bluuebunny/crossref_metadata_2025_split huggingface dataset:
Derivatographic Studies on Transition Metal Complexes. XVIII. Thermal Isomerization of cis-[CrCl2tn2]Cl·0.5H2O in Solid Phase
Authors: Yoshikuni Tadatsugu , Tsuchiya Ryokichi , Uehara Akira , Kyuno Eishin 
Published: July 2006

Abstract
The thermal cis-to-trans isomerization of cis-[CrCl2tn2]Cl·0.5H2O in a solid phase was studied by means of derivatographic and isothermal measurements. It was found that cis-[CrCl2tn2]Cl·0.5H2O in which trimethylenediamine(tn) forms six-membered chelate ring with chromium undergoes isomerization to the trans-complex in contrast with the isomerization of trans-[MX2(diam)2]X·HX·nH2O (M=Co or Cr, X=halogen) to the cis-one in which the diamine (diam) forms five-membered chelate ring with metal M. The isomerization proceeded in anhydrous state. The activation energy of the isomerization of the complex was found to be 163 kJ mol−1 from the isothermal measurements, which is fairly greater than that of the trans-[CoCl2pn2](H5O2)Cl2 and cis-[CoCl2tn2]Cl·H2O. The difference was explained by whether or not water molecule involved as a lattice water contributes to the isomerization.
Derivatographic Studies on Transition Metal Complexes. XIX. Thermal Isomerization of trans-[CrCl2(en)2](H5O2)Cl2 and trans-[CrCl2(pn)2]Cl·1.5H2O in Solid Phase
Authors: Yoshikuni Tadatsugu , Tsuchiya Ryokichi , Uehara Akira , Kyuno Eishin 
Published: July 2006

Abstract
Thermal trans-to-cis isomerization of [CrCl2(en)2](H5O2)Cl2 and [CrCl2(pn)2]Cl·1.5H2O was studied in the solid phase by derivatographic and isothermal measurements. The former complex was found to isomerize in anhydrous state after the complete elimination of hydrogen chloride and water, the latter in the temperature range for dehydration. The activation energies for the isomerization of these two complexes were isothermally estimated to be 202 and 193 kJ mol−1, respectively. The same type of isomerization mechanism is suggested for these complexes, differing from that for the corresponding cobalt(III) complexes in which lattice waters participate.
Stereochemistry of Nucleophilic Addition Reactions. 5. Formation of Stabilized Ylides from Methyl 4,6-O-Benzylidene-2,3-dideoxy-3-nitro-β-d-erythro-hex-2-enopyranoside with Some S-Ylides; An Important Role of the Nitro Group for Stabilization of the Ylides
Authors: Sakakibara Tohru , Sudoh Rokuro , Nakagawa Toshio 
Published: July 2006

Abstract
Treatment of methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-d-erythro-hex-2-enopyranoside (1) with dimethyloxosulfonium methylide and dimethylsulfonium α-methylphenacylide afforded cyclopropane derivatives, whereas similar reactions with dimethylsulfonium phenacylide and dimethylsulfonium ethoxycarbonylmethylide gave stabilized ylides. In all cases the S-ylides enter the C-2 position of 1 from the side trans to the anomeric methoxyl group. The ylide structures were determined from IR and NMR data and confirmed by transformation into the desulfurized products. Anomalous stability of these ylides are attributed to the delocalization of the negative as well as positive charge over the carbonyl and the nitro group, respectively.
The Benzannelated Annulenones. Syntheses and Properties of 10-Methylbenzo[d]-6,8-bisdehydro[15]annulenone and 12-Methylbenzo[f]-8,10-bisdehydro[15]annulenone
Authors: Ojima J\={u}ro , Shiroishi Y\={u}ji 
Published: July 2006

Abstract
Synthesis of two methylated monobenzannelated bisdehydro[15]annulenones is described. It was found by means of 1H-NMR spectra that the protonated annulenones are diatropic.
Equilibrium Study of the Fe–V–S System by Thermogravimetry
Authors: Wada Hiroaki 
Published: July 2006

Abstract
An equilibrium study of the Fe–V–S system was carried out in the range of log(PS2/atm)=−4 to −0.8 at temperatures between 723 and 1093 K. The gravimetric method was employed by making use of a quartz spring balance. The partial pressure of sulfur was controlled in an N2-sulfur vapor system by temperature regulation. The partial pressure of S2 was calculated from the thermodynamic data, taking account of the existence of different molecular species: S2 through S8. Three kinds of ternary sulfides with different Fe/V ratios were used as starting material. The PS2-T-X relation was established through in situ measurements at high temperatures. It was found that the Fe–V–S system has an extensive ternary solid solution with the NiAs type of fundamental structure.
Magnetic and Spectral Properties of Copper(II) Chloride Complexes of Tridentate Salicylideneamines with ONN Set of Donors
Authors: Muto Yoneichiro , Tokii Tadashi 
Published: July 2006

Abstract
Four complexes with the general formula of Cu[sal·(CH2)n·N(R)R′]Cl (sal=·\overset2O·C6H4·\overset1CH=N·; n=2 and 3; R=H and CH3; R′=CH3) were characterized by elemental analyses, IR and visible reflectance spectra, ESR spectra, and magnetic susceptibilities. The complexes where n=2, Cu[sal·(CH2)2·NHCH3]Cl and Cu[sal·(CH2)2·N(CH3)2]Cl, showed normal paramagnetic behavior. The Cu[sal·(CH2)3·N(CH3)2]Cl complex was obtained in two forms, one red-violet and the other green. The red-violet form showed the usual magnetic behavior expected for a mononuclear copper(II) complex, whereas the green one exhibited the antiferromagnetic behavior typical of binuclear copper(II) complexes. The magnetic properties of these complexes are discussed in terms of structural considerations. The characterization of the Cu[sal·(CH2)3·N(CH3)2Br complex is also reported.
Synthesis and Unusual Properties of Trimethylsilylmethyl, Neopentyl, and Related Alfcylthallium Compounds
Authors: Kurosawa Hideo , Numata Shigeaki , Konishi Toshifumi , Okawara Rokuro 
Published: July 2006

Abstract
Synthesis of some new trimethylsilylmethyl, neopentyl, and isobutylthallium compounds is described. Dialkykhallium halides containing these bulky alkyl substituents were found to be dimeric, in marked contrast to the polymeric dimethylthallium halide analogs. Trimethylsilylmethylthallium diisobutyrate possesses much higher stability than the methyl and ethylthallium analogs. These facts were discussed in terms of the steric bulk of the alkyl groups attached to thallium.
A Synthetic Route to 3,3-Diphenyl-2-indolinone Derivatives
Authors: Sen\={o} Manabu , Shiraishi Shinsaku , Suzuki Yukio , Asahara Teruz\={o} 
Published: July 2006

Abstract
N-Aryl-α-chloro-α,α-diphenylacetimidoyl chlorides were prepared from Schiff bases and dichlorocarbene generated by use of the phase transfer catalyst. Treatment in sulfuric acid gave 3,3-diphenyl-2-indolinone derivatives. The synthetic route to 2-indolinone was found to give a higher overall yield than that by other methods. 2,2-Dichloro-1,3-diphenylaziridine gives α-chloro, α-acetoxy or α-hydroxy-α,α-diphenylacetanilide on treatment with sulfuric acid. Comparison of 2,2-dichloro-1,3-diphenylaziridine, 2,2-dichloro-1,3,3-triphenylaziridine and N-aryl-α-chloro-α,α-diphenylacetimidoyl chloride in their reactivities with sulfuric acid shows that the pathway of the reaction is governed by the character and number of substituents at the reaction center where carbonium ions are developed.
Temperature Effect on the Molecular Weight and the Optical Purity of Anhydropolyaspartic Acid Prepared by Thermal Polycondensation
Authors: Kokufuta Etsuo , Suzuki Shinnichiro , Harada Kaoru 
Published: July 2006

Abstract
Anhydroyplyaspartic acid (APAA) was prepared by the thermal polycondensation of l-aspartic acid in the solid state at 160-220 °C for 5 h. The effect of temperature on molecular weight and optical purity of APAA was investigated. The molecular weight increases rapidly in the temperature range 180–200 °C, the yield of APAA also increasing rapidly. The optical purity deecreases rapidly with rise in temperature from 160–180 °C.
The Reaction of O(3P) Atoms with Indene and Phenanthrene Induced by the γ-Radiolysis of Liquid Carbon Dioxide
Authors: Goto Seizi , Hori Akira , Takamuku Setsuo , Sakurai Hiroshi 
Published: July 2006

Abstract
The γ-radiolysis of liquid CO2 with indene and phenanthrene gives the corresponding oxirane and carbonyl compounds, together with some products which are unexpected on the basis of the reaction of (3P) with aliphatic olefins: (i) the corresponding cyclic carbonate; (ii) 1H-2-benzopyran and a dimer for indene, and (iii) dibenz[b,d]oxepin and 2,2′-biphenyldicarbaldehyde for phenanthrene. The mechanisms of the formation of these products are discussed.
Syntheses of Aromatic Mannich Bases Involving Nitrogen Heterocycles by Means of Amine-exchange Reaction
Authors: Kamogawa Hiroyoshi , Kubota Kuniaki , Nanasawa Masato 
Published: July 2006

Abstract
Amine-exchange reactions of aliphatic Mannich bases involving nitrogen heterocycles, such as 2-(2-dimethylaminoethyl)-substituted pyridine, quinoline, benzothiazole, and 3,3-dimethyl-3H-indole, with arylamines readily provided the corresponding aromatic Mannich bases which are otherwise hardly accessible.
Calorimetric Study of the Glassy State. XIV. Calorimetric Study on Unusual Glass Transition Phenomena in CFCl2–CFCl2
Authors: Kishimoto K\={o}ji , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
The heat capacities of the glassy crystalline, plastic crystalline, and liquid phases of CFCl2–CFCl2 were measured by an adiabatic calorimeter over a temperature range from 13 to 310 K, with a sample of 99.93% purity. The triple point was determined to be 297.91 K, the enthalpy and entropy of fusion being 3.666 kJ mol−1 and 12.30 J K−1 mol−1, respectively. Three kinds of relaxation phenomena were found during the heat capacity measurement centered at around 60, 90, and 130 K, respectively. The first was attributable to the β relaxation. The second was for primary glass transition, where overall rotation or reorientation of the molecules might be frozen. The third was analyzed by ascribing it to the freezing of conversion between the trans and the gauche conformers of the molecule. Activation enthalpy for the internal rotation and energy difference between the two conformers were determined to be 41 kJ mol−1 and (790±60) J mol−1, respectively. This experiment provides the first example in which three different freedoms of molecular motion are frozen successively at different temperatures as the crystal is cooled down. An effort to get a possible low-temperature ordered crystalline phase was partially successful by long annealing of the crystal. The extremely sluggish nature of the phase transition into the ordered phase will be related with the slow rate of the internal rotation of the molecule below the transition temperature.
Copper(II)-2,2′-Bipyridine-Eriochrome Cyanine R Ternary Complex and Its Application to the Spectrophotometric Determination of Copper(II)
Authors: Ishida Ryoei , Narita Hifumi , Tonosaki Koichi 
Published: July 2006

Abstract
Copper(II) ion reacted with 2,2′-bipyridine (bpy) and Eriochrome Cyanine R (ECR) to give one of two kinds of ternary complexes according to the amount of reagents in a weakly basic medium. The combining ratios of three components in the complexes were estimated to be Cu(II): bpy: ECR= 1 : 1 : 2 and 1 : 1 : 1, respectively, the former having an absorption maximum at 515 nm and the latter at 550 nm. The color development of the 1 : 1 : 2 complex was utilized in the spectrophotometric determination of copper(II) at microgram level. The ternary complex gave a maximum absorbance at 515 nm in the pH range 10.2–10.6. Under optimum pH, 2,2′-bipyridine and Eriochrome Cyanine R concentrations, a linear relationship holds between the absorbance of the complex and copper(II) concentration up to 6×10−5 mol dm−3. The apparent molar absorption coefficient at 515 nm is about 20400 dm3 mol−1 cm−1, corresponding to Sandell’s sensitivity index of 0.0031 μg cm−2.
Conditions for the Precipitation of Heavy Metals from Wastewater by the Lime Sulfurated Solution (Calcium Polysulfide) Process
Authors: Aratani Toshiro , Yahikozawa Kiyochika , Matoba Hitoshi , Yasuhara Shigeki , Yano Takeo 
Published: July 2006

Abstract
A new chemical precipitation process utilizing CaSx solution as a single coagulant was tested for the removal of heavy metals from a batch stirred vessel. The precipitation of heavy metals from the simulated wastewater was investigated under varing conditions of pH, temperature, and heavy metal concentrations. Several agitating speeds were studied for the gases (atmospheric air and CO2 gas) blown into the water to decompose the coagulant (CaSx). The findings are as follows: Heavy metal removal in keeping with the water quality standards in Japan was achieved for the simulated wastewater having pH’s between 3 and 11, and the temperatures from 10 to 85 °C. The agitating speed for optimum removal was found to be 10 Hz. More than 250 ppm of the initial heavy metal concentration gives sufficient removal at stoichiometric quantities of coagulant, while less than 50 ppm of the initial concentration results in rather poor removal owing to the colloidal properties of the metal sulfide or hydroxide. For low concentrations of heavy metals, several units of the coagulant over stoichiometric amount are necessary for sufficient precipitation to achieve the water quality standards.
Reactions of 4H-Pyran-4-thiones with Ammonia, Hydrazine, and Guanidine
Authors: Besso Hiromichi , Imafuku Kimiaki , Matsumura Hisashi 
Published: July 2006

Abstract
The reaction of 4H-pyran-4-thiones with ammonia gave 4(1H)-pyridinethiones or bis(4-pyridyl) disulfide, while that of 3-methoxy-2-methyl-4H-pyran-4-thione with guanidine gave the 1,3-thiazine derivative. 4H-Pyran-4-thiones reacted with hydrazine to afford pyridazines, pyrazoles, and 1-amino-4(1H)-pyridinethiones. 4H-Pyran-4-thiones having the hydroxyl group in the β-position gave the pyridazine derivatives.
Solvent Effects on the Photoamination of 1-Amino-2,4-dibromoanthra- quinone. I. Photoamination in Benzene via Intramolecular Charge Transfer Excited Triplet State
Authors: Inoue Haruo , Hida Mitsuhiko 
Published: July 2006

Abstract
The bromine atom at the 4 position of 1-amino-2,4-dibromoanthraquinone (1) was substituted by butylamine and aniline by the irradiation of visible light. In ethanol the dissolved oxygen promoted the reaction and anthracene, a triplet quencher, had little effect. In benzene, the dissolved oxygen retarded the reaction and anthracene had a considerable quenching effect. Kinetic analysis indicated that in ethanol the photoamination of 1 proceeds mainly through the interaction of 1 in S1(1CT) with the ground state oxygen, while in benzene it does through the T1(3CT) of 1 without the aid of oxygen. The detailed reaction mechanism in benzene has been discussed and the rate constant of each process including the deactivation constant of the upper excited T2(3nπ*) level evaluated.
Autoxidation Reactions of Hydrocarbons Catalyzed by Co(II) Tetra(p-tolyl)porphyrin
Authors: Ohkatsu Yasukazu , Tsuruta Teiji 
Published: July 2006

Abstract
Autoxidation reactions of saturated and unsaturated hydrocarbons were carried out using Co(II) tetra(p-tolyl)porphyrin as the catalyst in ethyl acetate at 30°C The Co(II) complex activated the oxygen molecule to the superoxide ion, which abstracted a hydrogen atom from a saturated hydrocarbon or added to the double bond of an unsaturated hydrocarbon, to initiate autoxidation. The reactivity of the activated oxygen molecule was found at the site of the free radical rather than that of the anion thereof. The reactivities were compared with those of superoxide ions derived from other origins.
The Preparation of a Seven-Coordinate Dimethyllead(IV) Complex, (CH3)2Pb(gbha)(H2O), and Ionic Dissociation of the Coordinated Water
Authors: Majima Tetsuro , Kawasaki Yoshikane 
Published: July 2006

Abstract
A seven-coordinate dimethyllead(IV) complex, (CH3)2Pb(gbha)(H2O), was prepared. From spectroscopic studies the water molecule in the complex was found to coordinate rather strongly to the lead atom as the seventh ligand. An interesting feature of the complex is that the dissociation of a proton from the coordinated water occurs in such coordinating solvents as DMSO and HMPA.
A-Substituted 5β-Steroids. VIII. Synthesis and Bromination of 3-Alkyl-5β-cholestan-2-one
Authors: Satoh J Yasuo , Horiuchi C Akira , Hagitani Akira 
Published: July 2006

Abstract
3α-Alkyl-5β-cholestan-2-one (R=CH3, C2H5, and CH3CH2CH2) was prepared by the direct alkylation of 5β-cholestan-2-one with alkyl iodide and potassium t-butoxide in a reflux of t-butyl alcohol-benzene. The 3α-benzyl ketone was prepared from 5β-cholestan-2-one by aldol condensation with benzaldehyde in the presence of potassium hydroxide, followed by hydrogenation of the condensation product. The bromination of these 3α-alkyl ketones gave 3β-bromo-3α-alkyl-5β-cholestan-2-ones.
Vibrational Fine Structure of the Ligand Field Absorption Band of Halogenoammine Cobalt(III) Complexes
Authors: Fukuda Kunimasa , Urushiyama Akio 
Published: July 2006

Abstract
The crystal absorption spectra of some halogenoammine complexes of Co(III) were measured at liquid helium temperature. The vibrational fine structures observed for the spin-allowed ligand field bands were interpreted in terms of a vibronic intensity mechanism in comparision with the vibrational frequencies of the skeletons. It was found that all the vibrational fine structures consist of the uniquantal progression of totally symmetric Co–N stretching vibration. This suggests that the equilibrium Co–N distances of these complexes are elongated in the ligand field electronic excited state as compared with those in the ground state.
Fluorescence Spectra of 1,1′-Binaphthyl and Related Compounds at High Pressures
Authors: Hara Yoji , Nicol Malcolm F 
Published: July 2006

Abstract
Relative to the related compounds 2,2′-binaphthyl (I) and 2,2′-dimethoxy-1,1′-binaphthyl (II), the pressure dependence of the fluorescence of crystals of 1,1′-binaphthyl (III) is complex. Compression to 30 kbar at room temperature shifts the 1La fluorescence spectra of all three compounds to longer wavelength but, for I and II does not change the intensity profile, except for some 0-0 reabsorption. For III, this red shift characteristic of 1La fluorescence spectra is dominated by growth of new bands about 3.5 to 5.0×103 cm−1 to lower energy. Similar new bands are observed when 1,1′-binaphthyl crystals are compressed at 90 K or resolved crystals are compressed at room temperature, but are not found to 30 kbar for dilute solutions of 1,1′-binaphthyl in polyacrylonitrile. The planes of adjacent naphthyl residues along \overrightarrowb in the crystal are parallel but offset, the normal distance between planes being 3.55 Å; Raman spectra provide no evidence for a structural phase transformation upon compression. These new bands are assigned as the binaphthyl excimer.
Hydrogen-Deuterium Exchange Rate between a Peptide Group and an Aqueous Solvent as Determined by a Stopped-Flow Ultraviolet Spectrophotometry
Authors: Takahashi Tetsuo , Nakanishi Mamoru , Tsuboi Masamichi 
Published: July 2006

Abstract
When an 1H2O solution of N-methylacetamide was rapidly mixed with 2H2O, a time-dependent decrease of the ultraviolet absorbance at 227 nm was observed. This was not the case with N,N-dimethylacetamide. Hence, the time-dependent decrease in absorbance was attributed to be caused by the deuteration (NH→ND) reaction of N-methylacetamide. This provides an appropriate method for determining deuteration rate of the peptide group in a polypeptide or in a protein. By this method the deuteration rate of poly-d,l-alanine has been examined in the pH=5—8 and temperature=10—40 °C range. In this range, the deuteration was found to proceed always as a single first-order reaction, and the rate constant ke is expressed within an experimental error as ke=6.4×10(6+pH−3850⁄T) This is to be used as a standard rate-constant value in estimating the attenuation factor γj=kj⁄ke of a given peptide group (j) in a protein molecule whose rate constant value is kj.
Branched-chain Sugars. XII. The Stereoselectivities in the Reaction of Methyl 4,6-O-Benzylidene-α- and -β-d-hexopyranosid-3-uloses with Diazomethane
Authors: Sato Ken-ichi , Yoshimura Juji 
Published: July 2006

Abstract
The stereoselectivities in the diazomethane reaction of methyl 4,6-O-benzylidene-2-O-methyl-α-d-ribo-hexopyranosid-3-ulose (2), its 2-epimer (3), β-anomer of 2 and the corresponding 2-O-Benzoyl derivative were examined, in comparison with those in the Grignard reaction and sodium borohydride reduction. The complemental stereoselectivity of diazomethane reaction in the case of 2 and 3 indicated that the electrostatic attractive effect in the transition state between diazomethyl cation and the axial methoxyl oxygen at the α-position to carbonyl function in 3 is much stronger than that at β-position which is predominat in the case of 2. In cases of β-anomers having no axial oxygen, stereoselectivies were preferentially controlled by the usual steric factors.
A Stereoselective Rule for the Cross-bicyclization in Linear Conjugated Polyenes
Authors: Tanaka Kazuyoshi , Fukui Kenichi 
Published: July 2006

Abstract
A concept of the cross-bicyclization complementary to that of the cycloaddition is defined for interpreting the mechanism of the simultaneous bicyclizations in linear conjugated polyenes based on the perturbation treatment in the frame of Hückel MO’s. Stereoselective modes in thermal and photo-induced reactions are shown to depend on the sign of the bond-bond-polarizability, Πrs,tu, of the concerned polyene, where r, s, t, and u refer to the atomic positions at which the bicyclization occurs. From the properties of Πrs,tu of linear conjugated polyenes, these modes are simply determined by the relationship among r, s, t, and u in thermal cases, but not in photo-induced ones. The predicted stereoselective modes are discussed in line with experimental observations. It is demonstrated that the “symmetry-disfavored” reactions inferred from the usual cycloaddition mechanism can be interpreted as the concerted cross-bicyclization reactions.
Molecular Structure and Conformation of Ethyl Methyl Ether as Studied by Gas Electron Diffraction
Authors: Oyanagi Kazuko , Kuchitsu Kozo 
Published: July 2006

Abstract
The bond distances (rg) and angles (rα) in ethyl methyl ether have been determined by gas electron diffraction as follows: average of C(methyl)–O and C(methylene)–O=1.418±0.002 Å, C–C=1.520±0.004 Å, C–H=1.118±0.004 Å, ∠C–O–C=111.9±0.5°, ∠O–C–C=109.4±0.3°, ∠H–C–H=109.0±0.4°, where uncertainties represent estimated limits of experimental error. The two rg(C–O) distances have been estimated independently with the aid of the rotational constants for the trans conformer reported by Hayashi et al.: C(methyl)–O=1.413±0.009 Å and C(methylene)–O=1.422±0.007 Å. The dihedral angle for the gauche conformer, 84±6°, and the relative abundance of the trans and gauche conformers in the gas phase at 20 °C, nt⁄(nt+ng)=0.80±0.08, have also been determined.
The Two n,π* Transitions of Monohalogenoanthraquinones
Authors: Matsuzaki Sanae Y , Kuboyama Akira 
Published: July 2006

Abstract
The n,π* absorption and phosphorescence spectra of 1-fluoro-, 2-fluoro, 1-chloro-, 2-chloro-, 1-bromo-, and 2-bromoanthraquinones were studied in solutions, mainly at 77 K. These phosphorescence spectra and their lifetimes resemble those of anthraquinone (AQ), except for those of 1-F-AQ. The phosphorescence spectrum of 1-F-AQ is at longer wavelengths than that of AQ, and its lifetime is 0.8 ms in the methylcyclohexane solution, much shorter than that of AQ. All of the 1-halogenoanthraquinones showed two distinct n,π* singlet-singlet absorption bands at 77 K, and 1-Br-AQ showed an additional band of the n,π* singlet-triplet transition at 492 nm. The low-energy n,π* singlet and triplet states of these compounds are discussed on the basis of these experimental results.