bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiempirical Molecular Orbital Considerations of the Electronic Structures of Transition Metal Complexes. II. Acetylene- and Azo-Nickel Complexes
Authors: Tatsumi Kazuyuki , Fueno Takayuki , Nakamura Akira , Otsuka Sei 
Published: July 2006

Abstract
The electronic structures of zerovalent nickel π complexes, Ni(HC≡CH)(HNC)2 and Ni(trans-HN=NH) (HNC)2, have been investigated by the INDO method. Both complexes are found to favor the square-planar geometry, in accord with the observed structures of Ni(C6H5C≡CC6H5)(t-BuNC)2 and Ni(C6H5N=NC6H5)(t-BuNC)2. Ni(trans-HN=NH) (HNC)2 is predicted to be more stable than Ni(cis-HN=NH)(HN)2. The increment in the C–C and N–N bond lengths effected by the complexation seems to well reflect the net effects of σ donation and π back-donation. For the isocyanide N–C bond, an approximately linear relationship is found to hold between the calculated bond index and the observed force constant. It is suggested that both the Ni–C(of acetylene) and Ni–N(of diimide) bondings tend to have greater covalent bond strengths as the electron-releasing ability of the isocyanide ligand increases.
A Systematic Study of the Yields of γ-Radiolysis Products in C1, C2, and C3-Chlorofluorocarbons
Authors: Tominaga Takeshi , Fukumizu Takefumi , Aoyama Takashi , Okuda Akihiko , Makide Yoshihiro 
Published: July 2006

Abstract
In the presence of bromine as a scavenger, the yields of the radiolysis products in eleven kinds of C1–C3 chlorofluorocarbons were investigated by means of gas chromatography. The G-values for the rupture of bonds in radiolysis were found to correlate with the halogen composition and the structure of their molecules. The G-values for the C–Cl (or C–F) bond rupture generally appear to increase with the number of chlorine (or fluorine) atoms in the chlorofluorocarbons; there was a marked difference between the G-values for the C–Cl rupture in each pair of structural isomers of chlorofluoroethanes. A striking selectivity in bond rupture was observed between the two C–C bonds in the chlorofluoropropanes.
Donor–Acceptor Interactions in the Ground State of the Systems Forming Heteroexcimers in the Excited State
Authors: Okada Tadashi , Mataga Noboru 
Published: July 2006

Abstract
Several systems which form heteroexcimers in the excited state were forced to aggregate in low temperature rigid matrices, and their absorption, fluorescence excitation and emission as well as fluorescence rise and decay curves were determined. The results indicate the existence of several kinds of donor-acceptor pairs emitting heteroexcimer fluorescence at different wavelengths. Temperature dependence of absorption spectra of those systems in liquid solutions were examined, and collisional enhancement of the absorption intensity was observed.
The Viscosity of Tetraphenylphosphonium and -arsonium Halides in Water
Authors: Takaizumi Katsuko , Wakabayashi Toshiki 
Published: July 2006

Abstract
A viscometer, the inside of which was thoroughly coated by silicon grease, was prepared because it is difficult to measure precisely the viscosities of aqueous solutions of tetraphenylonium salts by means of a usual flow-type viscometer because of the characteristic peculiar to these solutions, that they make the glass wall water-repellent and water droplets tend to adhere to it. By comparing the relative viscosities on sucrose and LaCl3 in water obtained by the coated viscometer with those found in the literature, it was confirmed that the viscometer operates adequately. The viscosities of Ph4PCl, Ph4PBr, Ph4PNO3, Ph4AsCl, and Ph4AsBr in water have been measured at 15, 25, and 35 °C. The ionic B-coefficients determined at 25 °C are 1.09 mol−1 for both cations, while the ionic activation energies for viscous flow are +4.98 and +5.02 kJ/mol for Ph4P+ and Ph4As+ respectively.
Magnetic Circular Dichroism Studies on o-, m-, and p-Nitroanilines and o-, m-, and p-Aminobenzoic Acids
Authors: Kaito Akira , Tajiri Akio , Hatano Masahiro 
Published: July 2006

Abstract
The MCD and UV spectra of o-, m-, and p-nitroanilines and o-, m-, and p-aminobenzoic acids were measured. Some ambiguous absorption bands, which strongly overlap each other, can be separated in the MCD spectra. The Faraday B terms were calculated using wave functions obtained from the Pariser-Parr-Pople (PPP) method; the values are in good agreement with the experimental values derived from the MCD spectra. The spectral assignments are discussed not only by comparing the excited states of nitroanilines and aminobenzoic acids with those of benzene itself, but also by taking account of the electron migration between the benzene ring and the substituent groups. On the other hand, it turns out from the measurements of the MCD spectra that the zwitterion, C6H4(NH3+)CO2−, exists in aqueous solutions of o- and m-aminobenzoic acids.
Reactions of Recoil 80Br Activated by the (n, γ) Process with Some Gaseous Cyclanes (C4–C6)
Authors: Saeki Masakatsu , Tachikawa Enzo 
Published: July 2006

Abstract
The reactions of 80Br from the (n,γ) process with cyclanes (C4–C6) have been systematically investigated. The primary products formed by the 80Br-for-H reaction were excited and underwent at least two modes of unimolecular decomposition. One was the elimination of the H80Br molecule, and the other was the cleavage of the ring, giving the corresponding bromo-olefin and olefin. The former process was important particularly in the lower-pressure end. Thus, the reaction was easily suppressed by increasing the pressure. However, the latter process showed a different feature; that is, the yields of the decomposition products stayed at an almost constant level over the whole pressure range studied. This indicates that a highly excited product decomposes preferentially through a ring-cleavage reaction. When the total organic yield from each reaction system was plotted against the carbon number of the reactant molecules, a linear correlation was obtained. After some possible consideration, it was concluded that the life of the intermediate complex might play a more important role in the reaction of 80Br with cyclanes than the other factors. Some considerations about the radiolysis of the reactant molecule are also mentioned.
Photocyclization of Diphenylmaleonitrile in the Crystalline State
Authors: Ichimura Kunihiro , Watanabe Shoji 
Published: July 2006

Abstract
Diphenylmaleonitrile shows polymorphism. The crystals are photochromic and afford 9,10-dicyanophenanthrene and 9,10-dihydro-9,10-dicyanophenanthrene after prolonged irradiation. The rates of photodecomposition and properties such as photochromism, absorption and fluorescence spectra depend upon the crystal form. Photochromism results from the formation of the 4a,4b-dihydrophenanthrene which is successively converted into the photoproducts.
Ring-enlargement of Methoxynaphthalenes with Dichlorocarbene to Benzotropone Derivatives
Authors: Sato Masaru , Tsunetsugu Josuke , Ebine Seiji 
Published: July 2006

Abstract
The dichlorocarbene addition to various di- and trimethoxynaphthalenes has been investigated systematically. It has been found that the carbene addition is oriented by the 1-methoxyl group to the 3,4-double bond and by the 2-methoxyl group to the 1,2-double bond of naphthalene nucleus, and that the spontaneous cyclopropane ring-opening of the intermediate carbene-adducts leads to the preferencial formation of 2,3-benzotropone over 4,5-benzotropone derivatives. The steric effects by methoxyl group seem not to be significant in either the carbene-addition or ring-opening reaction.
Kinetics on the Carbonylation of Cyclohexene in a Methanol Solution Catalyzed by Palladium(II) Chloride–Triphenylphosphine
Authors: Yoshida Hajime , Sugita Nobuyuki , Kudo Kiyoshi , Takezaki Yoshimasa 
Published: July 2006

Abstract
Methyl cyclohexanecarboxylate was obtained in high yields by the carbonylation of cyclohexene in a methanol solution using palladium(II) chloride–triphenylphosphine as the catalyst. The effects of variables, such as initial concentration of palladium(II) chloride, pressure of carbon monoxide, and temperature, upon the rate of carbonylation were examined kinetically. A probable reaction mechanism is proposed.
New Cross Aldol Reactions. Titanium Tetrachloride-promoted Reactions of Silyl Enol Ethers with Carbonyl Compounds Containing A Functional Group
Authors: Banno Kazuo 
Published: July 2006

Abstract
It was found that, in the presence of titanium tetrachloride, silyl enol ethers selectively react with aldehyde or ketone function of various carbonyl compounds containing another functional group giving the corresponding cross aldols in good yields. The present cross aldol reaction was successfully applied to the synthesis of arturmerone, one of the volatile principles of turmeric oil.
Cation, Solvent, and Substituent Effects on the Optical Spectra of Alkali Metal Salts of Arylthiolate Anions
Authors: Miyashita Tokuji , Aoki Takao , Matsuda Minoru 
Published: July 2006

Abstract
The optical spectra of the alkali metal salts of arylthiolate anions have been studied in the two aprotic solvents, tetrahydrofuran (THF) and dimethylformamide (DMF). In the former solvent the position of the absorption maxima depends on the size of the counter cations, even at low temperatures (−72 to −76 °C); nearly linear relationships were observed between the inverse of the alkali metal radius (rc) and the wave number of the transition (\ ildeνmax) for both room and low temperatures. The intercepts for the extrapolation of both lines for 1/rc→0 agree with the \ ildeνmax of the ion pairs observed in DMF at room temperature, and the absorption maxima for this solvent are independent of the size of the counter cations. Thus, the existence of contact ion pairs in THF over the temperature range investigated and that of the solvent-separated ion pairs in DMF at room temperature were revealed. In the latter solvent, however, a hypsochromic shift was observed on lowering the temperature. The substituent effect of arylthiolate anions and the solvent effect of dimethoxyethane and dioxane on the absorption maxima are also discussed. From an inspection of optical spectral data it has been suggested that negative charge of arylthiolate anions is localized mainly on the sulfur atom.
Studies of the Surface of Titanium Dioxide. III. The Electrical Conduction and the Hydrogen Uptake
Authors: Iwaki Toru , Miura Masaji 
Published: July 2006

Abstract
The changes in the electrical conductance and the hydrogen uptake of titanium dioxide were examined with the introduction of hydrogen at 250–500 °C. The former was found to approach the equilibrium rapidly, compared with the latter above 350 °C.
Rapid Qualitative and Quantitative Microanalysis of Organic Substances by Means of a Glass-ring Oven Technique. III. Determination of a Trace Amount of Brucine in Strychnine Nitrate
Authors: Chiba Atsushi 
Published: July 2006

Abstract
A rapid and highly selective method for the microdetermination of brucine in strychnine nitrate by the ring oven technique is presented. Nitric acid was used as a developing solution and color reagent. The detection limit was 0.2 μg, and the time needed for the determination about 5 min.
Morpholinobenzoquinones: Synthesis and Reactions
Authors: Omote Yoshimori , Komatsu Toshihiko 
Published: July 2006

Abstract
Two 4-morpholino-1,2-benzoquinones (5-t-butyl- and 5-methyl-) have been prepared by the oxidation of the corresponding catechols with silver oxide. The quinones were then condensed with o-phenylenediamine to give phenazines.
Pyrolysis of S-[2-(Phenylthio-, Phenylsulfinyl-, and Phenylsulfonyl)ethyl]-N-p-tosylsulfilimine
Authors: Furukawa Naomichi , Hatanaka Toshifumi , Harada Katsumasa , Oae Shigeru 
Published: July 2006

Abstract
The β-substituent effect on the rate of Ei reaction was investigated by using S-(2-phenylthio-, phenylsulfinyl-, and phenylsulfonyl)ethyl]-N-p-tosylsulfilimines. The reactivity lies in the order of β-substituents: Ph-SO2&gt;PhSO&gt;PhS&gt;Ph. From this and the kinetic isotope effect, the rate determining step is the intramolecular β-hydrogen abstraction by the N-p-tosyl group.
Tri(hetero)substituted Carbonium Ions. XII. A Novel Ring Expansion of 1,3-Dithiolanyiium Salts into 1,3-Dithia-4-cyclohexene (1,3-Dithiine) System
Authors: Hiratani Kazuhisa , Nakai Takeshi , Okawara Makoto 
Published: July 2006

Abstract
Pyrolysis of 2-dialkylamino-4-bromomethyl-4-methyl-1,3-dithiolanylium bromides (2) readily prepared by bromination of the S-(2-methylallyl) dithiocarbamates afforded the six-membered 2-alkylimino-5-methyl-1,3-dithiines (4) in good yields. A reasonable mechanism for the novel ring expansion is presented.
Substituent Effects for the Benzene Ring on Solvolysis of 3,4-Benzotricyclo[4.3.1.01,6]dec-3-en-2-yl p-Nitrobenzoate
Authors: Ohkata Katsuo 
Published: July 2006

Abstract
Preparations of anti-4′-substituted 3,4-benzotricyclo[4. 3. 1. 01,6]dec-3-en-2-yl p-nitrobenzoates (1a–d) are described. The solvolysis of these esters was examined in 80% aqueous acetone. The rates were relatively high but the sensitivity to substituents on the benzene ring was low in comparison with other secondary systems. It is considered that σ-participation rather than π-conjugation might contribute to the rate accelerative effect. In the presence of a base, 1a–d gave anti-alcohol (12a–d) (13 to 17%), syn-alcohol (13a–d) (31 to 78%), and tert-alcohol (14a–d) (5 to 54%). The product distributions are explained in terms of a nonclassical homonaphthalenium cation (24).
Heat of Ion Exchange Reaction as Determined by Means of Flow Micro-Calorimetry. I. Cation Exchange in Aqueous System
Authors: Morimoto Tetsuo , Naono Hiromitu , N\={o}so Kuniji , Shigetomi Yasumasa 
Published: July 2006

Abstract
The applicability of flow micro-calorimetry to the measurement of ion exchange heat was investigated by use of H-form resin of Dowex 50W×4 having a low degree of cross-linking. It was found that: accurate measurement of ion exchange heat can be performed by means of flow micro-calorimetry; the data obtained include additional heat effects such as heats of invasion and dilution; the effects can be exactly analyzed experimentally and eliminated for calibrating the data of pure ion exchange heat. The ion exchange heat thus obtained for the H-form resin and alkali metal ions was found to agree with the results obtained by means of heat of immersion measurements.
Photochemistry of Cyclobutanes. I. Photolysis of Naphthalene peri-Fused Cyclobutanes in Rigid Media. Photocleavage from an Upper Triplet State
Authors: Honda Koichi , Yabe Akira , Tanaka Hideaki 
Published: July 2006

Abstract
The photocleavage reaction of naphthalene perp-fused cyclobutanes (I–IV) in rigid media is found to proceed from one (or several) of the upper triplet states. Nearly planar cyclobutanes (I–III), which were photocleaved in fluid solutions to yield acenaphthylene and 1,2-ethylenedicarboxylic acid derivatives, afford 1,8-naphthalenediacrylic acid derivatives in addition to the above products by irradiation in rigid media. Twisted cyclobutane (IV), which is considerably stable to irradiation in fluid solutions, was also photocleaved in rigid media to give dimethyl 1,8-naphthalenediacrylate. An NMR study shows that the formation of these diacrylic acid derivatives from I–IV in rigid media is considerably stereospecific. The yield ratio of diacrylic acid derivatives to acenaphthylene formed in the photolysis of I–III is independent of the viscosity of the solvents, i.e., of the matrix rigidity, but depends on other properties of the rigid solvents. A concerted mechanism is proposed for the photocleavage reaction of I–IV in rigid media in order to explain the photochemistry different from that in fluid solutions.
Hydrogen Bonding Systems Containing Hydrogen Fluoride. III. Infrared Frequency Shifts and CNDO/2 Calculations on HF-Carbonyl Compound Complexes
Authors: Tsuda Mitsunori , Touhara Hidekazu , Nakanishi Koichiro , Watanabe Nobuatsu 
Published: July 2006

Abstract
CNDO/2 calculations were carried out for the hydrogen bonded complexes between hydrogen fluoride (HF) and a series of organic compounds having a carbonyl group as a proton acceptor. Infrared spectral measurements were also made to obtain the frequency shifts of H–F stretching vibration, ΔνHF, for the same complexes in dilute carbon tetrachloride solution. Optimum geometry was obtained on the assumption of planar complex. For all the carbonyl compounds used, the interatomic angles, ∠C–O···H, were 120°–123° for the most stable conformation. The changes in the distance between H atom and F atom, ΔRHF, were in good correlation with ΔνHF obtained from IR spectra. Calculated hydrogen bond energies were also in good correlation with ΔνHF, though their absolute values were somewhat larger than those derived from experimental observations. This indicates that the CNDO/2 calculations give relatively correct enthalpy values for the hydrogen bond complexes of a given donor with a series of molecules having a common acceptor group. Other correlations of ΔνHF with properties expected to change with the hydrogen bond formation were also confirmed. These include the energies of each bond obtained by the partitioning of the total energy and the force constant of H–F bond. The electron population on the oxygen atom and other atoms participating in the hydrogen bond formation, the charge transfer, ionization potentials and dipole moment enhancements were also calculated and discussed in terms of the measure of hydrogen bond strength.
An INDO-MO Study of the Conformations and Electronic Structures of HCHOH+, CH3CHOH+, (CH3)2COH+, HCO2H2+, CH3CO2H2+, and CH3OH2+
Authors: Ohkubo Katsutoshi , Yoshida Toshiaki , Tomiyoshi Katsumi 
Published: July 2006

Abstract
INDO-SCF calculations were performed on several protonated compounds, HCHOH+ CH3CHOH+, (CH3)2COH+, HCO2H2+, CH3CO2H2+, and CH3OH2+, and also on the corresponding parent molecules in order to investigate their conformations and electronic structures. Geometric optimization resulted in reasonable conformations as compared with the previous ab initio calculations and in sufficient magnitudes of the energy differences between the rotational isomers in comparison with the NMR observations. The change in the electronic structures of the parent molecules due to protonation is also discussed by paying attention to the polarization caused by electron delocalization, hybridization at the proton-bound oxygen atom, the protonation energy, and the ionization potentials.
Solvolysis of 2,3-Cyclopenteno-4H-homochromen-4-ol Acetate: Comparison with the Corresponding Carbocyclic System
Authors: Yamaoka Hiroshi , Ohkata Katsuo , Hanafusa Terukiyo 
Published: July 2006

Abstract
A novel secondary cyclopropylphenylmethyl acetate was prepared from a chromone skeleton via homochromone derivatives in order to study solvolytic behavior. Reduction of the cyclopropyl ketone (homochromone) with lithium aluminum hydride in ether to the corresponding secondary alcohol, was found to be highly stereospecific giving only one of the geometrical isomers. The alcohol was converted into its acetate and subjected to solvolysis in 80% acetone–water. The acetate was hydrolyzed at the rate of 3×10−5 s−1 (25 °C) undergoing alkyloxygen fission. This rate constant was as high as the most reactive secondary esters in solvolyses ever reported, and about 20 times as high as the corresponding carbocyclic ester by estimation of the same leaving group. Product studies were undertaken in the presence of sodium hydrogencarbonate, and seven-membered hemiacetal was obtained in good yield. The structural characteristics of the homochromenol ester in the solvolysis are discussed and benzohomopyrylium ion, an extremely delocalized homoaromatic species, is proposed as an intermediate carbocation.
A Light Scattering Study of the Hydrolytic Behavior of Zirconium(IV) and Niobium(V) in a Hydrochloric Acid Solution
Authors: Shiokawa Yoshinobu , Sato Akiko , Suzuki Shin 
Published: July 2006

Abstract
The hydrolytic behavior of zirconium(IV) and niobium(V) in a hydrochloric acid solution was studied using light scattering measurements. It is found that the species of zirconium(IV) have a degree of polymerization of 3 and a charge per monomer unit of 1.5 in a 1.5 M hydrochloric acid solution with [Cl−]=1.7 M. Also, it was found that for a chloride ion concentration of 11 M, the species of niobium(V) are monomeric in 8–11 M hydrochloric acid and colloidal below 8 M. The effect of standing time of the hydrochloric acid solution of niobium(V) was also investigated.
Binuclear Metal Complexes. XV. Copper(II) and Nickel(II) Complexes of Binucleating Ligands Derived From 3-Formyl-salicylic Acid and Diamines
Authors: Tanaka Mitsunori , Kitaoka Michiyo , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
Copper(II) and nickel(II) complexes of the 3-formylsalicylic acid-diamine Schiff bases, H4fsaen, H4fsapn, H4fsatn, H4fsaph, and H4fsach, where en, pn, tn, ph, and ch denote ethylenediamine, propylenediamine, trimethylenediamine, o-phenylenediamine, and 1,2-cyclohexanediamine respectively, have been obtained and characterized. Binuclear copper(II) complexes, Cu2(fsaen)·2H2O, Cu2(fsapn)·2H2O, Cu2(fsatn)·2H2O, Cu2(fsaph)·H2O, and Cu2(fsach)·2H2O, show a strong antiferromagnetic spin-exchange interaction between metal ions, −2J values being more than 555 cm−1. It was revealed that Ni2(fsaen)·3H2O, Ni2(fsapn)·3H2O, Ni2(fsaph)·5H2O, and Ni2(fsach)·3H2O are novel binuclear complexes composed of one paramagnetic and one diamagnetic nickel(II) ions. On the other hand, Ni2(fsatn)·5H2O is a binuclear complex of paramagnetic nickel(II) ions. Its magnetism obeys the Curie-Weiss law in the range from liquid nitrogen temperature to room temperature with the Weiss constant of −40 K.
Successive Spectrophotometric Determination of Palladium and Platinum
Authors: Mizuno Kingo , Miyatani Giroku 
Published: July 2006

Abstract
The absorbance of the water soluble red complex of palladium(II) and 4-(2-pyridylazo)resorcinol (PAR) was measured at 513 nm. Coned hydrochloric acid and tin(II) chloride were added to an aliquot of the red solution, and both the palladium complex and the excess of PAR were decolorized by the reduction of the azo radical of PAR. The absorbance of the platinum complex with tin(II) chloride was measured at 403 nm.
Kinetics of Ligand Substitution Reaction of Some Aminopolyacetatonickel(II) Complexes with Reference to Activation Parameters
Authors: Funahashi Shigenobu , Tanaka Motoharu 
Published: July 2006

Abstract
The substitution reactions of some Ni(II)–L complexes (L: ethylenediamine-N,N′-diacetate, edda2−·, nitrilo-triacetate, nta3−·, iminodiacetate, ida2−) with 4-(2-pyridylazo)resorcinol (H2par) have been studied spectrophoto-metrically at I=0.10. Rate constant k (mol dm−3, s) at 25°C, activation enthalpy ΔH\eweq/kJ mol−1 and activation entropy ΔS\eweq/J K−1 mol−1 are respectively: 1.7×103, 58.5 and 12.5 for k[Ni2+][Hpar−]; 4.0×102, 51.8 and −22 for k[Ni(nta)−][Hpar−]; 1.0×103, 41.8 and −46 for k[(par)Ni(edda)][Hpar−]; 2.7×10−4, 109 and 30 for k[(par)Ni(edda)2−]; 5.1×103, 88 and 17 for k[(par)Ni(Hedda)−]; 1.7×103, 122 and 226 for k[Ni(ida)][Hpar−]. In terms of activation parameters some discussions are made on the effect of coordinated ligands on the lability of leaving ligands and pre-equilibrium involving partial dissociation of leaving ligands.
Photolysis of Organic Azides. II. The Photolysis of 2,2′-Diazido-biphenyl in Rigid Matrices at Low Temperatures
Authors: Yabe Akira , Honda Koichi 
Published: July 2006

Abstract
The direct, triplet-sensitized, and low-temperature photolyses of 2,2′-diazidobiphenyl have been studied. The direct irradiation afforded 4-azidocarbazole, and the triplet sensitization resulted in the predominant formation of the azo dimer, accompanied by a low yield of benzo[c]cinnoline. The photolysis in a rigid matrix at 77 K afforded benzo[c]cinnoline quantitatively. The mechanism for its preferential formation in low-temperature matrix photolysis is discussed, and we propose a biphotonic process involving a dinitrene via a mononitrene.