bluuebunny/crossref_metadata_2025 huggingface dataset:
Potentiometric and Calorimetric Studies on Formation of Glycinato Complexes of Nickel(II) in Water and in an Aqueous Dioxane Solution
Authors: Ishiguro Shin-ichi , Pithprecha Taweesri , Ohtaki Hitoshi
Published: July 2006

Protonation equilibria of glycinate (gly−) ion and complex formation equilibria between nickel(II) and glycinate ions have been studied by potentiometry and calorimetry in water and in 0.2 mole fraction (55.0%w/w) dioxane–water mixture, each containing 3 mol dm−3 LiClO4 as a constant ionic medium at 25 °C. A series of mononuclear complexes, [NiLn](2−n)+ (L−=gly− and n=1–3) were found in both solutions and their formation constants, enthalpies and entropies were determined. It elucidated that the stepwise Gibbs energies of formation of the metal complexes varied in the sequence, ΔG1°<ΔG2°<ΔG3°, and the stepwise enthalpies, ΔH1°>ΔH2°>ΔH3°, and thus, the stepwise entropies markedly decreased in the order, ΔS1°>ΔS2°>ΔS3°. The result was discussed in relation to changes in the metal–water and metal–ligand bond lengths within [NiLn(H2O)6−2n](2−n)+ (n=1–3) with n. As to the solvent effects, the formation constants of each metal complex increased with the addition of dioxane to water, the increase was caused by both enthalpies and entropies of formation of the complexes, the former mainly contributing to the formation of [NiL2] and the latter to [NiL]+ and [NiL3]−. The Gibbs energies of transfer of single species from water to the dioxane–water mixture were also evaluated. The enthalpy and entropy of transfer of any ionic species mostly compensated each other, so that the Gibbs energies of transfer of ions were rather small.
The Axial-Ligand Replacement of the [Tetrakis(1-methyl-4-pyridinio)porphine]iron(III) Ion by the Cyanide Ion in a Highly Alkaline Aqueous Solution
Authors: Arifuku Fumihiro , Ujimoto Kikujiro , Kurihara Hirondo
Published: July 2006

The axial-ligand replacement of the [Tetrakis(1-methyl-4-pyridinio)porphine]iron(III) ion by the cyanide ion was investigated in a highly alkaline aqueous solution by means of the spectrophotometric method at 25 °C. In the course of the replacement, a protolytic equilibrium between monocyanomonoaqua- and monocyanomonohydroxo complex ions was observed; the p(Ka/mol dm−3 value of the monocyanomonoaqua complex ion was found to be 12.2±1.1. In the formation of the dicyano complex ion, the rate-determining step was the second replacement of axial ligands, i.e., from the monocyano complex ion to the dicyanocomplex ion; according as the pH is 11 or 13, the equilibrium constant was found to be 38.0 mol−1 dm3 or 11.0, while the rate constant was 1.07×10−3 or 4.23×10−3 mol−3 dm3 s−1.
Preparations and Thermal Isomerization of Some Tricarbonyl(1-silacyclohexadiene) Iron Complexes. Silyl and Hydrogen Migration in the Diene and the Diene Complex
Authors: Nakadaira Yasuhiro , Kobayashi Toshiaki , Sakurai Hideki
Published: July 2006

The reaction of 1,1-dimethyl-2,5-diphenyl-1-silacyclohexa-2,4-diene with iron pentacarbonyl or diironnonacarbonyl gave a mixture of tricarbonyl(1,1-dimethyl-2,5-diphenyl-1-silacyclohexa-2,4-diene)iron and tricarbonyl(1,1-dimethyl-3,6-diphenyl-1-silacyclohexa-2,4-diene)iron. Similarly, on treatment with iron pentacarbonyl 1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,5-diene yielded a mixture of tricarbonyl-(1,1-dimethyl-3,6-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,4-diene)iron, tricarbonyl(1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,4-diene)iron, and tricarbonyl(1,1-dimethyl-2,5-diphenyl-6-trimethylsilyl-1-silacyclohexa-2,4-diene)iron as a result of migration of the hydrogen on the ligand competing with silyl migration. On thermolysis, 1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,5-diene underwent only 1,3-silyl-migration to yield 1,1-dimethyl-2,5-diphenyl-6-trimethylsilyl-1-silacyclohexa-2,4-diene. The mechanism of transition-metal assisted hydrogen-migration is discussed.
The Effect of Triple-Ion Formation on the Electron-Exchange Reaction Rate between Quinone and Semiquinone Anion Radical
Authors: Takiguchi Tsuyoshi , Suga Kosaku , Aoyagui Shigeru
Published: July 2006

The rate constant and activation parameters of electron-exchange reactions between duroquinone, p-benzoquinone and 2,5-di-t-butyl-p-benzoquinone and their respective semiquinone anions which form ion-pairs or triple-ions with Na+ and K+ were determined. The rate constants of triple-ions were smaller than those of corresponding ion-pairs; the rate constants of potassium ion pairs and triple-ions were larger than those of the corresponding sodium aggregates; and the rate constants of triple-ions decreased upon increasing the size of the substituent for quinone. These results were explained on the basis of a mechanism which is generally accepted for electron-exchange reactions of ion pairs of anion radicals.
Adsorption of Cationic Surfactants on Phospholipid Membranes and Its Contributions to Membrane-Surface Potential
Authors: Matsumura Hideo , Iwamoto Miyako , Furusawa Kunio
Published: July 2006

The adsorption behavior of cationic surfactants (alkyltrimethylammonium ions) on the phospholipid (phosphatidylethanolamine) membranes has been studied by means of interfacial electrostatic measurements, i.e., the surface potential of the monolayer and the zeta potential of the vesicles, in order to elucidate the balance between hydrophobic and electrostatic interactions. The data have been analyzed in terms of the interfacial electrochemical concept; these analyses have revealed that the hydrophobic interaction of a surfactant with the phospholipid membrane is the main motive force for adsorption and there is a critical alkyl-chain length to promote the surfactant adsorption. Furthermore, it was found that the electrostatic interactions between the surfactant and the phospholipid membrane, and among the surfactants themselves, also play a role in their adsorption.
Studies in the Extraction of Cadmium with Some Sulfur Ligands
Authors: Lahiri Roma , Rao G N
Published: July 2006

Extraction of cadmium(II) with 2-(2-pyridyl)-2,3-dihydrobenzothiazole, O,O′-diethyl hydrogenphosphorodithioate, 1-phenyl-3-methyl-4-thiobenzoyl-5-pyrazolone, N-(2-naphthyl)mercaptoacetamide, and 2-(o-hydroxyphenyl)-2,3-dihydrobenzothiazole has been studied. Extraction constants (Kex) have been calculated for these systems. These reagents have been compared with some common reagents used for the extraction of cadmium. Separation factors have been calculated for the separation of cadmium from zinc with some of these reagents.
Reaction of 2-Aminobenzohydrazides with Schiff Bases. A New Route to 3-Benzylideneamino-4(3H)-quinazolinones and 2-[2-(Methylamino)phenyl]-5-aryl-1,3,4-oxadiazoles
Authors: Reddy Padi Pratap , Reddy Cheppala Kista , Reddy Padala Satyanarayana N
Published: July 2006

Reaction of 2-aminobenzohydrazides with Schiff bases in methanol followed by KMnO4 oxidation has resulted in the respective formation of 3-benzylideneamino-4(3H)-quinazolinones and 2-[2-(methylamino)phenyl]-5-aryl-1,3,4-oxadiazoles, characterized by spectral and analytical methods.
Synthesis of New Arginine Derivatives as Substrates of Trypsin
Authors: Somorin Oyin , Ameghashitsi Leo
Published: July 2006

Eight new chromogenic arginine substrates: Nα-benzyloxy-carbonyl-l-arginine 3,5-dinitroanilide hydrochloride (l-ZADA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitroanilide hydrochloride (l-ZANA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-chloroanilide hydrochloride (l-ZANCA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-bromoanilide hydrochloride (l-ZANBA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-fluoroanilide hydrochloride (l-ZANFA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-iodoanilide hydrochloride (l-ZANIA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-(methylsulfonyl)anilide hydrochloride (l-ZANMA·HCl), and Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-(trifluoromethyl)anilide hydrochloride (l-ZANTA·HCl) were synthesized by coupling 5-substituted 3-nitroanilines with Nα-benzyloxycarbonyl-l-arginine hydrochloride. These substrates were found to be susceptible to trypsin-catalyzed hydrolysis. These series of substrates are suitable for studying electronic effects on trypsin activity.
The Positional Dependence of Anodic Peak Potentials in N-Substituted Adenines
Authors: Sato Takeo , Fukuzaki Kentaro , Fujii Tozo
Published: July 2006

In order to determine the structural dependence on the anodic potential, cyclic voltammetric measurements were carried out for 1-, 3-, 7-, 9-, and N6-alkyladenines in N,N-dimethylformamide (DMF) or in acetonitrile (AN). The anodic peak potential, Epa, in DMF was found to be sensitive to the substitution and shifted anodic in the order, 7-<1-<3-, N6-<9-substituted derivatives. These data, with the aid of solvent effects, are useful for determining the substitution pattern in N-alkyladenines.
[Cr(acac)3] as a New Calibrant for Magnetic Susceptibility Experiments
Authors: Sharma R P , Bhasin K K
Published: July 2006

The merits of a common coordination compound, [Cr(acac)3] obtained by a new and useful method, as a calibrant for magnetic susceptibility experiments are discussed.
Molecular Rearrangements. XXIV. Thermolysis of Phenylhydrazones
Authors: Mahgoub Safaa Abd El-Salam , Fahmy Atiat Mohammed , Aly Morsy Mohammed , Badr Mahmoud Zaif Amin
Published: July 2006

Thermolysis of acetophenone phenylhydrazone by reflux in air for 24 h gives ammonia, benzonitrile, acetophenone, biphenyl, aniline, o- and p-toluidines, together with 7-methyl-3-phenylindole, while that of benzophenone phenylhydrazone gives ammonia, benzophenone, N-benzhydrylideneaniline, biphenyl, aniline, benzonitrile, and 9-phenylacridine.
Induced Cholesteric Mesophases as a Probe for the Stereochemistry of Chiral Biphenyls
Authors: Gottarelli Giovanni , Spada Gian Piero , Seno Kaoru , Hagishita Sanji , Kuriyama Kaoru
Published: July 2006

In the studies of the induced cholesteric mesophases, the twisting powers of cisoid- and transoidbridged 2,2′-diaminobiphenyl derivatives having R-configuration were found to be negative and positive respectively. In the cases where CD spectroscopy is inadequate, the liquid crystal method is sensitive to the helicity of the biphenyl moiety. The conformation of 2,2′-diamino-6,6′-dimethylbiphenyl is discussed.
Kinetics of Axial Substitution of the Iron(II) Complex of 2,3,9,10-Tetraphenyl-1,4,8,11-tetraaza-1,3,8,10-cyclotetradecatetraene in Acetonitrile. Evidence for a Dissociative-Interchange Mechanism
Authors: Funahashi Shigenobu , Uchiyama Naotaka , Tanaka Motoharu
Published: July 2006

The reaction of the iron(II) complex of 2,3,9,10-tetraphenyl-1,4,8,11-tetraaza-1,3,8,10-cyclotetradecatetraene ([FeL(CH3CN)2]2+, 1) with imidazole and thiocyanate ion in acetonitrile has been investigated spectrophotometrically at various temperatures and pressures. The axial substitution of 1 with imidazole is first order with respect to the concentration of the iron(II) complex and imidazole and the rate constant and the activation parameters are obtained as k (25.0 °C)=0.69 mol−1 kg s−1, ΔH\eweq=76±4 kJ mol−1, ΔS\eweq=7±13 J mol−1 K−1, ΔV\eweq=13.7±0.9 cm3 mol−1. It has been demonstrated that at higher concentration of imidazole there exists self-associated imidazole which does not react directly with the complex. The axial substitution of 1 with thiocyanate ion proceeds through the ion-association between 1 and SCN− prior to the rate-determining step from the outer-sphere complex to the inner-sphere complex. The activation parameters for the rate-determining step were determined as follows: k0 (25.0 °C and 0.1 MPa)=2.35 s−1, ΔH\eweq=86±2 kJ mol−1, ΔS\eweq=51±6 J mol−1 K−1, ΔV\eweq=10.1±0.2 cm3 mol−1. The positive activation volumes strongly indicate a dissociative character of the activation process.
The Microwave Spectrum of Methyl Isoselenocyanate
Authors: Sakaizumi Takeshi , Yasukawa Atsushi , Miyamoto Hirobumi , Ohashi Osamu , Yamaguchi Ichiro
Published: July 2006

The microwave rotational spectra of two isotopic species of methyl isoselenocyanate(CH3NCSe with 80Se and 78Se) in the ground vibrational state(A-species) have been assigned in the 9 to 40 GHz frequency range and the rotational and centrifugal distortion constants for the ground vibrational state have been determined. Three r0 structural parameters have been determined from the observed rotational constants of the two species.
Spectrophotometric Determination of Scandium(III) with o-Hydroxyhydroquinonephthalein in Cationic Micellar Media
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Usami Atsuko , Kawabe Hiroshi , Koshiyama Yozo , Tanaka Takeshi
Published: July 2006

A spectrophotometric method for determining trace amounts of scandium(III) has been established which makes use of formation of its ternary complex with o-hydroxyhydroquinonephthalein (Qnph) and N-hexadecyl-pyridinium chloride (HPC) as a cationic surfactant at pH 5.4. The molar ratio of the ternary complex among Qnph, scandium(III), and HPC is 3:2:6 in a weakly acidic medium, and its maximum absorbance is at 555 nm against a reagent blank. Beer’s law holds in the concentration range 0–4.5 μg of scandium(III) in a final volume of 10 cm3 at 555 nm. The apparent molar absorptivity is 1.0×105 dm3 mol−1 cm−1 with a Sandell sensitivity of 0.0005 μg cm−2. The coefficient of variation was 0.6% (n=5) for 2.7 μg of scandium(III).
Selective Photooxidation of Alkali Mandelates by a Flavin Bearing a Crown Ring as a Metal Recognition Site
Authors: Shinkai Seiji , Nakao Hideki , Ueda Kaori , Manabe Osamu , Ohnishi Masayoshi
Published: July 2006

The quantum yields (Φ) for photooxidation of mandelate salts by a crown-containing flavin (CrFl) and 3-methyl-10-ethylisoalloxazine (MeEtIA) were determined in acetonitrile. MeEtIA photooxidized tetramethylammonium mandelate more selectively than potassium mandelate (ΦK+⁄ΦMe4N+=0.42–0.64), while CrFl showed a high selectively for photooxidation of potassium mandelate (ΦK+⁄ΦMe4N+=19–42).
Induced Circular Dichroism in the Complexes of Sequential Lysine Polypeptides with Methyl Orange. On Intermolecular Aggregation of the Complexes and Distance between Lysine Residues
Authors: Yamamoto Hiroyuki , Nishida Ayako , Hayakawa Tadao , Nishi Norio , Yamamoto Ryo
Published: July 2006

Aggregation of the sequential poly(Lys HCl-X) (X: Gly, βAla, and εAhx)–Methyl Orange (MO) complexes was studied by means of a circular dichroism (CD) measurement. The intensity of the induced CD was affected by the concentration of the complexes and time after preparing the complex solutions. When MO molecules which are electrostatically bound to lysine residues are separated from each other, the aggregation of the complexes takes place to a lesser degree.
Aryliminodimagnesium Reagents. X. The Mild Reagent Derived from 2-Aminopyridine and Formation of Highly Reactive Azoxypyridines in the Reaction with Nitrobenzenes
Authors: Okubo Masao , Sugimori Chieko , Tokisada Mitsunao , Tsutsumi Toshiki
Published: July 2006

The reaction of iminodimagnesium reagent derived from 2-amino-4-methylpyridine with nitrobenzenes was examined. The relative yields of the azoxypyridine formed via condensation and the azopyridines via deoxygenation and oxidative dimerization were explained in terms of weak electron-donating ability of the reagent and the strong electron-accepting ability of the azoxypyridine.
The H-1 NMR Solvent Shifts and Reactivity Parameters of Several Aromatic Compounds
Authors: Tamaoki Akihiro , Takahashi Kensuke
Published: July 2006

H-1 NMR solvent shifts were measured for 7 aromatic hydrocarbons and 13 heteroaromatic compounds. The chemical shifts can be correlated to the selfpolarizabilities of the carbon atoms attached to the hydrogens in the aromatic hydrocarbons and will be of use in predicting the reactivities of the compounds. However, in the case of heteroaromatic compounds, no good correlation has been found between the reactivity parameters and the H-1 NMR solvent shifts.
Dehydrogenation of Ethylbenzene on Potassium-Promoted Iron Oxide Catalysts Containing Various Transition Metal Oxides
Authors: Hirano Takenori
Published: July 2006

Various transition metal oxides, i.e., CeO2, Cr2O3, ZrO2, V2O5, WO3, and MoO3, were added to a potassium-promoted iron oxide catalyst to study their effects on the dehydrogenation activity of the catalyst. CeO2 was found to promote styrene formation most strongly among the oxides examined, by lowering the activation energy.
Thermically-Initiated Fluorinations at Saturated Carbon Atoms with Xenon Difluoride
Authors: Zajc Barbara , Zupan Marko
Published: July 2006

The heating of several hydrocarbons with xenon difluoride at 95–120 °C in stainless steel reactors equipped with teflon jackets resulted in mono-, di-, and trisubstituted products.
Rapid Spectrophotometric Determination of Scandium(III) with (Pyridylazo)- and (Thiazolylazo)naphthols
Authors: Sharma Chander Dhar , Nagarkar Sujansingh G , Eshwar Muppalla C
Published: July 2006

Scandium(III) reacts with 1-(2-pyridylazo)-2-naphthol [PAN] and 1-(2-thiazolylazo)-2-naphthol [TAN] in weakly acidic media to yield red colored 1:1 and 1:2 chelates, respectively. These complexes are sparingly soluble in water but readily soluble in ≥24% (v/v) acetone and ≥32% (v/v) methanol, giving maximum absorbances at 545 and 570 nm for the PAN and TAN complexes, respectively. Beer’s law is obeyed over the concentration ranges of 0.16 to 1.40 μg and 0.08 to 1.40 μg of Sc(III) per ml with PAN and TAN. The scandium(III) complexes formed with PAN and TAN have the molar absorptivities of 1.90×104 and 2.93×104 dm3 mol−1 cm−1 at their absorption maxima, respectively. The effect of diverse ions on the determination of scandium with these reagents is also investigated.
Phase-Shift Studies of the Quenching of NH(c1Π) and NH(A3Π) by Hydrocarbons
Authors: Sasaki Shun-ichiro , Kano Akiko , Tsunashima Shigeru , Sato Shin
Published: July 2006

The cross-sections for quenching NH(c1Π) and NH(A3Π) by hydrocarbons were determined at room temperature by using a phase-shift method. The NH(c1Π) was produced by the photolysis of HN3 using an amplitude-modulated Xe-resonance lamp. The apparent decay rate of the NH(c1Π) was estimated from the difference in phase angle between the excitation light and the fluorescence of NH(c1Π) at 325 nm. In the presence of Xe, the fluorescence of NH(A3Π) at 336 nm was enhanced. The difference in the phase angle between the fluorescences at 325 and 336 nm was found to correlate with the decay rate of NH(A3Π). From the decay rates obtained in the presence of hydrocarbons, the quenching cross-sections were determined.
Preparation and Characterization of [RhCl2(edpp)2]+ (edpp=(2-aminoethyl)diphenylphosphine). Crystal Structures of trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH and cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O
Authors: Galsbøl Frode , Kojima Masaaki , Ishii Toshio , Ohba Shigeru , Saito Yoshihiko , Fujita Junnosuke
Published: July 2006

Two of the five possible geometrical isomers of [RhCl2(edpp)2]+ were formed by reaction of RhCl3·2H2O with edpp (edpp=(2-aminoethyl)diphenylphosphine) in 1:2 molar ratio in ethanol. The chlorides of the isomers were separated by fractional crystallization from ethanol. The structures of the more soluble (main product) and the less soluble (minor product) complexes were determined by X-ray analyses to have the trans(Cl,Cl), cis(P,P) and cis(Cl,Cl), trans(P,P) configurations, respectively. Crystal data are: for trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH, triclinic, space group P\bar1, with a=10.024(3), b=18.865(3), c=9.833(2) Å, α=97.66(1), β=103.92(2), γ=82.30(2)°, and Z=2, and for cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O, triclinic, space group P\bar1, with a=11.341(4), b=17.780(6), c=8.712(3) Å, α=95.60(4), β=112.31(3), γ=82.56(4)°, and Z=2. The trans influence of the P atom on the Rh–N and Rh–P bond lengths is observed. The mean Rh–N and Rh–P bond lengths (2.125(4) and 2.300(1)Å) in the trans(Cl,Cl), cis(P,P) isomer are respectively longer and shorter than those of the cis(Cl,Cl), trans(P,P) isomer (2.078(12) and 2.336(3)Å). 13C NMR and absorption spectra of the isomers were recorded and are discussed.
AlCl3-Promoted Conjugate Reduction of α,β Unsaturated Carbonyl Compounds with 1,3-Dimethyl-2-phenylbenzimidazoline
Authors: Chikashita Hidenori , Itoh Kazuyoshi
Published: July 2006

The reduction of a variety of α,β-unsaturated carbonyl compounds, except for α,β-unsaturated aldehyde, to the corresponding saturated carbonyl compounds was effectively performed by using 1,3-dimethyl-2-phenylbenzimidazoline (DMBI) as a reducing agent with the aid of AlCl3. The reduction is discussed on the basis of the hydride-donating ability of DMBI, together with the role of AlCl3 as an electrophilic activator for the substrates. The catalytic efficiency of Lewis acids was found to be proportional to the efficiency to form a complex with a carbonyl group. The reduction of 2-cinnamoylpyridine with 2-deuterated DMBI revealed that in the reduction product, a deuterium atom was located at the β-position with respect to the carbonyl group. On the other hand, the reduction of the same substrate with DMBI followed by quenching with D2O gave a reduced product which contained a deuterium label at the α-position. These results were interpreted in terms of a mechanism involving an enolate intermediate produced by either a one-step hydride transfer or a sequential transfer of an electron (e) and a hydrogen atom (H·) from the reducing agent to the substrate.
Homogeneous Asymmetric Hydrogenation Using a Chiral Phosphinite Derivative of Carbohydrates as Ligand
Authors: Yamashita Mitsuji , Kobayashi Mineaki , Sugiura Motoyuki , Tsunekawa Kenji , Oshikawa Tatsuo , Inokawa Saburo , Yamamoto Hiroshi
Published: July 2006

Diphenylphosphinite derivatives of sugars were conveniently synthesized by the reaction of diphenylphosphinous chloride–triethylamine with sugar derivatives. Homogeneous asymmetric hydrogenations of several prochiral olefins, i.e., (Z)-α-acetylaminocinnamic acid, (Z)-α-benzoylaminocinnamic acid, itaconic acid, tiglic acid, and their esters, were carried out using rhodium(I) catalysts with the tervalent chiral phosphorus derivative of sugars. The highest optical yields for all the prochiral substrates investigated were obtained when di-μ-chloro-bis(cyclooctadiene)dirhodium(I) and methyl 2,3-O-isopropylidene-4-O-(diphenylphosphino)-α-l-rhamnopyranoside were used.
Synthesis of Oligodeoxyribonucleotides Involving a Rapid Procedure for Removal of Base-Protecting Groups by Use of the 4,4′,4″-Tris(benzoyloxy)trityl (TBTr) Group
Authors: Sekine Mitsuo , Masuda Narihiro , Hata Tsujiaki
Published: July 2006

Fully protected building units for oligodeoxyribonucleotide synthesis in the phosphoramidite approach were prepared in high yields by the 5′-dimethoxytritylation of N-[4,4′,4″-tris(benzoyloxy)trityl]deoxyribonucleosides followed by the 3′-phosphitylation with methoxymorpholinochlorophosphine. The solid phase synthesis of oligodeoxyribonucleotides on a controlled pore glass gel using the amidite units was examined. The efficiency of condensation was discussed in detail. The 4,4′,4″-tris(benzoyloxy)trityl (TBTr) group was removed rapidly from a protected tetramer synthesized on the controlled pore glass gel to give dGpCpApT.
Ni(II)-Bearing Green Rust II and Its Spontaneous Transformation into Ni(II)-Bearing Ferrites
Authors: Tamaura Yutaka
Published: July 2006

When solutions containing Fe(II), Ni(II), and SO42− ions were oxidized by a mixed gas of air and nitrogen at pH 7.1 (25 °C), a Ni(II)-bearing green rust II (GR-II), which is a uniform crystalline precipitate with a definite chemical composition, was formed. The Ni(II) content in the Ni(II)-bearing GR-II increased with an increase in the Ni(II) concentration in the reaction solution. The Ni(II)-bearing GR-II was spontaneously transformed into Ni(II)-bearing ferrite under a nitrogen atmosphere without any oxidant. The metal mole ratio of [Ni(II)/ Fe(III)]fer in the ferrite increased linearly with an increase in that of [Ni(II)/Fe(III)]grn in the Ni(II)-bearing GR-II (slope=0.193). From this relationship, the spontaneous transformation reaction was described as

2(Ni2+)x(Fe2+)2−x(Fe3+)(SO42−)(OH−)5→Ni0.39xFe3−0.39xO4+(2−1.61x)Fe2++1.61xNi2++Fe(OH)2+2SO42−+4H2O.

This equation shows that Fe(II) ion in the GR-II is more readily incorporated into the ferrites than Ni(II) ion.
Analytical Use of Luminescence Induced Ultrasonically in Solution. I. Sonic Chemiluminescence of Luminol for Determination of Cobalt(II) at Sub-pg Levels by Flow Injection and Continuous Flow Methods
Authors: Komatsu Takayuki , Ohira Minoru , Yamada Masaaki , Suzuki Shigetaka
Published: July 2006

Ultrasonic irradiation of alkaline luminol solution produces intense light emission (sonic chemiluminescence) as a result of the reaction of luminol with reactive species which are generated ultrasonically from water molecule. For the analytical application of ultrasound-induced luminescence, the sonic chemiluminescence of luminol is first utilized for the determination of ultratraces of cobalt(II) by flow injection and continuous flow methods. This novel method is based on the measurement of sonic chemiluminescence enhanced by the presence of cobalt(II); it provides analytical characteristics comparable to those for the conventional luminol chemiluminescence method using hydrogen peroxide as an oxidizing agent. The limit of detection is 0.06 pg(10-μl sample injection) or 0.06 pg ml−1 (continuous sample flow), the linear dynamic range is 3 orders of magnitude (10-μl sample injection), the sampling rate is 120 h−1, and the relative standard deviation is 3.9% for 6 pg Co(II) (n=10). The method is successfully applied to real samples. Possible explanation of sonic chemiluminescence is also presented; the mechanism involving superoxide anion radical is proposed for the cobalt(II)-catalyzed sonic chemiluminescence.
The Distribution and Characterization of 137Cs in Shallow Water Sediments
Authors: Terada Kikuo , Hamano Madoka , Komura Kazuhisa , Matsumoto Ken
Published: July 2006

The distribution and characterization of 137Cs in shallow water sediments are investigated. The concentration of 137Cs in surface sediments which have been collected from the 10–20 m depth of Tsukumo Bay, Noto Peninsula, tends to decrease with an increase in the distance from the inner part of the bay to the outer part. Vertically, 137Cs contents gradually decrease to the 10 cm depth and then steeply decrease beyond this depth, until at the 15 cm depth no activity is observed. A sequential extraction technique with several kinds of extractants has been employed to survey the chemical form of the nuclide in the sediments. 137Cs is completely extracted with an ammonium nitrate solution suggesting that the nuclide is strongly adsorbed in the crystal lattice of some clay minerals and is exchangedly desorbed from the sediment phase by ammonium ions in a high concentration. A core sample has been elutriated in five components of different grain sizes, and the contents of sodium, potassium, and 137Cs have been determined. It has been revealed that a unit amount of the finest component contains about three times as much of the nuclide as that of the coarsest one. On the contrary, the potassium contents slightly decrease with the decrease in the particulate size.
Formation and Identification of Aryldiazenyl Radicals Using the ESR Technique
Authors: Suehiro Tadashi , Masuda Seiichi , Tashiro Takaaki , Nakausa Ryuichi , Taguchi Masamichi , Koike Akemi , Rieker Anton
Published: July 2006

Aryldiazenyl radicals were formed at −104–−116°C by photoirradiation of cyclopropane solutions of 1-aryl-2-(arylthio)diazenes and of l-aryl-3,3-dimethyltriazenes in the presence or absence of olefins, and also by irradiation of cyclopropane solutions of substituted 1,2,3-benzothiadiazoles in the presence of di-t-butyl peroxide. The ESR spectra were analyzed and the hfs constants were assigned by reference to the spectra of methyl, 2H, and 15N-labelled aryldiazenyl radicals and to the results of CINDO calculations. Aryldiazenyl radicals are relatively persistent and the –N=N group rotates about the C–N2 bond axis. The preferred conformations of the radicals were considered.
Base-Catalyzed Hydrolysis of Acetylcholine Chloride in the Presence of Cationic and Nonionic Surfactants
Authors: Nakagaki Masayuki , Yokoyama Shoko
Published: July 2006

The base-catalyzed hydrolysis of acetylcholine chloride (Ach) in the presence of cationic and nonionic surfactants was investigated. The rate of hydrolysis of Ach was determined by following the disappearance of Ach spectrometrically. At a constant pH of 9.0, addition of dodecyltrimethylammonium chloride (DTAC) at concentrations below the critical micelle concentration results in a large decrease in the apparent rate constant for the hydrolysis of Ach, kapp. The plot of kapp against the concentration ratio of DTAC to Ach (CDTAC/[D]0) gives a break point at CDTAC/[D]0=1. This is considered to be due to the formation of 1 : 1 complex between Ach and DTAC. In the presence of heptaoxyethylene dodecyl ether (HED)–DTAC mixed micelles, kapp decreases with the mole fraction of DTAC, in contradistinction to the usually presupposed electrostatic effect. This is because Ach molecule penetrates into the micellar phase and is shielded from the attack by OH− for hydrolysis. The decrease of kapp has been successfully interpreted on the basis of the data on the distribution of Ach between the micellar and aqueous phases.
Photochemical Reactions of N-Methyl-1,2-naphthalenedicarboximide with Alkenes. Preferential Naphthazepinedione Formation
Authors: Kubo Yasuo , Toda Rie , Yamane Kengo , Araki Takeo
Published: July 2006

Irradiation of benzene solutions of N-methyl-1,2-naphthalenedicarboximide (1) in the presence of alkenes (2a,b,d–i) gave two regio-isomers of naphthazepinediones (3a,b,d–i and 4a,b,d–i). Stereospecificity of the naphthazepinedione formation was observed in the reaction with cis- and trans-2-butene (2a and 2b). Naphthazepinediones (3j and 4j) produced by the irradiation of 1 with ethyl vinyl ether (2j) underwent secondary photoreactions to give 7 and 8, respectively. On the other hand, irradiation of 1 with 2,3-dimethyl-2-butene (2k) resulted in the formation of oxetanes (13a,b) and 1 : 1-adducts of 1 and 2k at the carbonyl groups of 1 (14 and 15a,b). Irradiation of 1 with cis-stilbene (2l) afforded oxetanes (22a,b) and fragmentation products of oxetanes (23a,b, and 24). Stern-Volmer slopes (kqτ) obtained from quenching of fluorescence of 1 by alkenes (2a–e,k) correlated to some extent with relative rates for disappearance of 1 in the reaction. Preferential formation of the naphthazepinedione was rationalized by the nature of the excited singlet state of 1 compared with those of other N-methylarenedicarboximides.
Synthesis of ara-Cadeguomycin. 2-Amino-3,4-dihydro-4-oxo-7-(β-d-arabinofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine-5-carboxylic Acid
Authors: Okamoto Kaoru , Kondo Tadao , Goto Toshio
Published: July 2006

2-Amino-3,4-dihydro-4-oxo-7-(β-d-arabinofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine-5-carboxylic acid, an analogue of cadeguomycin, has been synthesized via glycosylation of 3-methoxymethyl-5-methyl-2-methylthio7H-pyrrolo[2,3-d]pyrimidin-4(3H)-one with 2,3,5-tri-O-benzyl-d-arabinofuranosyl chloride.
Crystal Structue and Absolute Configuration of a New cis-Fused Caryophyllene Derivative. Naematlin 3-p-Bromobenzoate
Authors: Tsuboyama Sei , Sakurai Tosio , Tsuboyama Kaoru , Doi Kozo
Published: July 2006

The molecular structure of naematolin 3-p-bromobenzoate has been determined by X-ray diffraction analysis. Unlike known caryophyllene derivatives isolated so far, the stereochemistry of the ring juncture is cis (1S,9S) form. The absolute configurations of five chiral centers of this compound are 1S,2S,3R,6R, and 9S, and the geometry of endocyclic double bond is E mode. This is the first example of a cis-fused 1S,9S-caryophyllane sesquiterpenoids confirmed by X-ray structure determination. Crystal data and the final R factor are: Mr=491.36, orthorhombic, space group P212121, a=10.650(2), b=20.650(6), c=10.526(2) Å, U=2315(1) Å3, Z=4, Dc=1.410 Mg m−3, μ=1.791 mm−1, R=0.084 for 1666 observed unique reflections.
Base-Catalyzed Hydrolysis of Acetylcholine Chloride in the Presence of Anionic and Nonionic Surfactants
Authors: Nakagaki Masayuki , Yokoyama Shoko
Published: July 2006

Base-catalyzed hydrolysis of acetylcholine chloride (Ach) in the presence of anionic and nonionic surfactants was investigated. The rate of hydrolysis was determined by measuring the rate of disappearance of Ach with a spectrophotometer. At a constant pH of 9.0, addition of heptaethylene glycol dodecyl ether (HED) at concentrations above the critical micelle concentration (cmc) results in a slight increase in the apparent rate, υ, which is expressed by two reaction rates, υf and υm, in the aqueous and micellar phases, respectively. The increase in the apparent rate is due to increase in υm. In the presence of sodium dodecyl sulfate (SDS), the apparent rate constant, kapp, is approximately constant at concentrations below the cmc, and kapp decreases above the cmc. In the presence of SDS–HED mixed micelles, kapp decreases with the mole fraction of SDS. In these cases, the decrease in the apparent rate is due to the decrease in both υf and υm. These two kapp decreases are due, respectively, to the decrease in Ach in the aqueous phase and the electrostatic repulsion between OH− and DS− at the micelle surface in conformity with the Gouy-Chapman theory.
The Formal Potentials of Quinones0⁄- and Quinones-⁄2- in an Aqueous Solution
Authors: Suga Kosaku , Aoyagui Shigeru
Published: July 2006

Cyclic voltammograms of p-benzoquinone and its methyl derivatives are measured in a strongly alkaline aqueous solution. All of them have shown one reversible or quasi-reversible wave corresponding to the reduction of the quinones. Except for the 2,3,5,6-tetramethyl-p-benzoquinone (duroquinone), they have all also shown one or two additional small waves corresponding to the reduction of the OH− adducts of the quinones. Their main waves can reasonably be explained by the calculated values of E1° and E2°, which have been determined by the two-electron reduction potential and the several equilibrium constants of the quinones. The differences in the E1° and E2° values for these quiones are very small (0.007–0.046 V) in contrast to those in an aprotic solvent.
The Microwave Spectrum of Ethyl Isoselenocyanate
Authors: Sakaizumi Takeshi , Iida Kazuyuki , Ohashi Osamu , Yamaguchi Ichiro
Published: July 2006

The microwave spectra of two isotopic species (80Se and 78Se) of ethyl isoselenocyanate were measured in the frequency region of 10–28 GHz. Only a-type R-branch transitions in the ground vibrational state were identified. The rotational constants in MHz were obtained; A=15140±23, B=1090.443±0.016, and C=1029.261±0.016 for 80Se species and A=15112±28, B=1099.865±0.012, and C=1037.745±0.012 for 78Se species. The plausible structure of ethyl isoselenocyanate has deduced from the observed rotational constants to be the synperiplanar form with a plane of symmetry.
Production of Carbon Monoxide by Direct Thermal Splitting of Carbon Dioxide at High Temperature
Authors: Nigara Yutaka , Cales Bernard
Published: July 2006

The direct thermal decomposition of carbon dioxide CO2 to produce carbon monoxide CO have been studied as a mean of conversion and storage of a thermal energy, such as the solar heat, into a gaseous fuel. The process under investigation consists to displace the dissociation equilibrium of carbon dioxide by a selective pumping of oxygen at high temperature through a semipermeable membrane. Large amounts of carbon monoxide have been produced after the extraction of the oxygen arising from the CO2 dissociation with the aid of a membrane made of calcia-stabilized zirconia. The variations of the flow of CO evolved from the reactor vs. temperature and oxygen partial pressure are in good agreement with the theoretical variations that may be deduced from the general equations of electrochemical transport in stabilized zirconia. Thereby, the efficiency of this process appears to be directly limited by the low oxygen permeation rate through the material used as oxygen selective membrane.
Synthesis, Ion-Exchange Properties and Analytical Applications of Tin(IV) Tungstovanadophosphate
Authors: Nabi Syed Ashfaq , Siddiqui Weqar Ahmad
Published: July 2006

Samples of tin(IV) tungstovanadophosphate have been synthesized under varying conditions and their ion-exchange properties are studied. Among the various samples of tin(IV) tungstovanadophosphate, sample TTVP7R is chosen for detailed study and its ion-exchange properties are compared with sample TTVP7. Both the compounds are synthesized in excess of acid, i.e. at pH less than zero. Sample TTVP7 is synthesized by adding 0.025 mol dm−3 sodium metavanadate, 0.025 mol dm−3 sodium tungstate and 1.0 mol dm−3 phosphoric acid to 0.1 mol dm−3 tin(IV) chloride in the volume ratio of 1:1:1:1 at pH=0. Sample TTVP7R was prepared by refluxing the precipitate of sample TTVP7 in the reaction mixture. The chemical and thermal stabilities of this material have been determined. The reproducibility of the material is also checked. Distribution coefficients for numerous metal ions in formic acid-sodium formate buffer systems of different pH were determined. The utility of the material has been demonstrated by achieving a number of binary and ternary separations on its small columns.
Electrolytic Reduction of 1-Methylsulfinyl-1-methylthio-1-alkenes at Mercury Electrode in Nonaqueous Media
Authors: Kunugi Akira , Abe Kyo , Hagi Toshio , Hirai Taketsugu
Published: July 2006

In the electrolytic reduction of organic sulfur compounds of general formular (Remark: Graphics omitted.), the substrates with R=aryl are much easier to reduce than those with R=alkyl, and the former substrates afford the desulfinylated compounds, E-isomers of RCH=CH(SMe), in good yields, but the later substrates do not give the corresponding desulfinylated compounds.
The Crystal Structure of Bis(2,2′-bipyridyl)palladium(II) Picrate [Pd(bpy)2](pic)2. A Novel “Bow” Distortion
Authors: Maeda Sh\={u}ichi , Nishida Yuzo , Okawa Hisashi , Kida Sigeo
Published: July 2006

The title complex crystallized in the triclinic space group P\barl with a=8.228(2), b=13.493(2), c=7.753(1)Å; α=96.96(1), β=106.16(1), γ=99.99(1)°; Z=1. The structure was solved by the heavy-atom method and refined by the block-diagonal least-squares method to R=0.0366. It is found that picrate ions above and below the [pd(bpy)2]2+cation stack with the bpy molecules and that this stacking leads to a novel bow distortion of the cation.
Di-n-octyl Phenyl Phosphonate: A Plasticizer of Poly(vinyl chloride) Matrix Membrane Electrodes Behaving As a Li+-selective Agent
Authors: Hiratani Kazuhisa , Okada Tatsuhiro , Sugihara Hideki
Published: July 2006

PVC matrix membrane electrodes, which are composed of dioctyl phenylphosphonate (DOPP) as a plasticizer and potassium tetrakis(4-chlorophenyl)borate (KTCPB) as a lipophilic anionic additive, without any other ionophore, exhibit appreciable Li+-selectivity. The electrode has selectivity coefficients (logkLiMPot for Li+ over Na+ up to −1.2, over K+ up to −1.8, over Mg2+ up to −1.8, and over Ca2+ up to −1.2. The detection limit for Li+ was about 5.0×10−5 mol dm−3.
Palladium(0)-Catalyzed Coupling Reaction of Isoprene Bromohydrin with Aromatic Organolithium Reagents
Authors: Araki Shuki , Ohmura Masayuki , Butsugan Yasuo
Published: July 2006

Palladium(0)-catalyzed reaction of isoprene bromohydrin with aromatic organolithium reagents selectively gave good yields of coupling products without rearrangement.
Titrations by Temperature Difference Electrode: Entropy Titrations
Authors: Ikeshoji Tamio
Published: July 2006

A new type of potential-difference titration which has a relation with the entropy change of a reaction in a titrated solution was demonstrated using a Hg2+–EDTA reaction on an Hg electrode. The potential difference between two identical electrodes, one kept at a different temperature from that of the solution, was monitored during titration. This difference changed from a minimum to a maximum at the equivalent point.
Conformational Changes of 1,2,3-Triselena- and 1,2,3-Trithia[3]( 1,1′)ruthenocenophane
Authors: Akabori Sadatoshi , Kumagai Takeshi , Sato Masaru
Published: July 2006

1,2,3-Triselena[3](1,1′)rutnenocenophane was obtained by the reaction of 1,1′-dilithioruthenocene with selenium powder in 22% yield. The energy barriers of the bridge reversal inversion of 1,2,3-triselena- and 1,2,3-trithia[3](1,1′)ruthenocenophane are 78.8 and 91.5 kJ mol−1, respectively.
Reaction of Nitromethane with Aryl Isocyanates in the Presence of Triethylamine. A Formation of 1,3-Diaryl-5-(hydroxyimino)imidazolidine-2,4-diones
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Teramura Kazuhiro
Published: July 2006

1,3-Diaryl-5-(hydroxyimino)imidazolidine-2,4-diones were obtained from the reactions of nitromethane with several aryl isocyanates in the presence of a trace amount of triethylamine and their structures were established from spectroscopic evidence and their chemical behavior.
Chemistry of 1,2-Thiaphosphole 2-Sulfides. III. Cycloaddition Reactions with Some Acetylenic Dienophiles and Generation of Phosphorin 1-Sulfides
Authors: Tanaka Hideyuki , Motoki Shinichi
Published: July 2006

1,2-Thiaphosphole 2-sulfides reacted with dimethyl acetylenedicarboxylate or phenylacetylene to afford 1-phosphabarrelene 1-sulfides (1-phosphabicyclo[2.2.2]octa-2,5,7-triene 1-sulfides) via phosphorin 1-sulfides.
Oxidation Reactions of a System Composed of Chloro(5,10,15,20-tetraphenylporphyrinato)cobalt(III) and Its π Cation Radical with Phenols
Authors: Kohno Masahiro
Published: July 2006

The reactions of a system composed of chloro(5,10,15,20-tetraphenylporphyrinato)cobalt(III), [CoIIICl(tpp)], and its π cation radical coordinating axially two chloride anions, [CoIII(tpp)+·]Cl2, with several phenols were investigated by using ESR and optical absorption spectroscopy. The phenols were oxidized to phenoxyl radicals. The phenols investigated were classified into two groups after taking into account the differences in the reaction activities and their redox potentials, the phenols mainly reacting with [CoIII(tpp)+·]Cl2 and those reacting with both [CoIIICl(tpp)] and [CoIII(tpp)+·]Cl2. The oxidation reactions of phenols with [CoIII(tpp)+·]Cl2 were the second-order. A linear relationship between the rate constants of oxidation and the redox potentials of phenols was recognized. Active species in the reactions were determined to be composed of a chlorine radical which originates from axial ligands of [CoIIICl(tpp)] and [CoIII(tpp)+·]Cl2, and the porphyrin ligand of [CoIII(tpp)+·]Cl2 itself. A possible mechanism for the oxidation reactions is proposed. Finally, the reaction scheme of cobalt porphyrin, ([CoII(tpp)], [CoIIICl(tpp)], and [CoIII(tpp)+·]Cl2) with phenols is compared with oxidation reactions of phenols with horseradish peroxidase.
Electrochemical Properties of Electropolymerized Poly(1-pyrenamine) Films
Authors: Oyama Noboru , Hirabayashi Kazuhiko , Ohsaka Takeo
Published: July 2006

The electropolymerization of 1-pyrenamine (PA) in an acetonitrile solution led to the polymeric film formation on electrode surfaces. The chemical, spectroscopic, electrical and electrochemical characterization of the resulting poly(1-pyrenamine) (PPA) films was carried out. The number-average molecular weight of the PPA film, measured by gel permeation chromatography, was 1.8×103, corresponding to the degree of the polymerization of ca. 8. The PPA films were polymer-anion composites which contained ca. 0.3 anions (e.g., BF4−) per repeating aromatic unit, which is considered to be composed of three PA molecules. The oxidized form of the PPA film displayed the ESR response. The g factor was 2.0082 and the concentration of radical in the PPA film was determined to be 4.8×1019 e−g−1. The conductivities of the PPA films in the dry state at 300 K were in the range 10−11–10−10 S cm−1. The PPA film was electroactive in an aqueous solution as well as in a non-aqueous solution. The cyclic voltammetric responses depended on pH of aqueous solutions and supporting electrolyte in non-aqueous solutions. The thickness(φ) of the PPA film and the surface concentration(Γ) of the electroactive site in the PPA film were proportional to the amount (Q) of the charge passed during the electrolysis (when Q<ca. 120 mC cm−2). The volume concentrations of the electroactive site were 9.7×10−4 and 1.7×10−3 mol cm−3 for the PPA films prepared in the NaClO4 and TBABF4 (tetrabutylammonium tetrafluoroborate) electrolytes, respectively. From the normal pulse voltammetric, potential-step chronoamperometric and potential-step chronocoulometric experiments of the PPA films in a 0.2 M NaClO4 aqueous solution (pH 1.0), the effective apparent diffusion coefficient (Dapp) for the diffusion-like charge transport within the PPA films, and the standard rate constant (k°) and anodic transfer coefficient (αa) of the heterogeneous electron-transfer reaction between the In2O3 electrode and the electroactive site in the PPA film were estimated to be (1.5±0.5)×10−10 cm2 s−1, (1.9±0.4)×10−5 cm s−1 and 0.67±0.03, respectively.
Critical Behavior of the Correlation Function of Fluids Composed of Polar Diatomic Molecules
Authors: Ohba Masaharu , Arakawa Kiyoshi
Published: July 2006

A critical behavior of fluids composed of polar diatomic molecules is studied by the use of the Ornstein–Zernike (OZ) theory of critical phenomena extended to the interaction site model. Firstly, the asymptotic forms of the atom–atom direct correlation functions cαγ(r) for the polar fluids at large separation are obtained, which are valid off the critical point. Then, the OZ hypothesis that the asymptotic forms of cαγ(r) do not change near and at the critical point is examined, and the critical behavior of the total correlation function is investigated. It is found to be completely analogous to the case of simple fluids. The relation between the OZ hypothesis and some integral equation theories is also discussed.
Mössbauer Spectroscopic Studies of Tin(IV) Halide Adducts with Ruthenocene and with [2]Ferrocenophanes
Authors: Watanabe Masanobu , Motoyama Izumi , Sano Hirotoshi
Published: July 2006

Adducts of tin(IV) halide with [2]ferrocenophane were prepared by treating SnX4 (X=Cl or Br) with [2]ferrocenophane in hexane. The adducts were studied by means of 57Fe- and 119Sn-Mössbauer spectroscopy and other physicochemical measurements. Anomalously large quadrupole splittings (3.49 mm s−1 for [2]ferrocenophane–1.5SnCl4 adduct and 3.47 mm s−1 for [2]ferrocenophane–1.5SnBr4 adduct, both at 78 K) found in the 57Fe-Mössbauer spectroscopy and organotin(IV) species (e.g., isomer shift value, 2.14 mm s−1 for the [2]ferrocenophane–1.5SnCl4 adduct and 2.10 mm s−1 for the [2]ferrocenophane–1.5SnBr4 adduct, both at 78 K) found from the 119Sn-Mössbauer spectroscopy suggest that a direct chemical bonding between Fe and Sn atoms is formed in the [2]ferrocenophane adducts, as the Ru–Sn bonding in the ruthenocene–1.5SnCl4 adduct (isomer shift value, 2.08 mm s−1 at 78 K).

(Remark: Graphics omitted.)
Paramagnetic Shifts of DMF and DMA by Uranium(V)
Authors: Harazono Toshie , Fukutomi Hiroshi
Published: July 2006

Paramagnetic shifts of DMF (N,N-dimethylformamide) and DMA (N,N-dimethylacetamide) induced by U(V) were studied by the 1H and 13C NMR spectroscopy. It was found that the 1H and 13C NMR signals of bulk DMF and DMA exhibited the paramagnetic shifts to the higher field by U(V). Positive pseudocontact shift and negative contact shift for both DMF and DMA are discussed on the basis of the electronic structure of U(V) complexes. The values of magnetic susceptibilities of U(V) complexes are also presented.