bluuebunny/crossref_metadata_2025 huggingface dataset:
The Photoionization Mechanism of N,N,N′,N′-Tetramethyl-p-phenylenediamine in Acetonitrile
Authors: Nakamura Shigemasa , Kanamaru Nobuaki , Nohara Sawako , Nakamura Hiroki , Saito Yasuyoshi , Tanaka Jiro , Sumitani Minoru , Nakashima Nobuaki , Yoshihara Keitaro
Published: July 2006

The photoionization mechanism of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) in an acetonitrile solution was investigated by means of the fluorescence lifetime measurement, picosecond and nanosecond laser photolyses, and photocurrent measurement. The temperature dependence of the fluorescence lifetime was interpreted in terms of the thermally activated monophotonic ionization or the ion-pair-formation mechanism from the S1 excited level. Picosecond laser photolysis clearly showed that a direct ionization from higher S1,0 levels took place before relaxation into the S1.0 level. The relative yields of triplet, ion-pair, and cation formation were estimated from analyses of the transient spectra and the photocurrent.
Single-crystal ESR and X-Ray Crystallographical Studies of a Binuclear Copper(II) Complex with a Coaxially Stacked Square-pyramidal Geometry
Authors: Kajikawa Yuji , Sakurai Tosio , Azuma Nagao , Kohno Shizue , Tsuboyama Sei , Kobayashi Kimiko , Mukai Kazuo , Ishizu Kazuhiko
Published: July 2006

A binuclear complex of bis(μ-N,N′-dipicolinoyl-1,3-propanediamine)-bis(sulfato)dicopper(II) has been isolated as a blue single crystal tridecahydrate, [{Cu(SO4)(ppda)}2]·13H2O, from an aqueous solution. The crystals are orthorhombic, C2221, with a=15.42(1), b=24.92(2), c=25.73(2) Å, and Z=8. Each copper(II) ion is in a square-pyramidal coordination with two pyridine nitrogen atoms, two carbonyl oxygen atoms, and a sulfate oxygen atom at the apex. The two equivalent copper(II) ions, about 3.9 Å apart from each other, are aligned coaxially. The eight Cu–Cu vectors are approximately parallel to one another along the c axis. The most important feature of the crystal structure is the presence of the bulky ligands and of many water molecules, which magnetically isolate the Cu–Cu coupled pair from one another. This facilitates the ESR study of the molecular anisotropies by using the single crystal, even at room temperature. The ESR parameters determined are as follows: g⁄⁄=2.280(2), g⊥=2.067(1), |D|=422.4(8), |A⁄⁄|=170(2), and |A⊥|=14(1) in 10−4 cm−1. Bleaney and Bowers treatments of the exchange coupling contribution in the D parameter indicated a ground singlet state about 7 cm−1 below a triplet state for the coupled copper(II) ions. A comparison of the ESR parameters measured for the single crystal with those in the aqueous solution enabled us to conclude that the molecular structure in the solution was very similar to that in the crystalline phase, apart from the coordination of sulfate ions.
Effects of Hg(ClO4)2, HgCl2, and AgClO4 on the Conformations of Poly(S-carboxymethyl-l-cysteine) and Poly[S-(2-carboxyethyl)-l-cysteine] in Solution
Authors: Oka Kazuki , Maeda Hiroshi , Ikeda Shoichi
Published: July 2006

The effects of Hg(ClO4)2, HgCl2, and AgClO4 on the conformations of fully neutralized poly(S-carboxymethyl-l-cysteine) and poly[S-(2-carboxyethyl)-l-cysteine] in the absence of supporting electrolytes were examined by circular dichroism (CD) spectra. The induction of the β-form was suggested by the addition of Hg(ClO4)2 and AgClO4, while it could not be concluded in the case of HgCl2. Spectroscopic evidence for the coordination of metals with the two polypeptides was provided in the case of Hg(ClO4)2 and HgCl2 by the appearance of a new CD band around 250–260 nm as well as the distortion of the polymer CD spectra in the region of 200–230 nm, while it was not obtained in the case of AgClO4. The decrease of pH observed on addition of the three metal compounds also suggested the conformational change. Extraordinary lowering of pH and enhanced solubility were observed on addition of HgCl2.
The Influence of Anions on the Distribution Coefficients of Hard Acid-Metals for Anion-exchange Resin in HF–H3BO3 Media
Authors: Adachi Takeo , Yoshida Hideyo , Izawa Kimie , Kihara Sorin
Published: July 2006

The distribution coefficients, Kd, of eighteen hard acid-metal ions for a strongly basic anion-exchange resin were determined in HF–H3BO3 media in the presence of Cl− or NO3−, SO42−, and ClO4−, and the relation between the adsorbabilities of the coexisting anions and the Kd values of the metal ions was discussed. The fluoride-ion concentration is quite low in HF–H3BO3 media because of the complex formation of the fluoride ion with boric acid, and most of the hard acid-metal ions have lower Kd values in HF–H3BO3 media than those in a hydrofluoric acid solution. By varying the kinds of coexisting anions and their concentrations in HF–H3BO3 media containing less than 0.02 M(1M=1 mol dm−3) of fluoroborate ions, the Kd values of metal ions can be controlled to allow the anion-exchange separations. As fluoroborate ions, e.g., BF4− or BF3OH−, are strongly adsorbed on the resin, metal ions which are strongly held on the resin can be eluted by media including fluoroborate ions in higher concentrations. By using HF–H3BO3 media and selecting the coexisting anions, an effective mutual separation of titanium–zirconium, titanium–uranium, tin–niobium, and molybdenum–tungsten can be attined.
The Electronic Structure of the Fulvalene Trication Radical. A Localization of the Unpaired Electron
Authors: Toyota Azumao , Nakajima Takeshi
Published: July 2006

The restricted Hartree-Fock (RHF) solution for the trication radical of fulvalene, obtained by using the open-shell SCF formalism of the Pariser-Parr-Pople-type MO method, is found to be doublet unstable at the conventional D2h nuclear arrangement. We calculate the broken-symmetry charge-density wave solution lower in energy than the usual symmetry-adapted RHF solution and examine its properties. It is predicted that the unpaired electron should be localized on the single five-membered ring having a smaller positive charge. Finally, on the basis of the second-order Jahn-Teller effect, we examine the molecular-symmetry reduction of the trication radical from the fully-symmetrical D2h to the C2v nuclear arrangement.
Studies of Liquid Water by Computer Simulations. III. Dynamical Properties of a 2-D Model
Authors: Kataoka Yosuke
Published: July 2006

Molecular dynamics simulations of a water-like system are performed at many temperatures and densities. A 2-dimensional model of water is used for the system with 144 molecules in a square cell. The calculated self-diffusion coeffcient and the dipole direction relaxation time are in good agreement with the observed values in a wide temperature-pressure plane. Cross correlation function of displacement and local orientational order parameter are computed by the time-averaged configurations, where the average of period is several times longer than the velocity correlation time. The cross correlation is observed even in the third neighbor pairs, which proves the existence of hydrogen-bonded local structure. The lifetime of this local structure is about 2×10 ps at low temperatures and low density, where density maximum is known. The lifetime of the unstable species with a rather high energy is found to be about 0.5–2 ps at low temperatures and low density.
Correlation between Axial and In-Plane Coordination Bond Lengths in Tetragonal Six-coordinate Complexes of the trans-MX2N4 Type (M=Co3+, Ni2+, and Zn2+). X-Ray Structural and ab initio Molecular Orbital Studies
Authors: Ito Tasuku , Kato Masako , Ito Haruko
Published: July 2006

X-Ray data of 16 structures having coordination geometry of the trans-MX2N4 type show that (i) an out-of-plane coordination bond length decreases as an in-plane distance increases, (ii) the degree of the correlation is metal ion dependent and varies in the order, Zn2+>Ni2+>Co3+. In the Ni(II) systems, complexes having stronger ligands (X=NCS−) at axial positions show the weaker correlation as compared with complexes with weaker axial ligands (Cl−). Electronic origin that causes such negative correlations has been investigated in terms of the potential energy surfaces obtained from ab initio MO calculations for model compounds, trans-[MCl2(NH3)4]. A section of the potential surface along the M–Cl and M–N bond axes is an ellipse and the ellipse has a tilt with respect to the metal-ligand bond axes. The dependence of the M–Cl distances on the M–N distances becomes stronger, as the tilt of the ellipse increases, and/or as the ratio of the length of long to short axes of the ellipse is increased. The degree of correlation expected from the potential energy surfaces are consistent, in all respect, with experimentally observed results. The interrelationships, found both experimentally and theoretically, are associated with softness of metal ions. Among the metal ions studied, Co(III) is the hardest, Zn(II) is the softest, and Ni(II) is intermediate.
Reactions of Sodium Salts of Tosylhydrazone Compounds with Silver Chromate. Formation of Indazole, Pyrazole, and Benzonitrile Derivatives
Authors: Saito Katsuhiro , Toda Takashi , Mukai Toshio
Published: July 2006

Tropone tosylhydrazone sodium salt was allowed to react with silver chromate to give 2-tosyl-2H-indazole. The reaction is thought to proceed through the cyclization of the hydrazyl radical intermediate. Under the same conditions, sodium salts of m-nitrobenzaldehyde tosylhydrazone (5), benzylideneacetone tosylhydrazone derivatives (7a and 7b), and β-ionone tosylhydrazone (9) reacted to yield m-nitrobenzonitrile from 5 and pyrazole derivatives from 7a, b, and 9, respectively. m-Nitrobenzonitrile is formed by homolytic fission of nitrogen–nitrogen bond of 5. Formation of the pyrazole derivatives can be explained by intramolecular 1,3-dipolar additions of the corresponding diazo intermediates.
Condensations of 1,4-Cyclohexanediones and Secondary Aromatic Amines. The Formation of Alkyldiarylamines and Triarylamines
Authors: Haga Kazuo , Oohashi Masayuki , Kaneko Ryohei
Published: July 2006

Condensation of 1,4-cyclohexanedione with N-alkylarylamines gives N-alkyl-N-arylanilines, and that with diarylamines gives triarylamines. A mechanism involving dehydration of monoenamines of the 1,4-dione is proposed for the reaction. Relative rates of substituted N-ethylanilines on competitive reactions plotted vs. Hammet’s σ values gave −2.0 as the ρ value. In separate reactions, however, a different tendency is noted for the yield, that is, the ease of reactions with p-chloro and p-nitro derivatives. This discrepancy is explained in terms of acidities of the conjugate acids of the amines used as the actual catalysts.
Infrared Intensities in Methyl Chloride. II. Binary Overtone and Combination Bands
Authors: Kondo Shigeo , Koga Yoshinori , Nakanaga Taisuke , Saëki Shinnosuke
Published: July 2006

Infrared intensities of binary overtones and combinations of CH3Cl and CD3Cl molecules have been measured by the pressure broadening technique. Simplified formulas for the intensities of binary overtone and combination bands of symmetric top molecules were given. Contribution from the mechanical anharmonicity was calculated by use of these equations. Contribution from the electric anharmonicity was estimated by ab initio MO method (4–31 G*). The calculated intensities were compared with the observed values and discussed.
Photochemical Reaction of Phenyl-substituted 1,3-Diketones
Authors: Yoshioka Michikazu , Suzuki Tsuneji , Oka Masashi
Published: July 2006

Irradiation of 2,2-dimethyl-1-phenyl-1,3-diketones with 3-ethyl or 3-isopropyl substituents gave type II cyclization product, 3-hydroxy-2,2,4-trimethyl-3-phenylcyclobutanone or 3-hydroxy-2,2,4,4-tetramethyl-3-phenylcyclobutanone, along with type I cleavage products. The type II cyclization/type I cleavage ratio is greater with a 3-isopropyl group than with a 3-ethyl group. A similar irradiation of 2,2-dimethyl-1-phenyl-1,3-butanedione gave type I cleavage products and no type II cyclization product. Irradiation of 2,4-dimethyl-1-phenyl-1,3-pentanedione gave 3-hydroxy-2,2,4-trimethy1-3-phenylcyclobutanone and propiophenone. The geometry of 3-hydroxy-2,2,4-trimethyl-3-phenylcyclobutanone which arose from 2,2-dimethyl-1-phenyl-1,3-pentanedione was cis with respect to phenyl and 4-methyl groups and that which arose from 2,4-dimethyl-1-phenyl-1,3-pentanedione was trans.
The Structure of Aquatris(m-hydroxybenzoato)cerium(III), [Ce(HOC6H4CO2)3(H2O)]n
Authors: Koizumi Yukio , Sawase Hiroshi , Suzuki Yasuo , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The crystal and molecular structure of the title complex has been determined by the use of the single-crystal X-ray diffraction method. The crystal of CeC21H17O10, F. W. 569.48, was monoclinic; space group P21⁄c, a=13.401(2), b=19.173(5), c=8.079(1) Å, β=98.94(1)°, U=2050.6(8) Å3, Z=4, Dm=1.84(3), Dx=1.84 Mg m−3, and μ(Mo Kα)=2.31 mm−1. Each cerium(III) atom is ennea-coordinated and is in a tri-capped trigonal-prism geometry. They are in a linear polymer, and each cerium(III) atom is bridged to the next metal atom by three carboxylate ligands.
The Study of Metal Colloids Produced by Means of Gas Evaporation Technique. II. Reaction of Metal Sols in Organic Solvents
Authors: Kimura Keisaku
Published: July 2006

The reaction of copper colloid in ethanol was studied. In the beginning of the reaction, very small particles reacted with ethanol producing ethoxide. With the proceeding of the reaction, the 577-nm characteristic copper band showed a red shift together with the broadening of the line width. This was explaind by the size dependence of the particles on the spectrum. Lead colloid was also examined.
Induced Circular Dichroism in the Complexes of Histidine Polypeptides with Methyl Orange. Effect of Distance between Histidine Residues
Authors: Yamamoto Hiroyuki , Nakazawa Ayako , Hayakawa Tadao , Nishi Norio , Naruse Takumi
Published: July 2006

The induced circular dichroism (CD) spectra of the sequential histidine polypeptide–azo dye complexes were measured. The induced CD arose from the dye bound to the polypeptide in the random coil conformation. The intensity of the induced CD decreased with increasing distance between the intramolecular histidine residues.
Amperometric Determination of Silver(I) with Hydrazine Sulfide and Its Estimation in Presence of Lead(II)
Authors: Deshmukh Govind S , Kulkarni Arun G , Joshi Shashikant N
Published: July 2006

Silver(I) has been estimated by an amperometric method using hydrazine sulfide as titrant. The titration is carried out in ammonium tartrate–ammonia supporting electrolyte (pH≈9). Further, this method is extended to determine silver(I) in presence of lead(II). Under these conditions lead(II) reacts only after all silver(I) has been precipitated. The accuracy of the procedure is comparable with that obtained in classical method.
Solvent Effects on Optical and ESR Spectra of One-Electron Reduced Species of Cobalt(III) and Manganese(III) Tetraphenylporphyrins Produced by γ-Radiolysis at 77 K
Authors: Hoshino Mikio , Konishi Shiro , Imamura Masashi
Published: July 2006

One-electron reduction by γ-ray irradiation of cobalt(III) and manganese(III) tetraphenylporphyrins (ClCo(III)TPP, ClMn(III)TPP, and IMn(III)TPP) in ethanol and MTHF(2-methyltetrahydrofuran) solutions at 77 K results in the reduction of the central metals of these porphyrins. From the optical and ESR measurements, the reduced species are found to retain the axial anion, Cl− or I−, in MTHF but not in ethanol. The absorption spectroscopic studies of these porphyrins in ethanol solutions indicate that the axial halide ion is displaced by an ethanol molecule prior to γ-ray irradiation.
Saw-toothed Distributions of Deuterium in Butenes Formed by 1,3-Butadiene Deuteration on a Pt/Al2O3 Catalyst in D2SO4
Authors: Shimazu Katsuaki , Kita Hideaki
Published: July 2006

Saw-toothed distributions of deuterium are observed in butenes produced by the deuteration of 1,3-butadiene on Pt/Al2O3 catalysts suspended in 0.5 M D2SO4. The nature of the saw-tooth is sensitive to the purity of the solution and to the deuterium content of the solution. On the basis of the N-profiles (the distributions of hydrogen equilibrated with surface H/D pool) deduced from the observed distributions of deuterium in butenes, the saw-tooth distribution is explained by the reaction mechanism where cis- and trans-1-methyl-π-allyls are reaction intermediates for the formation of cis-2-butene and the other isomers of 1-and trans-2-butenes respectively.
Kinetic Studies of Fast Equilibrium by Means of High-performance Liquid Chromatography. VI. Separation of Rotamers of Formanilide
Authors: Moriyasu Masataka , Kawanishi Kazuko , Kato Atsushi , Hashimoto Yohei
Published: July 2006

The restricted rotation about the carbon–nitrogen bond of formanilide has been investigated by high-performance liquid chromatography. At lower temperatures, two peaks corresponding to two dynamic rotamers (E- and Z-form) have appeared on chromatograms, whereas at higher temperatures they have not been separated and a single peak has appeared on chromatograms, due to rapid bond rotation. The equilibrium concentration ratio of E- to Z-form has been found to vary in different solvents, suggesting the presence of solute–solvent and solute–solute interactions such as hydrogen bond formation. Determination of kinetic characteristics such as rate constant and activation energy of fast reactions has been established by high-performance liquid chromatography. The authors have named the present method “dynamic high-performance liquid chromatography,” in imitation of “dynamic nuclear magnetic resonance spectroscopy” which traces fast equilibrium.
Far Ultraviolet Electric Linear Dichroism. II. Pulsed Electric Dichroism Apparatus and Dichroic Spectra of Collagen in Aqueous Solution in the 230–187 nm Wavelength Region
Authors: Yamaoka Kiwamu , Asato Manabu , Matsuda Koichiro , Ueda Kazuyoshi
Published: July 2006

A Pulsed electric linear dichroism (ELD) apparatus is described for studying the optical properties and solution conformation of biologically important macromolecules whose chromophores absorb light in the far ultraviolet region. This apparatus is capable of generating a rectangular-wave electric pulse field with a duration of 5 μs–5 ms and an amplitude of 0.2–8 kV over the 360–185 nm region. A special feature to this apparatus is its ability to record both parallel and perpendicular dichroism signals simultaneously and independently. To prove the instrumental performance, some dichroic spectra of calfskin collagen solution (pH 3.16 and concentration 0.03 g dm−3) in 0.001 mol dm−3 H3PO4 were measured in the 230–187 nm region, where the peptide chromophore shows a broad absorption spectrum. The reduced dichroism of collagen was positive but not constant throughout the wavelength region. A detailed analysis revealed that the peptide spectrum contains three overlapping absorption bands centered at 219, 200, and 189 nm. These transition moments were found to be inclined at ±(50.6–51.0°) (219 nm), ±(48.8–49.5°) (200 nm), and ±(56.0–55.8°) (189 nm) relative to the orientation axis of a triple-stranded collagen helix.
Equilibrium and Rate Data on Some Arsenite Transesterification Reactions
Authors: Edwards John O , Okumura Akiko , Rieger Philip H , Taylor Catherine M , Toyomi Yuiko
Published: July 2006

The arsenite transesterification reaction As(OCH3)3+ HOR\ightleftharpoonsAs(OCH3)2OR+HOCH3(with R equaling benzyl and t-butyl) has been studied in acetonitrile solvent. With benzyl alcohol, K, ΔH°, and ΔS° are 3.6 (25°C), 5.0 kJ mol−1 and 27 J mol−1 K−1 respectively; with t-butyl alcohol, the values are 0.36 (25°C), 4.0 kJ mol−1, and 5 J mol−1 K−1 respectively. The rate law for the approach to equilibrium in the case of benzyl alcohol is:

\frac−d[As(OCH3)3]dt=kf′[As(OCH3)3][HOCH2Ph]2−kr′[As(OCH3)2(OCH2Ph)][HOCH3][HOCH2Ph].

A mechanism which explains the unusual law has been postulated. The slower t-butyl alcohol reaction proceeds by a different mechanism which apparently involves catalysis by small amounts of water in the solvent. The steric effects are very significant.
Cation Ordering in (NaLa)(MgW)O6 with the Perovskite Structure
Authors: Sekiya Tadashi , Yamamoto Tetsuo , Torii Yasuyoshi
Published: July 2006

The title compound with an ordered monoclinic (pseudotetragonal) perovskite structure has been prepared. The lattice constants are a=5.5239(5), b=5.5253(4), c=7.8936(6) Å, β=90.16(1)°, and Z=2. The superstructure was found to be due to a layer-like ordering of Na+ and La3+ ions along alternate c-planes as well as a NaCl-type ordering of Mg2+ and W6+ ions in the octahedral sites. This new compound is the first example for the occurence of cation ordering in the A site. The origin of the superstructure was discussed.
Reaction of Enamines with Acetals or Trialkyl Orthoformates Activated by Lewis Acids
Authors: Takazawa Osamu , Kogami Kunio , Hayashi Kazuo
Published: July 2006

Enamines, prepared readily from various carbonyl compounds, react with acetals or trialkyl orthoformates in the presence of Lewis acids such as BF3·OEt2 to give corresponding β-alkoxy carbonyl compounds or α-dialkoxymethyl carbonyl compounds in good yields. The reaction of dienamines with acetals or trialkyl orthoformates also selectively gives corresponding β,γ-unsaturated α-(α-alkoxyalkyl) carbonyl compounds or β,γ-unsaturated α-diakoxymethyl carbonyl compounds in good yields.
The Selective Extraction and Spectrophotometric Determination of Copper and Silver by the Use of a Thiocrown Compound 1,4,8,11-Tetrathiacyclotetradecane
Authors: Saito Keiitsu , Masuda Yoshitaka , Sekido Eiichi
Published: July 2006

A highly selective solvent extraction and spectrophotometric determination of copper and/or silver is proposed; it is based on the extraction of the ion-pair formed by the copper(I)- or silver(I)-thiocrown ether complex cation and the appropriate dye anion. A comparative study of Bromocresol Green (BCG), Thymol Blue (TB), and picrate ions as the pairing ions for the extraction of copper using a 1,4,8,11-tetrathiacyclotetradecane (TTCT) solution of 1,2-dichloroethane is described. The use of BCG gave the highest sensitivity among these three kinds of anions and made it possible to determine copper in the range of 0.6–3.2 μg ml−1. The interferences of six kinds of cations and four kinds of anions were examined; only Ni2+ and ClO4− interfered, and they slightly. The separation by the extraction of silver and/or copper with TTCT solution of 1,2-dichloroethane from an aqueous solution containing seven kinds of metal ions (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Ag+) in the presence of picrate ion (Pic−) was also examined. Silver was first extracted quantitatively as the ion-pair compound, [Ag(ttct)2]+Pic−, and then copper as [Cu(ttct)]+Pic− after having been reduced to copper(I). The absorption maximum of both extracted species lies at 378 nm (ε:1.8×104), and the spectrophotometric determination of these metals is possible. This method was successfully applied to the determination of copper and silver in standard samples of steel.
Total Synthesis of Racemic and Optically Active Coronafacic Acids
Authors: Ohira Susumu
Published: July 2006

(±)-Methyl 3-ethyl-4-oxotricyclo[4.3.0.01,5]nonane-5-carboxylate (4), prepared by the stereoselective alkylation of methyl 4-oxotricyclo[4.3.0.01,5]nonane-5-carboxylate, was reduced with zinc borohydride, and the resultant hydroxy ester was treated with p-toluenesulfonyl chloride to give a mixture of α,β-unsaturated esters, having hydrindan skeletons. The mixture was submitted to hydroboration-oxidation to afford a keto ester, which was hydrolyzed to (±)-coronafacic acid (2). A diastereomeric mixture of l-menthyl 3-ethyl-4-oxotricyclo[4.3.0.01,5]nonane-5-carboxylates, prepared by a modification of the synthesis of (±)-4, was resolved by column chromatography on silica gel, and each diastereomer was converted into (+)-2 and (−)-2 in a similar way as (±)-2.
Palladium(II) Sulfate-Heteropoly Acid-catalyzed Oxidation of Cycloolefins in Liquid Phase
Authors: Ogawa Haruo , Fujinami Hideharu , Taya Kazuo , Teratani Shousuke
Published: July 2006

Heteropoly acid (HPA) was used as an oxidant in the Wacker catalyst system. Among the catalyst systems examined, the PdSO4–H3PMo6W6O40 catalyst system showed the highest activity with regard to the oxidation of cycloolefins, particularly cyclopentene and cyclohexene, to the corresponding cyclic ketones. The largest total turnover number with respect to Pd2+ was found to be 85 in water containing 20% N-methylformamide by volume. The initial rate of cyclohexene oxidation was expressed as

V o=k[Cyclohexene]1.0[PdSO4]1.0[HPA]0[O2]0.

The rate-determining step was suggested as being where cyclohexene was oxidized to cyclohexanone by Pd(II) salt. The apparent activation energy was 7.8 kcal mol−1 (1 cal=4.18 J). In the catalytic oxidation of cycloolefins (CnH2n−2: n=5, 6, 7, and 8), the yield of alicyclic ketone decreased as the carbon number n increased. Methyl-substituted cyclohexenes exhibited lower reactivities than cyclohexene.
The Oxidation of Biphenylene and Its Derivatives with Mn(OAc)3 and Pb(OAc)4
Authors: Kurosawa Kazu , Takamura Tetsuya , Ueno Yasunari , McOmie John F W , Pearson N D
Published: July 2006

The reaction of biphenylene with Pb(OAc)4 gave 2-substituted biphenylenes and 2,3-biphenylenedione. The reaction of 2-methylbiphenylene and 2,3-dimethylbiphenylene with Mn(OAc)3 yielded products in which the methyl substituent had been oxidized. The reaction of 2-methoxybiphenylene with Pb(OAc)4 gave 2-acetoxy-3-methoxybiphenylene and r-2,c-3-diacetoxy-2-methoxy-2,3-dihydrobiphenylene, which is the first example of a 2,3-dihydrobiphenylene. The reactions of 2-carboxy-, 2-methoxycarbonyl- and 2,7-dibromobiphenylene with Mn(OAc)3 and (in part) with Pb(OAc)4 yielded nuclear acetoxymethylated products. The conversion of r-2,c-3-diacetoxy-2-methoxy-2,3-dihydrobiphenylene into 5,10-diacetoxy-7(8H)-benzocyclooctenone was observed.
The Asymmetric Ullmann Coupling Reaction of Chiral Diol Diesters of 1-Bromo-2-naphthoic Acid and 2-Halo-3-nitrobenzoic Acids: Highly Diastereoselective Synthesis of Atropisomeric 6,6′-Dinitrodiphenic Acids
Authors: Miyano Sotaro , Handa Shigeru , Shimizu Kunitoshi , Tagami Katsuya , Hashimoto Harukichi
Published: July 2006

The copper-promoted Ullmann reaction of chiral diol diesters of 1-bromo-2-naphthoic acid induced axial dissymmetry into the newly formed 1,1′-binaphthyl bond: chiral diol, apparent net optical yield for the joining of two naphthyl units, and axial chirality induced are as follows: (S)-1,1′-binaphthyl-2,2′-diol, 71%, S; (1S,2S)-1,2-diphenyl-1,2-ethanediol, 32%, S; (1R,2R)-1,2-bis(ethoxycarbonyl)-1,2-ethanediol, 33%, S; (4S,5S)-bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane, 3.7%, R. The reaction of (R)-1,1′-binaphthyl-2,2′-diol esters of 2-halo-3-nitrobenzoic acids gave up to 85% net optical yield for the coupling; the intramolecular cyclization proceeded with virtually complete diastereoselectivity to give cyclic diester of R,R-configuration in a 42% isolated yield. This remarkable stereocontrol is ascribed to the steric requirement of the 12-membered cyclic diester structure containing rigid 1,1′-binaphthyl and 1,1′-biphenyl moiety.
The Synthesis of Li+-selective Polyether Carriers and Thier Behavior in Cation Transport through Liquid Membranes
Authors: Hiratani Kazuhisa , Taguchi Kazuhiro , Sugihara Hideki , Iio Kokoro
Published: July 2006

Noncyclic polyethers exhibiting lithium ion selectivity have been synthesized. Their competitive alkalimetal-ion transport through liquid membranes has been investigated, and the influence of their structures on the rates and selectivities of cation transport has been demonstrated. It has been found that the introduction of the oxytrimethylene chain on the polyethers is significant for the appearance of a high selectivity for the lithium ion, and also that the kind of terminal group might play an important role either in determining the rates of cation transport or the selectivity for the lithium ion. The introduction of a methyl group at the 2-position on the quinolyl terminal group of the polyether increased largely the selectivity for the lithium ion compared with that of the polyether having an unsubstituted quinolyl group. The cause of this was discussed on the basis of the NMR spectroscopic method and the CPK-model building.
Crystal and Molecular Structure of 4-t-Butyl-5-cyano-2-phenyl-1-thioxo-7-thia-1-phosphabicyclo[2.2.1]hept-2-ene
Authors: Uchida Tokiko , Kozawa Kozo , Saito Takao , Motoki Shinichi
Published: July 2006

The crystal and molecular structures of the title compound were determined by means of X-ray diffraction. Crystal data: C16H18NS2P, Mr=319.4, triclinic, a=12.731(2), b=13.143(1), c=12.483(1) Å, α=102.39(1), β=104.34(1), γ=117.96(1)°, V=1648.6 Å3, space group P\barl, Dm=1.30, Dx=1.287 g cm−3, Z=4, μ=4.02 cm−1 (Mo Kα). The structure was solved by the direct method and refined by the block-diagonal least-squares method to R=0.082 for 4495 observed reflections. The bond distances and angles are in good agreement with the ordinary values except for the P–S–C bridged angle of 82.5°. An asymmetric unit contains two crystallographically independent molecules, which are rotational isomers along the P–C bond.
A Convenient Method for the Regioselective Synthesis of 4-Alkyl(aryl)pyridines Using Pyridinium Salts
Authors: Akiba Kin-ya , Iseki Y\={u}ji , Wada Makoto
Published: July 2006

RCu·BF3 reacted with 1-ethoxycarbonylpyridinium chloride at the 4-position with almost complete regio-selectivity (>99%) to afford the corresponding 1,4-dihydropyridine derivatives in high yields (81–94%). The dihydropyridines were oxidized by oxygen to give 4-alkyl(aryl)pyridines (38–68%). Grignard reagents also reacted with 1-t-butyldimethylsilylpyridinium triflate with almost complete regioselectivity (>99%) to afford the corresponding 1,4-dihydropyridines, which were easily oxidized by oxygen to give 4-substituted pyridines in higher yields than above (58–70%).
Effects of Pore Size Distribution on the Catalytic Performance for Coal Liquefaction. I. The Activity and Selectivity of the Catalyst
Authors: Shimada Hiromichi , Kurita Minoru , Sato Toshio , Yoshimura Yuji , Kawakami Tomohiro , Yoshitomi Suehiko , Nishijima Akio
Published: July 2006

Coal liquefaction experiments were carried out by using seven catalysts with different pore structures. As for the unimodal catalysts, the total conversion increased with the pore radius of the catalyst because of the lesser pore-diffusional limitation. However, the ratio of oil to oil-plus-asphaltene decreased with the pore radius. In the case of a large-pore catalyst, heavy components with a large molecular size and a low reactivity can approach the intra-particle active sites and occupy them to prevent the hydrocracking of asphaltene to oil. Bimodal catalysts with micropores (r<10 nm) and macropores (r>300 nm) gave higher values of both the coal liquefaction and the oil yields than did the unimodal catalysts. The presence of macropores seems to enhance the pore diffusion and increase the efficiency of the micropore use, while mesopores with radii between 10 nm and 300 nm did not make such a high contribution to the pore diffusion as was shown for the macropores. For the removal of heteroatoms, there was little difference in the performance among the catalysts with different pore structures. It is suggested that the active sites for the heteroatom removal are deactivated easily by the heavy components.
Ab Initio MO Study on the 1,2-Hydrogen Migration from the Twisted Propene
Authors: Kikuchi Osamu
Published: July 2006

The 1,2-hydrogen migration from the 90°-twisted propene to the corresponding carbenes was examined on the basis of ab initio MO CI calculations. It was predicted that, in the polarized zwitterionic states of the twisted propene, the 1,2-hydrogen migration occurs from the negatively-charged carbon atom to the positively-charged one.
Equilibria in Aqueous Ternary System Containing Na+, CH3CO2−, and HPO42− between 38 and 75 °C
Authors: Wada Takahiro , Yokotani Fumiko , Matsuo Yoshihiro
Published: July 2006

Ternary system CH3CO2Na–Na2HPO4–H2O was investigated between 38 and 75 °C. No double salt formation occurs in this temperature range. Saturated CH3CO2Na solution has a strong dehydrating influence on Na2HPO4·2H2O and Na2HPO4·7H2O. The lowest formation temperature for anhydrous Na2HPO4 is about 57 °C.
Adsorption Isotherm Equation for Coexistence of Two Kinds of Metal Ions in Acidic Solution on Chelating Resin
Authors: Urano Kohei , Fujii Nobuhiko
Published: July 2006

Adsorption isotherms for the coexistence of two metal ions (combinations of Zn2+, Cd2+, and Pb2+) in acidic solutions on chelating resins were measured at 25 °C. They were analyzed in relation to the adsorption isotherm equation of a single metal ion, Q=Qmax⁄(1+ACM−αCHβ), as was reported in the preceding paper. It is found that the adsorption isotherms of two metal ions (i and j) in acidic solution on chelating resins can be generally expressed by the equation;

Q i,j=Qmax⁄{1+AiCi−αiCHβi(1+Ki,jCjαjCH−βj)}

over wide ranges of concentrations of the metal ion, C, and the hydrogen ion, CH (mol dm−3). Where Qi and Qi,j are the adsorption amounts (m mol/g-dry resin) of i metal ion in the absence and in the coexistence of j metal ion. Qmax is the maximum adsorption amount, α and β are parameters in the adsorption of single metal solution, A and K are correction factors, and subscripts i and j identifing i and j metal ions. The adsorption capacities of two metal ions in acidic solution can be obtained from the isotherms parameters Ai, αi, αj, βi and βj for an individual single metal ion and only one additional parameter Ki,j is needed.
The Volume, Adiabatic Compressibility, and Viscosity of Amino Acids in Aqueous Alkali-chloride Solutions
Authors: Ogawa Toshio , Mizutani Kiyoshi , Yasuda Motoo
Published: July 2006

The apparent molal volumes (φV), apparent molal adiabatic compressibilities (φKS), and relative viscosities (nr) at 25 °C have been obtained for the following amino acids in aqueous alkali-chloride solutions from measurements of the density, the ultrasonic velocity, and the flow time: glycine, l-alanine, β-alanine, α-aminoisobutyric acid, l-serine, and l-threonine. Viscosity measurements were also carried out in water for reference. The alkali chlorides used were lithium, sodium, and potassium chlorides. The limiting values φVo, φKSo and the extended Jones-Dole viscosity coefficients, B and D, were calculated by a linear extrapolation using the least-squares method. All the φVo, φKSo, and B values obtained in the mixed solvents were larger than the corresponding ones in water, except in a few cases of the B coefficient. The results are discussed in terms of the dehydration effect of the electrolytes upon the amino acids.
The Three-dimensional Structure of Plasminostreptin, a Bacterial Protein Protease Inhibitor, at 2.8Å Resolution
Authors: Kamiya Nobuo , Matsushima Masaaki , Sugino Hiromu
Published: July 2006

The three-dimensional structure of plasminostreptin, a bacterial protein protease inhibitor from Streptomyces antifibrinolyticus, was determined at 2.8Å resolution by the multiple isomorphous replacement technique. A dimer with the molecular weight of 11,402×2 was included in an asymmetric unit of the crystal. The monomer, composed of 109 amino acid residues, consisted of an antiparallel twisted β-sheet with five strands, two short helices, and irregular polypeptide-chain segments. The reactive site of plasminostreptin belonged to one of these irregular polypeptide-chain segments. The two monomers in the dimer were related by a non-crystallographic pseudo-two-fold axis, and the two β-sheets were arranged face-to-face with each other. The averaged angle between the strands of the two β-sheets was approximately 30° clockwise. In spite of 37 amino acid substitutions including the reactive site residues, the tertiary and quaternary structures of plasminostreptin were similar to those of Streptomyces subtilisin inhibitor (SSI). The main-chain conformations of the reactive site of plasminostreptin were similar to those of SSI and other protease inhibitors analysed previously. Moreover, the conformations of the side chain of the evolutionary conservative asparagine in the so-called “secondary contact region” resembled those found in the inhibitors of the pancreatic secretory trypsin inhibitor family.
A Novel Synthesis of Internal Alkenyldialkylborane by the Reaction of 1-Halo-1-alkenyldialkylborane with Grignard Reagent
Authors: Arase Akira , Hoshi Masayuki , Masuda Yuzuru
Published: July 2006

To synthesize internal alkenyldialkylboranes, coupling reactions were carried out by using 1-halo-l-alkenyldialkylboranes and Grignard reagents. Hydrogen peroxide oxidation and protonolysis with acetic acid of the reaction product revealed that internal (E)-alkenyldialkylborane was formed in 60–90% yield.
Hydrophobic Vitamin B12. III. Incorporation of Hydrophobic Vitamin B12 Derivatives into Single-Compartment Vesicles and Their Alkylation in Various Molecular Aggregates
Authors: Murakami Yukito , Hisaeda Yoshio , Ohno Teruhisa
Published: July 2006

The incorporation of hydrophobic vitamin B12 derivatives into the single-compartment vesicles of N,N-didodecyl-Nα-[6-(tyimethylammonio)hexanoyl]-l-alaninamide bromide (N+C5Ala2C12) was found to be primarily concerned with the extent of insolubility of the cobalt complexes in the aqueous bulk phase, while such incorporation into the single-walled vesicles of N,N-ditetradecyl-Nα-[6-(trimethylammonio)hexanoyl]-l-histidinamide bromide (N+C5His2C14) was enhanced by the coordination interaction between the cobalt complex and the imidazolyl group of the lipid. In molecular aggregates formed with hexadecyltrimethylammonium bromide, α-[4-(1,1,3,3-tetramethylbutyl)phenyl]-ω-hydroxypoly(oxyethylene), or N+C5Ala2C12, the alkylation rates of a hydrophobic vitamin B12 with 1-bromo-2-methylpropane and methyl 2-methyl-3-bromopropanoate were much enhanced relative to those in methanol. In the N+C5Ala2C12 vesicle, a two-step mechanism was observed for the alkylation with the latter reagent. The possible origin of such rate enhancement was discussed.
Synthesis, Spectral and Magnetic Properties and Crystal Structures of Alkoxo-oxygen Coordinated Copper(II) Complexes of N,N′-Disubstituted Malonamide and Oxamide Derivatives
Authors: Toki Takashi , Mikuriya Masahiro , Okawa Hisashi , Murase Ichiro , Kida Sigeo
Published: July 2006

1:1 Copper(II) complexes with N,N′-bis(2-hydroxyethyl)malonamide (abbreviated as H4maae), MCu(maae) (M=Ca, Sr, Ba), and 2:1 copper(II) complexes with N,N′-bis(5-amino-3-hydroxypentyl)malonamide and N,N′-bis(5-amino-3-hydroxypentyl)oxamide (abbreviated as H4madpl and H4oxdpl, respectively),[Cu2(madpl)]·3H2O and [Cu2(oxdpl)]·2H2O, were prepared and characterized by elemental analyses, infrared and electronic spectra, and magnetic susceptibilities. The 2:1 complexes exhibit a band at 23.3–27.0×103 cm−1 characteristic of alkoxo-oxygen bridged structure and show a very strong antiferromagnetic interaction, whereas the 1:1 complexes show no such band and their magnetic moments fall in the range of those for ordinary mononuclear copper(II) complexes. The crystal structures of [Cu2(madpl)]·3H2O and BaCu(maae)·7H2O were determined by the single-crystal X-ray diffraction method. The structure of [Cu2(madpl)]·3H2O consists of alkoxo-oxygen bridged binuclear molecules, where madpl4− functions as a sexadentate binucleating ligand with an N2O2N2 donor set. In BaCu(maae)·7H2O, the basic unit is a hetero-metal tetranuclear entity (H2O)2{Ba(H2O)4Cu-(maae)}2 in which the two Ba2+ are linked sharing two H2O and are also bound to alkoxo oxygens of Cu(maae)2−. On the basis of the crystal structures, their spectral properties were discussed.
Enantioselectivity Enhancement in the Deacylation of N-Acyl Amino Acid Esters by Vesicular Systems of Long Chain Dipeptide Nucleophiles and a Cationic Double Chain Surfactant
Authors: Ohkubo Katsutoshi , Matsumoto Noriko , Nagasaki Masaru , Yamaki Kazuhiro , Ogata Harumi
Published: July 2006

The enantioselective deacylation of short chain and long chain N-acyl amino acid p-nitrophenyl esters, CH3(CH2)nCONH\overset*CH(R)–CO2C6H4NO2-p (R=C6H5CH2, (CH3)2CHCH2, CH3; n=0, 8, 12), was carried out at 4–25°C (pH 7.68) with the vesicular systems composed of N,N-didodecyl-N,Ndimethylammonium bromide and long chain nucleophiles, Nα-dodecanoyl-l-histidine, Nα-(N-dodecanoyl-l-leucyl)-l-histidine(3a), Nα-(N-dodecanoyl-l-phenylalanyl)-l-histidine (3b), and N-(Nα-dodecanoyl-l-histidyl)-l-leucine (3c). Both the deacylation rate and the enantioselectivity were the largest in the deacylation of the substrates possessing a long N-acyl chain (n=8) with the efficient dipeptide nucleophiles (3a and 3b) including the l-histidine moiety in their terminal position, and the neighboring amino acid binding to the l-histidine in 3a, 3b, and/or 3c was found to play an important role in the enhancement of enantioselectivity. The lowering of the reaction temperature decreased the deacylation rate and increased the enantioselectivity. The maximum enantiomer rate ratio of 24.5 was obtained in the deacylation of p-nitrophenyl N-dodecanoylphenylalaninates with the dipeptide nucleophile 3b. The characteristic features of the present reaction are discussed on the basis of kinetic parameters (binding constants and activation parameters) and isokinetic relationships.
Reactions of 2-Chloroacyltrimethylsilanes with Grignard Reagents. Preparation of 3-(Trimethylsilyl)-2-alkanones and 2-(Trimethylsilyl)-1-alkanols
Authors: Sato Toshio , Matsumoto Kazuhisa , Abe Toru , Kuwajima Isao
Published: July 2006

Reactions of 2-chloroacyltrimethylsilanes with Grignard reagents have been examined. Thus, treatment with methylmagnesium iodide affords the corresponding 3-(trimethylsilyl)-2-alkanones through an initial addition followed by removal of chloride anion and 1,2-rearrangement of silyl group. In contrast, the reaction proceeds with 2 equiv of the Grignard reagents bearing β-hydrogen to give 2-(trimethylsilyl)-1-alkanols, where initial reduction of the silylcarbonyl group followed by such rearrangement and addition of the Grignard reagents to the resulting 2-(trimethylsilyl)alkanals have been proposed.
Axially Dissymmetric Bis(aminophosphine)s Derived from 2,2′-Diamino-1,1′-binaphthyl. Synthesis and Application to Rhodium(I)-Catalyzed Asymmetric Hydrogenations
Authors: Miyano Sotaro , Nawa Masayoshi , Mori Akira , Hashimoto Harukichi
Published: July 2006

Axially dissymmetric bisphosphine ligands, (R)- and (S)-2,2′-bis(diphenylphosphinoamino)-1,1′-binaphthyl (BDPAB) and (R)-2,2′-bis[N-(diphenylphosphino)methylamino]-1,1′-binaphthyl (Me-BDPAB) were conveniently prepared from 2,2′-diamino-1,1′-binaphthyl. The rhodium(I)-catalyzed asymmetric hydrogenation of α-acylamidoacrylic acids and esters gave the corresponding amino acids of up to 95% optical purity. The sign of the centro-chirality of the product amino acids was always the same to that of the axial chirality of the ligand in both cases of BDPAB and Me-BDPAB.
Electrical Conductivities of the Complexes of Naphthaceno[5,6-cd:11,12-c′d′]bis[1,2]dithiole and Its Analogs Obtained by Electrochemical Crystallization and Diffusion Method
Authors: Nogami Takashi , Tanaka Hidekazu , Ohnishi Shigeo , Tasaka Yoshihiko , Mikawa Hiroshi
Published: July 2006

Electrochemical crystallizations of the complexes of naphthaceno[5,6-cd: 11,12-c′d′]bis[1,2]dithiole (TTT), anthra[1,9-cd:4,10-c′d′]bis[1,2]dithiole (TTA), anthra[1,9-cd:4,10-c′d′]bis[1,2]diselenole (TSA), and naphtho[1,8-cd:4,5-c′d′]bis[1,2]dithiole (TTN) were made in 1,1,2-trichloroethane or tetrahydrofuran as a solvent. Most of the crystals were obtained with non-stoichiometric compositions, and they included the solvent. Some charge-transfer complexes including the above donors were also made by a diffusion method. The electrical conductivities of the crystals were measured by a two-probe or four-probe method. TTT(PF6)0.61 was found to be the most conductive materials in the complexes studied. Its electrical conductivity was 762 (Ω cm)−1 at room temperature, and it showed metallic behavior above 220 K. The conductivities of the other complexes varied widely in the range 102–10−7 (Ω cm)−1.
Restricted Rotation Involving the Tetrahedral Carbon. LV. Differential Effects of the peri-Substituents on the Rotational Barriers in 9-Ethyl-, 9-Allyl-, and 9-Benzyltriptycenes
Authors: Yamamoto Gaku , Oki Michinori
Published: July 2006

Energy barriers to rotation about the bridgehead-to-substituent bond in 9-ethyl-, 9-allyl-, and 9-benzyltriptycene derivatives with varying degrees of peri-substitution were studied by dynamic NMR and in one case by the classical kinetic method. In the singly peri-substituted series (1,4-dimethoxy derivatives) the barrier decreases in the order of 9-ethyl>9-allyl>9-benzyl. In the doubly peri-substituted series (1,8-dichloro derivatives) the barriers are alike irrespective of the 9-substituent, and in the triply peri-substituted series (1,4-dimethyl-8,13-dichloro derivatives) the barrier decreases in the order of 9-benzyl>9-allyl>9-ethyl. The reversal of the trend on the change in peri-substitution patterns may be explained on the basis of the change in the interaction between the peri- and 9-substituents in both the ground and the transition states.
Basic Behaviors and Properties of the Electrodeposited Polyaniline
Authors: Kitani Akira , Izumi Jinko , Yano Jun , Hiromoto Yasuyuki , Sasaki Kazuo
Published: July 2006

Basic behaviors and properties of polyaniline(PA) deposited anodically on platinum electrodes have been studied on the following points. 1) Effect of the mode of electrolysis and supporting electrolytes in the film forming process. 2) Characteristics of charging-discharging processes. 3) Electric conductivity and elemental composition of PA. The different modes of electrolysis do not affect the characteristics of the PA electrode obtained. The growth rate of PA film is 2.7–2.8 times faster in sulfuric acid than in perchloric, nitric or hydrochloric acid. It is indicated that there are two types of doping; one is associated with the acid-base equilibrium between amino or imino group in the film and proton in the solution and the other is associated with the excess charge in the film produced by anodic oxidation. The electric conductivity of PA markedly decreases by the immersion in alkali solutions. The release of doped anion from PA by treating with an alkali solution is confirmed by the elemental analysis. The amount of anions occluded by the electrochemical doping process is determined to be 0.25–0.29 per monomer unit.
Intramolecular Interactions in the Ground and Excited States of 1,3-Bichromophoric Propanes in the Aqueous Cyclodextrin Solutions
Authors: Itoh Michiya , Fujiwara Yoshihisa
Published: July 2006

The enhanced fluorescence of several 1,3-bichromophoric propanes in aqueous cyclodextrin solutions has been investigated by the steady-state fluorescence spectra and fluorescence lifetimes. 1-(9,10-Dicyano-2-anthryl)-3-(1- and 2-naphthyl)propanes exhibit the intramolecular charge transfer complex fluorescence generated in the ground state in the presence of γ-cyclodextrin. Two bichromophoric propanes, 1,3-di-2-naphthylpropane and 1-(1-naphthyl)-3-(2-naphthyl)propane, in the aqueous β- and γ-cyclodextrin solutions show not only the intramolecular excimer but also the ground state complex fluorescences, though the ground state complex formation of dinaphthylpropane has never been observed in the homogeneous solution even at low temperature. The intramolecular interactions in the ground and excited states seem to be attributable to their intramolecularly geometrical restriction in the extraordinary nonpolar cavity of the cyclodextrins.
The Extraction of Organomercury with 8-Quinolinol into Benzene
Authors: Sugimoto Takao , Naito Kunishige , Takei Shinsuke
Published: July 2006

The extraction of organomercury(II)(RHg+, R; ethyl, n-propyl, n-butyl, phenyl) with 8-quinolinol into benzene has been studied by means of spectrophotometry. This study confirmed that there was no co-extraction of electrically neutral species RHgOH by its investigation of the effect of the pH on the extraction of ethylmercury(II) chloride into benzene. Moreover, it was found that RHg+ forms 1:1 complexes with both HPO42− and PO43−. The formation constants of these complexes and of hydroxo complexes have been determined.