bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric Relaxation Mechanism in Some Substituted Phenones
Authors: Sahni Neera , Shukla J P , Saxena M C 
Published: July 2006

Abstract
Dielectric constants and losses at microwave frequency as well as static dielectric constants and refractive indices have been measured for o-methylacetophenone, m-methylacetophenone, o-hydroxybutyrophenone, 2′,4′-dihydroxyacetophenone and 2′,4′-dihydroxypropiophenone in dilute solutions of 1,4-dioxane. These values are used to calculate the dielectric relaxation times, distribution parameters, dipole moments and activation energies of the molecules. The results have been discussed in terms of the molecular motion of the system in the medium. Comparatively higher relaxation times and their variations irrespective of the molecular size, have been attributed to the intermolecular hydrogen bonding between the solvent and solute molecules.
The Electronic Spectra of α,ω-Di-1- and α,ω-Di-2-naphthylpolyenes in Solution and in Solid State
Authors: Mandal Krishnagopal , Misra T N 
Published: July 2006

Abstract
The electronic absorption spectra of α,ω-di-1- and α,ω-di-2-naphthylpolyenes have been studied in solution and in the crystalline state. Both polyenes have four distinct electronic band systems. The spectral properties indicate that the terminal naphthyl group reduces the symmetry of the short-chained polyene molecules whereas long naphthylpolyenes retain the usual conjugated polyene symmetry of C2h. A plot of λmax2-n gives a straight line and a nearly all-trans form seems to be retained by the polyene chain. Unlike that in some conjugated polyenes a good overlap between the first absorption band and the highest energy emission band is observed. This suggests that there is no low-lying forbidden state in these polyenes. Some of the absorption bands of naphthylpolyene crystal could be explained in terms of factor group split components. Two extra bands observed in α,ω-di-2-naphthylpolyenes seem to be related to naphthalene transitions.
Rotational Isomerism in β-Diketone cis and trans Enol Ethers. An IR and PMR Study
Authors: Dabrowski Janusz , Tencer Michal 
Published: July 2006

Abstract
The cis (Z) isomers of β-alkoxy-α,β-unsaturated ketones, R1COCH=CR2OR3, have been shown by IR spectra to exist as a mixture of s-cis (ZZ) and s-trans (ZE) rotamers, with the equilibrium shifting towards the former upon increasing the steric requirements of the R1 substituent. The trans (E) isomers have uniformly the s-cis (EZ) structure. O-s-trans (or non-planar) and O-s-cis conformations due to rotation around the Csp2–O bond have been proposed for the Z and E isomers, respectively. Based on known structures, a rationalization of the rule governing the chemical shifts of R1 and R2 protons, called here the “ene-one cross shielding rule”, has been offered.
New Red Pentaamminenitrosylcobalt(III) Complexes Obtained by the Reaction of a Cobalt(II)-ammoniacal Solution with Nitrogen Oxide
Authors: Miki Eiichi , Ishimori Tatsujiro 
Published: July 2006

Abstract
New Red Pentaamminenitrosylcobalt(III) chloride and nitrate, [Co2(N2O2)(NH3)10]Cl4·4H2O and [Co2(N2O2)(NH3)10](NO3)4·2H2O were prepared by the reaction of NO at ca. 0 °C with a cobalt(II)-ammoniacal solution which had been exposed to air for 20 h at ca. 20 °C. Data of the new red salts were compared with those of the red salt [Co2(N2O2)(NH3)10](NO3)4·H2O prepared by Sand and Genssler. The new red salt may be considered to be a linkage isomer of the red salt, a binuclear complex in which two of the Co(NH3)5 groups are bridged through a dimer of nitrosyl group, N–O–O–N2− ion.
Phase Equilibria in Fe–Fe2O3–Ln2O3 (Ln=Sm and Er) Systems at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi 
Published: July 2006

Abstract
Phase equilibria in Fe–Fe2O3–Ln2O3 (Ln=Sm and Er) systems were established at 1200 °C. In the Fe–Fe2O3–Sm2O3 system, perovskite, garnet, magnetite, wustite, and metallic iron were stable, while in the Fe–Fe2O3–Er2O3 system, the ErFe2O4 phase appeared in addition to the other five phases. On the basis of the phase equilibria, the Gibbs free energy for the reaction of LnFeO3, Ln3Fe5O12, and ErFe2O4 from Ln2O3, metallic iron, and oxygen was determined to be as follows: SmFeO3 −64.1±0.1 kcal, Sm3Fe5O12 −298.5±0.5 kcal, ErFe2O4 −100.8±0.1 kcal, ErFeO3 −59.7±0.3 kcal, and Er3Fe5O12 −286.2±0.7 kcal.
Kinetic Studies in the Selective Formation of Thymol from m-Cresol and Propylene in the Liquid Phase over “FeSO4–Al2O3” Catalysts
Authors: Yamanaka Tohr , Nakata Fumio 
Published: July 2006

Abstract
The kinetics in a liquid-phase isopropylation of m-cresol (I) with 9–25 kg/cm2 of propylene (VI) was studied at 240–280 °C over catalysts prepared from FeSO4 and γ-Al2O3. The rates of the formation of thymol (II) and 4-isopropyl-5-methylphenol (III) and the subsequent isopropylations of II and III were fitted to an irreversible, firstorder rate equation with respect to each starting material. All of the rate constants were roughly proportional to the 1.5th power of the surface acidity of 1≤H0≤3 of catalysts and the 2.2nd power of the pressure of VI. The apparent activation energies were 22 kcal/mol for Steps I→II, II→2,4-diisopropyl-5-methylphenol (V), and III→V and 6.5 kcal/mol for Steps I→III and II→2,6-diisopropyl-5-methylphenol (IV).
Generation of Ketocarbenoid by α-Elimination of ω,ω-Dibromoacetophenone with Copper, and Trapping by Cycloaddition to Olefins
Authors: Kawabata Nariyoshi , Fujii Tetsuya , Naka Michiharu , Yamashita Shinzo 
Published: July 2006

Abstract
Ketocarbenoid was generated by the reaction of ω,ω-dibromoacetophenone with copper in aromatic hydrocarbon, and was trapped by cycloaddition to olefins. This is the first example of cyclopropanation of olefins by formally divalent carbon intermediate without use of diazoketones.
The Analytical Application of Oleophilic Quaternary Ammonium Salts. X. The Extraction of the Niobium–Pyrocatechol Violet-Tridodecylethylammonium Ternary Complex
Authors: Shijo Yoshio 
Published: July 2006

Abstract
The formation and extraction of the niobium–Pyrocatechol Violet–tridodecylethylammonium ternary complex have been examined. The optimal pH for the extraction is 4–5. The molar absorptivity of the complex is 4.4×104 cm−1·mol−1·l at 553 nm. Its composition is estimated to be (Remark: Graphics omitted.).
The Electrochemical Behavior of Mononitrophenyltrimethylsilanes and 2,4-Dinitrophenyltrimethylsilane
Authors: Watanabe Hamao , Aoki Masafumi , Matsumoto Hideyuki , Nagai Yoichiro , Sato Takeo 
Published: July 2006

Abstract
The CV data for o-, m-, and p-nitrophenyltrimethylsilanes and 2,4-dinitrophenyltrimethylsilane revealed that the former three show Epe slightly more anodic than the corresponding nitrotoluenes; the latter shows a third peak (O3) together with two successive reversible couples, while the methyl analogue exhibits no peak corresponding to O3, but shows extremely weak O1. The behavior of these silyl compounds are interpreted in terms of less electron-donating nature of trimethylsilyl group and (p-d)π bonding between the siliicon and benzene ring.
Synthesis and Electrical Conductivity of Phosphorus-Nitrogen Compounds. V. Synthesis and Electrical Resistivity of Poly[bis(amino)phosphazenes]
Authors: Hayashi Takashi , Saito Hajime 
Published: July 2006

Abstract
Three new poly [bis(amino)phosphazenes] of formulas [NP(NHC6H13)2]n, [NP(NHCH2CHCH2)2]n, and [NP(NHCH2C6H5)2]n have been synthesized by direct aminolysis of (NPCl2)n. The electrical resistivity and thermal stability of a series of poly[bis(amino)phoshazenes], (NPR2) (R: amino group), have been examined. Most polymers showed an increase in resistance with time to an equilibrium value, possibly due to space charge effects, allowance for this conductivity being ohmic up to 500(V/cm). The aliphatic amino derivatives have a lower resistivity and a lower ΔE value than the aromatic amino derivatives. The resistivity of the poly [bis(amino)phosphazenes] was found to decrease in the order, R : NHC2H5&gt;NHC3H7&gt;NHC4H9&gt;NHC6H13&gt;&gt;N(CH3)2. This seems to be predominantly due to the nature of an inductive electron supply of amino side groups. In some polymers the change of energy gap, ΔE, was observed in the range 70–90 °C. The ΔE value was usually lower in the low temperature region than in the high temperature region. All the polymers were found to decompose at about 200 °C, losing the amino side group.
The Crystal and Molecular Structures of trans-Dichlorobis(dimethyl-neomenthylphosphine)nickel(II), an Asymmetric Hydrosilylation Catalyst of Olefin
Authors: Kan Kojiro , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami 
Published: July 2006

Abstract
The molecular structure of [NiCl2{Me2neoMen)P}2], an asymmetric hydrosilylation catalyst of olefin was determined by means of X-ray diffraction. This complex forms dark red monoclinic crystals; a=9.527(1), b=8.048(2), c=19.461(3) Å, β=99.12(1)°, space group P21 with Z=2. The structure, determined by the heavy-atom method, has been refined anisotropically by a least-squares procedure to R=0.099 for 3023 non-zero reflections. The geometry around the nickel atom is trans-square planar [Ni–Cl 2.151(5) and 2.175(6) Å, Ni–P 2.239(5) and 2.230(5) Å], Two neomenthyl groups are located above and below the co-ordination plane.
Photoemission and Solvation Free Energies of Electrons in Polar Solvents
Authors: Yamashita Kazuo , Imai Hideo 
Published: July 2006

Abstract
The red limit potential of electron photoemission was measured in various polar solvents, and the apparent solvation free energies of the electrons were estimated. The energy state and transformation of photoemitted electrons in solution were discussed as regards the role of dry or damp electrons as an intermediate species. A proportionality between the intermediate solvation free energy and the energy quantum of the optical absorption band maximum of solvated electron in various polar solvents is pointed out.
Studies on 5-8 Fused Ring Compounds. I. Halogenation of 4,4-Dimethylbicyclo[6.3.0]undecane-2,6-dione
Authors: Umehara Misao , Hishida Shinzaburo , Fujieda Kunimi , Sasaki Hirooki 
Published: July 2006

Abstract
Bromination and chlorination of 4,4-dimethylbicyclo[6.3.0]undecane-2,6-dione (2) with pyridinium bromide perbromide and sulfuryl chloride gave several α-halo-diones. The substituted positions and the stereochemistry of the halogen atoms have been assigned on the basis of their dehydrohalogenation and spectral data. The chlorination of 2 also gave a tricyclic dione (8) containing a cyclopropane ring. The structure of 8 was determined by means of 13C-NMR, as well as other types of spectroscopy. Dehydrochlorination of 7 gave a 5H-benzocyclo-heptene derivative (18).
A Three-Component Reaction of Isocyanides with Halogens and Cyclic Ethers
Authors: Yamazaki Takeshi , Wada Yasuo , Tanimoto Shigeo , Okano Masaya 
Published: July 2006

Abstract
In the presence of a Lewis-acid catalyst, such as HgCl2 or ZnCl2, cyclohexyl isocyanide reacted with chlorine and tetrahydrofuran to give, after hydrolysis, 4-chlorobutyl cyclohexylcarbamate in a fair yield. When one of the reactants was replaced by another isocyanide, bromine, or another cyclic ether, the reactions proceeded similarly, but the corresponding carbamate yields were rather poor.
Oxidative Addition of α-Bromo Esters to Tetrakis(isocyanide) Rhodium(I) Complexes. Evidence for a Chain Mechanism
Authors: Otsuka Sei , Ataka Kikuo 
Published: July 2006

Abstract
The oxidative additions of chiral alkyl halides, (S)-(−)-ethyl α-bromopropionate [α]d−18.9° (c 3.3, CHCl3) and (S)-(+)-ethyl α-phenylbromoacetate [α]d+56.4° (c 1.6, C2H5OH) to [RH(R′NC)4]+ (R′=t-Bu, p-CH3C6H4) produced the corresponding adducts, trans-[RhBr(R)(R′NC)4]+ (R=CH3CHCO2Et, PhCHCO2Et), which were well characterized by elemental analysis, IR and 1H NMR spectra. These adducts were found optically inactive, a fact which precludes a concerted mechanism. The reaction of C6H5CHBrCO2C2H5 with [Rh(t-BuNC)4]+ commenced immediately in the absence of light. Taking this system as a typical example, the rate was studied by the stopped-flow method to find a rate equation, R=k[Rh(I)]2[RX]. The relative rate of addition of p-XC6H4CHBrCO2C2H5 to [Rh(t-BuNC)4]+ decreases in an order of Cl&gt;H&gt;CH3 for X. The addition of C6H5CHBrCO2C2H5 to [Rh(p-CH3C6H4NC)4]+ in the dark proceeds only slowly, but rapidly under a low energy photo-irradiation (440 nm) with a large quantum yield (φ 4.8). The addition of CH3CHBrCO2C2H5 requires photo-initiation. The optical activity of (S)-(−)-CH3CHBrCO2C2H5 was completely lost before the oxidative addition commenced. The rate of decrease in optical activity of the system (S)-(−)-C6H5CHBrCO2C2H5/[Rh(t-BuNC)4]+ exhibited approximate second order kinetic behavior, and quantitative racemization took place prior to the completion of the oxidative addition. A chain mechanism appears to be consistent with all these results. Alternate mechanisms are also discussed in the light of the present results.
Effect of Hydrogen Bonding on the Rotational Barriers of Partial Double Bonds. III. 2,6-Dihydroxyaryl Carbonyl Compounds
Authors: Hirota Minoru , Suzuki Toshio , Abe Kazuhisa 
Published: July 2006

Abstract
Activation parameters of internal rotation around Car–Ccarbonyl bonds are determined by means of DNMR spectroscopy for 2,6-dihydroxybezaldehyde and some 2,6-dihydroxybenzoates. The ΔG\eweq and ΔH\eweq of these compounds are ca. 10 kJ mol−1 higher than those for the reference compounds void of ortho-hydroxyl groups, and the excess stabilization is attributed to the contribution of the intramolecular hydrogen bonding. The intramolecular hydrogen bonding in these compounds were discussed on the basis of their infrared spectra in the νOH region.
Synthesis of Ferrocene–Phenol Resins and Liberation of Iron Particles by Pyrolysis
Authors: Omori Mamoru , Nagashima Kazuo , Yajima Seishi 
Published: July 2006

Abstract
Ferrocene–phenol resin was synthesized from 1-ferrocenylethanol, phenol, and formaldehyde in the presence of an ammonia catalyst. The resin structure was elucidated by chemical and infrared analyses and then confirmed by micro Vickers hardness measurements. To liberate iron atoms from ferrocene skeletons, the resin was pyrolyzed in vacuo at 400 °C. The properties of the iron dispersed in a glasslike carbon matrix were investigated by magnetic susceptibility measurements, ESR, and Mössbauer spectroscopy. The iron atoms coagulated into ferromagnetic iron particles in the glasslike carbon matrix. This coagulation is discussed in connection with the resin structure.
A New Method for the Preparation of δ-Alkoxy-α,β-unsaturated Aldehydes and Polyenals
Authors: Ishida Akihiko , Mukaiyama Teruaki 
Published: July 2006

Abstract
Dienoxysilanes (2) react with acetals in the presence of TiCl4 and also in the coexistence of TiCl4 and Ti(OiPr)4 to give δ-alkoxy-α,β-unsaturated aldehydes (3–5) in good yields. In the presence of 1,8-diazabicyclo[5.4.0] undec-7-ene or 1,5-diazabicyclo[4.3.0]non-5-ene and molecular sieves 3A or 4A, the elimination reaction of δ-alkoxyl group of α,β-unsaturated aldehydes (3–5) proceeds smoothly to afford the corresponding polyenals in good yields.
Branched-chain Sugars. IX. Reaction of 3,6-Anhydro-1,2-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose with Nitromethane or Hydrogen Cyanide
Authors: Sato Ken-ichi , Yoshimura Juji , Shin Chung-gi 
Published: July 2006

Abstract
3,6-Anhydro-1,2-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose (2) was converted into 5,6-di-O-acetyl-1, 2-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose (5) by the protection of the carbonyl function with hydroxylamine, followed by acetylation and removal of the protecting group with chromium(II) acetate. Nitromethane condensation of 2 and 5 at room temperature gave the corresponding 3-nitromethyl derivatives having d-gluco- and d-allo-configuration, respectively. The difference in the stereoselectivity was explained by the easiness of isomerization of the initial product to thermodynamically stable epimer, because the reaction temperature was essential to control the selectivity in the same reaction of 1,2 : 5,6-di-O-isopropylidene-α-d-ribo-hexofuranos-3-ulose. Reaction of 2 with hydrogen cyanide in dry pyridine followed by acetylation gave the corresponding 3,5,6-tri-O-acetyl-3-cyano derivative of d-allo-type, whereas, the reaction in water gave instantly 3-(hydroxycarbonimidoyl)-1,2-O-isopropylidene-α-d-allofuranose 3′,5-lactone, by the participation of the C5-hydroxyl group.
Adsorption of Benzoic Acid on a Mercury Electrode
Authors: Taniguchi Isao , Machida Koji , Sato Norio , Sekine Taro 
Published: July 2006

Abstract
The differential capacity and the surface tension at the electrode-electrolyte interface of a dropping-mercury electrode were measured in 0.5 M H2SO4 and 0.5 M Na2SO4 solutions for various concentrations of benzoic acid. On the basis of the Frumkin-Damaskin theory, the adsorption of benzoic acid on mercury was studied in the acid solution, and the parameters involved in the F-D theory were determined: A=1.6 μJ cm−2 (Γm=6.5×10−10 mol cm−2), B0=597 l mol−1, a=−0.35–2.5 E/V, and C′=5.95 μF cm−2. The experimental values of the capacity and the surface tension are in good agreement with the theoretical values calculated by using the parameters obtained. The absence of an anodic maximum in the capacity-potential curve in the presence of benzoic acid was determined to be associated with a strong repulsive force between the adsorbed molecules. The value obtained for the maximum surface excess of benzoic acid is explained in terms of adsorption of the acid molecules for a vertical orientation on the electrode surface. This conclusion was supported by comparing the B0 value for benzoic acid with those for phenol and aniline. The adsorption of benzoic acid in neutral solutions is also discussed.
Interaction between Aromatics and Zinc Chloride in the Molten State. The Formation of σ-Complexes and Radicals
Authors: Morita Mikio , Hirosawa Kunio , Sato Toshio 
Published: July 2006

Abstract
The electronic absorption spectra of naphthalene, anthracene, and naphthacene in dried, molten zinc chloride were measured and found to be almost the same as those of aromatics–aluminum chloride complexes in the solid state. ESR measurements were also made; they confirmed the presence of radicals. From these results, it was concluded that the aromatics reacted with molten zinc chloride to form EDA-complexes, i. e., σ-complexes and cation radicals.
A Method for the Preparation of Potassium Hexafluorovanadate(III) and Its Polymorphic Transitions
Authors: K\={o}yama K\={o}ichir\={o} , Hashimoto Yasuhiko 
Published: July 2006

Abstract
In order to determine the best conditions for the preparation of potassium hexafluorovanadate(III), the reaction of V2O3 with KHF2 was studied by means of thermogravimetric analysis, differential thermal analysis and X-ray diffraction analysis. The reaction begins at about 225 °C and terminates at about 300 °C and the decomposition of excess KHF2 terminates at from 300 to 450 °C, depending on the amount of the mixture of V2O3 and KHF2. Potassium hexanuorovanadate(III) is stable in air up to about 300 °C and is oxidized at temperatures higher than 300 °C. Potassium hexanuorovanadate(III) has four polymorphic forms, and the transition points are 158, 200, and 218 °C. The transition from δ to γ or from γ to β on cooling is hindered by adding a small amount of sodium ion.
A Note on the Rates of Complex Formation of Indium(III) with Murexide and the Decomposition of Murexide in the Presence of Indium(III)
Authors: Ohtani Yoshimi , Yagihashi Shin-ichi , Fujimoto Masatoshi 
Published: July 2006

Abstract
Kinetics of the complex formation between In(III) and murexide was studied by means of the temperature-jump method and the rate of decomposition of the ligand in acid nitrate media. The complex formation of InOH2+ with murexide is about 10 times faster than that of In3+. The stability constants indirectly obtained from the decomposition rate of murexide coincide with those from direct stopped-flow measurements.
Photoreaction of Ferrocene with Some Acetylene Derivatives
Authors: Watanabe Haruo , Ito Kazuo , Nakanishi Fumio , Akiyama Takeo , Sugimori Akira 
Published: July 2006

Abstract
The UV-irradiation of ferrocene and dimethyl acetylenedicarboxylate in acetic acid–water solution afforded dimethyl ferrocenylmaleate and dimethyl ferrocenylfumarate in 40 and 5% yield, respectively. Methyl 3-carbamoylpropiolate, dicyanoacetylene, and methyl propiolate were also reactive and the corresponding substituted ferrocenes were obtained. The reaction can be considered to proceed via the excitation of the charge transfer complex between ferrocene and acetylene derivatives.
The Elimination Reaction of Chlorobutane over Some Molten Salts
Authors: Kikkawa Sh\={o}ichi , Nomura Masakatsu , Ikeuchi Takashi 
Published: July 2006

Abstract
The elimination reactions of hydrogen chloride from 1-chlorobutane and 2-chlorobutane over molten salts (ZnCl2, SnCl2, CuCl melts) have been studied by using both a microreactor and a conventional flow reactor. The preferential formation of cis-2-butene in the reaction of 2-chlorobutane can be explained in terms of the stereochemistry of the surface-adsorbed carbonium ion.
Diorganostannylenes. II. Photolytic Reaction of Diphenyltin with Alkyl Halides
Authors: Kobayashi Kazuhiko , Kunô Kazuko , Kawanisi Mituyosi , Kozima Sinpei 
Published: July 2006

Abstract
Photolysis of diphenyltin polymer, (Ph2Sn)m, afforded diphenylstannylene, Ph2Sn:, which was captured by alkyl halides, R′X, to give the insertion products, Ph2R′SnX. The reactivity of Ph2Sn: was found to be lower than that of dibutylstannylene, Bu2Sn:.
Photoreduction of Quinones. I. One-electron Transfer to p-Benzoquinone in Ethanol Studied by ESR during Continuous Photolysis
Authors: Kambara Yoshihiko , Yoshida Hiroshi 
Published: July 2006

Abstract
Electron spin resonance was examined during the continuous photolysis of a flowing solution of p-benzoquinone in ethanol at room temperature. It was found that both semiquinone anions and semiquinone radicals were generated, but their relative yields changed depending on the experimental conditions. The semiquinone anion was generated in a comparatively high yield at low concentrations of p-benzoquinone and at high flowing rates. Its formation was, however, quenched by the addition of acetic acid without transformation to the semiquinone radical. The semiquinone radical was generated efficiently at high p-benzoquinone concentrations and at low flowing rates. Its formation was enhanced by the addition of hydroquinone. These results, as well as the previous results on the effect of the wavelength of light, indicate, in contrast with the currently accepted view, that there is effectively no equilibrium in ethanol between the semiquinone radical and the semiquinone anion under the present experimental conditions, and that the latter is formed by a photoinduced one-electron transfer from solvent to p-benzoquinone. The semiquinone radical seems to arise from the hydrogen abstraction of excited p-benzoquinone from the hydroquinone formed as a product during photolysis.