 mol dm−3. The reduction of [Co(nta)(mal)]2− is, however, faster at [H+]<0.1 mol dm−3. The activation parameters for the reduction of [Co(gly)(mal)2]2−, [Co(py)2(mal)2]−, [Co(nta)(mal)]2−, and [Co(nta)(ox)]2− are respectively as follows:

ΔH≠=49.8±4.8, 51.2±2.6, 41.1±3.2, and 41.4+3.6 kJ mol−1

ΔS≠=−98.3±8.3, −93.7±7.2, −119.2±9.7, and −114.6+9.6 J K−1 mol−1.

The proposed mechanism invokes [Co(L)(H2O)(mal)(malH)] (l-py2 or gly) formed in a H+-assisted step as the reactive species for the bis(malonato) complexes. [Co(nta)(mal)]2− is proposed to be present as [Co(nta)(malH)(H2O)]− while [Co(nta)(ox)]2− remains unaffected by H+.
Synthesis, Dehydration Studies, and Cation-Exchange Behavior of a New Phase of Niobium(V) Phosphate
Authors: Qureshi Mohsin , Ahmad Anees , Shakeel Naseem Ahmad , Gupta Anek Pal
Published: July 2006

Twenty-three samples of niobium(V) phosphate have been synthesized under different conditions using niobium sulfate and phosphoric acid solutions. The amorphous sample having the ion-exchange capacity of 1.06 mEq g−1 and niobium to phosphorus mole ratio of 0.670 was studied in detail for its cation-exchange behavior. Molar distribution coefficients for 25 cations have been studied on this gel at pH 1,2,3, and 5.5. Four quantitative separations of Mg2+–Ca2+, Mg2+–Ba2+, Zn2+–Cd2+, and Bi3+–Zn2+ have successfully been achieved on it. The properties of this sample have been compared with those of niobium arsenate, niobium antimonate, and niobium molybdate. A tentative structural formula is proposed for this sample of niobium phosphate on the basis of chemical composition, cation-exchange capacity, pH-titration, IR spectra, T.G.A., water absorption, and heat treatment data.