bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Acyl(carboxylato)bis(tertiary phosphine)palladium(II) Complexes by C–O Bond Cleavage of Carboxylic Anhydrides on Interaction with Palladium(0) Complexes. Catalytic Hydrogenation of Carboxylic Anhydrides to Aldehydes by Palladium Complexes
Authors: Nagayama Kazuhiro , Kawataka Futoshi , Sakamoto Masato , Shimizu Isao , Yamamoto Akio
Published: December 2003

Acyclic anhydrides oxidatively added to [Pd(styrene)(PMeR2)2] (R = Me, 2a; Ph, 2b) under mild conditions with C–O bond cleavage to give the corresponding trans-acyl(carboxylato)palladium complexes 3a—3h. Cyclic acid anhydrides also added to 2a to yield trans-acyl(carboxylato)palladium complexes 4a—4c, while reaction of 2a with phthalic anhydride afforded the palladalactone 4d generated via oxidative addition followed by decarbonylation. The acetyl(acetato)palladium complex 3a reacted with dihydrogen or formic acid to give acetaldehyde and acetic acid. Catalytic hydrogenation of acyclic anhydrides by a palladium complex was achieved to form the corresponding aldehydes and carboxylic acids.
Study on a New Iron Phosphate Crystalline Phase
Authors: Ai Mamoru , Ohdan Kyoji
Published: December 2003

An iron phosphate having a new crystalline phase was obtained by a partial reduction of iron(III) orthophosphate with a reducing agent, usually oxalic acid, in the presence of oxygen and a large amount of water vapor at a low temperature of 200 to 250 °C. XRD spectra of the new phase (designated as M-phase) are similar to those of clay minerals. The effects of reaction variables, such as reducing agent, reaction period, starting iron phosphate, temperature, and oxygen feed rate, on the formation of M-phase were studied. Some characterizations of this M-phase were also attempted.
π-Conjugated Polymers Bearing Electronic and Optical Functionalities. Preparation by Organometallic Polycondensations, Properties, and Their Applications
Authors: Yamamoto Takakazu
Published: December 2003

Various π-conjugated polymers have been obtained by using organometallic polycondensations mediated by organotransition metal complexes. For example, Ni(0) complex-promoted dehalogenation polycondensation of dihaloaromatic compounds X–Ar–X affords poly(arylene)s,n. Pd-catalyzed polycondensation gives poly(arylene–ethynylene)s,n. These polymers are electrochemically active, electrically conductive, and light-emitting. Their well-characterized linear structure brings about unique packing of the polymer molecules in the solid. In this paper, we describe preparation by the organometallic polycondensations, basic properties, the ordered structure in the solid, and applications for electronic and optical devices of π-conjugated polymers.rr–C≡C–Ar′–C≡C
Magnetic Properties of TTF-Type Charge Transfer Salts in the Mott Insulator Regime
Authors: Yoneyama Naoki , Miyazaki Akira , Enoki Toshiaki , Saito Gunzi
Published: December 2003

We have investigated the magnetic properties of several TTF-based Mott insulators consisting of dimerized/trimerized-donor units, which are classified into three subgroups: (1) β′-(BEDT-TTF)2X (X = ICl2, AuCl2) and (BEDT-TTF)2GaCl4 as strong dimer systems, (2) α′-(BEDT-TTF)2IBr2 salt as a weak dimer system, and (3) (BMDT-TTF)3ClO4(1,2-dichloroethane) and (BMDT-TTF)3AsF6(1,1,2-trichloroethane) as weak trimer systems. The group (1) compounds have localized spin systems with an S = 1/2 localized spin per dimer unit. In group (2), weak dimerization produces a fractional magnetic moment, which reflects the delocalization of the electrons, although the magnetism is described in terms of an S = 1/2 low-dimensional antiferromagnet. The ClO4 salt in the group (3) indicates the existence of a localized spin per trimer, whereas the trimerization is quite weak, because the inter-trimer Coulomb interactions generate the charge disproportionation resulting in the localization of electrons. The absence of the charge disproportionation brings about the feature of fractional magnetic moments in the AsF6 salts.
Cooperative Ligand Binding to Globular Protein(II). Binding of Dianionic Azo Dyes to Hen Egg White Lysozyme
Authors: Murakami Kiyofumi , Tsurufuji Katsuyoshi
Published: December 2003

The binding of five dianionic azo dyes: disodium 3-hydroxy-4-(2,4,5-trimethylphenylazo or 1-naphthylazo)-2,7-naphthalenedisulfonate, disodium 6-hydroxy-5-(4-sulfonatophenylazo or 4-sulfonato-1-naphthylazo)-2-naphthalenesulfonate, and disodium 2-(2-hydroxy-1-naphthylazo)-5-(4-sulfonatophenylazo)benzenesulfonate, to hen egg white lysozyme has been studied by an equilibrium dialysis method at pH = 7.0 (0.1 mol dm−3 phosphate buffer) and 25 °C. The measured binding isotherms showed that all of these dyes cooperatively bind to the protein, but the degree of the cooperativity differs from dye to dye. From the result that the maximum binding number (6) was about half of those for monoanionic dyes, these dye molecules were found to bind bifunctionally with their two sulfonato groups to the cationic residue pairs on the protein. The binding isotherms were analyzed on the basis of the stepwise binding scheme by a nonlinear regression analysis, and all the binding constants have been evaluated. The differences in the cooperative-binding behavior between dyes have been examined from the viewpoints of the structural difference between dyes and of the distribution of cationic residues on the protein. It was found that the hydrophobicity of each ligand plays a central role for the cooperativity, and that the orientation of the hydrophobic part of ligand in bound state as well as the distribution of charged residues on the protein also affect the binding behavior.
A Study of Electron Spin Polarization Transfer in a System of Photo-Excited Triplet Phthalocyanine and a Nitroxide Radical
Authors: Saiful Islam SM , Fujisawa Jun-ichi , Kobayashi Nagao , Ohba Yasunori , Yamauchi Seigo
Published: December 2003

Electron spin polarizations were studied for a system of excited triplet (T1) phthalocyanine (MTNPc; M = H2, Zn) and a nitroxide radical (TEMPO) in toluene solution by means of time-resolved EPR (TREPR) spectroscopy. TREPR spectra of the T1 state and the radical (R) were observed simultaneously. Spin polarizations of both signals were found to consist of two components with different decay rates. From analyses of the polarizations and the decay curves, it was found that the triplet polarizations are generated from anisotropic S1→T1 intersystem crossings and thermal populations. The initial and late polarizations on TEMPO were interpreted in terms of electron spin polarization transfer (ESPT) from T1 and a radical-triplet pair mechanism (RTPM) with a quartet precursor under J < 0 (J; exchange coupling parameter), respectively. The ESPT rate was determined and found to be dependent on temperature and the central atom(s) of MTNPc. In the H2TNPc system, the ESPT rate is much slower than the diffusion rate and axial ligation of TEMPO remarkably accelerates the ESPT rate in the ZnTNPc system.
A Deuterium-Labeling Study on the Dehydrogenation of 2-Propanol with Ru–Pt/Carbon Catalyst in the Liquid-Film State Effective for the 2-Propanol/Acetone/Hydrogen Chemical Heat-Pump System
Authors: Meng Ning , Ando Yuji , Shinoda Sumio , Saito Yasukazu
Published: December 2003

A unique feature of the dehydrogenation of 2-propanol with Ru–Pt/carbon catalyst in the liquid-film state has been elucidated by means of various kinds of deuterium labeling. A quite large kinetic isotope effect for 2-propanol-d8 (kH/kD = 14.6) suggests that fission of the methine C–H bond in the isopropoxy intermediate is rate-determining in the overall process. The dominant formation of H2 for 2-propanol-O-d1 is explained in terms of rapid scrambling of deuterium together with a large kinetic isotope effect for fission of the methine C–D bond. This picture is supported by both the absence of an appreciable kinetic isotope effect for 2-propanol-O-d1 and the deuterium distribution among the liquid-phase components. The extent of hydrogen transfer from 2-propanol to acetone-d6 during the dehydrogenation reaction suggests suppression of the inhibitive adsorption of acetone, leading to a high catalytic activity in the region of high acetone concentration, which is essential for a 2-propanol/acetone/hydrogen chemical heat-pump system with high thermal efficiency.
Monomolecular Layer of the Alkylated Cytochrome b562 Formed at the Air/Water Interface
Authors: Kobayashi Kazutoshi , Nagamune Teruyuki , Furuno Taiji , Sasabe Hiroyuki
Published: December 2003

A method is provided for forming a monomolecular layer of cytochrome b562 at the air/water interface by introducing dialkyl chains onto a water-soluble cytochrome b562. The purpose of the present study was to form densely and/or regularly packed two-dimensional arrays of protein molecules. Protoheme, which is a prosthetic group of cytochrome b562, was extracted from cytochrome b562, and then dialkylated(dioctadecylated) with the synthetic-chemical procedure. This dioctadecylated heme was reconstituted with apo-cytochrome b562 in dimethyl sulfoxide–water mixtures in vitro. The reconstitution reaction was successful when the reaction time was greater than 50 min, the dimethyl sulfoxide content was 63% and the temperature was maintained at 10 °C. Surface pressure–area per molecule isotherm of the reconstituted dioctadecylated holo-cytochrome b562 was measured and this clearly shows the monolayer formation of the water-soluble protein on the water subphase. The coefficient of compressibility of the protein film was estimated and is discussed. It is found that reconstituted dioctadecylated holo-cytochrome b562 forms a stable and closely packed monomolecular layer on the water surface.
A Better Synthesis of Biruthenocene and Molecular Structures of [RuIICp(C5H4C5H4)CpRuIVNCC2H5](BF4)(B2F7)CH3NO2, [RuIICp(2,2′-bipyridine)(p-benzoquinone)]BF4 and Related Salts
Authors: Watanabe Masanobu , Sato Masaru , Nagasawa Akira , Kai Masahiro , Motoyama Izumi , Takayama Toshio
Published: December 2003

An interesting dimerization occurred during the oxidation of ruthenocene with an excess of p-benzoquinone containing BF3·Et2O (abbreviated p-Bq/BF3) in a mixed solution of benzene and hexane, which gave biruthenocenium(BF4)2 (A) in 89% yield. Reduction of A with TiCl3 gave biruthenocene in a good yield (68% from ruthenocene), which is the most elegant preparation of biruthenocene. Recrystallization of A from CH3NO2 containing C2H5CN gave a mixed-valence salt 3 formulated as [RuIICp(C5H4C5H4)CpRuIVC2H5CN](BF4)(B2F7)CH3NO2 in which C2H5CN coordinated to the RuIV center. The crystal of 3 was found to be monoclinic, space group P21/a, a = 9.8930(8), b = 15.445(3), c = 19.728(3)Å, β = 92.57(1)°, V = 3011.3(1) Å3, Z = 4, and the final R = 0.075and Rw = 0.093. Recrystallization of A from CH3NO2 containing 2,2′-bipyridine and p-benzoquinone gave a yellow planar salt 4 formulated as [RuIICp(2,2′-bipyridine)(p-benzoquinone)]BF4 in which the olefin moiety of p-benzoquinone coordinated to the RuIV center in η2-form. Salt 4 was also synthesized by the reaction of bromoruthenocenium (BF4) with p-benzoquinone and 2,2′-bipyridine in CH3NO2. The crystal of 4 was found to be monoclinic, space group P21, a = 8.516(3), b = 9.934(4), c = 11.995(4) Å, β = 103.78(1)°, V = 985.6(6) Å3, Z = 2, and the final R = 0.040 and Rw = 0.050. The same p-Bq/BF3 oxidation of osmocene gave an orange red salt 5 formulated as [Cp2OsIVFBF3]BF4 in which one of the F− atom of the BF4− ion coordinated to the OsIV center. The crystal of 5 was found to be monoclinic, space group P21/c, a = 8.065(1), b = 12.048(1), c = 16.730(2) Å, β = 94.497(8)°, V = 1620.6(3) Å3, Z = 4, and the final R = 0.055 and Rw = 0.070.
The γ-Silicon Effect. I. Solvent Effects on the Solvolyses of 2,2-Dimethyl-3-(trimethylsilyl)propyl and 3-(Aryldimethylsilyl)-2,2-dimethylpropyl p-Toluenesulfonates
Authors: Nakashima Tohru , Fujiyama Ryoji , Fujio Mizue , Tsuno Yuho
Published: December 2003

The solvolysis rates of 2,2-dimethyl-3-(trimethylsilyl)propyl and 3-(aryldimethylsilyl)-2,2-dimethylpropyl p-toluenesulfonates were measured in a wide variety of solvents at 45 °C. The solvent effects were analyzed by using the Winstein–Grunwald equation. The solvent effects observed did not give simple linear correlations with the 2-adamantyl YOTs parameter, but showed dispersion behavior in a series of binary solvents. The m values of 0.59—0.67 were remarkably lower than unity for the limiting kc solvolysis of 2-adamantyl p-toluenesulfonate. The deviation patterns could not be interpreted in terms of nucleophilic assistance by the solvent. The dispersion behavior with reduced m values was found to be more significant for the 3-(aryldimethylsilyl) than for the 3-(trimethylsilyl) derivatives and was compatible with the delocalization of the incipient cationic charge by participation of the Si–Cγ bond in the rate-determining step. An extended dual-parameter treatment, log (k/k80E) = mcYOTs + mΔYΔ, successfully correlated such γ-silyl assisted solvolyses. The MΔ values of 0.24—0.49 so obtained, where MΔ = 0.51mΔ/(mc + 0.51mΔ), are a measure of the extent of charge delocalization, suggesting that the γ-silyl group in the percaudal interaction is more effective in delocalizing the cationic charge than the alkyl group in C–C σ-participation, but less so than π-assisted interaction by the β-aryl group.
Three New Quassinoid Derivatives and Related Compounds as Antitumor Promoters from Brucea javanica
Authors: Rahman Shakila , Fukamiya Narihiko , Tokuda Harukuni , Nishino Hoyoku , Tagahara Kiyoshi , Lee Kuo-Hsiung , Okano Masayoshi
Published: December 2003

Three new quassinoid derivatives [desmethyl-brusatol (1), desmethyl- bruceantinoside A (2), and butyl ester (3) of bruceoside D (6)] were isolated from the extract of Brucea javanica. Their structures were elucidated by spectral evidence and chemical transformation to or from known compounds. The three new quassinoid derivatives and related compounds have shown inhibitory effects against TPA-induced Epstein–Barr virus early antigen (EBV-EA) activation.
Association Behavior of 1-Pyrenyl Pendants Introduced into the Papain Active Site
Authors: Sakurai Tadamitsu , Miyata (nee Nojima) Kazue , Watanabe Kenichiro , Kubo Kanji , Inoue Hiroyasu
Published: December 2003

1-(Bromoacetyl)pyrene (BAP) was found to selectively alkylate the cysteine-25 residue (Cys-25) of papain, inactivating the enzyme. A comparison of the spectroscopic behavior of BAP-modified papain with that of the reference compound, 1-{[2-(acetylamino)ethylthio]acetyl}pyrene (TAP), showed that the pyrenecarbonylmethyl pendant (covalently bound to Cys-25 in a 1 : 1 stoichiometric ratio) gives a new absorption around 390 nm and a long-wavelength fluorescence at 465 nm, which are both characteristic of an associated dimer. Effects of solvent and concentration on the absorption and emission spectra of TAP as well as the derivatized enzyme substantiate the dimer formation in the ground state. The finding that the pendant-carbonyl-13C carbon signal undergoes a large upfield shift in the papain active site, as compared to the corresponding signal of 13C-labeled TAP, confirms that the pyrenecarbonyl moiety adopts an enolate-type resonance structure (making the pyrene ring electron-deficient) on formation of a strong hydrogen bond to the neighboring amino acid residue(s). It is proposed that the significant contribution of the enolate-type resonance structure is a driving force for promoting the dimerization of the pyrenecarbonylmethyl reporter group attached to Cys-25 mainly through dipole–dipole and hydrophobic interactions. On the other hand, the introduction of the imino spacer between the 1-pyrenyl carbon and the acetyl carbonyl carbon in BAP-derived pendant greatly weakened a tendency to produce a pendant dimer in the ground state, providing a piece of evidence in support of this proposal.
Reactions of 1,8-Dimethoxy-9-phenylxanthen-9-ol in the Presence of an Acid, and Its Basicity
Authors: Wada Masanori , Kirishima Katsuhiko , Oki Yuichi , Miyamoto Masafumi , Asahara Masahiro , Erabi Tatsuo
Published: December 2003

In the presence of a catalytic amount of acid, the title xanthenol (1) reacted in acetone to give 1,8-dimethoxy-9-phenylxanthen-9-ylmethyl methyl ketone. Analogous reactions were observed for ethyl methyl ketone and acetophenone, but not for diethyl ketone. Propanal and butanal also reacted to give 2-(1,8-dimethoxy-9-phenylxanthen-9-yl)propanal and 2-(1,8-dimethoxy-9-phenylxanthen-9-yl)butanal, respectively. In hot primary and secondary alcohols, 1 was reduced to give 1,8-dimethoxy-9-phenylxanthene. 1 also reacted with methoxybenzenes, phenol, and N-alkylanilines to give 9-aryl-1,8-dimethoxy-9-phenylxanthenes. The basicity of 1, or the stability of the carbenium ion (pKR+ = −0.81), was measured in hydrochloric acid and compared with those of related 9-arylxanthen-9-ols, such as 1,8-dimethoxy-9-(2,6-dimethoxyphenyl)xanthen-9-ol (1.14), 9-(2,6-dimethoxyphenyl)xanthen-9-ol (4.80) (8), and 9-phenylxanthen-9-ol (0.75). The drastic differences in the reactivities and the basicity between 1 and 8 were attributed to a steric effect rather than an electronic effect.
Copper-Mediated Nucleophilic Displacement Reactions of 1-Haloalkynes. Halogen-Halogen Exchange and Sulfonylation
Authors: Abe Hajime , Suzuki Hitomi
Published: December 2003

Some copper(I) and (II) compounds have been found to act as efficient reagents for the nucleophilic displacement of 1-haloalkynes. Copper(I) iodide smoothly transforms 1-bromoalkynes (2) into 1-iodoalkynes (1) which, on further treatment with copper(II) bis(arenesulfinate), are readily converted to the corresponding alkynyl aryl sulfones (4). The kinetic data of the halogen exchange between (4-chlorophenyl)ethynyl bromide (2d) and CuI have shown that the reaction is linearly dependent on the concentrations of both compounds. A mechanistic pathway involving the single electron transfer between 1-haloalkynes and copper(I) salt has been proposed for the present copper-assisted halogen exchange reaction at acetylenic carbon atom.
Synthesis of Disilacycloalkenes by Ruthenium Alkylidene Catalyzed Ring-Closing Metathesis (RCM) Reaction of α,ω-Bis(allyldimethylsilyl)-Substituted Compounds
Authors: Hoshi Takashi , Yasuda Hiroyuki , Sanji Takanobu , Sakurai Hideki
Published: December 2003

Ruthenium-catalyzed ring-closing metathesis (RCM) reactions of various α,ω-bis(allyldimethylsilyl)-, bis(dimethylvinylsilyl)-, and bis(dimethylvinyloxysilyl)-substituted compounds are examined. The steric and electronic influences of the substrates on the RCM reaction were discussed. Although the successful ring-closing reactions are limited to seven- and eight-membered rings, disilacycloalkene derivatives constructed with –SiMe2–CH2–SiMe2–, –SiMe2–(CH2)2–SiMe2–, –SiMe2–O–SiMe2–, –SiMe2–N(Ph)–SiMe2–, and a vinylene unit in the ring system were obtained in good to reasonable yields under the mild reaction conditions. The limitation of the reactions is mainly ascribed to Si–C and Si–Si bonds being longer than the C–C bond in the ring system.
A New Efficient Method for S–CH2–S Bond Formation and Its Application to a Djenkolic Acid-Containing Cyclic Enkephalin Analog
Authors: Ueki Masaaki , Ikeo Takayoshi , Hokari Kumiko , Nakamura Keiko , Saeki Akihiko , Komatsu Hiroshi
Published: December 2003

An efficient methylene insertion reaction to construct an S–CH2–S bridge between two cysteine residues occurred when the thiol-protecting dimethylphosphinothioyl (Mpt) group of Z–Cys(Mpt)–OMe was removed with tetrabutylammonium fluoride hydrate in CH2Cl2. The thiol-free form gave similar results, albeit the yields were somewhat lower. In both cases, the best yields were obtained using 2 molar amounts of the reagent. Higher amounts of the reagent reduced the yield because of dehydroalanine formation. In the case of penicillamine, the thiol-free form was better in reactivity than the S-Mpt form, which required double the amount of the reagent to give the same yield. The reaction was successfully used in a synthesis of a cyclic enkephalin analog with the S–CH2–S bridge.
Photoreactive and Inactive Crystals of 1-Alkylthymine Derivatives
Authors: Tohnai Norimitsu , Inaki Yoshiaki , Miyata Mikiji , Yasui Nobuyoshi , Mochizuki Eiko , Kai Yasushi
Published: December 2003

Two kinds of crystal structures were found for 1-octylthymine from X-ray structure analysis: Structure I was obtained from Crystal I recrystallized from ethyl acetate, and Structure II was obtained from Crystal II recrystallized from ethanol. The thymine bases in Crystal I had high reactivity for photodimerization. Crystal II, however, was inactive for the photodimerization of thymine bases. This paper presents the crystal structure of 1-octylthymine crystallized from ethanol (Crystal II) by X-ray crystal structure analysis. Thymines in Crystal II were concluded to be inactive for photodimerization because of unsuitable orientation of thymine bases in the crystal and because of insufficient space for rotation of thymine during photodimerization.
Thermal Behavior of Diynes with Formally Conjugated Heteroaromatic Sidegroups
Authors: Sarkar Abhijit , Talwar Satya S
Published: December 2003

Diynes with heteroaromatic sidegroups directly linked to the acetylenic backbone were found to show liquid crystalline behaviour upon heating. Thus, 1,4-di(2-thienyl)-1,3-butadiyne, 1,4-di(3-thienyl)-1,3-butadiyne, 1,4-di(3-benzo[b]thienyl)-1,3-butadiyne, 1-(3-quinolyl)-4-(2-thienyl)-1,3-butadiyne, 1-(3-quinolyl)-4-(3-thienyl)-1,3-butadiyne, and 5-(2-thienyl)-2,4-pentadiyne-1-ol were investigated for their thermal behavior. These diynes also underwent polymerization in their liquid crystalline state, although the polymers so formed did not show liquid crystalline behavior. It was found that the S-atom of the heteroaromatic moieties tends to play a role in making the diynes show liquid crystalline behavior. Differential scanning calorimetry, thermogravimetric analysis and hot stage microscopy were used to investigate the liquid crystalline nature of the diynes. All of them showed a nematic liquid crystalline phase upon annealing, whereas smectic phase was totally absent.
Synthesis and Evaluation of Superior Calcium and Mercury Transport by Simple Monocarboxylic Acids of Kemp’s Triacid
Authors: Hirose Takuji , Wang Zhen-He , Baldwin Bruce W , Uchimaru Tadafumi , Kasuga Kazuyuki
Published: December 2003

Transport abilities of alkaline earth, transition, and heavy metal ions were examined for three kinds of disubstituted monoacid derivatives of Kemp’s triacid as transport agents for a liquid membrane system. Diamide derivatives showed high transport ability for CaII over MgII, with selectivity ratios greater than 25. Imide monoacids were also CaII selective. For transition and heavy metal ions, all monoacids including diester monoacid showed very high HgII transport, but with different selectivities depending on the functional group. High HgII/AgI ( = 24), HgII/CuII ( = 194), and HgII/PbII ( = 85) selectivities were observed for diamide, diester, and imide monoacids, respectively. The transport mechanisms are discussed for alkaline earth, transition, and heavy metal ions utilizing ion chromatography analysis of anions co-transported.
Synthesis and Chemical Properties of Metalladithiolene and Metalladithiazole Rings. Unique Reactions Due to Coexistence of Aromaticity and Unsaturation
Authors: Sugimori Akira , Akiyama Takeo , Kajitani Masatsugu , Sugiyama Toru
Published: December 2003

The syntheses and unique chemical properties of metalladithiolene rings (especially in [CpM(S2C2R1R2)]-type complexes) found by our research group are reviewed. The constructions of metalladithiolene rings by one-pot reaction among [CpM(CO)n], alkyne, and elemental sulfur and by the reaction between [CpM(CO)n] and sulfur-containing heterocyclic compounds are described. Several ionic and radical substitution reactions are presented. The substitutions by carbon-centered and sulfur-centered radicals occur in the metalladithiolene rings. Benzoyloxy-substitution by dibenzoyl peroxide (BPO) and succinimido-substitution by N-halosuccinimides (NXS) proceed via ionic mechanisms induced by the heterolysis of BPO and NXS in the interaction with the lone pair electrons at the sulfur atoms. These substitutions are due to the aromatic character of the metalladithiolene rings. The unique addition reactions due to the unsaturated character of the metalladithiolene rings are also described. Diazo compounds and azides react with [CpM(S2C2R1R2)]-type metalladithiolenes to form alkylidene- and imido-bridges between metal and sulfur. Quadricyclane and dimethyl acetylenedicarboxylate add between metal and sulfur. These addition products undergo a variety of types of dissociation: by heating, illumination, or electrochemical redox.
Femtosecond Regular Reflection Spectroscopic Study on Ultrafast Photoinduced Heat Generation in Copper Phthalocyanine Solid
Authors: Hosokawa Yoichiroh , Watanabe Kazuya , Asahi Tsuyoshi , Fukumura Hiroshi , Masuhara Hiroshi
Published: December 2003

A femtosecond regular reflection spectroscopic system was developed and applied to a β-copper phthalocyanine (β-CuPc) pellet. Transient regular reflection spectra were converted into extinction coefficient change (Δk) ones, which correspond to transient absorption spectra, by using Kramers-Kronig transformation. The Δk spectrum observed immediately after excitation was assigned to the excited state of β-CuPc solid, which relaxed by an exciton–exciton annihilation. The spectra remaining over several nanoseconds were assigned to a hot band due to a vibrationally excited state of the electronically ground state. We have clarified that a fast photothermal conversion process is induced by the exciton–exciton annihilation, which was analyzed by a simulation using a time dependent rate (proportional to t−1/2) of the annihilation.
Acid–Base and Monomer–Dimer Equilibria of Methylene Blue in Dip-Coated Thin Films
Authors: Nishikiori Hiromasa , Nagaya Satoshi , Tanaka Nobuaki , Katsuki Akio , Fujii Tsuneo
Published: December 2003

Thin films including Methylene Blue (MB) have been prepared. They were dip-coated using the sol–gel reaction of tetraethyl orthosilicate (TEOS). The absorption spectra of the individual thin films have been observed as a function of time after preparation of the films. The relative contributions of the monomer (MB+), dimer ((MB+)2), and protonated species (MBH2+) existing in the individual thin films to the total absorption spectra were obtained. The acidity in each film was estimated from the relative abundance of the MBH2+. In the case of the system including a large amount of HCl as a catalyst, MB formed MBH2+ in addition to MB+ and (MB+)2 just after preparation of the films. However, MBH2+ in every film disappeared 5—10 min after the preparation. The formation of MBH2+ indicates the very high acidity around MB molecules. In each film just after the preparation, the rate of the hydrolysis became slower and the concentration of the released proton remarkably increased because the polycondensation rapidly proceeded with the contraction in volume. Although growing –SiOSi– networks prevent the evaporation of the acid together with water and ethanol, the decrease of MBH2+ indicates the lowering of acidity in the films due to the evaporation.
Study of a New Crowned Azobenzene: Photochromism and Langmuir?Blodgett Film [Retracted]
Authors: Li Hongqi , Yao Zhongqi , Liu Renhua , Tan Ganzu , Yu Xianda
Published: December 2003

A new crowned azobenzene derivative, 4-[(aza-15-crown-5)-13-yl]-4′-methoxyazobenzene (APCM), was synthesized and incorporated into a β-cyclodextrin derivative, heptakis(6-undecylamino-6-deoxy)-β-cyclodextrin (ACD). The crowned azobenzene showed a large red shift of the maximum UV-vis absorption wavelength upon 254 or 365 nm irradiation. The results from UV-vis and ESR spectral analyses revealed that the photochromic mechanism for the crowned azobenzene was a photoinduced intramolecular charge-transfer (CT) process. APCM/ACD formed a stable Langmuir monolayer at the air–water interface. A multilayer Langmuir–Blodgett (LB) film was constructed from APCM/ACD monolayers, which showed a nonlinear polarisability (β) of 4 × 10−29 esu after one month of storage.
Semi-Empirical Calculations of the Transport Properties of Eight Binary Gas Mixtures at Low Density by the Inversion Method: Part II
Authors: Ghatee Mohammad Hadi , Papari Mohammad Mehdi , Boushehri Ali
Published: December 2003

The viscosities, diffusion coefficients, and thermal diffusion factors for eight binary gas mixtures: He + SF6, He + CO2, He + O2, He + N2O, CH4 + SF6, CH4 + CO2, CH4 + O2, and CH4 + N2O were determined from the extended law of corresponding states for viscosity using the inversion technique for the corresponding interaction potential energies. Lennard–Jones (12-6), (LJ (12-6)), potential function is used as the initial model potential required by the technique. The interaction potential energies from this inversion technique reproduce the viscosities within 1%, the diffusion coefficients within 5%, and the thermal diffusion factors within 25%. The interaction potential energy determined from this inversion method for He + SF6 system is compared with other methods.
Monocyclic Heterocyclic Biomolecules Conform to the Rule of Topological Charge Stabilization
Authors: Aihara Jun-ichi , Ishida Toshimasa
Published: December 2003

Some difficulty is felt in applying the rule of topological charge stabilization (TCS rule) to monocyclic heterocyclic biomolecules, such as substituted pyrroles, furans, thiophenes, imidazoles, and thiazoles. We found that the TCS rule can be reasonably extended to include such heterocycles. We propose that, if all carbon atoms in a hydrocarbon anion are charged uniformly, one or more of them can be replaced by eletronegative heteroatoms to stabilize the π-electron system. Thus, it is still true that the TCS rule dominates general biosynthesis and geochemistry. Coenzyme PQQ (pyrroloquinolinequinone) satisfies the TCS rule in both its oxidized and reduced states. Even apparently antiaromatic 1,2-dithiin seems to conform to the TCS rule.
Phase Transitions of Pure Long-Chain α,ω-Alkanediols from C13 to C24
Authors: Ogawa Yoshihiro , Nakamura Naotake
Published: December 2003

A series of pure α,ω-alkanediols HO-(CH2)n-OH (n = 13—24) was prepared and the effects of chain length and parity on their thermal properties were investigated. Crystal structures of odd α,ω-alkanediols were orthorhombic, while those of even α,ω-alkanediols were monoclinic. α,ω-Alkanediols with n = 13—24 showed solid–solid transitions except for n = 14. The solid–solid transition was found to be reversible. Transition temperatures from the crystal to the high-temperature phase indicated distinctive and regular odd-even effects, while from the high-temperature phase to the liquid, slightly odd–even effects were noted. The average enthalpy increment per methylene unit from the crystal to liquid for odd α,ω-alkanediols was 4.0 kJ mol−1. Enthalpies of transition from crystal to high-temperature phases considerably exceeded those of n-alkanes. HOC13H26OH lost 62% total enthalpy at the solid–solid transition and only 38% at melting. High-temperature phases of α,ω-alkanediols may possibly be liquid crystal phases.
Copper(II) Ion-Catalyzed and Molecular Packing-Dependent Dimerization of Pyridoxal 5-Phosphate–Pyridoxamine 5-Phosphate Schiff Base as a Structural Model for in Vitro Transformation of Amino Acid by Pyridoxal 5-Phosphate: X-Ray Crystal Structural Investigation
Authors: Ishida Toshimasa , Manabe Reijirou , In Yasuko , Takashima Hajime , Kitamura Kunihiro , Wakahara Akio
Published: December 2003

X-Ray crystal structures of the end products, obtained by in vitro Cu(II)-mediated transamination reaction of l-alanine by the vitamin B6 coenzyme, show that the Cu(II) complex of pyridoxal 5-phosphate–pyridoxamine 5-phosphate (PLP–PMP) Schiff base (Cu·C16H18N3O10P2, 1) is spontaneously covalent-bonded between the azomethine carbons of two neighboring Schiff bases with the (R,R)- or (S,S)-configuration, and is led to a dimer structure of the trans (2a) or cis (2b) conformational isomer around the covalent bond, depending on the molecular packing in the crystal. Since crystals of 1 have been obtained, the C–C covalent bond could be formed at the crystalline state. Molecular orbital calculations suggest that the electronic structure of the Schiff base is significantly delocalized by the coordination of the copper(II) ion; also the vertical stacking of 1 aromatic rings, which is suitable for the dimer formation, is promoted by electrostatic interactions between the Pz orbitals of the azomethine nitrogen and carbon atoms. Based on the transformation of 1 to 2a/2b, we propose a transition pathway via the aldimine or ketimine dimer form concerning the metal- and PLP-catalyzed biomimetic transformation of amino acid.
A Reason of Linear Additivity of ‘π Energy’ in Polyenes
Authors: Ichikawa Hiroshi , Yoshida Atsushi , Kagawa Hirotaka , Aihara Jun’ichi
Published: December 2003

The Hückel molecular orbital theory stands on the approximation that a π electron moves in the average field of potentials from other (σ and π) electrons and nuclei, where the nuclear–nuclear repulsion energies are not taken into consideration. A strange property of the Hückel energy is that it has a linear additivity with respect to the ethylene unit in polyenes. Based on the molecular virial theorem and a previous finding that the Hückel energy represents the kinetic energy of π electrons (π), the linearity problem is reduced to two points: (1) why the ratio of π to the total kinetic energy () is constant in linear polyenes and (2) why  is linear with respect to the ethylene unit.

We treated the second problem using a newly developed energy-partitioning technique, and found that the total atomic interactions are well localized around the region between neighboring atoms in spite of strong long-range interactions of the individual potential-energy terms. If we adopt the fact that π/ is constant, the riddle of why π or Hückel energy includes the information on the nuclear configuration is also understood through the virial theorem.
Temperature- and Pressure-Induced Phase Transition in Tetrafluoro-1,4-benzoquinone Crystal
Authors: Ikuta Akihiko , Suzuki Yoshio , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi
Published: December 2003

The temperature and pressure effects on the Raman-active inter- and intramolecular vibrations of tetrafluoro-1,4-benzoquinone crystal were studied. The diffuse Raman bands observed in the intermolecular vibrational spectrum could be resolved with decreasing temperature or increasing pressure. The observed spectral structure due to the intermolecular vibrations changed as the temperature fell and also as the pressure increased. The vibrational frequencies of some intramolecular vibrational bands changed discontinuously under a certain pressure when the applied pressure was increased. The calculated pressure-induced frequency shifts for these vibrations deviate from the observed frequency shifts under high pressure. The DSC curve shows no distinct endothermic or exothermic peaks at temperatures between 77 and 520 K. These observations indicate that a displacive phase transition takes place at a temperature of around 180 K under 1 atm or under a pressure of 0.8 GPa at 300 K in a tetrafluoro-1,4-benzoquinone crystal.
The Binding Characteristics of Conventional and α,ω-Type Ionic Surfactant Mixtures to Polyion
Authors: Satake Iwao , Fukunaga Kenichi , Miyazaki Atsuko , Maeda Tamaki , Hayakawa Katumitu
Published: December 2003

The binding isotherms of decyltrimethylammonium bromide (DeTAB) to poly(potassium vinyl sulfate) were determined potentiometrically in mixed solutions with N,N,N,N′,N′,N′-hexamethyl-1,20-icosanediammonium dibromide (ETMAB) and 1,1′-1,20-icosanediylbispyridinium dibromide (EPB). In both systems, an addition of the α,ω-type surfactant causes a remarkable decrease in the slope of the binding isotherm of DeTA+. In addition, the binding isotherm tended to shift regularly to a low concentration range with increasing concentration of the α,ω-type surfactant. A regular solution treatment of the mixed clusters on the polyion chain suggests that substantially all of the added α,ω-type ions bind to the polyion under our experimental conditions. The observed binding isotherms can well be reproduced with interchange energies of −0.6 kT for DeTA+–ETMA2+ and −1.6 kT for DeTA+–EP2+ pairs in the mixed clusters, respectively.
Thermodynamic and Magnetic Studies on the Formation of gem-Diol in an Aldehyde–Water Mixture
Authors: Nakazawa Yoshinori , Takahashi Fujio
Published: December 2003

A thermodynamic study on the formation of gem-diol in an aldehyde–water mixture was carried out by NMR measurements. The equilibrium constants for the formation of gem-diol were determined at 280.3—298.4 K. From the relationship between the equilibrium constant and the temperature, ΔH and ΔS were obtained to be −20.4 kJ mol−1 and −101 J K−1 mol−1 in the case of acetaldehyde, and −22.9 kJ mol−1 and −110 J K−1 mol−1 in the case of propionaldehyde, respectively. It is difficult to isolate the gem-diol from an aldehyde–water mixture. The diamagnetic susceptibility of gem-diol was estimated by measuring the susceptibilities of the aldehyde–water mixture at various molar ratios. The diamagnetic susceptibility was determined using Gouy’s method. The diamagnetic susceptibilities of 1,1-ethanediol and 1,1-propanediol were −39.1 × 10−6 cm3 mol−1 and −51.5 × 10−6 cm3 mol−1 at 287 K, respectively.
Structural Evidence for an Intramolecular CH–π Interaction in Ternary Metal (Cu(II), Pd(II)) Complexes Involving o-/m-/p-Methyl Substituted Phenylalanine and 1,10-Phenanthroline
Authors: Mizutani Mamoru , Tomosue Shinya , Kinoshita Hitoshi , Jitsukawa Koichiro , Masuda Hideki , Einaga Hisahiko
Published: December 2003

The existence of a CH-π interaction has clearly been demonstrated by use of the ternary metal (Cu(II), Pd(II)) complexes involving o-/m-/p-methyl substituted l-phenylalanine (l-o-mPhe, l-m-mPhe, l-p-mPhe) and 1,10-phenanthroline (phen) on the basis of 1H NMR, electronic absorption, and CD spectroscopies, and X-ray diffraction method. The crystal structure of [{Cu(p-mPhe)(phen)}2{Cu(phen)2}(μ3-CO3)](ClO4)2 has revealed a marked structural feature suggesting CH-π and/or π–π interactions, although [Cu(l-o-mPhe)(phen)(H2O)]ClO4 does not show any interaction. CD spectra in the d–d region for [Cu(l-o-mPhe)(phen)]ClO4, [Cu(l-m-mPhe)(phen)]ClO4, and [Cu(l-p-mPhe)(phen)]ClO4 in aqueous solution have exhibited an obvious negative Cotton effect, and the magnitudes have significantly been reduced in dioxane/water in the order: [Cu(l-p-mPhe)(phen)]ClO4 ≤ [Cu(l-m-mPhe)(phen)]ClO4 < [Cu(l-o-mPhe)(phen)]ClO4. 1H NMR spectra of [Pd(l-o-mPhe)(phen)]ClO4, [Pd(l-m-mPhe)(phen)]ClO4, and [Pd(l-p-mPhe)(phen)]ClO4 have exhibited larger ring current shifts for m- and p-CH3 protons of the latter two complexes both in D2O and in DMSO-d6, whereas o-CH3 protons for the former complex do not. The magnitudes have greatly been reduced in this order: [Pd(l-p-mPhe)(phen)]ClO4 ≤ [Pd(l-m-mPhe)(phen)]ClO4 in D2O–dioxane-d8, but not for [Pd(l-o-mPhe)(phen)]ClO4.
Emission Quenching of Double-Complex Salt Crystals of [RuL3]3[Co(bpydc)3]2·nH2O (L: 2,2′-Bipyridine, 2,2′-Bipyrazine or 4,4′-Dimetyl-2,2′-bipyridine, and bpydc: 2,2′-Bipyridine-4,4′-dicarboxylate)
Authors: Uddin Md Jamal , Yoshimura Akio , Ohno Takeshi
Published: December 2003

The emission quenching of double-complex salt crystals, [RuL3]3[Co(bpydc)3]2·nH2O (L: 2,2′-bipyridine, 4,4′-dimetyl-2,2′-bipyridine or 2,2′-bipyrazine and bpydc: 2,2′-bipyridine-4,4′-dicarboxylate), were studied over a wide temperature range. Electron-transfer (ET) quenching of the phosphorescent emission of RuL32+ in the presence of an anionic Co(bpydc)33− and the yields of ET-product formation were examined for aqueous solutions by means of laser transient-absorption spectroscopy. The high fraction of ET-product formation in the quenching and the slow rate of the reverse ET reaction establish the mechanism of emission quenching of Ru(bpy)32+ and Ru(dmbpy)32+ in the solution. The decreasing rate of uni-molecular quenching within the encounter complexes formed between 3[RuL3]2+ and Co(bpydc)33−, Ru(bpy)32+ > Ru(dmbpy)32+ > Ru(bpz)32+, was found for emission quenching of double-complex salt crystals. The magnitude and temperature independence of the emission quenching rate for the double-complex salt are discussed from an ET point of view, except for Ru(bpz)32+.
Complex Metal Halide Oxides (3). Structural Characteristics and Catalytic Performance of Lanthanum-Substituted X1X2 Type Complex Bismuth Chloride Oxides
Authors: Lin Sui Wen , Ueda Wataru
Published: December 2003

The replacement of bismuth ions with lanthanum ions in the cation-oxygen sheets of layered Bi3SrCl3O4 catalyst promoted the activity for the oxidative dehydrogenation of ethane prominently. The structure of Bi3−nLanSrCl3O4 remained in the X1X2 structure by the replacement untill the lanthanum ion content (n) was in excess of 0.75, and the value of a of the sub-unit cell and the value of c representing thickness of the layer structure were changed reversely. The Rietveld analysis of the Bi2.25La0.75SrCl3O4 catalyst revealed that the thickness of the double chlorine sheet decreased when the coordination number of lanthanum ion facing the double chlorine sheet increased from 8 to 9, suggesting that the interaction between the metal-oxide sheet and the chlorine sheet became stronger. This is supported by a reduced binding energy of chlorine in Bi2.25La0.75SrCl3O4 observed by XPS analysis. The activation of structural chlorine into a radical form is promoted by the replacement with lanthanum ion, which turns out to cause an increase of the oxidation activity of ethane.
A Novel Decyanogenative Coupling of α-Cyanoimines Mediated by Samarium. A Facile Route to α-Diketimines
Authors: Thakur Ashim J , Prajapati Dipak , Sandhu Jagir S
Published: December 2003

Conversion of α-cyanoimines 1 into α-diketimines 2 has been achieved successfully by using samarium diiodide in dry tetrahydrofuran in high yields without formation of anilinoanil 3, 1,2-diamines 4 or anilides 5.
Studies on the Fast Drying Hybrid Urushi in Low Humidity Environment
Authors: Nagase Kisuke , Lu Rong , Miyakoshi Tetsuo
Published: December 2003

Four kinds of hybrid urushi, fast drying in a low humidity environment, have been synthesized with an organic silicone compound. Their characteristics and drying mechanism have been analyzed based on IR and RPT measurements.
Self-promoted Aldol Reaction between Aldehyde Having Lewis Base Moiety and Trimethylsilyl Enolate
Authors: Nakagawa Takashi , Fujisawa Hidehiko , Mukaiyama Teruaki
Published: December 2003

Self-promoted aldol reaction between aldehydes having Lewis base moieties and trimethylsilyl enolates proceeded smoothly to afford the corresponding aldols in good to high yields. It is noted that various functionalized aldols can be directly obtained without protection of functional groups in the above reaction.
Isolation of Tribromoacetamide from an Okinawan Alga and Biological Activities of Its Analogs
Authors: Kigoshi Hideo , Ichino Takao , Takada Noboru , Suenaga Kiyotake , Yamada Akihiro , Yamada Kaoru , Uemura Daisuke
Published: December 2003

Tribromoacetamide was isolated from the Okinawan alga Wrangelia species, and the biological activities of this compound and its analogs were investigated.
Investigations on Coherence of Active Control of Traffic Noise Transmission through an Open Window into a Rectangular Room in High-Rise Buildings
Authors: Zhang Jiping
Published: December 2003

A method for theoretically calculating the coherence between sound pressure inside a rectangular room in a high-rise building and that outside the open window of the room is proposed. The traffic noise transmitted into a room is generally dominated by low-frequency components, to which active noise control (ANC) technology may find an application. However, good coherence between reference and error signals is essential for effective noise reduction and should be checked first. Based on traffic noise prediction methods, wave theory, and mode coupling theory, the results of this paper enable one to determine the potentials and limitations of ANC used to reduce such a transmission. Experimental coherence results are shown for two similar, empty rectangular rooms located on the 17th and 30th floors of a 34 floor high-rise building. The calculated results with the proposed method are generally in good agreement with the experimental results and demonstrate the usefulness of the method for predicting the coherence.
World-Class Engine Testing in the UK
Authors: Minett Steve , Taylor Chris
Published: December 2003

Perkins is a name with a worldwide reputation for diesel engines, won from more than 70 years manufacturing at its Peterborough, UK, factory site. Now part of the Caterpillar organisation, it is winning even more acclaim for the quality of its engine testing, backed by Six Sigma quality credentials. Motor manufacturers from around the world are coming to Perkins for objective, ‘benchmark’ measurements of their products, against stringent current operating and/or legislative criteria.
A Revised Simplex Search Procedure for Stochastic Simulation Response Surface Optimization
Authors: Humphrey David G. , Wilson James R.
Published: December 2003

We develop a variant of the Nelder-Mead (NM) simplex search procedure for stochastic simulation optimization that is designed to avoid many of the weaknesses encumbering similar direct-search methods—in particular, excessive sensitivity to starting values, premature termination at a local optimum, lack of robustness against noisy responses, and computational inefficiency. The Revised Simplex Search (RSS) procedure consists of a three-phase application of the NM method in which: (a) the ending values for one phase become the starting values for the next phase; (b) the step size for the initial simplex (respectively, the shrink coefficient) decreases geometrically (respectively, increases linearly) over successive phases; and (c) the final estimated optimum is the best of the ending values for the three phases. To compare RSS versus NM and procedure RS+S9 due to Barton and Ivey, we summarize a simulation study based on four selected performance measures computed for six test problems that include additive white-noise error, with three levels of problem dimensionality and noise variability used in each problem. In the selected test problems, RSS yielded significantly more accurate estimates of the optimum than NM or RS+S9, and both RSS and RS+S9 required roughly four times as many function evaluations as NM.
Practical Piecewise-Linear Approximation for Monotropic Optimization
Authors: Kontogiorgis Spyros
Published: December 2003

Piecewise-linear programs are routinely used in applications to approximate nonlinear programs with a separable, concave objective function and linear constraints. We present a general and simple method for constructing and solving such problems. We use a spline algorithm to construct the approximant, a variant of the Δ-form to formulate the LP, and the interior point method to solve the LP. In computational experiments on a large-scale application benchmark, the method produces a 99.7% accurate solution in a sixth of the time it takes to solve the problem exactly with a state-of-the-art nonlinear solver.
Fault-Tolerant Virtual Path Layout in ATM Networks
Authors: Ball Michael O. , Vakhutinsky Andrew
Published: December 2003

Asynchronous Transfer Mode (ATM) is a communications architecture for the provision of broadband integrated services digital networks. Two fundamental features of ATM networks are hierarchical routing and statistical multiplexing. This paper addresses the problem of laying out virtual paths (VPs), which are logical network links that provide direct connections between certain nodes. A bi-criteria integer-programming model is developed that includes a throughput-maximization objective, a delay/overhead minimization objective, and a diversity constraint whereby link-disjoint VPs are found so as to provide fault tolerance. The formulation employs a new model for approximating the effects of statistical multiplexing. An approximate solution method is developed, which employs constraint generation for bound tightening, and heuristics based on rounding of a linear programming solution.