bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Properties, and Crystal Structure of Binuclear Nickel(II) and Palladium(II) Complexes of Tridentate Thiolic Ligands with NNS-Donor Set
Authors: Handa Makoto , Mikuriya Masahiro , Zhong Zhuang Jin , Okawa Hisashi , Kida Sigeo
Published: July 2006

Nickel(II) and palladium(II) complexes with tridentate thiolic ligands of the NNS-donor set have been prepared and characterized on the basis of elemental analyses, IR and electronic spectra, molar conductances, and magnetic susceptibilities. The crystal structure of the nickel(II) perchlorate of 3-[2-(2-pyridyl)ethylamino]-1-propanethiol was determined by single-crystal X-ray diffraction method. The structure consists of thiolatebridged binuclear units. Each metal ion is coordinated by the amino nitrogen, pyridine nitrogen, and two bridging sulfur atoms, forming an essentially planar coordination unit, and the two N2S2 planes are connected at the S1–S2 edge with a dihedral angle of 136.1°.
Calorimetric and Raman Spectroscopic Studies of Cadmium(II) Thiocyanato Complexes in N,N-Dimethylformamide
Authors: Ishiguro Shin-ichi , Takamuku Toshiyuki , Ohtaki Hitoshi
Published: July 2006

Formation of thiocyanato complexes of cadmium(II) ion has been calorimetrically studied in N,N-dimethylformamide (DMF) at 25 °C. Calorimetric data obtained were well explained in terms of the formation of a series of four mononuclear [CdXn](2−n)+ (n=1–4, X=SCN) complexes, and their formation constants, enthalpies, and entropies were determined. Raman band shifts for the C–S stretching vibration of SCN− ion indicated that SCN− ion binds to cadmium(II) ion only with the N end within the mono- or dithiocyanato complex, [Cd(NCS)]+ or [Cd(NCS)2]. Within the tri- and tetrathiocyanato complexes, thiocyanate ions binds with both the N and S ends, and the coordination modes, [Cd(NCS)2(SCN)]− and [Cd(NCS)3(SCN)]2−, were suggested. The coordination modes for the di- and tetrathiocyanato complexes in DMF, [Cd(NCS)2] and [Cd(NCS)3(SCN)]2−, are different from those in water, [Cd(NCS)(SCN)] and [Cd(NCS)2(SCN)2]2−. It is thus shown that the N-bonding becomes more favorable in DMF than in water. Such a result may mainly be ascribed to relatively weakened solvation of the SCN− ion in DMF, especially at the N atom site which is hydrogen-bonded with water molecules but not with DMF.
Rotational Isomerism in Fluorene Derivatives. XIII. Conformational Equilibria of 9-(2-Methylaminophenyl)fluorene and the Effect of Acid on It
Authors: Nishida Akiko , Takeshita Makoto , Fujisaki Shizuo , Kajigaeshi Shoji
Published: July 2006

The compound 9-(2-methylaminophenyl)fluorene (2) was obtained by treatment of 9-(2-dimethylaminophenyl)-9-fluorenol (1b) with dry hydrogen bromide in acetic acid. The conformational equilibrium (ap\ightleftarrowssp) of 2 was investigated on the basis of dynamic 1H NMR spectra in CDCl3. The stabilization of the ap-iorm could be ascribed to an N–H···π interaction between the methylamino group and the fluorene ring. The effect of trifluoroacetic acid on the equilibrium of 2 is also discussed.
Reduction of Sulfur Dioxide and Carbon Dioxide with Benzoin Carbanion. Oxygen Transfer from Products Formed by the Reduction of Sulfur Dioxide to 7,7,8,8-Tetracyanoquinodimethane
Authors: Akiyama Fuminori
Published: July 2006

A reaction of sulfur dioxide (SO2) with benzoin carbanion (the lithium salt of benzoin dianion, 1) in tetrahydrofuran (THF) gave a mixture of benzil (2) and benzoin (3) in yields of 83 and 17%, respectively, irrespective of the reaction temperature between −78 and 25 °C. The reaction of carbon dioxide (CO2) with 1 in THF gave a mixture of 2 and 3 accompanied by the formation of a small amount of lithium benzoate (4). The proportion of 2 in a mixture of 2 and 3 formed in the reaction of CO2 with 1 were 49, 30, and 20% at −78, −22, and 25 °C, respectively. The reaction of SO2 with 1 in the presence of 7,7,8,8-tetracyanoquinodimethane (TCNQ) gave oligomers of TCNQ with a yield of 60%, in which some parts of the cyano groups were transformed to carboxylato groups.
Facile Formations of o- and p-Tropoquinone Mono- and Bisacetals by Anodic Oxidations of 2,3-, 2,5-, 2,7-, and 4,5-Dimethoxytropones
Authors: Mori Akira , Kubota Tadahiko , Takeshita Hitoshi
Published: July 2006

o- and p-Tropoquinone mono- and bisacetals (tetramethoxycycloheptadienones) were prepared from 2,3-, 2,5-, 2,7-, and 4,5-dimethoxytropones by means of anodic oxidations in practical yields. Cerium(IV) salt oxidations of dimethoxytropones afforded a mixture of products i.e., a hydrolysis product and/or a methanol adduct of tropoquinone bisacetals. By treating with sulfuric acid in a mixture of acetic acid and acetic anhydride, 4,4,7,7- and 2,2,7,7-tetramethoxycycloheptadienones gave the Thiele-type reaction products with a high positional selectivity. Similarly, 2-bromo-7-methoxytropone was anodically oxidized to 4,4,7,7-tetramethoxycycloheptadienone and its 2-bromo derivative. The mechanism of the reaction is also discussed in detail.
Footprint Catalysis. I. A New Method for Designing “Tailor-Made” Catalysts with Substrate Specificity: Silica (Alumina) Catalysts for Butanolysis of Benzoic Anhydride
Authors: Morihara Kensaku , Kurihara Sachiyo , Suzuki Junko
Published: July 2006

The design of tailor-made specific catalysts for a given organic reaction was investigated. Dibenzamide or N-benzoylbenzenesulfonamide, transition state analogs of benzoic anhydride on transacylation, was found to act as a template upon aluminium ion-doped silica gel and to imprint specific adsorption sites, “footprints,” on the surface. The footprints were particular Lewis acid sites with a complementary structure to the template. They demonstrated an enzyme-like specific catalytic function on the butanolysis of benzoic anhydride through their specific affinities for substrate molecules in the transition state.
The Photochemistry of Steroidal 6-Membered Cyclic α-Nitro Ketones
Authors: Suginome Hiroshi , Kurokawa Yoshitaka , Orito Kazuhiko
Published: July 2006

The results of the photolysis of five steroidal 6-membered cyclic α-nitro ketones in ethanol are described. Irradiation with a Pyrex-filtered light of 2-nitro-5α-cholestan-3-one in ethanol, which exists exclusively in the enol form in the solvent, resulted in a new photorearrangement and gave 5α-cholestane-2,3-dione 3-oxime with the accompanying formation of the corresponding α-diketone. We propose a path involving a nitro–nitrite rearrangement for this anomalous formation of 5α-cholestane-2,3-dione 3-oxime. However, similar irradiation of 4,4-dimethyl-2-nitro-5α-choloestan-3-one, which exists exclusively as the enol form in ethanol, and 3-nitro-5α-cholestan-2-one, which is in an 1 : 1 equilibrium mixture of keto and enol forms in ethanol, gave the corresponding α-hydroxyimino ketone and α-diketone respectively. Irradiation of 4β-nitro-5β-cholestan-3-one and 6α-nitro-5α-cholestan-7-one, both of which exist as the keto form in ethanol, gave similarly the corresponding α-hydroxyimino ketone respectively, but without the accompanying formation of α-diketone. The α-hydroxyimino ketones from the above four 6-membered cyclic α-nitro ketones arise through the hydrogen abstraction by the n,π* excited nitro group of the keto forms of the α-nitro ketones followed by the elimination of the element of water, while α-diketones are formed via the nitro–nitrite rearrangement of the excited nitro group of the enol forms.
1H NMR Study of Intramolecular Hydrogen-Bonding Interaction in Cyclodextrins and Their Di-O-methylated Derivatives
Authors: Onda Mitsuhiko , Yamamoto Yasuhiko , Inoue Yoshio , Chûjô Riichirô
Published: July 2006

Intramolecular hydrogen bonding of α-, β-, and γ-cyclodextrins, and α- and β-dimethyl cyclodextrins has been investigated in dimethyl sulfoxide-d6 by 1H NMR spectroscopy. The temperature dependence of 1H chemical shifts of secondary hydroxyl protons of cyclodextrins and dimethyl cyclodextrins reveals the existence of the intramolecular hydrogen bond. The strength of hydrogen bond becomes stronger as the ring size becomes smaller and by methylation. The intramolecular hydrogen bond in which the OH(3) is proton donor is preferred in α-cyclodextrin as well as in α- and β-dimethyl cyclodextrins. The orientation of secondary hydroxyl groups was estimated with the Karplus-type equation and the orientation is found to be suitable for making intramolecular hydrogen bond.
A Highly Chemoselective Reduction of Conjugated Nitro Olefins with Hantzsch Ester in the Presence of Silica Gel
Authors: Fujii Masayuki
Published: July 2006

An effective system to reduce conjugated nitro olefins into the corresponding nitroalkanes is described. The system composed of Hantzsch ester (HEH) and silica gel in benzene exerts high yield and excellent chemoselectivity under almost neutral conditions. Facile applications of the system to the syntheses of natural products are also described.
Multinuclear NMR and the Rotational Barriers about the C–N Bonds of Several, N,N-Disubstituted Arenecarboxamides
Authors: Suezawa Hiroko , Tsuchiya Kin-ya , Tahara Eiji , Hirota Minoru
Published: July 2006

The 15N, 17O, and 13C NMR spectra of substituted N,N-dimethyl- and N,N-dibenzylbenzamides and N,N-dimethylnaphthamides were measured and correlated with the height of their rotational barriers. The 15N and 17O chemical shifts of the amides were shown to be controlled predominantly by the extent of the contribution of the polar mesomeric structure (II) and, especially in the case of 15N, could be used to estimate the rotational barrier.
Solvation and Ionic Association of Bis(β-diketonato)(diamine)cobalt(III) Perchlorates in Alcohols and Ketones
Authors: Ito Kazuaki , Isono Hiroyuki , Iwamoto Etsuro , Yamamoto Yuroku
Published: July 2006

The conductances of bis(2,4-pentanedionato)(diamine)cobalt(III) perchlorates, [Co(acac)2(diamine)]ClO4 (where acac:2,4-pentanedionato; diamine:en (ethylenediamine) and N,N,N′,N′-tmen (N,N,N′,N′-tetramethylethylenediamine)) in methanol (MeOH), ethanol (EtOH), 2-propanol (i-PrOH), methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK) and of bis(β-diketonato)(ethylenediamine)cobalt(III) perchlorates, [Co(β-dik)2(en)]ClO4 (where β-dik: acacBr (3-bromo-2,4-pentanedionato) and acacNO2 (3-nitro-2,4-pentanedionato)) in EtOH, acetone (Me2CO), and MEK were measured at 25 °C. [Co(acac)2(en)]ClO4 in the alcohols was found to be more dissociated than [Co(acac)2(N,N,N′,N′-tmen)]ClO4. This behavior was explained as being due to the strong solvation of [Co(acac)2(en)]+ by the alcohols. [Co(acac)2(N,N,N′,N′-tmen)]+ seems to be solvated in ketones rather than alcohols. The sequence of the ionic association constant for [Co(β-dik)2(en)]ClO4, acac<acacBr<acacNO2, could be interpreted in terms of an enhanced polarity of the cations with the electron-withdrawing groups.
Extraction–Spectrophotometric Determination of Pd(II) with 4-(3,5-Dichloro-2-pyridylazo)-1,3-diaminobenzene and Trichloroacetate. I
Authors: Fontán C A , Marone C B , Olsina R
Published: July 2006

In acid acqueous ethanol solutions Pd(II) reacts with 4-(3,5-dichloro-2-pyridylazo)-1,3-diaminobenzene (3,5-C12PADAB=L) making up three colored complex species. The three complexes have a 1 : 1 metal–ligand molar ratio and they differ from each other only in their protonation degree. In solutions with H2SO4 or HClO4 concentrations higher than 10 or 8 M, respectively, the complex species is yellow, and in less acid solutions (pH 0.80 to 2 M H2SO4 or pH 0.8 to 3 M HClO4 range) it changes in a reversible way to a violet color while its intensity increases (molar absorptivity 8.2×104 dm3 mol−1 cm−1 at 588 nm and 5.2×104 dm3 mol−1 cm−1 at 545 nm). The red purple complex formed in the pH range 3–4 are insoluble in 10% (v/v) ethanol–water solutions. The complex species were given the formulation PdHnL(n+2)+ (n>1)(H2SO4>10 M, or HClO4>8 M), PdHL3+ (pH 0.8 to 2 M H2SO4 or pH 0.8 to 3 M HClO4 range) and PdL2+ (pH 3–4), and the existence of one or another depends exclusively upon the acidity of the reaction medium. In 10% (v/v) ethanol–water solutions acidified with H2SO4 or HClO4, only the last two species are extracted into benzene as PdL2+·(TCA−)2 and PdHL3+(TCA−)3 (TCA−=trichloroacetate) ion-associations. The composition of the complexes formed in aqueous solutions was estimated by the composition of the ion-association complexes transferred to the organic phase.
Conformational Dependence of Mass Spectral Fragmentation of Pinane Derivatives
Authors: Ho Tse-Lok
Published: July 2006

The major fragmentation pathway for pinane derivatives on electron impact involves cleavage of the cyclobutane bond which is part of a boat-cyclohexane. This trend is followed by ketones, alcohols, and hydrocarbons of the same skeleton.
Studies on Metal Chelates of 8-Hydroxy-5-quinolyl Ketone Oxime, O-Carbamoyl and O-Thiocarbamoyl Derivatives as Bactericides
Authors: Khalil Z H , Abdel-Hafez A A , Yanni A S , Moharam A M
Published: July 2006

The reaction of 5-acetyl-8-quinolinol (1) and corresponding chalcone derivatives 2a–f with hydroxylamine hydrochloride in boiling pyridine gave the corresponding oximes 3 and 4a–f respectively in almost quantitative yields. Further interaction of 3 and 4a–e with phenyl isocyanate and/or thiocyanate the corresponding carbamate and/or thiocarbamate (5a,b) and (6a–e, 7a–e) were achieved. Metal chelates of 1, 3, and 4e,f with bivalent metal cations like Fe(II), Cu(II), and Zn(II) have been synthesized and characterized by elemental and IR-spectral analysis. The synthesized compounds were biologically screened to study the structure activity relationship, (SAR) and the effect of complexation and type of metal cation on the potency of the more biologically active compounds.
Terpenoids. XI. Mayurone Oxide
Authors: Nagahama Shizuo , Fuchinoue Takafumi , Tazaki Masato
Published: July 2006

Epoxidation of mayurone 7 gave mayurone oxide 21 in good yield. Grignard methylation of 21 gave epoxy alcohols, 17 and 22. Thujopsadiene monoepoxide 23 was synthesized from 21 by Wittig reaction. Oxide 21 and 23 were found in the autoxidation product of 1. Oxide 21 was found in the autoxidation product of 2, 3, and 6.
Selective Nuclear Halogenation of Polymethylbenzenes with Alumina-Supported Copper(II) Halides
Authors: Kodomari Mitsuo , Satoh Hiroaki , Yoshitomi Suehiko
Published: July 2006

The halogenation of polymethylbenzenes with alumina-supported copper(II) halides under heterogeneous conditions in nonpolar solvents gave nuclear-halogenated compounds selectively in high yields; no side-chain-halogenated compounds were formed.
Racemization of Optically Active Cysteine via Formation of 2,2-Dimethyl-4-thiazolidinecarboxylic Acid
Authors: Shiraiwa Tadashi , Kataoka Kazuo , Sakata Shinji , Kurokawa Hidemoto
Published: July 2006

Optically active cysteine (Cys) was racemized via formation of (RS)-2,2-dimethyl-4-thiazolidinecarboxylic acid ((RS)-DMT) by refluxing in the presence of acetone in 10-fold molar amount in acetic acid. The formed (RS)-DMT was hydrolyzed by adding water to the reaction mixture to give (RS)-Cys in 95–97% yield.
Oxygen Evolution by Means of Water Oxidation Catalyzed by Mononuclear Ruthenium–Ammine Complexes
Authors: Kaneko Masao , Ramaraj Ramasamy , Kira Akira
Published: July 2006

Water oxidation was achieved catalytically by the use of mononuclear ruthenium–ammine complexes and using Ce(IV) as an oxidant. Cyclic voltammetric studies of the mononuclear ruthenium–ammine complexes [Ru(NH3)5Cl]2+ and [Ru(NH3)5(H2O)]3+, have been carried out using Basal Plane Pyrolytic Graphite (BPG) coated with poly(p-styrenesulfonate), Nafion, or Kaolin clay. The electrochemical properties of these ruthenium–ammine complexes show that they can be used as two-electron oxidants for water oxidation. It has also been found that these complexes oxidize water to evolve oxygen in the presence of excess Ce(IV) under homogeneous as well as heterogeneous conditions. The oxygen evolution by means of water oxidation was confirmed by using the H218O isotope in the reaction medium. The water oxidation process was found to be dependent on the ionic strength of the medium. Higher acidic conditions gave higher O2 yields. Heterogeneous catalysis with the Ru complex adsorbed in Kaolin clay was as effective as the homogeneous one. The water oxidation reaction catalyzed by ruthenium–ammine complexes was also discussed.
Measurements of the Polarized ATR Spectra for Adsorbed Dye Layers by Using a Stack of Thin Glass Plates
Authors: Kobayashi Michio , Tokunaga Hitoshi , Okubo Jun , Hoshi Toshihiko , Tanizaki Yoshie
Published: July 2006

Polarized ATR spectra have been measured for the dye layers adsorbed on stacked, thin glass plates. For the adsorbed Crystal Violet (CV) layer, the metachromasy band in the || polarized ATR spectrum is blue-shifted and intensified in comparison with that in the ⊥ polarized ATR spectrum. This is in marked contrast to the observation for the adsorbed Methylene Blue (MB) layer that the || polarized ATR spectrum is similar in shape and position to the ⊥ polarized ATR spectrum. The blue shift and the enhancement of the metachromasy band in the || polarized ATR spectrum for the adsorbed CV layer is ascribed to an optical property characteristic of the adsorbed CV layer; the adsorbed CV layer exhibits an extra electronic transition band located at the high-energy side of the metachromasy band and polarized normal to the glass plane. Two possible explanations for the occurrence of this extra band are presented.
Structure and Optical Properties of a Thermochromic Schiff Base. Thermally Induced Intramolecular Proton Transfer in the N,N′-Bis(salicylidene)-p-phenylenediamine Crystals
Authors: Hoshino Naomi , Inabe Tamotsu , Mitani Tadaoki , Maruyama Yusei
Published: July 2006

A thermochromic derivative of salicylideneaniline, N,N′-bis(salicylidene)-p-phenylenediamine (BSP), has been prepared and subjected to structural and optical studies in the crystalline state. An X-ray crystallographic analysis has shown that the molecules are planar and are stacked in a parallel fashion to form one-dimensional columns. The interplanar spacing has been found to be quite short, suggesting the existence of an intermolecular charge-transfer interaction. The molecule contains fairly short O–H··· N hydrogen bonds, the strength of which is manifested in an OH stretching absorption band in the infrared region, showing considerable broadening and a low-frequency shift. The BSP crystals are remarkably thermochromic, and visible absorption and emission spectral changes with temperature have been interpreted in terms of an intramolecular proton transfer from the hydroxyl oxygen to imine nitrogen through the O–H··· N hydrogen bond. The emission spectra have also been examined under high pressures.
Charge Transfer Complexes Based on the Twin-TCNQ-Type Acceptor 11,11,12,12,13,13,14,14-Octacyano-1,4:5,8-anthradiquinotetramethane (OCNAQ)
Authors: Inabe Tamotsu , Mitsuhashi Tsutomu , Maruyama Yusei
Published: July 2006

Charge transfer complexes of OCNAQ with pyrene, PT (phenothiazine), TMTTF (tetramethyltetrathiafulvalene), TTF (5,6 : 11,12-bis(epidithio)naphthacene), and TTF (tetrathiafulvalene) have been prepared. The pyrene and PT complexes are electrically insulating and the ground state is neutral. In most of the other complexes OCNAQ is fully charged. One of the TTT complexes, (TTT)2OCNAQ(DMF), where DMF is N,N-dimethylformamide, has been found to show metallic conductivity. A structural study has revealed that short S···N contacts exist between TTT and OCNAQ, in addition to one-dimensional TTT stacks. This transverse interaction has been demonstrated by the small anisotropy of the conductivity. The 2 : 1 TTF complex is also metallic down to 43 K, at which point a metal-to-insulator transition occurs. A structure analysis and thermoelectric power data suggest that the charge conduction in this crystal takes place not only through the TTF stacks but also through a two-dimensional network of the OCNAQ molecules.
Reactivities of Stable Rotamers. XXIV. Formation of Isomeric Ketones by Cydization of Rotameric 3-Methyl-3-(1,2,3,4-tetrahalo-9-triptycyl)butanoyl Chloride and Barriers to Isomerization of the Ketones
Authors: Oki Michinori , Tanuma Toshihiro , Tanaka Yasuhiro , Yamamoto Gaku
Published: July 2006

Rotational isomers of 3-methyl-3-(1,2,3,4-tetrahalo-9-triptycyl)butanoic acid, where the halo is either fluoro or chloro have been prepared. Cyclization of their acid chlorides afforded ap- and sc-ketones from ap- and sc-isomers, respectively. The barriers to isomerization were 29.9 and 26.8 kcal mol−1 at 363 K, for the fluoro and the chloro ketones, respectively, for the ap→±sc process. The equilibrium constants (sc/ap) at 363 K were 2.34 and 18.5 for the fluoro and the chloro compounds respectively. The barriers to isomerization and the relative stabilities of the isomeric ketones were discussed based on the MMP2(NONPLANAR) calculation results and the steric congestion in the ground state.
New Ferroelectric Liquid Crystal Materials: (+)-4-(2-Methylbutoxycarbonyl)phenyl 4-(5-Alkyl-1,3-dioxan-2-yl)benzoate
Authors: Haramoto Yuichiro , Kawashima Katumasa , Kamogawa Hiroyoshi
Published: July 2006

(+)-4-(2-Methylbutoxycarbonyl)phenyl 4-(5-alkyl-1,3-dioxan-2-yl)benzoate (12), (+)-4-(2-methylbutoxy)-phenyl 4-(5-alkyl-1,3-dioxan-2-yl)benzoate (11) and the corresponding 1,3-oxathiane (13, 14) and 1,3-dithiane compounds (15, 16) were synthesized. The mesomorphic behaviors of these compounds were measured. Compounds 12 exhibited the ferroelectric liquid-crystal behavior (R=n-C11H23: −4 SmC* 94 °C), while the corresponding 1,3-oxathiane (13, 14) and 1,3-dithiane compounds (15, 16) did not exhibit such behavior. Therefore, 1,3-dioxane compounds are more favorable for transition of SmA to SmC* than the 1,3-oxathiane or 1,3-dithiane analogs.
Synthesis of Fluorescent Amino Acids and Peptides with 2-Aminopyridine at the Carboxyl or Amino Terminus
Authors: Mega Tomohiro , Hamazume Yasuki , Ikenaka Tokuji
Published: July 2006

N-(2-Pyridyl) derivatives of glycine (1), Dl-alanine (2), Dl-valine (3), and Dl-norleucine (4) were synthesized as fluorescence labeled amino acids. These amino acids were used for the synthesis of N-terminal fluorescencelabeled peptides. N-(2-Pyridyl)-1,2-ethanediamine (7) was synthesized and used for the C-terminal labeling of amino acids and peptides. With these amino acid derivatives, some peptides labeled with 2-aminopyridine were synthesized and their spectroscopic characteristics were examined.
Preparation and Properties of Inclusion Compounds of η3-Allylpalladium Complexes with Cyclodextrins
Authors: Harada Akira , Takeuchi Mizutomo , Takahashi Shigetoshi
Published: July 2006

Inclusion compounds of di-μ-chloro-bis(η-allyl)dipalladium and its analogues with cyclodextrins (CDs; α-CD, β-CD, and γ-CD) were prepared. One-to-one inclusion compounds were obtained in high yields by the treatment of β- and γ-cyclodextrin with di-μ-chloro-bis(η-allyl)dipalladium and its analogues. The formation of inclusion compounds is selective. β-CD formed inclusion compounds with di-μ-chloro-bis[1-3-η-(2-methylallyl)]dipalladium in high yield, but it did not form any inclusion compounds with di-μ-chloro-bis(1-3-η-2-butenyl)dipalladium. γ-CD formed inclusion compounds with all the η3-allylpalladium complexes tested in high yields. α-CD did not form inclusion compounds with any η3-allylpalladium complexes tested. The thermogravimetric measurements show that η3-allylpalladium complexes are stabilized when they are included in the CD cavity. The inclusion compounds were characterized by 1H NMR, IR, UV, and circular dichroism spectra.
The Redox Reaction by Ferrocene Derivatives Introduced to a Crown Ether in a Liquid Membrane System
Authors: Ozeki Eiichi , Kimura Shunsaku , Imanishi Yukio
Published: July 2006

In an organic liquid membrane system, 4′-(ferrocenylcarbonylamino)benzo-18-crown-6 (FCC) dissolved in a dichloromethane membrane was found to reduce hexacyanoferrate(III) ions in the aqueous phase to hexacyanoferrate(II) ions at a rate dependent on the type of metal ion coexisting in the aqueous phase, and bound to the benzo-18-crown-6 unit of FCC.
Studies on Coupling Reaction of 1-Naphthol. XI. Effect of Additives on the Dissociation Equilibrium of 4-(4-Nitrophenylazo)-1-naphthol in Pyridine
Authors: Kishimoto Satoshi , Okushi Tsuneo , Hirashima Tsuneaki
Published: July 2006

The dissociation of 4-(4-nitrophenylazo)-1-naphthol (azo dye) in pyridine was found to be accelerated by the addition of small amounts of quaternary ammonium compounds, R4N+X−. The apparent equilibrium constant of the azo dye was influenced enormously by the species of X−, but was little affected by the structures of R. The effect increased as the X− became more basic, ClO4−<I−<BF4−<Br−<HSO4<Cl−, in proportion to the ability of X− to bind with protons formed by dissociated azo dye. The basicity of the X−, pKc, was correlated linearly with the variation of the equilibrium constant, owing to the addition of R4N+X−, δpKa. The dissociation of the azo dye in pyridine–water mixtures was also accelerated upon increasing the amount of water (0–10 vol%), correlating with an increase in the basicity of the solution.
Synthetic Photochemistry. XLV. Photoconversion of 2-Methylenehomobarrelenes to 9-Methylenebarbaralanes
Authors: Tian Guan Rong , Sugiyama Shigeru , Mori Akira , Takeshita Hitoshi
Published: July 2006

The photolysis of 4-methoxycarbonyl-2-oxatricyclo[6.2.2.01,5]dodeca-4,6,9,11-tetraen-3-one derivatives yielded 9-methylenebarbaralanes along with 5-methylenetricyclo[4.3.0.02,9]nonadiene and 1-methyleneindan derivatives. From the benzophenone-sensitization experiments, 9-methylenebarbaralane and 5-methylenetricyclo[4.3.0.02,9]nonadiene were formed via a triplet excited state, but 1-methyleneindan was formed via a singlet excited state.
Efficiency of Azodyes in Retarding the Dissolution of Aluminium in Hydrochloric Acid
Authors: Fouda Abd El-Aziz El-Sayed , Abu-El-Nader Hamed , Moussa Mahmoud Nor El-Din , Shehata Ibrahim
Published: July 2006

The inhibition of the corrosion of aluminium in hydrochloric acid solution by some 4-(m-Substituted phenylazo)pyrazoles has been studied by three different techniques. The inhibitor efficiency calculated from the three techniques are in good agreement. The corrosion rate is a function of temperature, concentration, and nature of the inhibitor. The inhibitors appear to function through general adsorption following the Langmuir adsorption isotherm. Thermodynamic parameters for adsorption of inhibitors have been calculated and discussed.
1,1′-Bis(selenocyanatomercurio)ferrocene as Ligand towards M(NCS)2 [M=Co(II), Ni(II), and Zn(II)]
Authors: Singh Pashupati Prasad , Singh Divya , Singh Narendra Bahadur
Published: July 2006

A comparative study of the behaviors of 1,1′-bis(selenocyanatomercurio)ferrocene (FBMS) with those of its thiocyanate analog (FBMT), has been made. Various physicochemical studies indicate that the Lewis acids and the adducts formed by FBMS are less stable than those of FBMT. The Dq values of FBMS adducts are higher, but the β values are lower. The matching constant values of FBMT complexes are higher than their corresponding FBMS complexes. The structures of Lewis acids and the adducts are similar in both the cases.
Solvent and Reversed-Phase Extraction Chromatographic Separation of Niobium, Zirconium, and Hafnium with Aliquat 336
Authors: Das Nitya Ranjan , Chattopadhyay Putul
Published: July 2006

Aliquat 336 has been employed as an effective anionic extractant for the radiochemical separation of niobium, zirconium, and hafnium in mixtures using solvent extraction and reversed phase extraction chromatography (RPEC). In solvent extraction, niobium and zirconium are extracted with reagent solutions in the respective concentration ranges <0.001–0.04 mol dm−3 and 0.5 mol dm−3 leaving hafnium in the aqueous phase. In RPEC, niobium and zirconium are extracted by the reagent impregnated column and hafnium is completely eluted with water. Zirconium and niobium subsequently are eluted successively with 0.5 mol dm−3 HNO3 and 1 mol dm−3 HF solutions. Distribution studies indicate that the extracted species for niobium and zirconium are respectively mono- and dinegative in charge. The extent of separation and the purity of the separated species were verified by means of gamma-ray spectrometry.
Organophosphorus Analogues and Derivatives of the Natural l-Amino Carboxylic Acids and Pep tides. IV. A PhosphaC-Peptide Analogue of Plumbemycin A
Authors: Natchev Ivan A
Published: July 2006

A condensation of 1,2-azaphosphorine 1 and the dipeptide 2 to the entirely protected phosphaC-tripeptide 3 was carried out by the DCC method. A high selectivity was achieved in the enzyme-catalyzed hydrolysis of the ethoxycarbonyl groups with alkaline mesintericopeptidase to 4 and of the peptide bond Ala–Asp with α-chymotrypsin to 5, which in acid-catalyzed hydrolysis releases the norvaline 6. Antitumor activity of the phosphaC-peptides 4 and 5 was found.
Crystal Structure of K4[H2P2Mo5O21]·2H2O
Authors: Ozeki Tomoji , Ichida Hikaru , Miyamae Hiroshi , Sasaki Yukiyoshi
Published: July 2006

K4[H2P2Mo5O21]·2H2O crystallizes in monoclinic system, P21/a with a=13.648(4), b=15.591(7), c=10.889(4) Å, β=94.21(2)°, U=2311(1) Å3, Z=4. It contains a discrete pentamolybdodiphosphite anion, [H2P2MO5O21]4−, which has, approximately, a C2v symmetry. Its framework is the same as those found in the pentamolybdodiphosphate and the pentamolybdodiphosphonate anions. The P–O and Mo–O distances are 1.49–1.55 and 1.69–2.46 Å, respectively.
Hexacarbonylmolybdenum-Induced N–N Bond Cleavage of Pyrazoles. Conversion of 1-Acylpyrazoles to Pyrimidines
Authors: Nitta Makoto , Hamamatsu Tatsuo , Miyano Hiroyuki
Published: July 2006

[Mo(CO)6]-induced reactions of 1-acyl-3,5-disubstituted pyrazoles underwent N–N bond cleavage and subsequent cyclocondensation to give pyrimidines as well as deacylation to give 3,5-disubstituted pyrazoles. Under similar conditions, 1,3,5-trisubstituted pyrazoles, which have no electron-withdrawing substituent on N1, gave no product, except for the starting materials.
General Synthesis of 2-, 3-, and 4-Hydroxyalkylphosphonium Salts by the Reaction of Triphenylphosphine with Cyclic Ethers in the Presence of Strong Acids
Authors: Yamamoto (formerly Nakamura) Shin-ichi , Okuma Kentaro , Ohta Hiroshi
Published: July 2006

Cyclic ethers were efficiently converted to the corresponding hydroxyalkylphosphonium salts by the reaction with triphenylphosphine and trifluoromethanesulfonic or trifluoroacetic acid. The reaction of these salts with bases afforded the corresponding phosphonium inner salts which reacted with carbonyl compounds to give homoallylic alcohols.
Withacoagin, a New Withanolide from Withania coagulans Roots
Authors: Neogi Partha , Kawai Masao , Butsugan Yasuo , Mori Yuji , Suzuki Makoto
Published: July 2006

The structure of withacoagin, a new withanolide isolated from Withania coagulans, has been elucidated as (20R,22R)-5α,20-dihydroxy-1-oxowitha-2,6,24-trienolide by spectral analysis and chemical transformation to a known compound. This is the second report of a Δ6-withanolide. Isolation of three known compounds, (20R,22R)-6α,7α-epoxy-5α,20-dihydroxy-1-oxowitha-2,24-dienolide, (20S,22R)-6α,7α-epoxy-5α-hydroxy-1-oxowitha-2,24-dienolide, and withaferin A, are also reported.
Synthesis and a Novel Fragmentation of 6-Alkoxy-5,6-dihydro-4H-1,2-oxazine 2-Oxide
Authors: Tohda Yasuo , Yamawaki Norihiko , Matsui Hiroko , Kawashima Toshihide , Ariga Masahiro , Mori Yutaka
Published: July 2006

An electron-deficient nitro olefin, methyl α,p-dinitrocinnamate, reacts with vinyl ethers to give cyclic nitronic esters, which are stable as compared with those produced by reactions of nitro olefins with enamines. Stability of the cyclic nitronate depends on the properties of the substituents at 4- and 6-positions of the ring. The adducts undergo fragmentation by a catalytic amount of base to β,γ-unsaturated α-hydroxyimino esters.
Autoxidation of Solid Guaiazulene and of the Solution in DMF in the Presence of Base or Acid: A Comparative Study of the Product Distribution
Authors: Takekuma Shin-ichi , Matsubara Yoshiharu , Yamamoto Hiroshi , Nozoe Tetsuo
Published: July 2006

Autoxidation of guaiazulene was examined in detail under the following conditions: in a highly diluted DMF solution, in DMF in the presence of acid or base (at 80–100 °C), and as solid state under sunlight or in the dark (at 25–50 °C). In all cases a wide variety of products were obtained (33 separable compounds altogether), and a comparable study on the distribution of the products under the various reaction conditions was made to establish more precise reaction pathways for the formation of these interesting compounds.
Anomalous Reaction of Arylmalononitriles with Nitric Acid. Para-Directing Nature of Dicyanomethyl Group and a Through-Ring Nitro/aci-Nitro Tautomerism of 4-Nitrophenylmalononitrile
Authors: Suzuki Hitomi , Koide Hideki , Ogawa Takuji
Published: July 2006

Phenylmalononitrile reacts with nitric acid in dichloromethane at room temperature to afford 1,2-bis(4-nitrophenyl)-1,1,2,2-tetracyanoethane as an initial product, which readily suffers oxidative cleavage to give 4-nitrobenzoyl cyanide. Contrary to common understanding, dicyanomethyl group exhibits no meta-directing property. 4-Nitrophenylmalononitrile is found to exist in two stable tautomeric forms, which undergo a facile nitro/aci-nitro interconversion across aromatic ring depending on the nature of solvent employed.
Hydrogen Separation Using LaNi5 Films Deposited on Polymer Membranes
Authors: Sakaguchi Hiroki , Adachi Gin-ya , Shiokawa Jiro
Published: July 2006

Hydrogen separation has been investigated using LaNi5 films deposited by means of a sputtering method on a nickel-coated Teflon or on a nickel-coated polyimide membrane. Separation factors were estimated for an H2(50 mol%)–Ar(50 mol%) gas mixture. The permeation rate of the Ni/LaNi5 multilayered film was found to be larger than that of the Ni film. Hydrogen was concentrated to as high as 97.6 mol% under the best conditions.
The Isomerization of 1-Butene to cis-2-Butene over CaO by Means of the Pulse-Reaction Method
Authors: Arata Kazushi , Hino Makoto , Kobayashi Sakari
Published: July 2006

The title reaction was studied over CaO catalysts which had been prepared by the calcination of Ca(OH)2 in air, followed by heating in a He stream or by thermal decomposition in a He flow. The former catalysts gave high cis/trans ratios (up to 21.6), while the latter ones were higher in activity but showed much lower ratios (ca. 1).
The Crystal and Molecular Structure of 1 : 2 Molecular Complex of 1,4-Diazabicyclo[3.3.3]octane (DABCO) with p-Cresol
Authors: Takama Masaaki , Yasui Masanori , Harada Shigeharu , Kasai Nobutami , Tanaka Koichi , Toda Fumio
Published: July 2006

X-Ray crystal structure analysis of the title compound is described. C6H12N2,2C7H8O, F. W. 328.5, monoclinic, space group C2⁄c, a=18.494(1), b=9.250(1), c=11.414(1) Å, β=103.67(1)°, V=1897.4(3) Å3, Dc=1.150 g cm−3 for Z=4. The DABCO molecule in the crystal is bound to two p-cresol molecules by the strong O–H···N hydrogen bonds, and the crystal is composed of p-cresol···DABCO···p-cresol complex units.
Time-Dependent Metastable Fragmentations. The H2O Loss from Ethyl Acetate Ions
Authors: Arakawa Ryuichi
Published: July 2006

The metastable transitions for CH3COOC2H5+→C4H6O+ +H2O have been measured as a function of the ion lifetime of 0–200 μs by using trapped ion mass spectrometry (TIMS). The experimental data were well explained by tunneling corrections to the prior isomerization rate.
Stereoselective Alkylation of Lithium Enolates Generated from t-Butyl Esters of 4-Alkyl-Substituted 5-Hydroxypentanoic Acids
Authors: Ukaji Yutaka , Narasaka Koichi
Published: July 2006

Alkylation of lithium enolates generated from t-butyl esters of 4-alkyl-substituted 5-hydroxypentanoic acid by treatment with lithium pyrrolidinide in THF–HMPA proceeded stereoselectively to afford the corresponding anti-α-alkylated esters.
The Solubilization Equilibrium of 7-Ethoxycoumarins in Ionic Micelles
Authors: Moriya Tetsuo
Published: July 2006

The solubilization behavior of 7-ethoxycoumarin (7EC) and 7-ethoxy-4-methylcoumarin (7E4MC) in aqueous micellar solutions of sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium chloride (HDTC) was studied by fluorescence spectroscopy. The equilibrium constants for the binding of the fluorophores into micelles and their fluorescence yields in the micellar phase were determined.
Charge-Transfer Rates in Thin Polyelectrolyte Films Incorporating a Redox Molecule with Two Separate Electroactive Centers Having Different Redox Potentials. An Alizarine Red S–Cationic Perfluoropolymer Film System
Authors: Ohsaka Takeo , Takahira Youko , Hatozaki Osamu , Oyama Noboru
Published: July 2006

The diffusion coefficients for the charge-transport processes through 9,10-dihydro-3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonate (Alizarine Red S, 1)-incorporating cationic perfluoropolymer (CPFP) polyelectrolyte films on electrodes undergoing oxidation or reduction of two separate electroactive centers with different redox potentials, i.e., the two-electron reduction of 1 to 3,4,9,10-tetrahydroxy-2-anthracenesulfonate (2) and the two-electron oxidations of 2 to 1 and 1 to 3,4,9,10-tetrahydro-3,4,9,10-tetraoxo-2-anthracenesulfonate ( 3) were measured by potential-step chronoamperometry and chronocoulometry. The apparent diffusion coefficients for 1 to 2, 2 to 1, and 1 to 3 processes where the first two processes are reversible and the 1 to 3 process is irreversible, represented as Dapprev(1→2), Dapprev(2→1) and Dappirrrev (1→3), respectively, decreased with increasing the concentration (Cfilm) of 1 (or 2) in the CPFP film, and for a given Cfilm they were found to be in the following order: Ds′>>Dapprev (1→2)∼Dapprev(2→1)>Dappirrev (1→3), where Ds′ represents the diffusion coefficients corresponding to the diffusion of supporting electrolyte ions coupled to electron transfer and molecular motion of reactant itself. It became apparent that the difference in Dapprev(1→2) (or Dapprev(2→1)) and Dappirrev (1→3) can be attributed to different contributions of electron exchange between electroactive centers to the overall charge-transport rates. The results demonstrate that the contributions from molecular motion of reactant itself and electron exchange between reactants to the overall charge-transport rates can be estimated depending upon which redox center is employed in an electrochemical measurement of diffusional rates.
Physicochemical Properties of α,ω-Type Surfactant in Aqueous Solution. Bis(triethylammonium) 1,20-Eicosanediyl Disulfate
Authors: Ikeda Kenji , Ishikawa Motoharu , Yasuda Masaaki , Esumi Kunio , Meguro Kenjiro , Binana-Limbele William , Zana Raoul
Published: July 2006

The physicochemical properties of the α,ω-type (bolaform) surfactant, bis(triethylammonium) 1,20-eicosanediyl disulfate (α,ω C20N2Et6), in aqueous solution have been investigated by means of surface tension, electrical conductivity, dye solubilization and time-resolved fluorescence quenching. The critical micelle concentration of α,ω C20N2Et6 was 1–1.3×10−3 mol dm−3. The micelle ionization degree of the surfactant was larger than a conventional surfactant having the same head group. From surface tension measurements, the molecular area of α,ω C20N2Et6 at the air–water interface was found to be about twice as large as that of a normal type surfactant, such as sodium dodecyl sulfate (SDS). This reveals that α,ω C20N2Et6 probably forms vertical looping (“wicket-like” conformation) at the air–water interface. By time-resolved fluorescence quenching measurements, the aggregation number of α,ω C20N2Et6 micelle was found to be strongly dependent on the concentration, but only slightly dependent on the temperature. At low concentrations the aggregation number is close to half that corresponding to a normal type surfactant having a chain length that is that of the bolaform. The solubilizing power of a micellar solution of α,ω C20N2Et6 toward Orange OT was 7.6×10−3 mol of dye per mol of surfactant, that is, a value smaller than that of SDS.
Inversion and Deuteration at the Chiral Nitrogen Centers of [Co(acac or ox)2(Me-en or Me3en)]+or− (acac=2,4-Pentanedionate Ion; ox=Oxalate Ion; Me-en=N-Methylethylenediamine, Me3en=N,N,N′-Trimethylethylenediamine)
Authors: Ma Guilin , Hibino Tomomi , Kojima Masaaki , Fujita Junnosuke
Published: July 2006

The rates of the base-catalyzed proton exchange (deuteration, kD) and isomerization (epimerization, kep) at the chiral amine nitrogen centers of [Co(acac or ox)2(Me-en or Me3en)]+or− in aqueous solutions were measured at 34.0 °C, and the results were compared with one another and with those of related complexes. The deuteration rate is affected more by the nature of coexisting ligands than the overall charge on the complex. The uninegative ox complexes have larger kD values than the unipositive acac complexes. The kep values of the ox complexes are ca. 104 times as large as those of the acac complexes. For both ox and acac complexes, the complexes with Me3en have larger kD and kep values than the complexes with Me-en. The deuteration rates are ca. 104–105 and ca. 102 times greater than the inversion rates for the acac and ox complexes, respectively.
Preparation and Crystal Structure of New Gold(I) Complexes Linked to Pyrimidines
Authors: Amagai Takashi , Miyamoto T Ken , Ichida Hikaru , Sasaki Yukiyoshi
Published: July 2006

Two new gold(I) complexes linked to pyrimidines, (5-fluoro-2′-deoxyuridinato-N3)(triphenylphosphine)gold(I) (1) and [5-fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedionato-N3](triphenylphosphine)gold(I) (2) were synthesized and characterized by 31P, 1H NMR and IR spectra. The structure of 2 was determined by an X-ray diffraction method. A linear, two-coordination around gold(I) has been shown. In order to estimate the possible alteration of 1 and 2 in vivo, several factors such as the effect of pH, and reactions with thiol, thiophenol, and imidazole were examined.
Efficient Synthetic Method for Differentially Protected Naturally Occurring Acyclic Polyamines
Authors: Iwata Masaaki , Kuzuhara Hiroyoshi
Published: July 2006

A new systematic route to threefold protected natural polyamines, spermidine, spermine, thermine, and thermospermine, was developed through alternate regioselective manipulation on the terminal primary amino groups, starting from N,N-phthaloyl-1,3-propanediamine hydrochloride (3). When 3 was tosylated at the amine terminal and the phthaloyl terminal was subjected to transformation to the formamido group followed by substitution at the tosyl terminal with, e.g., N-(4-bromobutyl)phthalimide, threefold protected spermidine was obtained in excellent yield. After hydrolysis of the formamido group to amine salt, a sequence of the reactions was satisfactorily repeated to afford various types of threefold protected natural tetramines.
Induced Circular Dichroism Spectrum of α-Cyclodextrin Complex with Heptylviologen
Authors: Kodaka Masato , Fukaya Toshio
Published: July 2006

The rotational strength of α-cyclodextrin (α-CDx) complex with heptylviologen (1,1′-diheptyl-4,4′-bipyridinium dibromide) was calculated by using the Kirkwood–Tinoco expression. The calculation shows that electric transition polarized along the long axis of heptylviologen gives negative induced circular dichroism (ICD) whereas the short-axis polarized transition gives positive ICD, when HV is axially included in α-CDx and the electric transition moment is located out of the cavity of α-CDx (above the narrower rim). From the comparison between the experimental and calculated results, it is concluded that the heptyl chain of heptylviologen is involved in the cavity while the pyridinium part is situated out of the cavity.
Synthesis and Properties of the Tridecafulvene Derivatives. The Substituent Effect at the 14-Position on the Tropicity of Thirteen-Membered Fulvene System
Authors: Ojima Juro , Masumoto Masayuki , Katsuyama Jyunji , Kitamura Keiko , Iyoda Masahiko
Published: July 2006

Dimethylbisdehydrotridecafulvene derivatives bearing various substituents at the exocyclic bond have been synthesized and the inductive effect of substituents upon the tropicity of the thirteen-membered ring is discussed on the basis of the spectral data.
Polarography of Metal Hydroxamates. Individual and Simultaneous Determination of Tungsten and Molybdenum Using Benzo- and Cinnamohydroxamic Acids
Authors: Bhowal Sabooj Kumar , Bhattacharyya Mita
Published: July 2006

Methods for the determination of traces of tungsten have been developed by directly subjecting the organic extracts of its benzo- and cinnamohydroxamic acid complexes to d. c. and derivative pulse polarography. Well defined waves and peaks are obtained in a ternary solvent mixture containing the extract, methanolic lithium chloride and aqueous phase. The methods are highly selective and allow determination of the metal in the ppm range. A procedure has also been developed for the simultaneous determination of tungsten and molybdenum using their benzohydroxamates. Effects of acids and solvents on the system have been studied and the probable mechanism of reduction of the complexes has also been discussed.
Synthesis and Reactions of 2-Arylhydrazinotropones. II. Synthesis of 5-Aryltropolones and B-Ring-Open Colchicine Analogues via Benzidine Type Rearrangement of 2-(2-Arylhydrazino)troponesa
Authors: Nozoe Tetsuo , Takase Kahei , Yasunami Masafumi , Ando Masayoshi , Saito Hiroaki , Imafuku Kimiaki , Yin Bing-Zhu , Honda Masaaki , Goto Yasutomo , Hanaya Tadashi , Hara Yasushi , Yamamoto Hiroshi
Published: July 2006

Treatment of a wide variety of 2-(2-arylhydrazino)tropones with ethanolic acid at 50–80°C readily gave the benzidine type rearrangement products, 2-amino-5-(4-aminoaryl)tropones, besides minor amounts of byproducts of various type. The main products were conveniently led to the corresponding 5-aryltropolones. Similarly, 2-(2-arylhydrazino)tropones bearing an isopropyl and isopropenyl group at the 4-position afforded 4-substituted 2-amino-5-(4-aminoaryl)tropones as the main products, which were also led to 4-substituted 5-(4-acetamidoaryl)- and 5-(4-methoxyaryl)tropolones. Structural assignments of these products were made on the basis of 1H NMR and other spectral data as well as of chemical transformations to known 5-phenyltropolone and also to 2-acetamido-8-hydroxy-10,10-dimethylcyclohept[a]inden-7(10H)-one. This synthetic scheme may possibly be utilized for a convenient synthesis of B-ring-open analogues of colchicine.
Direct Determination of the Intermolecular Potential for Krypton
Authors: Boushehri Ali , Absardi Jalil Moghadasi
Published: July 2006

In recent years a procedure has been developed for determining potential energy functions directly from measurements of gaseous transport properties, without assuming any particular functional form for the interaction potential. Previous applications of this procedure have required that the potential well depth be known independently. It is shown that this requirement is not necessary, and that the entire potential can be directly obtained with reasonable accuracy from the accurate viscosity data presently avilable. The interaction potential discussed is that for the inert gases.
Crystal and Molecular Structure of the Dicobalt(III) Complex Containing Bridging Di-μ-hydroxo Ligands, [(gly)(en)Co(μ-OH)2Co(gly)(en)]2+
Authors: Hamada Kensaku , Ohta Etsuko , Fujiwara Takaji , Ama Tomoharu
Published: July 2006

The molecular and crystal structure of the title compound has been determined by the X-ray method. The cation structure consists of well-separated dimeric pairs of the octahedrally coordinated cobalt(III) atom linked by two μ-hydroxo bridges. There are two intramolecular N–H···O hydrogen bonds bridging the two chromophores.
The Amidation of Carboxylic Acid with Amine over Hydrous Zirconium(IV) Oxide
Authors: Takahashi Kyoko , Shibagaki Makoto , Kuno Hideyuki , Kawakami Hiroshi , Matsushita Hajime
Published: July 2006

The reaction of a carboxylic acid or an ester with an amine to give the corresponding amide was carried out efficiently over hydrous zirconium(IV) oxide, whether in the vapor phase or in the liquid phase.