bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Infrared Spectroscopic Study of Hydrogen Bonds. The Liquid-Liquid Interaction of Solvents with Trimethylsilanol
Authors: Kagiya Tsutomu , Sumida Yūzō , Watanabe Takeshi , Tachi Toshihiro 
Published: July 2006

Abstract
An infrared spectroscopic study of the hydrogen-bonding interaction of binary solvents (S1–S2) with trimethylsilanol has been made, where CCl4 is used as S1 and the aromatic hydrocarbons and the O- and N-containing solvents, as S2. On the basis of the findings on the O–H frequency shifts (ΔνOH) of trimethylsilanol, the equilibrium constants (K) and the preferential coordination constants (α1−2) of hydrogen-bond formation, the difference in the O–H···π and the O–H···n hydrogen-bonding interactions has been discussed. The free-energy changes (−ΔG) were found to be better related to the apparent half-widths (Δν1⁄2) of the O–H bands than the ΔνOH. The ΔνOH of trimethylsilanol caused by the interaction with the solvent was in good correlation with the donor number defined as the heat of mixing of the solvent with antimony(V) chloride. From the linear relationship between the ΔνOH of trimethylsilanol and the ΔνSOH of the surface silanol caused by the gas-phase adsorption on silica gel, it was also found that the proton-donating power of the surface silanol was considerably larger than that of trimethylsilanol and was nearly equal to that of p-nitrophenol. There existed a linear relationship through the point of origin between the α1−2 and the separation factors (αS1−2) in the liquid-phase adsorption on the silica gel surface.
The Molecular and Crystal Structure of 3,4-Furandicarboxylic Acid Dimethylester
Authors: Okada Yasuyoshi , Nakatsu Kazumi , Shimada Akira 
Published: July 2006

Abstract
The crystals of 3,4-furandicarboxylic acid dimethylester are monoclinic of the space group P⁄21a, with unit cell dimensions a=12.64, b=8.16, c=7.97 Å, and β=100.0°. An approximate structure was determined by application of the symbolic addition phase determining procedure. After several cycles of least-squares refinement, the discrepancy index for the 901 observed reflections was reduced to 14%. In the molecule the furan ring is planar, and one carbomethoxy group is almost on the same plane as the furan ring, while the other makes an angle of 10.5° with the ring. The bond lengths and angles do not differ appreciably from the values found in the other compounds, except for those of C(3)–C(4)=1.41 Å, C(4)–C(3)–C(6)=131° and C(3)–C(4)–C(7)=132°, the latter two being larger than normal values probably because of interaction between the carbonyl-oxygens. The mode of packing of the molecules and a scheme of twinning found in this crystal is discussed.
Electronic Absorption Spectra of Crystals of Thymine, Uracil, and Their Derivatives
Authors: Tanaka Masashi , Tanaka Jiro 
Published: July 2006

Abstract
The electronic structures and spectra of thymine, uracil, and their derivatives have been studied by measuring the electronic absorption spectra of the single crystals. In the polarized absorption spectra of the crystal, an unusual absorption band appears at about 285 mμ in the tail of the usual π→π* transition when the crystal has the C=O···H–N-type hydrogen bond. The direction of the transition moment of this band is found to be along the direction of the hydrogen bond between a pair of C=O···H–N-groups, the nature of which is discussed from several viewpoints. The direction of the transition moment of the first and second π→π* bands is determined to be inclined at about +38° and +86° from the C4···N1 line toward the C5 atom. The result for the first band is not in perfect agreement with the finding of Stewart and Davidson regarding 1-methylthymine, who regarded this angle as either −14° or +19°.
Optical Activity of Nucleic Acid-Thionine Complexes
Authors: I’haya Yasumasa J , Nakamura Tomoyasu 
Published: July 2006

Abstract
The absorption spectra, optical rotatory dispersion, and circular dichroism (CD) of the DNA- and RNA-thionine complexes were measured at the nucleic acid phosphate to dye ratios (P/D) 0.01–50 and at the temperature range 20–85°C. The Cotton effects of P/D &gt;3 complexes were observed in the wavelength region 520&gt;680 nm, being resolved at least into four partial Cotton effects. From their transient profiles with changing P/D values and the observed temperature effect, they were interpreted to be induced from the dye monomers bound near the asymmetric environment of nucleic acids. The Cotton effects of P/D &lt;2 complexes in the wavelength region 450–580 nm are new and have not been reported for other DNA-dye systems. The trough of these Cotton effects completely disappeared at 50°C and the decreasing profile of its relative rotation with increasing temperature was roughly parallel to that of the dimer fraction. The newly developed Cotton effects are inferred to result from an interaction between the dye dimers aggregated in a helical fashion along the nucleic acid helices. The negative sign CD maximum observed in the wavelength region 300–330 nm is probably due to DNA-dye interactions, but its origin is not clear.
The Preparation and Nonstoichiometry of Samarium Hexaboride
Authors: Niihara Koichi 
Published: July 2006

Abstract
Samarium hexaboride was prepared by the borothermal reaction; 2 Sm2O3+(6+4x)B=4 SmBx+3 B2O2. The residual oxygen content amounted to less than 0.03 w/o under optimum reaction conditions heating at 1650°C for 2 hr under a high vacuum. It was found by X-ray intensity and density measurements that the samarium hexaboride stayed stable over a large nonstoichiometric region from Sm0.68B6 to SmB6. These extensive nonstoichiometric properties of samarium hexaboride can be explained in terms of the required electron numbers of the SmB6 network in hexaboride.
Observation and Interpretation of Triplet-Triplet Absorption Spectra of Substituted Naphthalenes
Authors: Takemura Takeshi , Hara Kiyoaki , Baba Hiroaki 
Published: July 2006

Abstract
Triplet–triplet (T–T) absorption spectra of naphthalene, α- and β-methoxynaphthalene have been observed in rigid-glass solutions at 77°K by the rapid-scan spectrophotometric method and in fluid solutions at room temperature by the flash spectroscopic method. Hydrogenbonding effects on the T–T absorption spectra were examined for α- and β-naphthol. α-Naphthol was found to give different absorption spectra, depending upon the solvents employed. In a certain case the spectrum is attributed to a photoproduct rather than to the triplet state of a-naphthol. Analysis of the spectral data leads to the conclusion that the T–T absorption spectra in α-derivatives involve two different electronic transitions, and those in β-derivatives are due to a single electronic transition which is analogous to the transition in naphthalene. In agreement with these observations, calculations performed by the Pariser-Parr-Pople method predict that in the low-energy region, α-naphthol should have two allowed and detectable transitions, 3Ψ1→3Ψ7 and 3Ψ1→3Ψ8, and naphthalene and β-naphthol have only one such transition, 3Ψ1→3Ψ9. The wave functions of triplet states are subjected to configuration analysis, with the result that 3Ψ7 and 3Ψ8 of α-naphthol are related predominantly to 3Ψ8 and 3Ψ9 of naphthalene, respectively.
The Role of Reaction Sites in the Radiolysis of Solid Succinic Acid
Authors: Miyazaki Tetsuo , Fujitani Yoshiteru , Wakayama Terunobu , Fueki Kenji , Kuri Zen-ichiro 
Published: July 2006

Abstract
The main gaseous products in the radiolysis of solid succinic acid are CO2, CO, and H2. It was found that the G(CO+H2) from the powder is much higher than that from the single crystal, while there is no difference in G(CO2) between the powder and the single crystal, indicating that CO2 is produced homogeneously in the solid. The clear difference in the G(CO+H2) between the powder and the single crystal cannot be attributed to the analytical procedure, the secondary reaction of CO, or the presence of H2O as an impurity. It may be due to the difference in the primary process of the radiolysis. It is conceivable that the mobile active entity formed by the γ-irradiation of the crystal migrates to the special reaction sites and produces CO and H2. The difference in G(CO+H2) may also be due to the different numbers of the sites between the powder and the single crystal. It is discussed whether the mobile entity is a cation, an electron, or an exciton.
Dielectric Relaxation and Molecular Structure. VI. Dielectric Measurements at the Frequency of 100 GHz
Authors: Chitoku Kazuo , Higasi Keniti , Nakamura Masahiko , Koga Yoshinori , Takahashi Hiroaki 
Published: July 2006

Abstract
This paper gives details of the equipment and the method of the measurement at 100 GHz. Dielectric constants and losses are measured at this frequency for ten organic molecules in benzene and four (aniline, phenol, and its derivatives) both in benzene and in dioxane. A majority of the molecules studied are of non-rigid configuration. Discussion is given of the relaxation times and the mechanism of internal rotation involved. Hydrogen bonding effects in aniline, phenol, and its derivatives are also discussed.
Osmotic Pressures of Polystyrene, Poly-p-chlorostyrene and Poly-o-chlorostyrene Solutions
Authors: Kubo Kenji , Ogino Kazuyoshi 
Published: July 2006

Abstract
Second virial coefficients for polystyrene (PS), poly-p-chlorostyrene (PPCS), and poly-o-chlorostyrene (POCS) were determined in various solvents by osmotic-pressure measurements. Free-energy parameters, χ, were estimated from the values of the second virial coefficients. It was shown that the values of χ in each solvent at 30°C became larger in the following order: PS, POCS, PPCS in toluene; PS, PPCS, POCS in chlorobenzene; PPCS, PS, POCS in n-butyl acetate. It was indicated that, in addition to the effect of intermolecular forces, another parameter related to the stiffness of the polymer chains should be considered in order to discuss the thermodynamic properties of polymer solutions. It was shown that the values of χ for two polychlorostyrenes in n-butyl acetate increased with an increase in the temperatures, unlike the behavior of PS in the same solvent.
Magnetic Properties of Copper(II) Complexes of 6-Aminopurine and 6-Hydroxypurine
Authors: Asakawa Toshiro , Inoue Motomichi , Hara Ken-ichi , Kubo Masaji 
Published: July 2006

Abstract
The magnetic susceptibilities of bis(6-aminopurinato)copper(II) trihydrate, dichlorobis(6-aminopurine)copper (II) sesquihydrate, and dichlorobis(6-hydroxypurine)copper(II) monohydrate obey the Bleaney-Bowers equation for binuclear clusters in conformity with the results of X-ray crystal analysis. The exchange integrals within binuclear clusters were evaluated as J⁄k=−156 to −208°K. Superexchange interaction rather than the interaction of direct nature operates predominantly between copper atoms through the pπ orbitals of the heterocycles. The J⁄k values of the compounds are nearly equal to the value, −204°K, of copper(II) acetate monohydrate, although the Cu–Cu distance in the former is greater than that in the latter. The magnetic susceptibilities of dibromobis(6-aminopurine)copper(II) dihydrate, dibromobis(6-hydroxypurine)copper(II) dihydrate, dichloro(6-aminopurme)copper (II), dichloro(6-hy droxypurine)copper (II) monohydrate, and dibromo(6-hydroxypurine)copper(II) hemihydrate indicate the presence of paired copper atoms in the crystals.
Infrared Intensities of Crystalline HCN and DCN
Authors: Uyemura Masakatsu , Maeda Shiro 
Published: July 2006

Abstract
The absolute infrared intensities of crystalline HGN and DCN were measured at the temperature of liquid N2. In comparison with the gaseous values, both stretching fundamentals (v1, v3) exhibited a striking increase in the integrated absorption, while the bending (v2) was almost unchanged. From the observed intensity change, the change in the dipole-moment derivatives with respect to the molecular internal coordinates was calculated to be ∂ΔM⁄∂rC=N=1.43 D/Å and ∂ΔM⁄∂rC−H=2.01 D/Å, those values were chosen from two alternative possibilities as the more probable set. The significance of these values, however, is somewhat peculiar to the optically-active crystalline vibrations, so they were then resolved into derivatives with respect to purely intramolecular and intermolecular coordinates: [∂ΔM⁄∂rC−H]=0.58 D/Å and [∂ΔM⁄∂rH···N]=−1.43 D/Å. The general intensity features were reasonably interpreted by considering the contribution of a charge-transfer structure to the H–N hydrogen bonding.
Activation of Iron-Alkyl Bonds in Dialkylbis (dipyridyl) iron(II) by Interaction with Olefins
Authors: Yamamoto Takakazu , Yamamoto Akio , Ikeda Sakuji 
Published: July 2006

Abstract
The reactions of dialkylbis(dipyridyl)iron (II) 1 with various substituted olefins were studied. Tetracyano-ethylene, maleic anhydride, and acrylamide gave olefin-coordinated π-complexes on reactions with 1, whereas other vinyl monomers with relatively large e-values were polymerized by the alkyl-iron complex. Kinetic study of the reactions of 1 with olefins by a spectroscopic method revealed that the reaction rate can be expressed by
−\fracd[FeR2(dipy)2]dt=\frac[olefin][FeR2(dipy)2]A+B[olefin]+C[dipy]
On the basis of kinetic results and from comparison with the reactions of dialkyl(dipyridyl)nickel with olefins, a mechanism involving partial dissociation of the dipyridyl ligand from 1, followed by a coordination of the olefin and activation of a Fe-alkyl bond was proposed.
The Stereochemistry of Nucleophilic Addition. IV. The Condensation of 2,2,6-Trimethylcyclohexanone with t-Butyl Acetate in the Presence of Lithium Amide
Authors: Matsumoto Takashi , Sakata Gojo , Tachibana Yakudo , Fukui Kenji 
Published: July 2006

Abstract
The stereochemistry of the condensations of 2,2,6-trimethylcyclohexanone with t-butyl acetate in the presence of lithium amide, with ethyl bromoacetate in the presence of zinc (Reformatsky reaction), and with ethylmagnesium iodide (Grignard reaction) was studied. The configurations of the products in these reactions were assigned on the basis of their chromatographic behavior, and on the basis of spectroscopic and chemical studies of them. From the present experiments it is evident that all of these nucleophilic addition reactions proceed in a similar fashion. Further, the treatment of t-butyl 1-hydroxy-2,2,t-6-trimethyl-r-1-cyclohexaneacetate (IIa) with potassium hydrogensulfate or with dilute sulfuric acid gave (±)-cis-tetrahydroactinidiolide (IX), which was isolated from the essential oil of cigar tobacco leaves by Kaneko and Hoshino, while the treatment of IIa with isopropenyl acetate in the presence of p-toluenesulfonic acid gave a mixture of IX and its trans-isomer (X).
Carbon-13 Magnetic Resonance Chemical Shifts in Alkylbiphenyls
Authors: Hasegawa Hideo , Imanari Mamoru , Ishizu Kazuhiko 
Published: July 2006

Abstract
Carbon-13 NMR spectra were observed for the seventeen alkyl biphenyls. For the meta- and para-alkyl derivatives, the observed ring carbon-13 chemical shifts could be adequately understood in terms of the Karplus-Pople’s formula by taking into account the hyperconjugative effect of the substituents. The observed chemical shifts of aliphatic carbon were in good agreement with the values of the corresponding alkylated benzenes within the limits of experimental error. For the ortho-derivatives, the conformation of substituents in the hindered biphenyls was particularly discussed in relation to the observed alkyl carbon-13 chemical shifts. In the cases of 2,2′-dimethylbiphenyl and 2,2′,6,6′-tetramethylbiphenyl, the chemical shifts of methyl carbons at the ortho-position revealed a high field shift of about 1 ppm, but that of 2,4,6-trimethylbiphenyl indicated only 0.4 ppm. The different shifts of the ortho-methyl carbons in the two cases suggested a spece interaction between the two methyl groups. This interaction may arise an orbital overlap between the methyl groups, which were considered to approach one another to take the cis-conformation.
Phenolyses of 1-Adamantyl Chloride, Bromide, and p-Toluenesulfonate in Binary Mixtures of Phenol with Benzene. The Rates and the Product Distribution
Authors: Okamoto Kunio , Matsubara Kôichi , Kinoshita Tomomi 
Published: July 2006

Abstract
Adamantyl derivatives, the bridgehead substrates, have been chosen as the reference compounds in the assessment of the ionizing power of phenolic solvents in the ,SN1-type solvolysis. The SN1-phenolyses of 1-adamantyl chloride, bromide, and p-toluenesulfonate have been studied at several temperatures in binary mixtures of phenol with benzene; the enthalpies and entropies of activation have been calculated. Phenolysis has also been made on t-butyl chloride in order to estimate the Grunwald-Winstein Y values for the phenol-benzene solvents. The solvolysis rates of 1-adamantyl compounds, including the literature values, have been correlated with the Y values and also with the dielectric constants ((D−1)⁄(2D+1)). A significant deviation is found for the phenolic solvents in both correlations; this deviation is discussed in terms of the electrophilic assistance by hydrogen-bonding of the phenolic solvents to the leaving group. The isolated phenolysis products have been characterized as 1-adamantyl phenyl ether, o-, and p-1-adamantylphenols. The product compositions for the reactions of the ion-pair intermediate with the phenol molecule and with the phenoxide ion have been estimated on the basis of the variation in the overall product compositions, caused by the increase in the concentrations of the added phenoxide or amine.
The Substituent Effect. I. Normal Substituent Constants from the Hydrolysis of Substituted-benzyl Benzoates
Authors: Yukawa Yasuhide , Tsuno Yuho , Sawada Masami 
Published: July 2006

Abstract
The rates of the alkaline hydrolyses of 24 m- and p-substituted-benzyl benzoates were measured in 70% (v/v) aqueous acetone at 25°C. The given set of σ0 constants was precisely identical with our standard set derived from m- and p-substituted ethyl phenylacetates. The general utility of σ0 constants is demonstrated for unexalted and exalted resonance reactivities as the reference scale in our LArSR equation:
logk⁄k0=ρ(σ0+r+Δ\barσ\overset+R+r−Δ\barσ\overset−R)
Magnetic Circular Dichroism Studies on High-intensity Bands of d8 Square-planar Metal Halides
Authors: Katô Hajime 
Published: July 2006

Abstract
The magnetic circular dichroism (MCD) of certain d8 square-planar metal halides is studied theoretically on the basis of the molecular orbital theory. The ground state wavefunctions of PtCl42− and PdCl42− are calculated by the semi-empirical ASMO SCF MO method for valence electron systems. The line shape of the MCD of the allowed transition is investigated in detail; the calculated line shape is in good agreement with the observed line shape. The results strongly suggest that the transitions at 43400 cm−1 and 46200 cm−1 in PtCl42− are 1A1g→1A2u(b2u—3b1g and 3a1g—2a2u) and 1A1g→1Eu(5d—6p) respectively, and that the transition at 44900 cm−1 in PdCl42− is 1A1g→1Eu(1).
Polarized Absorption Spectra of Crystals of Indole and Its Related Compounds
Authors: Yamamoto Yukio , Tanaka Jiro 
Published: July 2006

Abstract
The polarized absorption spectra of crystals of indole derivatives have been measured in order to confirm the presence of two types of electronic transitions, 1Lb and 1La, in the long-wavelength absorption region, and in order to determine the direction of their transition moments. The polarization spectra show that the 1A–1Lb electronic transition forms a sharp absroption band with vibrational structures lying below a broader absorption band of the 1A—1La transition. The transition memont direction of the 1Lb makes an angle of 54° to the long axis of the molecule, while that of the 1La lies at an angle of −38° to the same axis. These results were compared with the results of theoretical calculations of the P–P–P SCF MO–CI method.
Ultraviolet and Infrared Spectra of Cupferron and Neocupferron
Authors: Yoshimura Tetsuhiko , Miyake Chie , Imoto Shosuke 
Published: July 2006

Abstract
N-nitroso-N-phenylhydroxylamine, N-nitroso-α-naphthylhydroxylamine, and their sodium salts have been prepared from the ammonium salt of N-nitroso-N-phenylhydroxylamine (cupferron) and the ammonium salt of N-nitroso-α-naphthylhydroxylamine (neocupferron) respectively. The measurements of the UV spectra in solution and the IR spectra with Nujol mull have been carried out on these compounds, including their ammonium salts. The solvent effect and the deuteration effect on the IR spectra have also been examined for the compounds with a hydroxyl group. The formation of a rather strong hydrogen bonding in these aromatic nitrosohydroxyl-amines has been confirmed from the deuteration effect on the IR spectra and from the solvent effect on the UV and IR spectra. These compounds and their salts have shown the absorption band considered to be a chargetransfer band in the UV spectra, and they have also shown the N=O stretching mode between 1450 and 1468 cm−1 corresponding to those of nitrosamines in the IR spectra with the HCB mull.
Photooxidation of 1,4-Dihyropyridines
Authors: Mitsunobu Oyo , Matsumoto Shozo , Wada Makoto , Masuda Hiroaki 
Published: July 2006

Abstract
1,4-Dihydropyridines were successfully photooxidized to corresponding pyridines under suitable conditions. The substituents of the dihydropyridines, reaction mediums, and atmospheres affect the course of the reactions. When diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (1a), diethyl 1,4-dihydropyridine-3,5-dicar-boxylate (1b), 2,6-dimethyl-3,5-diacetyl-1,4-dihydropyridine (1c), and 3,5-diacetyl-1,4-dihydropyridine (1d) were irradiated by a super high pressure mercury lamp with filter in ethanol under air or oxygen, corresponding pyridines, diethyl 2,6-dimethylpyridine-3,5-dicarboxylate (2a), diethyl pyridine-3,5-dicarboxylate (2b), 2,6-dimethyl-3,5-diacethylpyridine (2c), and 3,5-diacetylpyridine (2d) were formed in good yields. Irradiation of 1a, 1c, and 1d in acetonitrile afforded 2a, 2c, and 2d irrespective of their atomosphere, oxygen or nitrogen. On the other hand, photolysis of 1b by the same lamp and filter in ethanol or acetonitrile in an atmosphere of nitrogen resulted in the formation of photodimer (3) which on irradiation by low pressure mercury lamp in acetonitrile dissociated to 1b followed by photooxidation giving 2b. Diethyl l-acetyl-1,4-dihydropyridine-3,5-dicarbolxyate (4e) and 1,3,5-triacetyl-1,4-dihydropyridine (4f) afforded 2b and 2d in fairly good yields when the photolyses were carried out in an atmosphere of air in ethanol or acetonitrile.
Intersystem Crossing Quantum Yields of Phthalazine and Pyridazine
Authors: Takemura Takeshi , Yamamoto Kohzaburo , Yamazaki Iwao , Baba Hiroaki 
Published: July 2006

Abstract
The quantum yields of S1→T1 intersystem crossing have been determined for phthalazine and pyridazine in EPA at 77°K by using the technique of T–T energy transfer. Phthalazine and pyridazine were used as the energy donor, and naphthalene-h8 and naphthalene-d8 as energy acceptor. The intersystem crossing quantum yields were found to be 0.49 for phthalazine and 0.24 for pyridazine. These values lead to the conclusion that the weakness or lack of phosphorescence in the compounds is due to an anomalously high rate of the radiationless transition from their phosphorescent triplet state as compared with the rate of the corresponding radiative transition.