bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper(II)-Thioether Bondings in Multidentate N,S-Donor Ligand Complexes. Structural Dependence of the Chemical Properties of the Copper(II) Complexes of 1,5-Bis(2-pyridylmethylamino)-3-thiapentane and 2,6-Bis(2,6-dithiaheptyl)pyridine
Authors: Masuda Hideki , Sugimori Tamotsu , Kohzuma Takamitsu , Odani Akira , Yamauchi Osamu 
Published: July 2006

Abstract
With a view to understanding the factors affecting the chemical properties of the copper sites in proteins, model copper(II) complexes of two multidentate ligands with nitrogen and sulfur atoms, 1,5-bis(2-pyridylmethylamino)-3-thiapentane (pmtp) and 2,6-bis(2,6-dithiaheptyl)pyridine (dthp), have been isolated as [Cu(pmtp)][Cu(pmtp)ClO4](ClO4)3 (1) and [Cu(dthp)(NO3)2] (2), respectively, and studied by X-ray diffraction, spectroscopic, and electrochemical methods. Complex 1 crystallizes in space group P21/a of the monoclinic system with four [Cu(pmtp)]2+ ions and four [Cu(pmtp)(ClO4)]+ ions in a cell of dimensions a = 24.180(7), b = 31.855(7), c = 9.760(3) Å, and β = 143.84(1)°. The coordinations around the coppers in the two independent complexes are square-pyramidal and octahedral, respectively, with an amine nitrogen, two pyridine nitrogens, and a thioether sulfur at the equatorial positions (eq) and an amine nitrogen (and a perchlorate oxygen in addition in the octahedral complex) at the axial position(s) (ax); Cu–Neq = 1.991(10), 2.001(14), and 2.009(9) Å, Cu–Seq = 2.353(6) Å, Cu–Nax = 2.276(8) Å for [Cu(pmtp)]2+, and Cu–Neq = 1.994(7), 2.002(6), and 2.013(14) Å, Cu–Seq = 2.355(6) Å, Cu–Nax = 2.306(10) Å, Cu–Oax = 2.698(14) Å for [Cu(pmtp)(ClO4)]+. Complex 2 crystallizes in space group P21/c of the monoclinic system with four [Cu(dthp)(NO3)2] molecules in a cell of dimensions a = 18.492(5), b = 14.375(3), c = 8.554(2) Å, and β = 101.19(2) Å. The coordination around copper is distorted trigonal-bipyramidal with two thioether sulfurs and a nitrate oxygen in the trigonal plane and a pyridine nitrogen and a nitrate oxygen at the axial positions; Cu–Seq = 2.344(2) and 2.402(2) Å, Cu–Oeq = 2.244(6) Å, Cu–Nax = 1.982(6) Å, Cu–Oax = 1.927(5) Å. The structures of these complexes in aqueous solution were concluded to be square-pyramidal from ESR and electronic spectra. Their reduction potentials (E1⁄2 vs. NHE) were +0.062 V for 1 in CH3CN with one coordinated S atom and +0.678 V for 2 in CH2Cl2 with two coordinated S atoms. The higher E1⁄2 value for 2 has been interpreted as due to the presence of the two coordinated sulfur atoms and the flexibility of the ligand which can accomodate the structural changes accompanying the Cu(II)/Cu(I) redox reaction.
Stereoselective Formation and Some Properties of Polynuclear Cobalt(III) Complexes with d-Penicillaminate
Authors: Okamoto Ken-ichi , Yonemura Toshiaki , Konno Takumi , Hidaka Jinsai 
Published: July 2006

Abstract
The novel mononuclear, dinuclear, and trinuclear cobalt(III) complexes with d-penicillaminate(d-pen), ΛDdd-fac(S)-[Co(d-pen-N,S)3]3−, ΛDdd-[Co{Co(d-pen-N,S)3}(dien)], ΛDdd-[Co{Co(d-pen-N,S)3}(d-pen-N,O,S)]2−, and ΛDddΔDdd-[Co{Co(d-pen-N,S)3}2]3− were prepared. These complexes were characterized from their electronic absorption, CD, and 13C NMR spectra. These complexes formed selectively each one isomer. The stereoselectivity for the d-pen complexes is discussed in comparison with that of the corresponding l-cys ones. The d-pen polynuclear complexes exhibited characteristic absorption spectral behaviors in the visible region. The 13C NMR spectral behaviors for the d-pen complexes are connected with those of the corresponding l-cys ones.
Synthesis of Optically Active Polymethacrylates Bearing Axially Dissymmetric 1,1′-Binaphthalene Skeleton as a Pendant Group and Their Optical Resolution Ability as Chiral Adsorbent for HPLC
Authors: Tamai Yasufumi , Qian Pu , Matsunaga Ken’ichi , Miyano Sotaro 
Published: July 2006

Abstract
Optically active polymethacrylates 6 and 8, which have pendant axially dissymmetric 1,1′-binaphthalene moiety, were synthesized by radical polymerization of (S)-2-methacryloyloxy- and (S)-2-(3-methacryloyloxypropoxy)-2′-methoxy-1,1′-binaphthalene, respectively. Specific rotation and CD spectrum of 6 are rather different from those of the model compound 2-(2,2-dimethylpropanoyloxy)-2′-methoxy-1,1′-binaphthalene (7), while the chiroptical properties of 8 are almost the same as those of the corresponding model compound. The difference of the chiroptical properties between 6 and 7 was attributed to the difference of the dihedral angles between the naphthalene planes of the 1,1′-binaphthalene skeleton. The polymethacrylates 6 and 8 were coated on a spherical silica gel to give HPLC chiral stationary phases (CSP-6 and CSP-8). These CSPs differentiated several enantiomeric 1-aryl-1-alkanols and 1,2-diols as the 3,5-dinitrophenylcarbamates, CSP-8 showing better resolution than CSP-6. Furthermore, (S)-2-(5-carboxypentyloxy)-2′-methoxy-1,1′-binaphthalene, a model compound of 8, was prepared and covalently bonded to an aminopropylsilanized silica gel to afford CSP-16, which also resolved these racemates. Thus, the chiral discriminating ability of the polymethacrylate 8 would be based not on the secondary and/or higher-ordered structure, but mainly on the interaction between the individual 1,1′-binaphthalene units of 8 and the racemates.
Efficient Six-Electron Photoreduction of Nitrobenzene Derivatives by 10-Methyl-9,10-dihydroacridine in the Presence of Perchloric Acid
Authors: Fukuzumi Shunichi , Tokuda Yoshihiro 
Published: July 2006

Abstract
Photoreduction of nitrobenzene derivatives by 10-methyl-9,10-dihydroacridine (AcrH2) occurs efficiently in the presence of perchloric acid in acetonitrile containing H2O (0.50 mol dm−3) to yield the corresponding six-electron reduced products (aniline derivatives) and 10-methylacridinium ion efficiently. The initial two-electron reduction of PhNO2 to PhNO by AcrH2 in the six-electron reduction of nitrobenzene (PhNO2) is started by electron transfer from AcrH2 to the n,π* triplet state (3PhNO2*), followed by acid-catalyzed thermal reduction of PhNO to PhNHOH by AcrH2 and the subsequent photoreduction of PhNHOH to PhNH2 by AcrH2.
Photochemical Reactions of 4-Acylstyrenes. Effects of Acyl Substituents on Photocyclodimerization via an Excited Triplet State
Authors: Tsubakiyama Kyoji , Miyagawa Kohji , Kaizaki Kiyotaka , Yamamoto Masahide , Nishijima Yasunori 
Published: July 2006

Abstract
The photochemical reactions of 4-acylstyrenes (1a–e; acyl = acetyl, benzoyl, 1-naphthoyl, 2-naphthoyl, and 9-phenanthrylcarbonyl, respectively) were investigated, and their excited state behavior and photoreactivities are discussed in relation to the aryl ketone structures. Photoirradiation of 1a–e in benzene gave two isomeric cyclodimers of trans- and cis-1,2-bis(4-acylphenyl)cyclobutanes(2a–e and 3a–e) as main products, accompanied by the formation of some oligomers and polymers. The fractions of the trans-form in the cyclodimers were ca. 80%; this indicated that the cyclodimerization proceeded via the π,π* triplet state. The quantum yields of the photodimerization for 1a–e were almost the same irrespective of the acyl substituents (Φ = 0.03–0.04 at [1a–e] = 0.1 mol dm−3). Phosphorescence spectra of 1c (τ = 0.48 s) and 1d (τ = 0.91 s) observed in a rigid solution at 77 K, which coincided with those of the respective model aryl ketones, were ascribed to the low-lying excited π,π* triplet states localized on the naphthalene moiety of the molecules. Phosphorescence emissions of 1a and 1b could not be detected. The transient absorption spectrum of 1d (τ = 23 ns) observed in a fluid solution at 293 K was tentatively assigned to the π,π* triplet state mainly localized on the styrene moiety of the molecule. The photoreaction mechanism is discussed in terms of the intramolecular triplet energy transfer.
Synthesis and Radical Polymerization of Itaconates Containing an Adamantyl Ester Group
Authors: Matsumoto Akikazu , Watanabe Hiroyuki , Otsu Takayuki 
Published: July 2006

Abstract
Itaconates containing a 1-adamantyl or a 3,5-dimethyl-1-adamantyl ester group were prepared and polymerized in the presence of a radical initiator. The polymerization reactivity has been investigated in relation to the structure of ester alkyl groups of the monomer. It has been clarified that the adamantyl-containing polyitaconates show high thermal stability, i.e., high glass transition temperatures and decomposition temperatures. The relationship between polymer structures and thermal properties of polymers from some α- and β-substituted acrylic esters, i.e., acrylates, methacrylates, crotonates, fumarates, and itaconates was discussed.
Preparation of Poly(2,5-diheptyl-1,4-phenylenevinylene) by Sulfonium Salt Pyrolysis
Authors: Sonoda Yoriko , Kaeriyama Kyoji 
Published: July 2006

Abstract
Poly(2,5-diheptyl-1,4-phenylenevinylene) (1) was prepared by the sulfonium salt pyrolysis procedure. Tough films of 1 were obtained by pyrolysis of its sulfonium salt precursor film. Due to flexible side chains, 1 was soluble in organic solvents such as chloroform. The molecular weights were Mn = 3.8−4.7 × 104 and Mw = 1.4−1.8 × 105. The ratio of trans to cis olefinic units was found to be 93 : 7 from the 1H NMR spectrum. Two arylmethylene peaks suggested that there were two kinds of stereochemically different methylene groups. Although the peak energy in the absorption spectra was almost identical to those of poly(1,4-phenylenevinylene) (PPV), the electrical conductivity of 1 was much lower than that of PPV.
Surface Adsorption and Micelle Formation of Dodecyltrimethylammonium Chloride and Dodecylammonium Chloride Mixture
Authors: Ikeda Norihiro , Sanefuji Norihiko , Abe Koji , Todoroki Natsuko , Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
The miscibility of dodecyltrimethylammonium chloride (DTAC) and dodecylammonium chloride (DAC) in the adsorbed film at water/air interface and in the micelle was investigated by measuring the surface tension of the aqueous solution of surfactant mixture as a function of the total molality and composition of surfactants. The compositions of surfactants in the adsorbed film and micelle were evaluated by use of the thermodynamic equations developed previously. The results indicated that DTAC and DAC molecules mix slightly nonideally in the adsorbed film and micelle. Furthermore, the composition of DAC in the micelle was found to be remarkably smaller than that in the adsorbed film at the critical micelle concentration. It was concluded that the bigger hydrophilic group of DTAC is geometrically favorable for the micelle formation.
Evaluation of Melting and Crystalline Relaxation Temperatures of Fatty Acid Monolayers on the Water Surface and Their Importances for Molecular Aggregation States in Monolayers
Authors: Kajiyama Tisato , Oishi Yushi , Uchida Motoko , Morotomi Naoaki , Ishikawa Jun-ichi , Tanimoto Youichi 
Published: July 2006

Abstract
The melting temperature, Tm and the crystalline relaxation temperature, Tαc of fatty acid monolayers on the water surface were evaluated by a combination of two kinds of measurements, the subphase temperature, Tsp dependence of monolayer modulus based on a π-A isotherm and also, the Tsp dependence of the electron diffraction, ED patterns of monolayer. Tms of myristic, palmitic, and stearic acid monolayers were evaluated to be 278, 301, and 317 K, respectively, on the basis of both apparent decrease in the Tsp vs. modulus curve and the change of the ED pattern from a crystalline Debye ring to an amorphous halo. The crystalline relaxation process corresponds to a change from elastic to viscoelastic characteristics in a crystalline phase due to a considerable contribution of anharmonic thermal molecular vibration. Tαcs of palmitic and stearic acid monolayers were evaluated to be 291 and 298 K, respectively, from both apparent decrease in the Tsp dependence of modulus and appearance of the break in the thermal expansion coefficient of crystalline lattice constant. This break may be attributed to a remarkable increase in contribution of the anharmonic term with respect to the intermolecular potential energy. The magnitude of Tm and Tαc of monolayers on the water surface is an important factor to decide the structure or aggregation state in the crystalline and amorphous monolayers and also, the formation process of a large-area monolayer, that is, the fusion or sintering behavior among crystalline monolayer domains.
Effect of Ascorbic Acid on the Desorption of Gold in Graphite Furnace Atomic Absorption Spectrometry
Authors: Imai Shoji , Hayashi Yasuhisa 
Published: July 2006

Abstract
In the graphite furnace atomic absorption spectrometry of gold, signals with a single peak were observed with a pyrolytic graphite (PG) furnace, while signals with a shoulder on the tailing edge were observed with a nonpyrolytic graphite (NPG) furnace. A thermal shift of the atomic absorption signals for gold occurs in response to changes in the concentration of ascorbic acid without any loss for each furnace. When the pre-pyrolysis of a 5% (m/V) ascorbic acid solution was carried out at 1270 K, although the background signal due to the release of amorphous carbon was not observed, a thermal shift of the gold signal was confirmed. At a pre-pyrolysis temperature over 1460 K, the peak absorbance was reduced by increasing the pre-pyrolysis temperature, while absorbance at the position of the signal for gold only was increased. The values of the Arrhenius activation energy for the desorption of gold were obtained to be 60 ± 2 kcal mol−1 for gold only, 93 ± 3 kcal mol−1 for gold with 5% (m/V) ascorbic acid and 99 ± 2 kcal mol−1 after a pre-pyrolysis of ascorbic acid at 1270 K.
Preparation of Cu Thin Films by the Decomposition of Copper Acetylacetonate on Catalytically Active Substrate Surfaces
Authors: Miura Hiroshi , Oki Kazuo , Ochiai Hisayoshi , Higuchi Hiroshi , Terasaka Michio , Matsuda Tsuneo 
Published: July 2006

Abstract
A selective CVD system used to deposit the central metal of a volatile complex preferentially on catalytically active substrate surfaces was examined. Copper(II) acetylacetonate was vaporized in a flow of hydrogen and decomposed on Ni, Pd, and Al plates in order to deposit metallic copper. When a Ni plate was used as the substrate, deposition of metallic copper occurred at temperatures in the range 13O–180 °C only on the substrate surfaces. The formation of an ultrathin film of Cu of uniform thickness was confirmed. On a Pd substrate, the formation of an ultrathin Cu film of uniform thickness was also observed. On an Al substrate, however, deposition occurred nonselectively at temperatures above 160 °C, not only on the substrate surface, itself, but also on the wall of the glass tube as well as the quartz wool surrounding the Al plate. In addition, the formation of fine particles of Cu, instead of thin film, was found to exist on the substrate. Because the deposition of Cu took place on catalytically active surfaces selectively, the deposition was considered to proceed by a catalytic hydrogenation of the C=O bond of the ligand, thus detaching it from the Cu ion and allowing it to decompose the complex and deposit Cu metal.
Mechanism on the Efficient Formation of Singlet Oxygen by Energy Transfer from Excited Singlet and Triplet States of Aromatic Hydrocarbons
Authors: Usui Yoshiharu , Shimizu Noriyo , Mori Satoshi 
Published: July 2006

Abstract
The formation efficiencies of singlet oxygen for the oxygen quenching in excited singlet of aromatic hydrocarbons; A and for the quenching in the triplet T1; B were estimated. The hydrocarbons were classified into three types: (i) A = 1 and B = 1 for dicyanoanthracene i.e., total 200% efficiency, (ii) A ≈ 0.3 and B = 1 for anthracene, (iii) A ≈ 0 and B = 1 for pyrene, as examples. It is suggested that the energy levels of T2 and a dissociative exciplex; (T11Δg) correlated to A and B values from the energetic considerations.
Preparation of 1,4,2-Dithiazolium Salts
Authors: Yonemoto Katsumi , Shibuya Isao , Taguchi Yoichi , Tsuchiya Tohru , Yasumoto Masahiko 
Published: July 2006

Abstract
N-(Substituted formyl)dialkylamino(thioxo)methanesulfenamides (R2NCSSNHCOR′ 3: R = alkyl, R′ = alkyl, dialkylamino, alkoxy, and heterocyclic substituent) were treated with a strong acid (HBF4 or HClO4) in Ac2O to afford 1,4,2,-dithiazolium salts (7) and/or 3,5-bis(dialkyliminio)-1,2,4-trithiolanes (9). The reactivity is markedly dependent on the nature of substituents (NR2 and R′) and the acid used. For R′ = MeO, the sulfenamides reacted successively with NaH and p-toluenesulfonyl chloride to give methyl bis(dialkylthiocarbamoylthio)carbamates (10). The mechanisms for the formation of 9 and 10 are discussed.
Generation and Cycloaddition Reactions of 3-Styryl-1,2-thiaphosphole 2-Sulfide and 1,5-Diphenyl-2,4-pentadiene-1-thione
Authors: Motoki Shinichi , Sakai Takaya , Matsuo Yoshihisa , Kametani Shunichi , Saito Takao 
Published: July 2006

Abstract
The cycloaddition reaction of 3-styryl-1,2-thia phosphole 2-sulfide and 1,5-diphenyl-2,4-pentadiene-1-thione derivatives generated by the thermolysis of 5,6-distyryl-3,8-diaryl-2,9-dithia-1-phosphabicyclo[4.3.0]nona-3,7-diene 1-sulfides have been described. Methacrylonitrile, methyl methacrylate, α-methylstyrene, norbornene, methyl acrylate, styrene, and mehyl vinyl ketone afforded the cycloadducts or their rearranged products with the thiaphosphole 2-sulfides, whereas diethyl azodicarboxylate, dimethyl acetylenedicarboxylate, and N-(p-methoxyphenyl)maleimide gave the cycloadducts with the thioketone.
Citreobenzofurans A, B, and C, First Isolation of Sesquiterpene-Type Metabolites of a Hybrid Strain KO 0031 Derived from Penicillium Citreo-viride B. IFO 4692 and 6200
Authors: Kosemura Seiji , Nagamatsu Harutoshi , Yamamura Shosuke 
Published: July 2006

Abstract
Three new sesquiterpene-type metabolites, citreobenzofurans A, B, and C, have been isolated ftrom the mycelium of the hybrid strain KO 0031 derived from Penicillium citreo-viride B. IFO 4692 and 6200. Their stereostructures have been also elucidated on the basis of their spectral data.
Synthesis of (±)-Isopiperitenol by Fluoride Ion Mediated Cyclization of Allylsilane Moiety Incorporated in Terpene Aldehydes
Authors: Nakamura Hideshi , Oya Toyohisa , Murai Akio 
Published: July 2006

Abstract
Fluoride ion mediated cyclization of aldehydes (1 and 2) having regioisomeric allylsilane functionalities give a mixture of cis- and trans-isopiperitenol (3). The aldehydes (1) reacted faster and showed better stereoselectivity than the regioisomeric aldehydes (2) regardless of geometry of the double bond at an unsaturated aldehyde.
A Novel Isobenzofuran Derivative Undergoing Photovalence Isomerization
Authors: Miki Sadao , Yoshida Masahiro , Yoshida Zen-ichi 
Published: July 2006

Abstract
4,5,6-Tri-t-butylisobenzofuran (1) and 4,5,7-tri-t-butylisobenzofuran have been synthesized. They were stable infinitely in solutions at room temperature. Upon irradiation, 1 undergoes photovalence isomerization to afford 2,3,4-tri-t-butyl-8-oxatetracyclo [4.3.0.02,4.03,5]nona-1(9),6-diene.
Semi-preparative Purification and Crystallization of Synthetic Analogs of Heat-stable Enterotoxins of Enterotoxigenic Escherichia coli
Authors: Sato Takashi , Ito Hideaki , Takeda Yoshifumi , Shimonishi Yasutsugu 
Published: July 2006

Abstract
The purification by high-performance liquid chromatography of synthetic analogs of heat stable enterotoxin (ST) of enterotoxigenic Escherichia coli from large amounts of their dilute solution on a laboratory scale is described. These analogs were also crystallized by gradually decreasing the temperature of their warm aqueous solution.
Intramolecular [2+2] Photocycloaddition. 15. Synthesis of 1,2-Ethano-9,10-methano[2.2]paracyclophanes
Authors: Nishimura Jun , Horikoshi Yoichiro 
Published: July 2006

Abstract
The title compounds were prepared in 30% yield by the sequence of photocycloaddition of styrene derivatives, followed by bromination and elimination. The isomer raito of the products was 5 : 4.
Reactivity of Lithium Alkylamide toward Vinylsilane Derivatives
Authors: Nagasaki Yukio , Morishita Shinya , Kato Masao , Kihara Yasuharu , Tsuruta Teiji 
Published: July 2006

Abstract
Kinetic studies concerning the addition reactions of lithium diethylamide (Et2NLi) to several vinylsilane derivatives, such as H2C=CH–Si(CH3)2X [X: methyl, phenyl, ethoxy, 2-(diethylamino)ethyl and vinyl], and H2C=CH–Si(CH3)2OSi(CH3)2X [X: 2-(diethylamino)ethyl and vinyl], were carried out. The reactivity of vinylsilane derivatives toward nucleophile was strongly influenced by the nature of the substituents on the Si atom. The reactivity of trimethylvinylsilane [rate constant k (trimethylvinylsilane; cHx; 50 °C) = 2.9 ± 0.2 · 10−4 dm3 mol−1 s−1] was found to be of the same order of magnitude as that of para-alkyl-substituted styrenes, such as 4-methylstyrene [k (4-methylstyrene; cHx; 50 °C) = 3.2 · 10−4 dm3 mol−1 s−1]. The reactivities of vinylsilane compounds having an aryl substituent, e.g. dimethylphenylvinylsilane [k (dimethylphenylvinylsilane; cHx; 50 °C) = 14.8 ± 0.3 · 10−4 dm3 mol−1 s−1] and dimethyldivinylsilane [k (dimethyldivinylsilane; cHx; 50 °C) = 14.8 ± 0.6 · 10−4 dm3 mol−1 s−1], were higher than that of trialkyl-substituted vinylsilane. This fact may be explained by a π-conjugation between the phenyl (or vinyl) and vinyl groups through an empty d-orbital of the Si atom. A vinylsilane compound having a 2-(dialkylamino)ethyl substituent, [2-(diethylamino)ethyl]dimethylvinylsilane, showed unique reactivity toward lithium diethylamide, indicating that the β-nitrogen atom plays an important role regarding the reactivity of the vinyl group. In the reaction between lithium diethylamide and vinylsilane having an ethoxyl group, an addition reaction to the vinyl group and a cleavage reaction of the Si–O linkage proceeded concurrently. No cleavage reaction, however, proceeded in the reaction of lithium diethylamide with vinylsilane compounds having a disiloxane linkage. 1,1,3,3-Tetramethyl-1,3-divinyldisiloxane exhibited a much higher reactivity than did the other vinylsilane compounds.
Footprint Catalysis. IV. Structural Effects of Templates on Catalytic Behavior of Imprinted Footprint Cavities
Authors: Shimada Toyoshi , Nakanishi Kiyoko , Morihara Kensaku 
Published: July 2006

Abstract
Footprint catalysts are silica(alumina)gel catalysts with tailored specificities. Their catalytic sites are “molecular footprint-like” cavities formed by a molecular imprinting procedure with templates, which are referred to as transition-state or reactive-intermediate analogs of the catalyzed reactions. To clarify the relationship between the structural feature of template molecules and catalytic behavior, seven footprint catalysts were prepared by imprinting with templates of several types closely related to the substrates, benzoic anhydride and acetic anhydride; their catalytic activity and thermodynamic parameters for 2,4-dinitrophenolysis were then estimated. Among these catalysts, a catalyst imprinted with N,N′-dibenzoylbenzenephosphonediamide, a tetrahedral intermediate analog for benzoic anhydride substrate, showed a 10-fold higher catalytic activity than did the other imprinted catalysts.