bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption Equilibria of 1,10-Phenanthroline and Its Fe(II) Complex on Octadecyl-Bonded Silica Gel
Authors: Kato Masanao , Kudo Shio , Hattori Toshiaki 
Published: August 2005

Abstract
Adsorption of 1,10-phenanthroline (phen) and its iron(II) complex (Fe(II)-phen) on octadecyl-bonded silica (ODS) gel from aqueous solution was studied by a batch method. The adsorption isotherms of phen and Fe(II)-phen were Langmiur type. Equilibrium constants for the adsorption reaction were estimated from the adsorption data in the system containing a small amount of adsorbates, in which the adsorption isotherm obeyed Henry’s law. It was clear that the adsorbed species of phen was not only the basic type but also the acidic type: protonated phen. The adsorption behavior in trace amounts (1.79 × 10−5 mol dm−3; 1 ppm) of Fe(II)-phen was analyzed by their equilibrium parameters. The distribution constants of Fe(II)-phen between ODS gel and aqueous solution were determined. The effect of co-existent anions on the adsorption of Fe(II)-phen was discussed from the obtained constants.
Complex Formation between Boric Acid and Triethanolamine in Aqueous Solutions
Authors: Sonoda Akinari , Takagi Norio , Ooi Kenta , Hirotsu Takahiro 
Published: August 2005

Abstract
The complex formation behavior between boric acid and triethanolamine (TEA, H3L) in aqueous solutions was thoroughly examined by 11B NMR spectroscopy. In chloroform, one 11B NMR signal appeared due to triethanolamine borate (TEA-B, L-B) at −4.6 ppm, whereas in aqueous solutions two signals appeared due to TEA-B and a new boron complex at −5.8and −9.5 ppm, respectively, in addition to a signal ascribed to boric acid and borate ion. The area ratios between the signals at −5.8 and −9.5 ppm were almost constant regardless of the molar ratios between boric acid and TEA, suggesting that the new complex is a 1 : 1 complex between boric acid and TEA. Both complexes were stable in aqueous solutions over the pH range of 6.7 to 10.9. Their chemical shift values were constant and independent of the pH value. This also implies that the new complex has a tetrahedral structure around the boron atom, similar to TEA-B. Based on 1H and 13C NMR spectroscopy and a preliminary examination of complexation between boric acid and aminoalkanols, we have concluded that the new complex (NB, HL-B(OH)) is a 1 : 1 boron to TEA complex with a bicyclo[3,3,0]structure having a boron–nitrogen bond.
Multi-Dimensional Structures Constructed by the Electrostatic Interaction of Potassium Salts of Cobalt(III) and Manganese(III) Complexes with 1,2-Bis(2-hydroxybenzamido)benzene
Authors: Sunatsuki Yukinari , Mimura Masaaki , Shimada Hiromitsu , Kai Fumiaki , Matsumoto Naohide 
Published: August 2005

Abstract
Potassium salts of cobalt(III) and manganese(III) complexes, K[CoL(py)2]·2EtOH·MeOH 1 and K[MnL(py)2]·py 2, have been prepared, where H4L = 1,2-bis(hydroxybenzamido)benzene and py = pyridine. 1 crystallizes in the monoclinic space group P21/n with the cell dimensions of a = 12.688(3), b = 17.555(4), c = 16.673(3) Å, β = 102.59(2)°, V = 3624(1) Å3, and Z = 4, in which potassium ion plays a role of connector for two adjacent [CoL(py)2]− molecules through K–O interaction (two phenoxo oxygen atoms of a cobalt(III) complex, two oxygen atoms of the solvent molecules, and an amido oxygen of the adjacent unit) to give an extended one-dimensional structure. 2 crystallizes in the orthorhombic space group P212121 with the cell dimensions of a = 14.358(1), b = 16.457(2), c = 13.703(2) Å, V = 3237.7(5) Å3, and Z = 4, in which potassium ion plays a role of connector for three adjacent [MnL(py)2]− molecules through K–O interaction to give an extended three-dimensional structure.
Reduction of CO2 Directed toward Carbon–Carbon Bond Formation
Authors: Tanaka Koji 
Published: August 2005

Abstract
This paper describes electrochemical reduction of CO2 directed toward carbon–carbon bond formation via metal–CO2 adducts. An electrophilic attack of CO2 to penta-coordinated low valent polypyridyl Ru complexes affords a Ru–η1-CO2 adduct, which is easily converted to Ru–CO species either by an acid-base equilibrium in protic media and oxide transfer to CO2 under aprotic conditions. Two-electron reduction of resultant Ru–CO in protic solutions competitively causes a cleavage of the Ru–CO bond (CO evolution) and formation of a thermally labile Ru–CHO bond. Besides further reduction of the latter to Ru–CH2OH as precursors to CH3OH and HOOCCH2OH, Ru–CHO reacts with CO2 to afford HCOOH with regenerating Ru–CO as the precursor to CO. Thus, the difficulty of multi-electron reduction of CO2 in protic solutions is ascribed to the thermal lability and strong hydride donor character of Ru–CHO. On the other hand, two-electron reduction of Ru–CO in the presence of (CH3)4N+ or CH3I under aprotic conditions produces thermally stable R–C(O)CH3, which works as a precursor to CH3C(O)CH3. Two-electron reduction of M3(μ3-S)2 clusters (M = Co, Rh, Ir) causes an M–M bond cleavage and the nucleophilicity of the μ3-S ligand is also enhanced. As a result, two CO2 molecules reductively activated probably on μ3-S and metal sites undergo the coupling reaction to give oxalate selectively.
Reactivities of Molybdenum and Tungsten Diazoalkane–Isocyanide Complexes Derived from Dinitrogen Complexes
Authors: Harada Yuji , Mizobe Yasushi , Aoshima Takayuki , Oshita Hiroyuki , Hidai Masanobu 
Published: August 2005

Abstract
The diazoalkane–isocyanide complexes cis,trans-[MX2(NN=CMePh)(CNBut)(PMe2Ph)2] (1a: M = Mo, X = Cl; 1b: M = W, X = Cl; 1c: M = W, X = Br), readily derived from dinitrogen complexes cis-[M(N2)2(PMe2Ph)4], reacted with AlMe3 at room temperature to give the aminocarbene–diazoalkane complexes cis,trans-[MX2(NN=CMePh){=C(Me)NHBut}(PMe2Ph)2] (2a: M = Mo, X = Cl; 2b: M = W, X = Cl; 2c: M = W, X = Br) after hydrolysis. Treatment of 1b with TfOH (Tf = CF3SO2) and then with ButNC at room temperature resulted in the formation of a cationic bis(isocyanide)–diazoalkane complex trans,trans-[WCl(NN=CMePh)(CNBut)2(PMe2Ph)2] [OTf] (3). The detailed structures of 2b and 3 have been determined by single-crystal X-ray analyses.
The Olefin Synthesis from β-Hydroxyalkylphosphonates Induced by Fluorides or Relatively Weak Bases
Authors: Kawashima Takayuki , Ishii Takafumi , Inamoto Naoki , Tokitoh Norihiro , Okazaki Renji 
Published: August 2005

Abstract
β-Hydroxyalkylphosphonates, which were prepared readily from alkylphosphonates and carbonyl compounds, were treated with a fluoride ion such as CsF or with relatively weak bases such as K2CO3 in N,N-dimethylformamide to give the corresponding olefins in good yields. One molar equivalent of water to bases is effective for increasing the yields of olefins. The stereochemistry of erythro-dimethyl (2-hydroxy-1-methyl-2-phenyl)ethylphosphonate was determined by X-ray crystallographic analysis. Use of threo-isomer gave (E)-olefin exclusively, while that of erythro-enriched isomer afforded predominantly (Z)-olefin, indicating that the present olefination proceeds stereospecifically in a manner of syn-elimination.
Structures and Tropicity of Hydrogenation Products of a Bisdehydro[13]annulenone and a Bisdehydro[15]annulenone
Authors: Higuchi Hiroyuki , Hiraiwa Naoki , Daimon Tomoyo , Kondo Shiro , Ojima Juro , Iyoda Masahiko , Yamamoto Gaku 
Published: August 2005

Abstract
The catalytic partial hydrogenation of the 5,10-dimethyl-6,8-bisdehydro[13]annulenone using Pd–BaSO4 afforded the 5,10-dimethyl[13]annulenone together with two isomeric 5,10-dimethyl-6-dehydro[13]annulenones. The dimethyl[13]annulenone, which is the first example of a monocyclic non-dehydro annulenone derivative larger than tropone, was found to be atropic on the basis of 1H NMR spectra. Molecular mechanics studies indicate the extensive deviation of the molecular skeleton from planarity and help to explain the lack of peripheral conjugation. Attempts to obtain the [15]annulenone and the [17]annulenone from the bisdehydro[15]annulenone and the bisdehydro[17]annulenone, respectively, were unsuccessful.
Vinylic SN2 Reaction of 1-Decenyliodonium Salt with Halide Ions
Authors: Okuyama Tadashi , Takino Tomoki , Sato Koichi , Oshima Kunio , Imamura Shohei , Yamataka Hiroshi , Asano Tsutomu , Ochiai Masahito 
Published: August 2005

Abstract
Reactions of (E)-1-decenyl(phenyl)iodonium salt with halide ions are examined under various conditions. The products are those of substitution and elimination, usually (Z)-1-halo-1-decene and 1-decyne, as well as iodobenzene, except for the reaction with fluoride which leads exclusively to elimination. The labeling experiments show that the elimination induced by fluoride occurs via an α mode, while that caused by the other halides is a syn β elimination. Kinetic results show that the substitution and β elimination occur mainly from the halo-λ3-iodane intermediate; the substitution occurs as a bimolecular reaction with the external halide ion while the elimination is a unimolecular (intramolecular) reaction. The intermediacy of the hypervalent λ3-iodane as well as of the iodate are also confirmed by UV spectroscopy. The secondary kinetic isotope effects, leaving group substituent effects, and pressure effects on the rate are compatible with the in-plane vinylic SN2 mechanism for the substitution with inversion. Some retained substitution product, (E)-1-halo-1-decene, is formed in polar protic solvents like trifluoroacetic acid, formic acid, and 1,1,1,3,3,3-hexafluoro-2-propanol. The reaction is very slow in these solvents and no sign of formation of ionic intermediates is found. This slow substitution with retention is considered to occur via ligand coupling within the halo-λ3-iodane intermediate.
Total Synthesis of Acanthacerebroside A and Astrocerebroside A via a Chiral Epoxide Intermediate Derived from l-Quebrachitol
Authors: Chida Noritaka , Sakata Noboru , Murai Katsuyuki , Tobe Takahiko , Nagase Toshihiko , Ogawa Seiichiro 
Published: August 2005

Abstract
The chiral and stereoselective total synthesis of novel cerebrosides, acanthacerebroside A (1) and astrocerebroside A (2), isolated from starfish, is described. The phytosphingosine moieties in 1 and 2 were prepared by the coupling reaction of dialkylmagnesium reagents with the common epoxide intermediate, 2-(t-butoxycarbonyl)amino-1-O-(t-butyldiphenylsilyl)-2-deoxy-3-O-(4-methoxybenzyl)-d-4,5-anhydroribitol (5). The epoxide (5) was synthesized from naturally occurring cyclitol, l-quebrachitol via the conduramine derivative, which was prepared regio- and stereoselectively by the Pd-catalyzed azidation of the allyl carbonate derivative. Condensation of phytosphingosines with 2-acetoxy fatty acid residue, followed by glycosidation, furnished the total synthesis. This work established an effective synthetic pathway to a wide variety of cerebrosides containing various phytosphingosines and 2-hydroxy fatty acid residue; the first total synthesis of astrocerebroside A (2) fully confirmed the proposed structure.
Surface-Enhanced Raman Imaging (SERI) of Patterned Self-Assembled Monolayers of Various Derivatized Thiophenols on Silver
Authors: Tryk Donald A , Yang Xiaomin , Hashimoto Kazuhito , Fujishima Akira 
Published: August 2005

Abstract
Surface-enhanced Raman imaging (SERI) has recently been developed in our laboratory as an imaging technique which is chemically selective, has monolayer sensitivity, and can be used under ambient conditions. A particularly interesting application of this technique is to image patterned self-assembled monolayers (SAMs). In the present work, we have used both photopatterning and microcontact printing techniques for preparing patterned SAMs with several different terminal functional groups (NO2, OH, COOH, and CH3) on evaporated silver films and have imaged them using SERI. The intrinsic subsurface roughness of the film provides sufficient enhancement for the imaging.
Ab Initio CASSCF Study on Doublet and Quartet States of 1,3,5-Tris(methylene)benzene and 1,3,5-Benzenetriamine Trication
Authors: Ito Akihiro , Taniguchi Aya , Yoshizawa Kazunari , Tanaka Kazuyoshi , Yamabe Tokio 
Published: August 2005

Abstract
Ab Initio CASSCF results of 1,3,5-tris(methylene)benzene (TMB) and 1,3,5-benzenetriamine trication (BTA3+), which are model molecules of the actively researched triradicals with star-branched topology, are presented. This study included a geometry determination of the four low-lying states (4A1″, 4A2, 2A2, 2B1) of TMB and BTA3+. The doublet–quartet splitting energies (ΔED–Q) of TMB and BTA3+ were calculated to be 12.7 and 3.1 kcal mol−1, respectively. Furthermore, the doublet-doublet splitting energies of TMB and BTA3+, which arise from a Jahn–Teller distortion of the doubly degenerate 2E″ state, were suitably estimated to be 2.5 and 6.8 kcal mol−1, respectively, due to obviation of the spin-contamination problem. As a result of configuration mixing, it was found that the doublet states for TMB and BTA3+ have to be represented at least by two configurations or more. In addition, the doublet states of TMB were regarded as being a doublet triradical, while those of BTA3+ were close to a doublet monoradical; associated with this result, the lowest doublet states of TMB and BTA3+ were found to be 2A2 and 2B1, respectively.
Crystal Structure of Acrylonitrile
Authors: Yokoyama Yoshihiro , Ohashi Yuji 
Published: August 2005

Abstract
Structure analysis of acrylonitrile, which is a low-melting-point (189.5 K) material, was performed using an imaging-plate-Weissenberg-camera-type-diffractometer at 153 K. The crystal was grown on the diffractometer. The molecule is almost planar and the molecular planes are stacked at regular distances along the a axis. The molecule takes a disordered structure since the N atom and the approximate center of the C=C double bond lie on the crystallographic mirror plane. This causes the C=C bond to be aligned to be in parallel or perpendicular arrangements to the neighboring ones along the stacking. If the solid state polymerization induced by radiation is carried out, the isotactic structure may be obtained for the parallel stacking and the syndiotactic structure may be obtained for the perpendicular stacking. Since the crystal structure is disordered, either structure or a structure with the two structures mixed (atactic structure) should be formed in the solid state polymerization.
Rotational Predissociation Dynamics of H2O (C1B1) by VUV Laser-Induced Photofragment Fluorescence Spectroscopy
Authors: Liu Shilin , Hishikawa Akiyoshi , Yamanouchi Kaoru 
Published: August 2005

Abstract
The rotational predissociation of water molecules in the vibrationless level of the B1 state was investigated under jet-cooled conditions (27—154 K) by exciting them with a tunable VUV laser in the wavelength range of 124.3—123.7 nm and by detecting the total fluorescence from electronically excited photofragments OH(A2Σ+). Due to the simple one-photon selection rule and the efficient rotational cooling, individual low-J rotational transitions of the B1–A1 origin band were observed with almost no overlap in the laser-induced photofragment fluorescence (LIPF) spectrum. The widths and intensities of these rotational transitions exhibited pronounced dependence on the parent rotational levels in the B1 state. The least-squares analysis of the observed line-widths (FWHM) of the resolved rotational transitions, Γ ’s, showed that they are well described by the formula, Γ = Γ0 + αa&lt;Ja′2&gt;, with optimized parameters Γ0 = 2.5(1) cm−1 and αa = 0.63(1) cm−1, indicating that (i) the homogeneous interaction couples the B1 state with the B1 state to form OH fragments in the electronically ground 2Πi state and (ii) the heterogeneous (a-axis orbital-rotation) interaction couples the B1 state with the A1 state to form OH fragments in the electronically excited A2Σ+ state. By taking account of the rotational line-broadening effect, the least-squares analysis was also performed to fit the observed spectral intensities to derive the branching ratio of the OH(A2Σ+) formation via the A1 state of H2O. It was found that the OH(A2Σ+) formation branching ratio can be expressed by an exponential form, exp (−γ&lt;Ja′2&gt;), which was proposed first by Hodgson et al. [Mol. Phys., 54, 351 (1985)], and reproduces well the observed rotational intensity pattern when γ = 0.097(7). By using this branching ratio and the previous data for the absorption oscillator strength, the absolute cross section to yield OH(A2Σ+) photofragments was obtained as a function of the excitation energy.
A Reversible Metalloporphyrin Oxygen Carrier Both in the Solid State and in Solution: Preparation, Characterization, and Kinetics of Formation of a Molybdenum(VI) 5,10,15,20-Tetramesitylporphyrin Dioxygen Complex
Authors: Tachibana Junichi , Imamura Taira , Sasaki Yoichi 
Published: August 2005

Abstract
The molybdenum(VI) porphyrin dioxygen complex, [MoVIO(O2)(tmp)] (tmp = 5,10,15,20-tetramesitylporphyrinato), prepared from the reaction of [MoIVO(tmp)] with dioxygen at room temperature is characterized in detail. Bulky mesityl substituents on the porphyrin rings enable the isolation of the dioxygen complex. Photoirradiation of the toluene solution of the dioxygen complex with visible light regenerated [MoIVO(tmp)] immediately. Upon heating the solid sample of the dioxygen complex, dioxygen gas was liberated around 40—90 °C, leaving [MoIVO(tmp)]. The solid and a toluene solution of [MoIVO(tmp)] thus formed, again absorbed O2 from air to make [MoVIO(O2)(tmp)]. The IR and 1H NMR data confirmed that O2 was coordinated as a peroxide mode to the central molybdenum(VI) ion from the same side of the porphyrin plane with the oxo ligand and that both the axial ligands (peroxo and oxo) eclipsed the trans-N atoms of the porphyrin rings. The second-order rate constant for the formation of the dioxygen complex in toluene was evaluated to be (3.9 ± 0.1) × 10−1 dm3 mol−1 s−1 at 20 °C. The rate constant is extremely small as compared with those of the oxygenation of iron(II) porphyrins, by at least a factor of 10−5.
Complex Formation of Lanthanide Ions with Sulfonated Crown Ethers in Aqueous Solution
Authors: Sasaki Takayuki , Umetani Shigeo , Matsui Masakazu , Tsurubou Shigekazu , Kimura Takaumi , Yoshida Zenko 
Published: August 2005

Abstract
A new type of water-soluble crown ether (3′-sulfobenzo-12-crown-4 (SB12C4), 3′-sulfobenzo-15-crown-5 (SB15C5), 3′-sulfobenzo-18-crown-6 (SB18C6), di(3′-sulfo)dibenzo-18-crown-6 (DSDB18C6), di(3′-sulfo)dibenzo-21-crown-7 (DSDB21C7), and di(3′-sulfo)dibenzo-24-crown-8 (DSDB24C8)) has been prepared. The complex formation constants (β) of lanthanide ions with sulfonated crown ethers in aqueous solution were determined via the solvent-extraction method. The stability of the resulting complexes increases with the number of sulfonic acid groups, 18C6 &lt; SB18C6 &lt; DSDB18C6. For mono and disulfonated crown ether complexes, the stability varies as SB18C6 &lt; SB15C5 &lt; SB12C4 and DSDB18C6 &lt; DSDB21C7 &lt; DSDB24C8. The β values of all the complexes of lanthanide ions decrease with the atomic number, which is a characteristic of macrocyclic ligands, and is quite opposite to the conventional complexing tendency. The extractive separability of lanthanide ions was found to improve by adding sulfonated crown ethers into the aqueous phase as ion-size selective masking reagents. The number of water molecules in the first coordination sphere of the central Eu3+ in the complex was determined by a laser-induced luminescence study. In addition, the fluorescence spectra were measured in order to evaluate the structure of the complexes. The stabilization of the complexes formed is discussed while taking into account an outer-sphere electrostatic attraction between the sulfonic acid group and the metal ion.
Statistical Characterization of Eleven Kinds of Helix Elements with Amino Acid Residues in the Middle of Triplets
Authors: Narita Mitsuaki , Sode Koji , Ohuchi Shokichi , Murakawa Yuka , Hitomi Mitsuo 
Published: August 2005

Abstract
Based on the definition of a helix region in terms of dihedral angles φ and ψ, 681 helices could be easily extracted from 125 kinds of analyzed proteins by using two-dimensional φ and ψ diagrams of their three-dimensional structures. The 8000 (203) possible kinds of amino acid residues in the middle of triplets consisting of consecutive residues were used for a precise analysis of helical segments in globular proteins. They correspond to the 8000 kinds of amino acid residues in a sequence of proteins. The 681 helices were built up from 8836 amino acid residues, which could be classified into 11 kinds of helix elements (a—k). Each of the amino acid residues in a sequence of helical segments could be allotted to one of 11 helix elements (a—k). Glycine residues in the proteins were used for its precise assignment as internal standards. The 11 kinds of helix elements could be statistically characterized with amino acid residues in the middle of triplets. Amino acid residues, observed as a specific helix element 3-times or more often in the total helical segments, were evaluated regarding their propensities for a specific helix element by using their inherent preference (IP)-values for the specific helix element, which had been defined in a previous paper. Amino acid residues found 13-times or more often in the data set are also listed to show their propensities for specific helix elements.
Preparation, Ligand Substitution, and Structural Stability of (η3-Allyl)dicarbonylnitrosyliron Complexes
Authors: Nakanishi Saburo , Memita Seiji , Takata Toshikazu , Itoh Keiji 
Published: August 2005

Abstract
[Fe(η3-allyl)(CO)2(NO)] complexes were prepared by the reaction of tetrabutylammonium tricarbonylnitrosylferrate with tosylates, trifluoroacetates and phosphonates of allylic alcohols and with allylic halides. However, acetates and carbonates of the allylic alcohols are ineffective for the preparation of the complexes. The reaction of [Fe{η3-(1-substituted allyl)}(CO)2(NO)] with phosphorus ligands (L) gave a mixture of diastereomeric [Fe{η3-(1-substituted allyl)}(CO)(NO)(L)] complexes, which have planar chirality and central chirality of the iron atom. Variable-temperature 1H NMR spectroscopy revealed that no isomerization between these diastereomers occurred upon heating up to 80 °C. Also, neither syn–anti isomerization of the allylic ligand nor isomerization of planar chirality of the complexes took place. The unsubstituted allylic ligand rotates about the iron-allyl ligand axis at room temperature, while η3-(1-substituted allylic) ligands do not.
Tetraanion Tetralithium with 8 Center/12 Electron π-System Stabilized by Silyl Groups. Synthesis and Characterization
Authors: Sekiguchi Akira , Matsuo Tsukasa , Akaba Ryoichi 
Published: August 2005

Abstract
Reduction of octasilyltrimethylenecyclopentene (2) with lithium metal in tetrahydrofuran yields orange crystals of the tetraanion tetralithium (3) with 8 center/12 electron π-system. The molecular structure of 3 is unequivocally established by X-ray crystallography. The tetralithium 3 has a monomeric structure and forms contact ion pairs (CIP) in the crystals. The two lithium atoms (η5) are located above and below the center of the five-membered ring, whereas the other two lithium atoms (μ2) are bonded to the two exocyclic carbon atoms. The structural parameters of 3 are discussed in comparison to that of the neutral starting molecule of 2. The structure of 3 in solution has also been discussed on the basis of NMR spectroscopic data.