bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unique Aspects of the 1-Methylimidazole Ligation to Corrphycenatoiron(III)
Authors: Neya Saburo , Ohgo Yoshiki , Nakamura Mikio , Funasaki Noriaki 
Published: September 2002

Abstract
The coordination behaviors of chloro corrphycenatoiron(III), a novel hemin isomer with a trapezoidal metallo core, against imidazole, 1-methylimidazole, and 2-methylimidazole were followed by spectrophotometry in chloroform at room temperature. The examined compound is chloro 12,17-bis(ethoxycarbonyl)-2,3,6,7,11,18-hexamethylcorrphycenatoiron(III). Titration of 2-methylimidazole and imidazole proceeded with and without accumulation of an intermediate mono imidazole species, respectively. On the other hand, a significant amount of an intermediate adduct was found to accumulate during 1-methylimidazole binding despite the absence of any steric hindrance in the iron(III)-N(1-methylimidazole) coordination bond. This is in remarkable contrast with the conventional results for porphyrinatoiron(III). The proton NMR analysis of the mono 1-methylimidazole binding to corrphycenatoiron(III) afforded a formation constant closely similar to that obtained from the visible spectra. EPR definitely assigned the iron(III) high-spin state for the intermediate. Accumulation of the mono 1-methylimidazole intermediate was explained in terms of the contracted core in corrphycene. The narrow iron cavity weakens the axial iron-chloride bond facilitating coordination of the first 1-methylimidazole. The four non-orthogonal iron(III)-N(pyrrole) bonds formed in the trapezoidal cavity further disturb the incoming motion of the iron(III) atom into corrphycene plane upon second 1-methylimidazole ligation. Accumulation of mono 1-methylimidazole intermediate was more evident in ferric corrphycenatoiron(III) with bromide and iodide, supporting the proposed changes in iron reactivity upon deformation of the equatorial coordination environment.
Five-Coordinate Geometry of Cadmium(II) with Octahedral Bidentate-S,S Complex-Ligand cis(S)-[Co(aet)2(en)]+ (aet = 2-aminoethanethiolate): Synthesis, Crystal Structures and Interconversion of S-Bridged CoIIICdII Polynuclear Complexes
Authors: Konno Takumi , Tokuda Keiji , Sakurai Junko , Okamoto Ken-ichi 
Published: September 2002

Abstract
An S-bridged CoIIICdII dinuclear complex molecule, [CdCl3{Co(aet)2(en)}]0 ([1]) (aet = 2–aminoethanethiolate, en = ethylenediamine), was prepared by the reaction of an S-bridged CoIIINiIICoIII trinuclear complex salt, [Ni{Co(aet)2(en)}2]Cl4, with excess CdCl2 in water. Treatment of [1] with NaNO3 in water gave an S-bridged CoIIICdIICoIII dinuclear complex salt, [CdCl{Co(aet)2(en)}2](NO3)3 ([2](NO3)3), which was further converted to a (CoIIICdIICoIII)2 hexanuclear complex salt, [Cd2Cl{Co(aet)2(en)}4](NO3)7 ([3](NO3)7), by treatment with NaNO3 in water. The crystal structures of [1], [2](NO3)3 and [3](NO3)7 were determined by X-ray crystallography. In [1] CdII ion is coordinated by three Cl- ions besides two S atoms from one octahedral C2-cis(S)-[Co(aet)2(en)]+ unit, while each CdII ion in [2]3+ and [3]7+ is coordinated by one Cl- ion besides four S atoms from two C2-cis(S)-[Co(aet)2(en)]+ units. The coordination geometry of each CdII center in [1], [2]3+ and [3]7+ is described as a distorted trigonal-bipyramid, considering an angular structural parameter, χ, which is proposed as a modified index of trigonality. The reverse conversions of [3]7+ to [2]3+ and [2]3+ to [1] were also achieved by treatment with NaCl in water.
Selective, Convenient and Efficient Deprotection of Trimethylsilyl and Tetrahydropyranyl Ethers, Ethylene Acetals and Ketals with Oxone under Non-aqueous Conditions
Authors: Mohammadpoor-Baltork Iraj , Amini Mohammad Kazem , Farshidipoor Siyamak 
Published: September 2002

Abstract
An efficient and selective method for the deprotection of trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers, ethylene acetals and ketals to their corresponding alcohols and carbonyl compounds using oxone in refluxing acetonitrile is described. Excellent chemoselectivity of this method makes it a useful and practical procedure in organic synthesis.
Rhenium Complexes-Catalyzed Alkylation of Arenes with Alkyl Halides
Authors: Nishiyama Yutaka , Kakushou Fujio , Sonoda Noboru 
Published: September 2002

Abstract
Rhenium complexes have been shown to catalyze the alkylation of arenes with alkyl halides. When arenes were reacted with an alkyl chloride in the presence of a catalytic amount of rhenium complexes, such as bromopentacarbonylrhenium(I) [ReBr(CO)5], tricarbonylcyclopentadienylrhenium(I) [Re(C5H5)(CO)3] and decacarbonyldirhenium [Re2(CO)10], alkylation of the arenes proceeded under mild conditions to give a mixture of mono- and dialkyl substituted arenes in moderate-to-good yields.
Mechanistic Studies of the Pyrene-Sensitized Photodecomposition of N-Phenylglycine: Acceleration of the Photodecomposition by the Addition of an Electron Acceptor
Authors: Ikeda Shingo , Murata Shigeru , Ishii Kunihiko , Hamaguchi Hiro-o 
Published: September 2002

Abstract
The processes of the pyrene-sensitized photodecomposition of N-phenylglycine (NPG) have been investigated by fluorescence quenching experiments, laser flash photolysis studies, and characterization of the reaction products. A mechanism involving electron transfer from NPG to singlet excited pyrene through emissive exciplex formation, as well as the intervention of PhNHCH2· as a reactive intermediate, has been established. The efficiency of NPG photodecomposition is enhanced by the addition of an electron acceptor, such as terephthalonitrile or diethyl isophthalate. The laser flash photolysis studies have revealed that the mechanism for the rate enhancement of NPG photodecomposition depends on the acceptor employed as an additive.
Lead(IV) Oxide-Mediated Oxidation of Azulen-2-ols to Form 1,1-Coupled Dimers and Hexacyclic Cage-Dimers.
Authors: Lin Yun-Shan , Lin Shih-Jue , Jiang Shuan-Ya , Huang Tian-Chyuan , Huang Chien-Yu , Kurihara Teruo , Mori Akira , Morita Tadayoshi , Takeshita Hitoshi , Nozoe Tetsuo 
Published: September 2002

Abstract
The lead(IV) oxide oxidation of various azulen-2-ol derivatives in acetic acid generates azulenoxy radicals via one-electron oxidation. The intermediates end up yielding recombined dimers, [1,1′-biazulene]-2,2′(1H,1′H)-dimers, as common type of products. In addition to these, hexacyclic cage dimers were obtained from 5-substituted azulen-2-ol derivatives. From dimethyl 2-hydroxyazulene-1,3-dicarboxylate, a hydroxyazulene having no substituent on the seven-membered ring was isolated a pair of dimethyl 2-hydroxy-4-[1,3-di(methoxycarbonyl)-2-oxo-1,2-dihydroazulenyl]azulene-1,3-dicarboxylate, but neither a cage dimer nor a 1,6-coupled dimer. The full structures of the dimers have been firmly established by an extensive X-ray crystallographic analysis and 13C NMR spectral comparisons of the key derivatives. Concerning the mechanism of the formation of the cage dimers, a [5+5] π cycloaddition followed by recombination of the resultant biallyl system is suggested.
Direct Synthesis of N-Hydroxy β-Amino Acid Esters from Carboxylic Esters and Nitrones
Authors: Kobayashi Kazuhiro , Matoba Takeshi , Irisawa Susumu , Takanohashi Atsushi , Tanmatsu Miyuki , Morikawa Osamu , Konishi Hisatoshi 
Published: September 2002

Abstract
The direct synthesis of the title amino acid derivatives from carboxylic esters and nitrones can be achieved in fair to good yields when lithium or magnesium ester enolates were treated with nitrones in THF at -78 °C or in Et2O at -20 to 0 °C, respectively. The products from the reaction of t-butyl acetate with 3,4-dihydroisoquinoline N-oxide or 5,5-dimethylpyrroline 1-oxide were transformed into (1,2,3,4-tetrahydroisoquinolin-1-ylidene)acetate or (pyrrolidin-2-ylidene)acetate derivatives in the presence of triphenylphosphine, carbon tetrachloride, and triethylamine in refluxing dichloromethane.
Solution Properties of Sodium Dodecylbenzenesulfonate (SDBS): Effect of Additives
Authors: Sulthana Shireen Basheer , Bhat Sodankoor Garadi Thirumaleshwar , Rakshit Animesh Kumar 
Published: September 2002

Abstract
The solution properties of sodium dodecylbenzenesulfonate (SDBS) in an aqueous medium in the presence of additives, like polyethylene glycol 400 (PEG 400), sucrose, and urea, have been investigated. The critical micelle concentration (cmc) was determined by both surface-tension and conductivity methods. The cmc values were found to increase along with an increase in the temperature in both the presence and absence of additives at all of the concentrations studied. The interfacial parameters, such as the maximum surface excess (Γmax) and minimum area per molecule (Amin), were computed from surface-tension data. The thermodynamic parameters of micellization and adsorption at air/water interfaces were also evaluated. Other properties, such as the micellar aggregation number (Nagg), viscosity, foaming, wetting, and detergency by dye solubilization, were also studied.
A Convenient Method for the Preparations of Carboxamides and Peptides by Using Di(2-pyridyl) Carbonate and
O
,
O
′-Di(2-pyridyl) Thiocarbonate as Dehydrating Reagents
Authors: Shiina Isamu , Suenaga Yoshihito , Nakano Masakazu , Mukaiyama Teruaki 
Published: September 2002

Abstract
Preparations of carboxamides and peptides are performed in high yields from free carboxylic acids and amines by dehydration condensation using di(2-pyridyl) carbonate (DPC) or O,O′-di(2-pyridyl) thiocarbonate (DPTC) in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP). The formation of 2-pyridyl esters, key intermediates of the reaction, from carboxylic acids by using DPC proceeded faster than by using DPTC; therefore, the former carbonate is more efficiently employed in the above condensation reactions.
Syntheses of Optically Active Citronellol, Citronellal, and Citronellic Acid by Microbial Oxidation and Double Coupling System in an Interface Bioreactor
Authors: Oda Shinobu , Sugai Takeshi , Ohta Hiromichi 
Published: September 2002

Abstract
We have already reported that (RS)-citronellol [(RS)-1] can be optically resolved via a transacetylation with acetyl coenzyme A [acetyl-CoA] by the aid of alcohol acetyltransferase [AATFase] in Pichia kluyveri IFO 1165, which we have referred to as a double coupling system (E value, 30 to 40). In this system, although (R)-1 is obtained at over 98% ee, (S)-citronellyl acetate [(S)-2] is prepared at 70 to 80% ee. In this article, we report on the conversion of (R)-1 to (R)-citronellal [(R)-3] and (R)-citronellic acid [(R)-4] in high yield without racemization by the aid of Rhodococcus equi JCM 6817 and Geotrichum candidum JCM 01747, respectively. On the other hand, the low ee of (S)-1 (78% ee) prepared via the alkaline hydrolysis of (S)-2 is converted to optically active (S)-1 and (S)-4 in high yield with a repeated double coupling system with P. kluyveri IFO 1165 and via enantioselective oxidation with Candida viswanathii IFO 10321, respectively. Thus, five optically active terpenoids related to citronellol, except for (S)-3, were efficiently synthesized via microbial transformations in an interface bioreactor.
A General Method for the Formation of Zinc Enolate Equivalents from Iodoacetates by Diisopropylzinc-Iodine Exchange Reaction: Preparation of β-Hydroxy Esters
Authors: Sato Itaru , Takizawa Yoshiko , Soai Kenso 
Published: September 2002

Abstract
Diisopropylzinc is found to be a highly efficient reagent for the formation of zinc enolate equivalents from various iodoacetates via iodine-zinc exchange reaction at room temperature, affording β-hydroxy esters in high yields by the reaction with aldehydes and ketones.
Synthesis of Diarylsulfoximines by the Friedel-Crafts Reaction of Sulfonimidoyl Chlorides
Authors: Furusho Yoshio , Okada Yuichiro , Takata Toshikazu 
Published: September 2002

Abstract
In the presence of an equimolar amount of FeCl3, sulfonimidoyl chlorides were allowed to react with aromatic compounds to give the corresponding sulfoximines. Structure of the sulfonimidoyl chlorides and the aromatic compounds had considerable influence on the yield of the sulfoximines.
Construction of Polymeric Self-Assembly Based on 2λ5,4λ5,6λ5-Cyclotriphosphazene and Its Inclusion Behavior of Iodine
Authors: Itaya Tomoyuki , Inoue Kenzo 
Published: September 2002

Abstract
The self-assembling of 2,2,4,4,6,6-hexakis(4-pyridylmethoxy)-2λ5, 4λ5, 6λ5-cyclotri(phosphazene) (PyPN) and 1,4-naphthalenedicarboxylic acid (DCN) in DMF gives needle-like crystals. From elemental analysis, the stoichiometry of the crystal was PyPN/DCN = 1 : 3. The FT-IR, fluorescence and X-ray diffraction data showed that the self-assemblies [PyPN·3(DCN)]n (1) formed by the hydrogen bonding with an alternating sequence of one PyPN and three DCN molecules take a cylindrical structure and are laterally packed into a hexagonal arrangement, where the naphthalene rings are placed to avoid steric congestion. The assembly 1 has an ability to include iodine molecules. From FT-Raman spectroscopy, the iodine in 1 was found to exist as a polyiodine linear I5- ion, indicating that the crystal of 1 has a tunnel-like void.
Potential Energy Surfaces for Liquid Ammonia: An Estimation of ab initio Calculations for Molecular Simulations
Authors: Honda Kazuhiko 
Published: September 2002

Abstract
Hydrogen-bond-enhanced interactions were generated for ammonia pairs by ab initio calculations using tempered basis sets. The potential function obtained by the generation of interaction energies was applied to a Monte Carlo simulation for the liquid state of ammonia. The simulated bulk properties were considered compared with a previous ab initio STO-3G based simulation. The thermodynamic properties were obtained in the simulation and compared with those of a liquid water system to which the same manner of enhancement for the hydrogen bond was applied. The qualitative difference between the two liquids was reproduced.
Formation of an Iron-Oxo Species upon Decomposition of Dinitrogen Oxide on a Model of Fe-ZSM-5 Zeolite
Authors: Yoshizawa Kazunari , Yumura Takashi , Shiota Yoshihito , Yamabe Tokio 
Published: September 2002

Abstract
The so-called ``α-oxygen" on Fe-ZSM-5 zeolite, a surface oxygen species responsible for high reactivity in oxidation of methane and of benzene, has been investigated. We present from density-functional-theory (DFT) calculations how such a reactive surface species is generated upon decomposition of dinitrogen oxide (N2O) and propose a possible form of ``α-oxygen" on Fe-ZSM-5 zeolite. In the initial stages of the reactions, a complex involving an Fe(ON2) moiety is formed, followed by dissociation into an iron-oxo species and N2. The activation energy for the decomposition of N2O on a possible iron active site model of Fe-ZSM-5 zeolite is predicted to be 2.4 kcal mol-1 at the B3LYP level of theory. Therefore the decomposition of N2O is expected to take place easily at a coordinatively unsaturated iron active center supported on zeolite. The iron-oxo species thus formed should play an essential role in the direct hydroxylation of methane, benzene, and other hydrocarbons if it involves a coordinatively unsaturated iron. The oxygen exchange on the iron-oxo complex was also investigated. The activation energy for the oxygen exchange on the ``α-oxygen" is predicted to be 26.8 kcal mol-1. We propose that the bare FeO+ complex and the so-called ``α-oxygen" on Fe-ZSM-5 zeolite involve similar catalytic active centers responsible for similar catalytic functions for methane and benzene.
Quantum Mechanical Interpretation and Evaluation of Hydrogen Evolution at Metal Electrodes
Authors: Sakata Tadayoshi 
Published: September 2002

Abstract
The quantum mechanical theory of electrode reactions was applied to a hydrogen evolution reaction. The dependence of the activation energy of the hydrogen exchange current densities on the kind of electrode metal was explained well by this theory. The magnitude of the hydrogen exchange current densities and hydrogen overvoltages at various metal electrodes were evaluated theoretically. The calculated results and the dependency on the kind of metal were found to agree well quantitatively with the experimental values.
Cationic Motions and Order-Disorder Phase Transitions in Layer Crystals with a Rotator Phase, (n-C5H11NH3)2ZnCl4 and (n-C12H25NH3)2ZnCl4
Authors: Horiuchi Keizo , Takayama Himiko , Ishimaru Shin'ichi , Ikeda Ryuichi 
Published: September 2002

Abstract
1H NMR spin-lattice relaxation times T1 and T1ρ as well as the electrical conductivity were measured as a function of temperature in (n-C5H11NH3)2ZnCl4 and (n-C12H25NH3)2ZnCl4. The highest-temperature solid phase in both compounds was found to be the rotator phase, where rod-like cations perform uniaxial reorientations about the molecular long axes accompanied by conformational disordering and translational self-diffusion of the cations within the layer perpendicular to c-axis. In the rotator phase, the cations are considered to have a non-intercalated double layer structure. These rotator phases were shown to be quite analogous to those reported in n-alkylammonium chlorides. (n-C5H11NH3)2ZnCl4 undergoes four structural phase transitions, while (n-C12H25NH3)2ZnCl4 exhibits a single transition above ca. 120 K. All of these transitions were shown to be of order-disorder type.
Chemical Modification of MgO(001) Surface by Utilizing Energy Decomposition Analyses for the Purpose of CO2 Adsorption
Authors: Takahashi Hideaki , Okuda Kazuhiro , Nitta Tomoshige 
Published: September 2002

Abstract
The intermolecular interaction between a CO2 molecule and an MgO cluster has been investigated by ab initio molecular orbital method in order to test a selection rule for chemical modifications of surfaces. Favorable adsorption geometry has been determined by partial geometry optimizations initiated from three possible formations of the molecular complex. A CO3-form where the carbon atom is coordinated to an O atom of the MgO cluster is found to be most stable. The Kitaura-Morokuma energy decomposition analysis has been carried out to investigate the nature of the intermolecular interaction between a CO2 molecule and an MgO cluster. It is found that charge transfer energy from the MgO cluster to CO2 is the dominant component in the total stabilization energy. Two Mg atoms are replaced by two Ca atoms to enhance the electron flow from an MgO cluster to a CO2 molecule, which resulted in the increase in the adsorption energy. The effect of the chemical modification is examined by the energy decomposition analysis. We confirm that the increase of the cohesive energy is a consequence of the increase in charge transfer interaction from the cluster to the CO2 molecule. The mechanism of the charge transfer is also studied by the molecular orbital analysis.
Analysis of the Infrared Spectrum of RbCl Vapor
Authors: Ogilvie John F , Uehara Hiromichi , Horiai Koui 
Published: September 2002

Abstract
With laser diodes we measured spectra of RbCl vapor near 1000 K in absorption in a region 43800—46400 m-1 and assigned vibration-rotational transitions, 226 of 85Rb35Cl up to ν′ = 9 and J′ = 160, 158 transitions of 85Rb37Cl and 125 of 87Rb35Cl, all with Δν = 2. We made a global fit of these 509 new data plus 28 published pure rotational transitions. Of eight evaluated parameters, six are adjusted, pertaining to a function for potential energy, and two are constrained, pertaining to nonadiabatic rotational effects; these parameters suffice to reproduce these data generally within uncertainties of their measurement. Comparison is made with corresponding spectral parameters of HCl, LiCl, NaCl and KCl.
Generalization of Partial Cycle Indices and Modified Bisected Mark Tables for Combinatorial Enumeration
Authors: Fujita Shinsaku 
Published: September 2002

Abstract
Generalized partial cycle indices have been proposed as a generalization of partial cycle indices (PCIs) in order to enumerate isomers with a given set of subsymmetries. To evaluate the coefficient of each term appearing in such a generalized PCI, the natures of a mark table and of its inverse have been examined after the proposal of (modified) bisected mark tables and their inverses as well as of (modified) bisected tables of unit subduced cycle indices with chirality fittingness (USCI-CFs). The inverse of a (modified) bisected mark table and the (modified) bisected USCI-CF table have been applied to the enumeration of chiral isomers and achiral isomers.
Tetrabutylphosphonium Cation as a Template in the Kinetics of the Crystallization of B-ZSM-5
Authors: Sundaramurthy Vedachalam , Lingappan Nachiappan 
Published: September 2002

Abstract
Pentasil zeolite, B-ZSM-5 and Al-ZSM-5, have been synthesized hydrothermally using orthoboric acid and sodium aluminate, respectively, with ethyl silicate-40 so as to obtain a gel mix with SiO2/M2O3 = 22 (where M = B or Al) employing a tetrabutylphosphonium bromide (TBPBr) template at temperatures of 423, 448, and 473 K. The crystallization kinetics followed by XRD, FTIR, and SEM studies clearly demonstrate the influence of the size of the hetero atoms on the rate of nucleation and crystallization. The values of the apparent activation energies for nucleation and crystal growth indicate that both nucleation and crystal growth are faster for the Al-ZSM-5 system than for the B-ZSM-5 system. Avrami-Erofeev parameters for both systems have been evaluated. Correlations were found between the kinetics of crystallization and the characteristics of the formed crystal. SEM pictures show similar, but larger sized, crystals for the Al-ZSM-5 system than those of the B-ZSM-5 system. XRD, FTIR, and chemical analysis have revealed that the mechanism operating during crystallization is the same, and that hetero atoms become incorporated with the framework during the nucleation step, itself, with boron at a slower rate.
The Direct Effects of Alkali Metal and Alkaline Earth Metal Perchlorates on the Equilibria of Acid-Base Indicators (Sulfonephthaleins) in Acetonitrile Solution
Authors: Hojo Masashi , Ueda Tadaharu , Kawamura Kazushi , Yamasaki Masanori 
Published: September 2002

Abstract
With the addition of alkali metal (M+) and alkaline earth metal (M2+) perchlorates, the cause of the color changes of several sulfonephthaleins of various pKa values, i.e., Thymol Blue, Phenol Red, Bromothymol Blue, and Bromocresol Green, in acetonitrile solutions were examined by means of spectrophotometry and 1H NMR. Upon the addition of ≥ 0.1 mol dm-3 LiClO4 to 1.0 × 10-4 mol dm-3 Phenol Red, the γ-sultone ring of the sulfonephthalein was cleaved to give absorption bands at around 410 and 500 nm. The band at 500 nm was assigned to the acid form, and that around 410 nm to a quinonoid structure (the intermediate form) which would be formed by deprotonation from the acid form. The effects of NaClO4 were much smaller than those of LiClO4. Magnesium and barium perchlorates caused larger effects than LiClO4; however, a nonmetallic salt, Et4NClO4, caused almost no effects. In addition, a purple-red colored species (λmax = 563 nm), a basic form, was also produced from Phenol Red by the addition of ≥ 0.2 mol dm-3 Mg(ClO4)2. Interestingly, the metal ions assisted not only the acid effects of CH3SO3H, but also the base effects of Et3N or 1,1,3,3-tetramethylguanidine on Phenol Red or Bromothymol Blue in acetonitrile. 1H NMR spectra of the sulfonephthaleins confirmed the opening of the γ-sultone rings in the presence of the metal salts. The ring cleavage upon the addition of the metal ions was considered from the standpoint of not ``medium effects'', but a direct chemical interaction between the metal ions and the sulfonate ion (function) in the sulfonephthaleins.