bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dehydrogenation of Nickel(II) Chelates of rac- and meso- 2,2′-[(1,2-Diphenylethylene)bis(iminomethylene)]diphenol and Related Compounds
Authors: Kanatomi Hajime
Published: July 2006

Nickel(II) acetate tetrahydrate and rac- and meso-2,2′-[(1,2-diphenylethylene)bis(iminomethylene)]diphenol (rac- and meso-BzPhen-H2) formed pale green complexes in methanol. A pyridine solution of these complexes deposited deep red diimine complexes after prolonged heating under aerobic conditions. The saturated ligand system of the initial complexes was dehydrogenated to an unsaturated one by molecular oxygen. From the pyridine solution of the meso-isomzr, [2,2′-(cis-1,2-diphenylethenylene)bis(nitrilomethylidyne)diphenolato]nickel(II)([Ni(SalStil)]) was isolated in addition to the diimine complex ([Ni(meso-SalPhen)]). In this case, the (Remark: Graphics omitted.) bridge was dehydrogenated to (Remark: Graphics omitted.) conjugated double bonds; that is, a fully conjugated metal chelate was formed by the dehydrogenation of the coordinated ligand.
A Potential-step Chronoamperometric Study of Ion Transfer at the Water/Nitrobenzene Interface
Authors: Kakutani Tadaaki , Osakai Toshiyuki , Senda Mitsugi
Published: July 2006

Potential-step chronoamperometry, cyclic voltammetry, and chronopotentiometry have been applied to the study of the transfer of the tetramethylammonium (TMA+) ion across the interface between a 0.1 mol dm−3 lithium chloride aqueous solution and a 0.1 mol dm−3 tetrabutylammonium tetraphenylborate nitrobenzene solution. An analysis of the current-time and current-potential curves obtained by means of potential-step chronoamperometry indicates that the transfer of the TMA+ ion across the water/nitrobenzene interface is a reversible diffusion-controlled process, which can be explained by the theory of the chronoamperometry of a reversible charge transfer at the electrode surface. The values of the diffusion coefficient of the TMA+ ion in the aqueous phase and of the reversible half-wave potential of the TMA+ ion transfer, as determined by means of potential-step chronoamperometry, agreed well with those determined by means of cyclic voltammetry and chronopotentiometry.
The Adsorption of Polypeptides on Polystyrene Latices and Their Effects on Colloid Stability
Authors: Furusawa Kunio , Sakai Hidetoshi , Watanabe Noribumi , Tomotsu Norio
Published: July 2006

The adsorption behavior of poly(l-lysine) and poly(l-glutamic acid) on negatively and positively charged latices was examined in combination with their stabilizing effects on the latex dispersion. It was realized that the polypeptide adsorption was, to a large extent, determined by the coulombic interaction between the polypeptide and the charged surface, and by the conformational change (helix-coil transition) in the polypeptide in the solution. The flocculation behavior of the dispersion in the presence of polypeptide was also explained reasonably by taking account of the results of electrophoretic measurements of the polypeptide-coated particles.
Kinetic Isotope and Pressure Effects in the Reaction of Leucocrystal Violet with Tetracyanoethylene and Chloranil
Authors: Nishimura Norio , Motoyama Takushi
Published: July 2006

The rates of reaction of Leucocrystal Violet (LCV) with chloranil (CA) and tetracyanoethylene (TCNE) were measured, and the kinetic isotope and pressure effects were examined. In the LCV–CA system, a very large isotope effect (kH⁄kD≈11) was observed, while in the LCV–TCNE system, it was not so large (kH⁄kD=5–6) suggesting the tunnel effect is not substantial. For both systems, the formation of a CT complex in equilibrium with the reactants was observed at low temperatures (<−50 °C). From the rate law, the isotope effect, the electronic and ESR spectra observed during the reaction, and their time dependence, possible reaction processes are proposed.
Reactions of trans-Chloro(cyanomethyl)bis(triphenylphosphine)- and Chloro(cyanomethyl){1,2-bis(diphenylphosphino)ethane}palladium(II) Complexes with Various Thallium(I) β-Diketonates
Authors: Ishio Noriaki , Nakamura Yukio , Okeya Seichi
Published: July 2006

Reactions of trans-chloro(cyanomethyl)bis(triphenylphosphine)palladium(II), trans-[PdCl(CH2CN)(PPh3)2] (1), with an equimolecular amount of Tl(β-dik) (β-dik=etac, acac, tfac, bzac, and dbm) in dichloromethane afforded the O,O′-chelated β-dik complexes [Pd(CH2CN)(β-dik)(PPh3)] (3). Hydrogen peroxide oxidation and chloride abstraction by AgClO4 or AgBF4 of 1 gave the neutral [PdCl(CH2CN)PPh3]n and the cationic [Pd(CH2CN)(PPh3)2]mXm (X=ClO4 or BF4), respectively, from either of which complexes 3 were also obtained by the reactions with the β-dik anions. No pure product corresponding to 3 was isolated by a similar treatment of 1 with Tl(hfac). On the other hand, chloro(cyanomethyl){1,2-bis(diphenylphosphino)ethane}palladium(II), [PdCl(CH2CN)(dppe)] (2), reacted only with Tl(hfac) in refluxing acetone to give the cationic [Pd(CH2CN)(dppe)]2(hfac)2, which was also derived from 2  via [Pd(CH2CN)(dppe)]2X2 (X=ClO4 or BF4).
Reaction of Organoboranes with Lead(IV) Acetate Azide. A Synthesis of Azidoalkanes from Alkenes via Hydroboration
Authors: Masuda Yuzuru , Hoshi Masayuki , Arase Akira
Published: July 2006

Trialkylboranes prepared from alkenes via hydroboration react with lead(IV) acetate azide in dichloromethane at −25 °C to form the corresponding azidoalkanes in a one-pot manner. One or two of the alkyl groups of trialkylboranes are utilized in the reaction. For example, 1-azidohexane is afforded from 1-hexene in 50% yield based on the alkene employed.
Nonacarbonyldiiron or Pentacarbonyliron Induced Decomposition of Organic Azides and an Azirine. Novel Reduction and Carbonyl Insertion of the Complexed Nitrene Intermediate in Protic Solvents
Authors: Nitta Makoto , Kobayashi Tomoshige
Published: July 2006

The thermal reactions of [Fe2(CO)9] or the photochemical reactions of [Fe(CO)5] with organic azides and an azirine in protic media have been investigated. The thermal reaction of azidobenzene (1) with [Fe2(CO)9] in methanol under mild conditions gave aniline and methyl phenylcarbamate, along with N,N′-diphenylurea, while in the presence of water, 1 afforded aniline and N,N′-diphenylurea, in good combined yield. Similarly, the thermal reaction of α-azidostyrene (4) with [Fe2(CO)9] in methanol gave methyl 1-phenylvinylcarbamate and acetophenone which could be derived from the corresponding enamine, while in the presence of water, 4 gave only acetophenone in good yield. The photoirradiation of [Fe(CO)5] with 1 or 4 also gave results similar to the [Fe2(CO)9]-induced reaction. However, the thermal reaction of 3-phenyl-2H-azirine (5) with [Fe2(CO)9] in methanol gave 2,5-diphenylpyrazine in low yield, in addition to acetophenone and methyl 1-phenyl-vinylcarbemate, although 5 afforded only acetophenone in the presence of water. The reaction pathways for the formation of the products are discussed on the basis of the formation of a complexed nitrene intermediate, reduction of which induces amine or enamine and carbonyl insertion to yield an organic isocyanate in protic media.
Stereoselective Catalytic Hydrogenation of α-Hydroxy Ketoximes
Authors: Harada Kaoru , Shiono Shozo
Published: July 2006

Two isomers(E and Z) of benzoin oxime and 2-hydroxy-1-phenyl-1-propanone oxime were catalytically hydrogenated by using palladium on charcoal and erythro amino alcohols were obtained in about 80% diastereomeric excess. The syn-anti isomerization of these oximes in the presence of palladium on charcoal was also studied in connection with the stereoselectivity of the catalytic hydrogenation of the oximes.
Effects of Surface Fluorination on Catalytic Activities and Surface Compositions of TiO2–Al2O3 and TiO2–SiO2–Al2O3
Authors: Okazaki Susumu , Kurosaki Akito , Suzaki Shinzo
Published: July 2006

Studies showed that the ternary oxide having the atomic ratio of Ti/Si/Al=47.5/47.5/5 exhibited a high catalytic activity for cumene cracking after a surface fluorination using 1 wt% hydrofluoric acid. The catalytic activity for CH3OH conversion into olefins was highly dependent on the preparation method. That is, the ternary mixed oxide promoted olefin formation slightly when the mixed oxide was prepared only by coprecipitation. Surface treatment, using gaseous CF3Cl was effective in enhancing catalytic activity. Although the binary oxide, TiO2–Al2O3, itself, was catalytically inactive for olefin formation, TiO2–Al2O3 prepared by coprecipitation became active after the treatment using CF3Cl. Such an enhancement was found also for the ternary oxide, TiO2–SiO2–Al2O3, and is ascribable to increased acid strength, as determined by NH3 adsorptions at various temperatures. The XPS measurements showed that F atoms introduced into mixed metal oxides by the fluorination using CF3Cl, selectively combined with Al atoms on the mixed oxides prepared by coprecipitation. The XPS measurements of the mixed oxides before and after fluorination using CF3Cl showed that the coprecipitation preparation is more preferable than the impregnation method in maintaining surface composition during fluorination.
Thermodynamic Study on Solvent Extraction of Alkali Metal Picrates by 15-Crown-5
Authors: Takeda Yasuyuki , Namisaki Tsuyoshi , Fujiwara Shizuo
Published: July 2006

In order to obtain enthalpy (ΔH1°) and entropy changes (ΔS1°) for overall extraction reactions of 15-crown-5 (15C5) with alkali metal picrates between benzene and water, and those (ΔH2° and ΔS2°) for partition of 15C5 itself, overall extraction equilibrium constants of 1:1:1 complexes of 15C5 with the salts and distribution coefficients of 15C5 were determined at 20, 30, 35, and 40 °C. The ΔH1° and ΔS1° values of 15C5 for the alkali metals are all negative. Both the ΔH2° and ΔS2° values are positive. In general, the ΔH2° and ΔS2° values play a major role in determining the magnitude of ΔH1° and ΔS1° values, respectively, except the case of entropy change for the potassium system. Enthalpy (ΔH4°) and entropy changes (ΔS4°) for ion-pair extractions of 15C5-alkali metal ion complexes by picrate anions were calculated by using the ΔH1° and ΔS1° values, and the literature values for complex-formation reactions of 15C5 with alkali metal ions in water. Both ΔH4° and ΔS4° values vary with the alkali metal ion held in the 15C5 cavity. The ΔH4° and ΔS4° values for Na+, Rb+, and Cs+ are all negative, whereas those for K+ are all positive.
Mössbauer Spectroscopic Studies of the Effects of the 6Li(n, α)T Reaction in Lithium Tris(oxalato)ferrate(III)
Authors: Akashi Junko , Uchida Yoshio , Kojima Tomoko , Katada Motomi , Sano Hirotoshi
Published: July 2006

The chemical effects of the 6Li(n,α)T reaction in lithium tris(oxalato)ferrate(III) crystals were examined by means of Mössbauer spectroscopy. Neutron irradiations were carried out under different conditions in order to clarify the mechanism of the effects. The reduced iron(II) species observed in the spectrum of Li3[Fe(C2O4)3]·4.5H2O, subjected to neutron irradiation (8.6×1015 n cm−2) at 200 K, shows a larger Q.S. value than that in the spectrum of the sample neutron-irradiated at an ambient temperature (300–320 K) in a reactor, suggesting that the initially produced iron(II) species changes into another iron(II) species during the irradiation at the ambient temperature. A species identical with the initial iron(II) species produced in the neutron irradiation was found to be prepared by the pyrolysis of Li3[Fe(C2O4)3]·4.5H2O. A comparison of neutron-irradiated hydrous and anhydrous Li3[Fe(C2O4)3] suggests that the change in the iron(II) species is influenced by the existence of crystal water.
Cross-coupling Reaction between Enol Phosphates and Organoaluminium Compounds in the Presence of Palladium(0) Catalyst
Authors: Takai Kazuhiko , Sato Mitsuyoshi , Oshima Koichiro , Nozaki Hitosi
Published: July 2006

The title reaction in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) affords alkylative coupling products in good to excellent yields in 1,2-dichloroethane at room temperature. This coupling reaction under C(sp2)–O cleavage proceeds stereospecifically. The reaction does not affect a coexisting vinyl sulfide group. This feature enables 1,2- and 1,3-carbonyl transposition with or without alkylation via phenylthio-substituted enol phosphates.
Kinetic Trace Determination of Molybdenum(VI), l-Ascorbic Acid, and Thiosulfate Using Landolt Reaction by the Aid of Fluorometry
Authors: Kataoka Masamitsu , Hemmi Hirotoshi , Kambara Tomihito
Published: July 2006

Trace amounts of molybdenum(VI) can be determined by the use of their catalytic effects on the peroxoborate–iodide redox reaction in acidic medium. The indicator reaction is transformed to a Landolt reaction by the addition of ascorbic acid into the reaction mixture, i.e., the iodine produced by the reaction is immediately reduced by ascorbic acid. The end of the induction period of the Landolt process was fluorometrically detected by the aid of disappearence of fluorescence of Rhodamine B. Trace determination of molybdenum(VI) was carried out by employing the linear relationship between the reciprocal of induction period and catalyst concentration. The most suitable concentrations of sodium peroxoborate, potassium iodide, and hydrochloric acid in the reaction mixture were found to be 9 mM, 0.1 M, and 0.1 M, respectively. By this method, molybdenum(VI) can be determined from 80 nM to 10 mM (7.675 ng ml−1 to 95.95 mg ml−1). The effect of foreign ions were studied and an equal amount of tungsten(VI), and 10-fold amounts of zirconium(IV), iron(II), iron(III), vanadium(IV), and copper(II) were found to show interference. Ascorbic acid and thiosulfate in micro mol l−1 levels were also determined by the present method employing the linear relationship between the induction period and the reductant concentration.
Ion Exchange Resins Anchoring 1,8-Diazabicyclo[5.4.0]undec-7-ene
Authors: Ishikawa Tomomichi , Yoneyama Atsushi
Published: July 2006

The synthesis of polymeric quaternary ammonium salts linked 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) to chloromethylated polystyrenes is described. The polymers so obtained become anion exchangers with both quaternary ammonium and tertiary amino groups. The values of the total ion-exchange capacities indicated that the quaternization of the tertiary amino groups on the polymers with hydrochloric acid is difficult. The chloride forms of the resins, in spite of their bulky and steric quaternary ammonium groups containing DBU, were effective as ion exchangers for a variety of bulky anions such as sulfate, oxalate, hexacyanoferrate(II), hexacyanoferrate(III), and tris(oxalato) ferrate(III) ions. The free base forms of the resins gave low reactivity for chloride and sulfate ions. Some examples of the application of the resins is also reported.
Effect of Ethanol on the Inclusion Complex Formation between β-Cyclodextrin and Pyrene
Authors: Nakajima Akira
Published: July 2006

The effect of the addition of ethanol on the formation of the inclusion compound between β-cyclodextrin and pyrene in aqueous solution has been studied. Based on the time dependences of the fluorescence spectra of pyrene as a probe, the rate constants estimated for the inclusion and further association in the presence of ethanol have been discussed.
The Crystal Structure of the B′-Form of Heptadecanoic Acid
Authors: Goto Midori , Asada Eiichi
Published: July 2006

X-Ray structural determination of the B′-form of heptadecanoic acid showed that the unit cell contains two crystallographically independent molecules. All-trans zigzag chains are found in both molecules.
The Crystal Structure of Calcium Sulfite Hemihydrate
Authors: Matsuno Takashi , Takayanagi Hiroaki , Furuhata Kimio , Koishi Masumi , Ogura Haruo
Published: July 2006

The crystal data for calcium sulfite hemihydrate are orthorhombic, Pbcn, a=10.664(1), b=6.495(1), c=9.823(1) Å, and Z=8. The structure consists of two alternating layers. The calcium ions are coordinated by six O atoms: Five originate from the sulfite ions, and one from the water molecule.
Binuclear Metal Complexes. LIV. Strongly Spin-coupled Copper(II)–Iron(III) Complex of a Salen Homolog Containing Pendant Phenolic Group
Authors: Kanda Wakako , Okawa Hisashi , Kida Sigeo
Published: July 2006

A copper(II)–iron(III) binuclear complex of N,N′-disalicylidene-2-methyl-4-(2-hydroxy-5-methylphenyl)-1,2-butanediamine has been prepared and characterized. Cryomagnetic measurements revealed the presence of an antiferromagnetic spin-exchange interaction of J=−70 cm−1 between the metal ions.
Synthesis of Sydnone Compounds Having Alternating Carbon-Nitrogen Chain and Heterocyclic Groups at the 4-Position
Authors: Fuchigami Toshio , Yeh Mou-Yung , Goto Takushi , Nonaka Tsutomu , Tien Hsien-Ju
Published: July 2006

Entirely new type sydnones having alternating carbon-nitrogen chain groups such as 3-aryl-4-(arylcarbonimidoylcarbamoyl)sydnones, 3-aryl-4-(dimethylaminomethylenecarbamoyl)sydnones, and 4-(dimethylaminomethylenethiocarbamoyl)-3-phenylsydnone were prepared in high yields from 3-aryl-4-chloroformylsydnone, 3-aryl-4-carbamoylsydnone, and 3-phenyl-4-thiocarbamoylsydnone, respectively. The cyclization of the alternating carbon-nitrogen chain groups provided new sydnone derivatives having heterocyclic substituents such as 1,2,4-oxadiazol-5-yl, 1,2,4-triazol-3-yl, and 1,2,4-thiadiazol-5-yl groups in good yields.
Regularity in Homolytic Lattice Energies of Anhydrous Formate, Acetate, Oxalate, and Glycolate of Metals
Authors: Sakiyama Minoru , Murata Shigeo
Published: July 2006

The homolytic lattice energy ΔUR of an ionic crystal MxAy was defined as the standard internal energy change at 298.15 K for the following vaporization process to yield neutral species M and A: (l/x)MxAy(c)=M(g)+(y/z)A(g). ΔUR and [ΔUR–(y/x)ΔHfo(A,g)] were calculated for formates and acetates and for oxalates and glycolates, respectively, of metals, and were analyzed empirically. ΔUR(formate)\simeqΔUR(acetate) holds for every metal. ΔUR of oxalates and glycolates may be expressed as follows: ΔUR(oxalate or glycolate)=aΔUR(formate or acetate)+b(y/x), where a is the constant close to unity, and b is the constant which is, possibly, close to zero for oxalates and about 40 kJ mol−1 for glycolates. The linear relations in ΔUR were discussed in relation to crystal structure of the salts and carboxyl O–H bond dissociation energy of the corresponding carboxylic acids.
The Molecular Structures of (+)-6-Benzylsparteine, (Ethyl)(bromo)[(+)-6-benzylsparteine]magnesium(II), and Dibromo[(+)-6-benzylsparteine]magnesium(II). Structure and Reactivity of the Grignard Reagent–(−)-Sparteine Derivative Complexes for Asymmetric Selective Polymerization of Racemic Methacrylates.
Authors: Kageyama Hiroyuki , Miki Kunio , Kai Yasushi , Kasai Nobutami , Okamoto Yoshio , Yuki Heimei
Published: July 2006

(+)-6-Benzylsparteine (a) crystallizes in orthorhombic systems; P212121, a=10.711(1), b=25.868(4), c=6.804(1) Å, and Z=4;EtMgBr-(+)-6-benzylsparteine (b) also belongs to orthorhombic system; P212121, a=11.020(4), b=23.660(10), c=8.666(6) Å and Z=4; and MgBr2−(+)-6-benzylsparteine toluene solvate (c), orthorhombic system; P212121, a=16.654(3), b=19.723(4), c=8.637(2) Å and Z=4. The structure of a was solved by the direct method and those of b and c by the heavy atom method. Refinements were carried out by the block-diagonal least-squares procedure; R values are: (a) 0.055. (b) 0.169, and (c) 0.118, respectively for 1342, 1445, and 1501 reflections. The a molecule takes a one-boat form, whereas by, coordination to the Mg atom it changes into all-chair form in b and c molecules. The Mg atom has a distorted tetrahedral geometry; b, Mg–N=2.13(4) and 2.19(4), Mg–C 2.34(5) and Mg–Be=2.506(16) Å and N–Ng–N=83.1(14)°; c, Mg–N=2.08(3) and 2.17(3), Mg–Br=2.454(12) and 2.473(12) Å and N–Mg–N=85.8(10)°. The structures of these molecules are compared with those of (−)-sparteine complexes with EtMgBr, t-BuMgCl, and MgCl2. On the basis of the molecular structures determined the activity of these Grignard reagent–(−)-sparteine derivatives for the enantiomer-selective polymerization of MBMA is discussed.
Decay Mechanism of the Aromatic Hydrocarbon Biradical, 1,1′-Biacenaphthene-2,2′-diyl. Effects of Solvent and Heavy-atom Perturbation
Authors: Kobashi Harumichi , Kondo Reiko , Ikawa Hiroki , Morita Toshifumi
Published: July 2006

Effects of solvents and heavy-atom (H–A) containing compounds on the lifetime of the title biradical (1) have been examined to elucidate the decay mechanism of 1 in fluid solutions by means of nanosecond laser spectroscopy. 1 was quenched effectively by H–A compounds such as diethylmercury and iodoethane. The decay rates of 1 showed no explicit correlation with solvent polarities, while a linear correlation was found between the decay rate and the sum of squares of the spin-orbit (S–O) coupling factors of heavy atoms involved in the solvents; chlorobezene, 1,2-dichloroethane, dichloromethane, bromobenzene, and dibromomethane. It has been shown that (i) the biradical lifetime is determined by intersystem crossing (ISC) from the triplet to singlet spin state prior to chemical reactions, (ii) ISC is enhanced by H–A perturbation through the S–O interaction, and (iii) the reactivity of the singlet biradical (11) but not the triplet one (31) sways the product distribution in the triplet-sensitized photodimerization of acenaphthylene.
Decrease in the Quantum Efficiency of a Cadmium Sulfide Photoanode Due to Sulfur Deposition. Determination of Quantum Efficiency by Temperature Measurement
Authors: Fujishima Akira , Li Tian-kai , Zhu Yau-ning , Zhou Guo-ding , Li Xue-ping
Published: July 2006

CdS photoelectrodes dissolve during photoanode reactions in a supporting electrolyte solution, and the quantum efficiency changes due to sulfur deposition. Temperature measurement technique has been used in this work to determine the quantum efficiency of the CdS photoelectrode. It has been found that decreases in the quantum efficiency can be monitored easily by this method.
Phase Equilibria in the Ln2O3–V2O3–V2O5 (Ln=Dy and Ho) Systems at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi
Published: July 2006

Phase equilibria in the systems, Dy2O3–V2O3–V2O5 and Ho2O3–V2O3–V2O5, were established at 1200 °C by changing the oxygen partial pressure from 4.32 to –7.50 Pa in terms of logPo2. In both systems, Ln2O3, LnVO4, LnVO3, VnO2n−1(n=2–7), VO2, and Ln8V2O17(4Ln2O3·V2O5) are stable, and compounds with mole ratio Ln2O3/V2O5=5⁄1 are not stable under the present experimental conditions. On the basis of the established phase diagrams, the standard Gibbs energies of reactions, (1) 3 Dy2O3+2 DyVO3+O2=Dy8V2O17, (2) DyVO3+1/2 O2=DyVO4, (3) 3 Ho2O3+2 HoVO3+O2=Ho8V2O17, and (4) HoVO3+1/2 O2=HoVO4, were determined to be −278, −123.8, −277, and −122.4 kJ, respectively. LnVO4, Ln8V2O17, V2O3, and VO2 have nonstoichiometric compositions. ΔG° values for reactions (2) and (4) fit well on the linear line presented by us.
Synthesis and Stereoselectivity of Cobalt(III) Complexes of Quadridentate Ligands Possessing SNNS Array of Donor Atoms
Authors: Yamanari Kazuaki , Takeshita Norimatsu , Shimura Yoichi
Published: July 2006

Several thiolato complexes of [Co(SNNS)(diamine)]+ type were prepared (diamine stands for en=1,2-ethanediamine, R-pn=(R)-1,2-propanediamine, and RR-chxn=(R,R)-1,2-cyclohexanediamine) and characterized from their visible–UV absorption, circular dichroism, and 13C NMR spectra, where SNNS denotes two kinds of open-chain quadridentate ligands, H2endet=3,6-dimethyl-3,6-diazaoctane-1,8-dithiol and R-H2pndet=(R)-3,4,6-trimethyl-3,6-diazaoctane-1,8-dithiol. Both the SNNS ligands gave the two geometrical isomers, cis-α(dark green) and cis-β(dark violet), whereas 3,7-dimethyl-3,7-diazanonane-1,9-dithiolate(2–) ligand gave no stable monomeric complex. Interestingly, stereoselective complex formation was found in Δ-cis-α-[Co(R-pndet)(en or RR-chxn)]+, Δ(SNRN)-cis-β-[Co(endet)(R-pn or RR-chxn)]+, and Δ(SNRN)-cis-β-[Co(R-pndet)(en or RR-chxn)]+, the Δ-cis-α configuration of the former complex being the novel one having the equatorially-oriented terminal chelate rings on the tertiary nitrogen atoms.
Chemical Synthesis of a Heat-stable Enterotoxin Produced by Enterotoxigenic Escherichia coli Strain 18D
Authors: Yoshimura Shoko , Miki Makoto , Ikemura Haruo , Aimoto Saburo , Shimonishi Yasutsugu , Takeda Tae , Takeda Yoshifumi , Miwatani Toshio
Published: July 2006

Two peptides with the two primary structures of 18 amino acid residues proposed for a heat-stable enterotoxin from enterotoxigenic Escherichia coli strain 18D were synthesized by solution methods and their physicochemical and biological properties were compared with those of native toxin. One of these peptides (Asn–Thr–Phe–Tyr–Cys–Cys–Glu–Leu–Cys–Cys–Asn–Pro–Ala–Cys–Ala–Gly–Cys–Tyr) showed the same heat-stability and 1H-NMR spectrum as those of the native toxin and evoked fluid secretion in suckling mice at a dose of 1.5–2.0 ng, which is similar to the effective dose of native toxin. Moreover, its toxicity was neutralized by antisera against the native toxin. The other peptide (Asn–Thr–Phe–Tyr–Cys–Cys–Glu–Leu–Cys–Cys–Tyr–Pro–Ala–Cys–Ala–Gly–Cys–Asn) showed different physicochemical and biological behaviors from those of the native toxin and exhibited toxic activity at a dose of 50–80 ng, which is about thirty times the effective dose of the native toxin. Moreover, its toxicity was not neutralized by antisera against the native toxin. These observations indicate that the former peptide is identical to native toxin but that the latter peptide differs in properties from the native toxin.
Kinetics and Mechanism of Complex Formation of Nickel(II) with 1-(2-Pyridylazo)-2-naphthol in Acetic Acid
Authors: Hioki Akiharu , Funahashi Shigenobu , Tanaka Motoharu
Published: July 2006

The complex formation reactions of nickel(II) nitrate, nickel(II) acetate, and nickel(II) chloride with 1-(2-pyridylazo)-2-naphthol (PAN) in acetic acid (HOAc) to form the 1:1 nickel(II)–PAN complex have been studied kinetically by using a stopped-flow technique. The second-order rate constants and activation parameters at 25 °C are k=(1.4±0.1)×104 mol−1 kg s−1, ΔH\eweq=51.2±1 kJ mol−1, ΔS\eweq=6.4±4 J mol−1 K−1, and ΔV\eweq=23.4±2.4 cm3 mol−1 for Ni(NO3)2, k=(1.1±0.1)×104 mol−1 kg s,−1, ΔH\eweq=49.5±1 kJ mol−1, ΔS\eweq=−1.3±4 J mol−1 K−1, and ΔV\eweq=15.5±2.6 cm3 mol−1 for Ni(OAc)2, and k=(4.8±0.1)×104 mol−1 kg s−1, ΔH\eweq=51.4±1 kJ mol−1, ΔS\eweq=17.0±4 J mol−1 K−1, and ΔV\eweq=35.4±5.5 cm3 mol−1 for NiCl2. The positive value of ΔV\eweq strongly suggests a dissociative mode of activation.
The Reaction of 5-Benzylidene-2,3,4,5-tetrahydropyridine with Some Nucleophiles
Authors: Nomura Yujiro , Bando Takashi , Takeuchi Yoshito , Tomoda Shuji
Published: July 2006

The reaction 5-benzylidene-2,3,4,5-tetrahydropyridine (1) with nucleophilic reagents, such as sodium tetrahydroborate, lithium tetrahydridoaluminate, organometallic reagents, pyrrole, or ethyl propiolate, has been studied. The reaction of 1 with sodium tetrahydroborate, lithium tetrahydridoaluminate, phenylmagnesium bromide, butyllithium gave exclusively respective 1,2-adducts. The reaction with pyrrole gave a tricyclic 1:1 adduct while 1 formed a 1:2 adduct with ethyl propiolate.
Catalytic Activity of Highly Dispersed Palladium. III. The Effect of Added Zirconium Oxide upon Palladium Metal Surface Revealed by a Combined Infrared Spectroscopic and Thermal Desorption Study of Carbon Monoxide Adsorption
Authors: Lee Bu Yong , Inoue Yasunobu , Yasumori Iwao
Published: July 2006

A combined infrared spectroscopic (IR) and thermal desorption (TD) study of CO adsorption was carried out to reveal the nature of Pd surface which is modified by the addition of ZrO2. The TD spectra of CO from SiO2- or α-Al2O3-supported Pd showed two broad peaks, α at 340 K and β at 530 K. The addition of ZrO2 in a range of atomic ratios of Zr/Pd=0.5–3.0 produced a new broad peak δ at 390–420 K and the β peak shifted toward higher temperature by 16–19 K. The IR spectra of CO on Pd/SiO2 catalysts, consisting of two broad bands: A (2030–2070 cm−1) and B (1880–1920 cm−1), were modified by the addition of ZrO2 to give rise to a new sharp band, Bh (1970–1985 cm−1) and to make the A band narrower. From the correspondence of the variation in intensities and position of the IR bands with those in the fraction of coverage of CO with temperature, the α peak was correlated to the A band, the δ peak to the Bh band, and the β peak to the B band. The changes in the TD peaks and the IR bands caused by added ZrO2 were semiquantitatively compared and are discussed in terms of the electronic and geometric effects; a high electron density state of Pd surface atoms as well as the formation of adsorption sites with specific structure is proposed. A brief study was made for the role of the sites in the catalytic hydrogenation of ethylene and cyclohexene.
Physicochemical Studies of an Activated Europium Ion-exchanged Mordenite
Authors: Arakawa Tsuyoshi , Takakuwa Midori , Adachi Gin-ya , Shiokawa Jiro
Published: July 2006

The physicochemical properties of an activated Eu(III) ion-exchanged mordenite (Eu–M) have been studied by the measurement of the fluorescence of the europium ion. When Eu–M (the exchanged level; 3.7%) was degassed only above 300 °C, a band emission which peaked at 488 nm appeared. This band emission was associated with the Eu2+ 5d–4f transition. The peak of the band emission shifted linearly to a shorter wavelength with the increase in the exchanged level of the Eu ions. For the Eu–M sample, which was reduced by H2 at 500 °C, the peak position of the band emission was almost 499 nm in all cases, and the quantum yield for a reduced sample was larger than that for a dehydrated sample. The quantum yield for a reduced sample fell off extremely above the exchanged level of 6%. Moreover, the Eu2+–Eu22+ energy transfer in the reduced samples was discussed.
Association between Polar Molecules. III. 1H and 13C NMR Studies on the Dipole Association of Acetonitrile Derivatives with Tetramethylurea and Dibutyl Sulfoxide in Nonpolar Solvents
Authors: Takagi Tatsuya , Fujiwara Hideaki , Sasaki Yoshio
Published: July 2006

Dipole association between acetonitrile derivatives and polar substances such as tetramethylurea and dibutyl sulfoxide is investigated in nonpolar solvents. Association parameters and thermodynamic parameters are derived and discussed in relation to the substituent constants. 1H and 13C NMR chemical shifts show that the major structures of the associate are antiparallel. Association energies are also determined using semiempirical MNDO MO method, which supports the experimental results for energies as well as structures.
Conductivity and Ion Association of Some Diastereoisomeric Salts in Water. I. Δ-[Co(NO2)2(en)2]Δ-[Co(edta)] and Λ-[Co(NO2)2(en)2]Δ-[Co(edta)] at 15, 25, and 35 °C
Authors: Yokoyama Haruhiko
Published: July 2006

Electric conductivities of the diastereoisomeric salts, Δ(−)589-[Co(NO2)2(en)2]Δ(+)546-[Co(edta)] and Λ-(+)589-[Co(NO2)2(en)2]Δ(+)546-[Co(edta)], were measured in water at 15, 25, and 35 °C. Results were analyzed in terms of the conductivity equations of Fuoss-Hsia and Pitts. The obtained values of the ion-association constant are large and decrease with increasing temperature. The results can not be entirely explained by the electrostatic theories of ion association and suggest the formation of contact ion pairs, attributable to the existence of interactions other than simple electrostatic ones between the complex ions. No appreciable difference is found in the obtained thermodynamic parameters of ion association between the two salts. Ion–solvent interactions and effective sizes of the dissolved complex ions are also discussed in connection with the estimation of the closest distance of approach of the ions.
An Analysis of the E(0g+) Ion-pair State of Bromine through Stepwise Excitation Technique
Authors: Ishiwata Takashi , Tokunaga Atsuto , Shinzawa Tsutomu , Tanaka Ikuzo
Published: July 2006

The pulses of the fundamental and its frequency doubled outputs from a tunable dye laser are used to promote a stepwise exciation of the E(0g+)–X1Σg+ transition through the B3Π(0u+) state in molecular bromine. The double resonance is detected by the associated UV emission which originates from the E(0g+) state radiating back to the B3Π(0u+) state. The E(0g+) state is analyzed in detail on the basis of the selection rules of two transition components and the E–B fluorescence spectrum. The molecular parameters are derived as Te=49778.5 cm−1, ωe=150.8 cm−1, ωexe=0.41 cm−1, and re=3.197 Å for the 79Br2 isotope species.
Intra- and Intermolecular [3++2] Cycloadditions of Aldehyde or Ketohydrazones
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Nakano Mineo , Teramura Kazuhiro
Published: July 2006

The reaction of several 2-(alkenyloxy)benzaldehydes (or 1-naphthaldehydes) (1) with arylhydrazine hydrochlorides leads to intramolecular [3++2] cycloadducts, 3-substituted 2-aryl-1,2,3,3a,4,9b(or 1,2,3,3a,4,11c)hexahydro[1]benzopyrano (or naphtho[1′,2′:5,6]pyrano)[4,3-c]pyrazole hydrochlorides (4), in good yields. Free bases (5) were obtained in high yields after the treatment of 4 with triethylamine. The thermal treatment of 5 at 150 °C gave 3-substituted 2-aryl-2,3,3a,4-tetrahydro[1]benzopyrano(or naphtho[1′,2′:5,6]pyrano)[4,3-c]pyrazoles. The reaction of 1 with methylhydrazine sulfate gave the corresponding 2-methyl derivatives. Analogous intramolecular [3++2] cycloadducts were obtained from the reaction of 2′-(alkenyloxy)acetophenones with arylhydrazine hydrochlorides. Intermolecular [3++2] cycloadducts were also obtained from a reaction mixture of 1-naphthaldehyde, arylhydrazine hydrochlorides, and styrene.
Ion Exchange Studies of Zinc Chloride and/or Perchlorate in Ethylene Glycol
Authors: Kumagai Tetsu
Published: July 2006

The formation constants of zinc chloride and/or perchlorate in ethylene glycol were measured by a cation exchange method using the resin for forced-flow liquid chromatography in three systems: zinc chloride, zinc perchlorate, and zinc chloride and perchlorate together. The values obtained for the formation constants were: logβ1Cl=3.03, logβ2Cl=4.80, logβ1ClO4=2.34, and logβ2ClO4=2.50. The formation constant for the mixed complex of zinc, logkmClO4, was 0.7 at the ionic strength of 0.1. The formation constants of zinc chloride in ethylene glycol containing 5 v/v% of water were 2.73 for logβ1Cl and 4.18 for logβ2Cl, and those containing 10% of water were 2.32 for logβ1Cl and 3.46 for logβ2Cl.
Synthesis of Sydnone Compounds Having Heterocyclic Groups at the 4-Positions from 4-(Bromoacetyl)sydnones
Authors: Fuchigami Toshio , Goto Takushi , Yeh Mou-Yung , Nonaka Tsutomu , Tien Hsien-Ju
Published: July 2006

New sydnone derivatives having heterocyclic substituents such as 4-thiazolyl, 3-thienyl, 2H-1,4-benzothiazin-3-yl, 2H-1,4-benzoxazin-3-yl, and 1,2-dihydro-3-quinoxalinyl groups at the 4-positions were prepared from 4-bromoacetyl-3-arylsydnones (1). Sydnone compounds substituted by a 1,2,3-triazol-4-yl group were prepared via new type phosphonium ylids derived from 1. Electroreduction of 1 was also attempted in order to prepare a syndnone derivatives having a furyl group.
Kinetics and Mechanism of Bromine Addition to Derivatives of Unsaturated Aliphatic Carboxylic Acids in Aqueous Solution
Authors: Mohamed Farook Syed Ahamed , Viswanathan Seshaiyer , Ganesan Ramachandran
Published: July 2006

This paper deals with the kinetics of bromine addition to unsaturated compounds in presence of added bromide ions at 22, 30, 38, 46, and 54 °C. The substrates used were acrylamide (AAm), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), t-butyl acrylate (tBA), methacrylamide (MAAm), methyl methacrylate (MMA), ethyl methacrylate (EMA), methyl crotonate (MC), and ethyl crotonate (EC). The kinetics was followed potentiometrically. The activation parameters (ΔH\eweq, ΔS\eweq, and ΔG\eweq) were calculated and compared. Estimation of product ratio of bromohydrin to dibromide showed the absence of any correlation of the product formation with reactivity of the substrates. The observed parameters are discussed in relation to the proposed reaction mechanisms.
A New Version of Inclusion of Overlap Charges in ω-Technique. π-Bond Energies, Heats of Formation, and Resonance Energies of Conjugated Hydrocarbons
Authors: Tewari Vindhya Prasad , Lal Krishna Behari , Srivastava Arun Kumar
Published: July 2006

With systematic approximations to Roothaan equation it has been possible to deduce the IOC-ω-technique (inclusion of overlap charges in ω-technique) which apparently approximates the SCF-equations by bringing in an approximate correction for the two center-two electron repulsion integrals and represents a better version of PPP (Pariser-Parr-Pople) method by involving the hybrid integrals which have been completely neglected in PPP-approximations. In the present communication a new version of IOC-ω-Technique has been used for evaluating the π-bond energies, heats of formation and resonance energies of some conjugated hydrocarbons. The calculated values are found to be in excellent agreement with the experimental data and with some previously calculated values.
Determination of the Vapor Pressures of Lithium Chloride and Sodium Bromide by a Molecular Effusion–Surface Ionization Method
Authors: Kawano Hiroyuki , Kenp\={o} Tsutomu
Published: July 2006

By means of molecular effusion from a Knudsen cell and of thermal positive ionization on a glowing polycrystalline rhenium filament, the vapor pressure P (in atm) of LiCl or NaBr was measured as a function of cell temperature T (in K). The following equations were established empirically.

log10P(LiCl)=(7.948±0.102)−(10954±76)⁄T for 662–848 K,

log10P(NaBr)=(7.716±0.072)−(11138±55)⁄T for 669–882 K.
Crystal Structure of Dimethyltin Molybdenum Tetraoxide, (CH3)2SnMoO4
Authors: Sasaki Yukiyoshi , Imoto Hideo , Nagano Osamu
Published: July 2006

Single-crystal X-ray analysis has shown that the title compound is tetragonal, P42/mbc, with a=13.705(2), c=7.271(1) Å. The structure is made of octahedra of trans-Sn(CH3)2O4 and tetrahedra of MoO4. These polyhedra share apices to form a three-dimensional structure.
Structural and Stereochemical Study of Galantinic Acid, a New Amino Acid from Peptide Antibiotic Galantin I
Authors: Wakamiya Tateaki , Ando Toshihiko , Teshima Tadashi , Shiba Tetsuo
Published: July 2006

A new amino acid, galantinic acid, was found as one of the constituent amino acids in a peptide antibiotic galantin I. The structure of galantinic acid was determined to be (2S,4S,5S)-5-amino-2-carboxymethyl-4-hydroxytetrahydropyran on the basis of NMR and CD studies.
Reactions of Arenesulfonyl Chlorides with cis- or trans-β-(Methylstyrene Catalyzed by Ruthenium(II) Complex
Authors: Kamigata Nobumasa , Narushima Tomoo , Sawada Hideo , Kobayashi Michio
Published: July 2006

The reactions of arenesulfonyl chlorides with cis- or trans-β-methylstyrene catalyzed by dichlorotris(triphenylphosphine)ruthenium(II) in the presence of triethylamine proceeded smoothly to give only (E)-2-arylsulfonyl-1-phenylpropene. The recovered cis-β-methylstyrene was isomerized to trans form, while trans-β-methylstyrene did not isomerize to the cis one.
Cyclosadol, Isocyclosadol, and Other Related Triterpene Alcohols Obtained from 24-Methylenecycloartanol by Acid-catalyzed Isomerization
Authors: Shimizu Naoto , Itoh Toshihiro , Ichinohe Yoshiyuki , Matsumoto Taro
Published: July 2006

The acid-catalyzed isomerization of 24-methylenecycloartanol with sulfuric acid afforded cyclosadol (23E-Δ23), isocyclosadol (23Z-Δ23), and other isomers, including lanostane- and cucurbitane-type isomers with (23E)- and (23Z)-Δ23- and Δ24-unsaturated side chains. The phytochemical significance of the isomers is discussed.
Asymmetric Synthesis of Alanine by Catalytic Hydrogenation of Chiral Nα-Acetyldehydroalaninamides
Authors: Harada Kaoru , Takasaki Michiaki
Published: July 2006

Asymmetric hydrogenation of chiral Nα-acetyldehydroalaninamides was studied. The asymmetric yield of the resulting alanine was in the range 0–24%. The effects of reaction temperature, solvent polarity and asymmetric moieties on the asymmetric yields were examined.
An Easy Preparation of Triphenylmethyl Carboxylates
Authors: Hashimoto Shun-ichi , Hayashi Masahiko , Noyori Ryoji
Published: July 2006

A new recipe for triphenylmethylation of carboxylic acids and phenol is disclosed.
Prenylation of Aromatic Amines and Nitrogen-containing Aromatic Heterocycles by Prenyl Diisopropyl Phosphate
Authors: Araki Shuki , Manabe Shin-ichi , Butsugan Yasuo
Published: July 2006

Lewis-acid catalyzed prenylation of aromatic amines with prenyl diisopropyl phosphate gave N-prenylated amines, whereas nitrogen-containing aromatic heretocycles gave nucleus prenylated products.
Oxidation of Alcohols via Alkoxymagnesium Halides by an NAD+ Model Compound
Authors: Shinkai Seiji , Era Hiroyuki , Tsuno Takaharu , Manabe Osamu
Published: July 2006

Alkoxymagnesium bromides prepared from phenylmagnesium bromide and alcohols are capable of reducing an NAD+ model compound to the 1,4-dihydronicotinamide in good yields. The carbonyl products were detected in quantitative yields from diphenylmethanol and 1-phenylethanol but in low yields from benzyl alcohol and aliphatic alcohols. This is a new route to 1,4-dihydronicotinamides with alcohols although it remains uncertainty whether or not the route has relevance as a model process for NAD+ oxidaiton of alcohols.
Resistance to Alkali of the Nascent Fibril Produced by Acetobacter xylinum
Authors: Kai Akira , Koseki Tomoki
Published: July 2006

The resistance of the nascent fibril produced by Acetobacter xylinum to alkali is lower than that of the crystalline cellulose I and higher than that of the amorphous cellulose. In the nascent fibril the cellulose chains are thougth to be in the form of cellulose sheets corresponding to the (1\bar10) plane of cellulose I.
Kinetics and Mechanism of Oxidation of Pyridoxine by Sodium N-Chlorobenzenesulfonamidate
Authors: Jayaram Beby , Mayanna Sarabaghatta Mayanna
Published: July 2006

Oxidation of pyridoxine (PRX) by chloramine-B (CAB) in HCl medium at 313 K shows first order dependence each on oxidant, substrate and Cl− ion concentrations, but is independent of [H+]. A first-order retardation of rate is observed by the addition of reaction product, benzenesulfonamide. Suitable mechanism is proposed.
Optically Active and Racemic Glycerides. I. The Thermodynamic and Structural Relationship between Optically Active and the Corresponding Racemic α-Monostearins in Their Crystalline, Molten, and Dissolved States
Authors: Iwahashi Makio , Watanabe Yasutoshi , Watanabe Toshihiko , Muramatsu Mitsuo
Published: July 2006

The thermodynamic and spectrographic properties, such as the melting temperature, the latent heat of fusion, the solubility, the heat of solution, and the infrared and NMR spectra, were studied for the stable β-forms of the optically active (S)- and the corresponding racemic (RS)-α-monostearin crystals. The phase diagram for the binary mixture and the IR spectra of (S)- and (RS)-crystals indicate that the (RS)- form is a racemic molecular compound consisting of (R)- and (S)-α-monostearin molecules. The latent heats of fusion for the (S)- and (RS)-α-monostearin crystals were 82.4 kJ mol−1 and 75.4 kJ mol−1 respectively. The heats of solution in benzene for the (S)- and the (RS)-crystals were 86.3 and 99.9 kJ mol−1 respectively. The difference in the heat of solution between the (S)- and the (RS)-crystals, Δ(ΔHs), was 13.6 kJ mol−1, which may be attributable to the difference in the extent of hydrogen bonding. These results suggest that (R)- and (S)-molecules in the (RS)-form strongly interact to form a racemic pair not only in the crystalline state, but also in the molten state. Such a racemic pair dissociates into the free molecules when it is dissolved in a nonpolar solvent. The conclusion is supported by the IR and NMR spectra for both the glycerides in dissolved states.
Catalytic Activities of 12-Molybdophosphoric Acid and Its Salts Supported on Silicon Dioxide for the Reduction of Nitrogen Monoxide
Authors: Mochida Isao , Nakashima Toshihiro , Fujitsu Hiroshi
Published: July 2006

12-Molybdophosphoric acid and its metal salts, supported on SiO2 (H3PA and MPA/SiO2), were found to exhibit significant activities for the catalytic reduction of nitrogen monoxide with hydrogen or ammonia, the latter reductant being more reactive. The activity orders of the catalysts were as follows, depending on the reductant: Cu2+>Ag+>Ni2+>Cs+\simeq Co2+\simeq H+ (hydrogen), Cu2+>Co2+>H+>Ag+>Ni2+>Cs+ (ammonia). It is of value to mention also that H3PA/SiO2 exhibited ten times many activity when ammonia was applied. The extent of the cation exchange (X) of CuXH3−2XPA/SiO2 influenced the catalytic activity differently, depending again on the reductant, although the maximum activity was obtained with both reductants when X was 1.1. Nitrogen monoxide was decomposed by a stoichiometric reaction with the reduced site on Cu1.1H0.8PA/SiO2, especially when the catalyst was reduced with hydrogen, although no oxygen was detected in the product, the initial rate being comparable to that of the reduction with hydrogen. The following rate-equations were obtained with the respective reductants on Cu1.1H0.8PA/SiO2 at 300 °C over the partial pressure range of NO (3.0–10.1 kPa) and reductants (3.0–35.5 kPa): V=kH2PNO0.8PH20.04, V=kNH3PNO0.6PNH30.04–−0.7. The wide range in the magnitude of powers with respect to the ammonia partial pressure in the latter equation implies the strong adsorption of ammonia on the catalyst. These results suggest that the redox and Langmuir mechanisms are plausible for the reactions with hydrogen and ammonia respectively. An ESR study of the copper and molybdenum ions of the catalyst supports the above mechanisms.
An Optical-optical Double Resonance Excitation of Bromine to a New D(0u+) Ion-pair State
Authors: Ishiwata Takashi , Tokunaga Atsuto , Shinzawa Tsutomu , Tanaka Ikuzo
Published: July 2006

An optical-optical double resonance (OODR) technique utilizing a sequential three-photon absorption has been applied to study the electronic structure of Br2. Two pulsed dye lasers were used to excite the molecules to appropriate rovibronic levels of the B3Π(0u+) state and subsequently into an ion-pair state by simultaneous two-photon transition. The OODR excitation spectra showed a number of transitions consisting of closely-spaced O, Q, and S branches which combine the B3Π(0u+) state with a new ion-pair state designated D(0u+). The following spectroscopic constants of the D(0u+) state were determined for the 79Br2 isotope species: Te=49925.4(6), ωe=135.7(3), ωexe=0.27(3), Be=0.04190(14), and αe=5.9(23)×10−5 cm−1.
The Circular Dichroism Spectra of cis-[Co(CN)2(CO3)2]3−, cis-[Co(NO2)2(CO3)2]3−, and Related Bis(dicarboxylato) Complexes
Authors: Fujinami Shuhei , Shimoda Akihide , Furukawa Toshihito , Shibata Muraji
Published: July 2006

Five kinds of cis-[Co(CN)2(OO2)]3− and cis-[Co(NO2)2OO)2]3− complexes (OO=CO32−, ox2−, mal2−) have been optically resolved. As to the dicarbonato complexes, one enantiomer has been obtained in a yield far exceeding 50% because of the rapid racemization. When the carbonato ligand is replaced with an oxalato or malonato ligand, the complex becomes inert for racemization and a new Cotton peak with an opposite sign appears at the lower frequency in the first-absorption-band region. The CD spectral change is different from the change observed in cis-[Co(a)2(OO)2]− complexes (a=NH3, py, en/2), suggesting the intimate participation of the unidentate ligands in determining the signs of the Cotton peaks.