Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 57 , Issue 6
Showing 1-50 articles out of 63 articles from the selected issue
  • Yoshiko Kawamura, Hiroaki Ohya-Nishiguchi, Jun Yamauchi, Yasuo Deguchi
    1984 Volume 57 Issue 6 Pages 1441-1445
    Published: 1984
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The magnetic susceptibility of four formazanyl–copper complexes have been measured by the use of a torsion balance in the range from 2 K to room temperature. Their ESR parameters have been measured on powdered samples at room temperature and the temperature of liquid nitrogen, and in solution at room temperature in order to elucidate the electronic structures of the complexes. The complexes which have shown the exchange-narrowed pattern in the spectra of powdered samples have been paramagnetic as low as 2 K. Nitro and carboxy derivatives characterized by a single, broad ESR absoption line have positive Weiss constants, indicating ferromagnetic interaction. Especially, the magnetic behavior of the carboxy derivative has been well interpreted in terms of a ground triplet-excited singlet model with the exchange parameter of 24 K. The nitro derivative showed an abnormally low magnetic moment. It has been concluded that the magnetic properties of formazanyl–copper complexes are very sensitive to substitution at the phenyl rings.
  • Makio Iwahashi, Yasutoshi Watanabe, Toshihiko Watanabe, Mitsuo Muramat ...
    1984 Volume 57 Issue 6 Pages 1446-1448
    Published: 1984
    Released: June 27, 2006
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    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.
  • Isao Mochida, Toshihiro Nakashima, Hiroshi Fujitsu
    1984 Volume 57 Issue 6 Pages 1449-1453
    Published: 1984
    Released: June 27, 2006
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    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.
  • Yuji Kajikawa, Tosio Sakurai, Nagao Azuma, Shizue Kohno, Sei Tsuboyama ...
    1984 Volume 57 Issue 6 Pages 1454-1458
    Published: 1984
    Released: June 27, 2006
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    A binuclear complex of bis(μ-N,N′-dipicolinoyl-1,3-propanediamine)-bis(sulfato)dicopper(II) has been isolated as a blue single crystal tridecahydrate, [{Cu(SO4)(ppda)}2]·13H2O, from an aqueous solution. The crystals are orthorhombic, C2221, with a=15.42(1), b=24.92(2), c=25.73(2) Å, and Z=8. Each copper(II) ion is in a square-pyramidal coordination with two pyridine nitrogen atoms, two carbonyl oxygen atoms, and a sulfate oxygen atom at the apex. The two equivalent copper(II) ions, about 3.9 Å apart from each other, are aligned coaxially. The eight Cu–Cu vectors are approximately parallel to one another along the c axis. The most important feature of the crystal structure is the presence of the bulky ligands and of many water molecules, which magnetically isolate the Cu–Cu coupled pair from one another. This facilitates the ESR study of the molecular anisotropies by using the single crystal, even at room temperature. The ESR parameters determined are as follows: g⁄⁄=2.280(2), g=2.067(1), |D|=422.4(8), |A⁄⁄|=170(2), and |A|=14(1) in 10−4 cm−1. Bleaney and Bowers treatments of the exchange coupling contribution in the D parameter indicated a ground singlet state about 7 cm−1 below a triplet state for the coupled copper(II) ions. A comparison of the ESR parameters measured for the single crystal with those in the aqueous solution enabled us to conclude that the molecular structure in the solution was very similar to that in the crystalline phase, apart from the coordination of sulfate ions.
  • Duanjun Xu, Yasushi Kai, Kunio Miki, Nobutami Kasai, Koichi Nishiwaki, ...
    1984 Volume 57 Issue 6 Pages 1459-1468
    Published: 1984
    Released: June 27, 2006
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    Molecular structures of novel trans-[NiR2L2] complexes, trans-[Ni{C6H3(OMe)2-2,6}2(PR3)2] [PR3=PMe3 (1a), PMe2Ph (1b)], and their m-brominated derivatives, trans-[Ni{C6H(OMe)2-2,6-Br2-3,5}2(PR3)2] [PR3=PMe3 (2a), PMe2Ph (2b)], were determined by X-ray crystal structure analysis. A remarkable effect of m-substitution on the conformation of the o-methoxyl groups was found. This correlated well with the reactivity difference toward carbon monoxide. Crystal data: 1a: monoclinic, space group P21/c, a=8.737(2), b=18.282(3), c=16.319(4) Å, β=105.06(2)°, Z=4, R=0.062; 1b: triclinic, space group P\bar1, a=16.993(5), b=10.180(3), c=17.177(5) Å, α=112.44(2), β=117.59(2), γ=66.25(2)°, Z=3, R=0.060; 2a: monoclinic, space group P21/c, a=9.294(2), b=14.091(3), c=10.770(2) Å, β=92.06(3)°, Z=2, R=0.067; 2b: triclinic, space group P\bar1, a=9.370(1), b=11.387(2), c=9.013(1) Å, α=94.52(2), β=107.24(2), γ=77.35(2)°, Z=1, R=0.058.
  • Takashi Ishiwata, Atsuto Tokunaga, Tsutomu Shinzawa, Ikuzo Tanaka
    1984 Volume 57 Issue 6 Pages 1469-1472
    Published: 1984
    Released: June 27, 2006
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    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.
  • Kazuki Oka, Hiroshi Maeda, Shoichi Ikeda
    1984 Volume 57 Issue 6 Pages 1473-1477
    Published: 1984
    Released: June 27, 2006
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    The effects of Hg(ClO4)2, HgCl2, and AgClO4 on the conformations of fully neutralized poly(S-carboxymethyl-L-cysteine) and poly[S-(2-carboxyethyl)-L-cysteine] in the absence of supporting electrolytes were examined by circular dichroism (CD) spectra. The induction of the β-form was suggested by the addition of Hg(ClO4)2 and AgClO4, while it could not be concluded in the case of HgCl2. Spectroscopic evidence for the coordination of metals with the two polypeptides was provided in the case of Hg(ClO4)2 and HgCl2 by the appearance of a new CD band around 250–260 nm as well as the distortion of the polymer CD spectra in the region of 200–230 nm, while it was not obtained in the case of AgClO4. The decrease of pH observed on addition of the three metal compounds also suggested the conformational change. Extraordinary lowering of pH and enhanced solubility were observed on addition of HgCl2.
  • Yoshiya Kera
    1984 Volume 57 Issue 6 Pages 1478-1482
    Published: 1984
    Released: June 27, 2006
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    Potassium vanadates, which were prepared from melts by rapid quenching and slow cooling over the composition range of K2O-contents of C=(K)/(V)=0–0.50, were examined by means of IR spectrometry and X-ray powder diffraction. In the composition range of C≤0.17, mixtures of V2O5, K2V18O45, and K2V8O21 were produced by the slow cooling. At the composition of C=0.33, however, an unknown compound and K2V8O21 were the main products upon rapid quenching from melts, while at C=0.50 the main products were K3V5O14 and an additional unknown compound. The unknown compound was confirmed to be metastable and was formed as a single compound only by a rapid quenching from melts of K2O and V2O5 especially at C=0.37. The X-ray diffractions for the compound were characterized as d=8.2 (very strong), 4.05, and 3.27 Å, and the V=O stretching frequencies, as 995, 968, and 955 cm−1. By comparing these characteristic data with those of lithium trivanadate and sodium trivanadate (γ-phase), it was suggested that the unknown compound was isomorphous with trivanadate (M1+xV3O8).
  • Shuhei Fujinami, Akihide Shimoda, Toshihito Furukawa, Muraji Shibata
    1984 Volume 57 Issue 6 Pages 1483-1486
    Published: 1984
    Released: June 27, 2006
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    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.
  • Takeo Adachi, Hideyo Yoshida, Kimie Izawa, Sorin Kihara
    1984 Volume 57 Issue 6 Pages 1487-1490
    Published: 1984
    Released: June 27, 2006
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    The distribution coefficients, Kd, of eighteen hard acid-metal ions for a strongly basic anion-exchange resin were determined in HF–H3BO3 media in the presence of Cl or NO3, SO42−, and ClO4, and the relation between the adsorbabilities of the coexisting anions and the Kd values of the metal ions was discussed. The fluoride-ion concentration is quite low in HF–H3BO3 media because of the complex formation of the fluoride ion with boric acid, and most of the hard acid-metal ions have lower Kd values in HF–H3BO3 media than those in a hydrofluoric acid solution. By varying the kinds of coexisting anions and their concentrations in HF–H3BO3 media containing less than 0.02 M(1M=1 mol dm−3) of fluoroborate ions, the Kd values of metal ions can be controlled to allow the anion-exchange separations. As fluoroborate ions, e.g., BF4 or BF3OH, are strongly adsorbed on the resin, metal ions which are strongly held on the resin can be eluted by media including fluoroborate ions in higher concentrations. By using HF–H3BO3 media and selecting the coexisting anions, an effective mutual separation of titanium–zirconium, titanium–uranium, tin–niobium, and molybdenum–tungsten can be attined.
  • Tsuyoshi Nomura, Genkichi Nakagawa
    1984 Volume 57 Issue 6 Pages 1491-1493
    Published: 1984
    Released: June 27, 2006
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    Ion-selective electrochemical sensors which respond to nitrate-ion activities have been developed. The sensor material consists of alkali-free magnesium phosphate glasses containing CuO, Al2O3, and SiO2. The response characteristics have been observed strongly on the glass composition. Studies of the selectivity coefficient and the electrode function of nitrate-ion activities have shown that the most suitable glass composition is 10CuO : 55P2O5 : 15MgO : 10Al2O3 : 10SiO2. The potential response is linear over the nitrate-ion activities of (10−1–10−5) mol/dm3, and it has a sub-Nernstian response of about 54 mV/decade change at 20 °C. The order of the selectivity is NO3>ClO4>I>NO2>Cl>SO32−>>SO42−. Therefore, its use to determine the nitrate-ion activities in a solution containing perchlorate ions is suggested. The physical and chemical properties, such as the glass transition temperature, the softening temperature, the thermal expansion, the membrane resistance, and the chemical durability, were measured and compared with those of other glasses.
  • Ken-ichi Okamoto, Takumi Konno, Masayo Nomoto, Hisahiko Einaga, Jinsai ...
    1984 Volume 57 Issue 6 Pages 1494-1498
    Published: 1984
    Released: June 27, 2006
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    The crystal structure and the absolute configuration of the spontaneously resolved title complex cation, (−)500CD-[Co(aesei)(en)2]2+, has been determined by X-ray diffraction. The red crystalline needle was monoclinic, space group P21, a=9.572(4), b=10.410(3), c=8.838(5) Å, β=115.35(3)°, Z=2, and the final R value was 0.035 for 2358 independent reflections with |F0|>3σ(|F0|). The crystal used showed a negative CD value at 500 nm and had Δ configuration. The 2-aminoethaneseleninate is bound to the cobalt atom by the nitrogen and oxygen atoms, and the asymmetric selenium atom takes an S configuration. The value of the protonation constant (pKa) was determined to be 1.91±0.05, on the basis of the major absorption spectral change at 304 nm of the title complex by spectrophotometric titration (μ=1.0 mol dm−3 (NaClO4) and 25 °C). The electronic absorption and CD spectral behavior were compared with those of the related sulfinato complexes, in which the S-bonded sulfinato complex, (+)500CD-[Co(S(O)2CH2CH2NH2)(en)2]2+, was resolved in this work.
  • Tadashi Hara, Fujio Okui
    1984 Volume 57 Issue 6 Pages 1499-1504
    Published: 1984
    Released: June 27, 2006
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    A new method by which the component elements: C, H, O, and N, in an organic compound can be simply, rapidly, and economically identified was established on the basis of the reaction of an organic compound with sulfur at atmospheric pressure. The apparatus for this method consists of two gas chromatographs and an original reactor for reacting an organic compound with sulfur vapor. One component separated from a given mixture by the use of one gas chromatograph was made to react with sulfur vapor in the original reactor and then the reaction products were analyzed by the use of the other gas chromatograph. The reaction products were restricted to seven kinds of compounds irrespective of the chemical structure of the target component. According to this method, the component elements: C, H, O, and N, in an organic compound could be easily identified by the reaction products within 20 min with a detection limit of a few pmol.
  • Makoto Nitta, Akihiko Omata, Shuji Okada
    1984 Volume 57 Issue 6 Pages 1505-1509
    Published: 1984
    Released: June 27, 2006
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    The cycloaddition reactions of 1,5-dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one (1a), its corresponding -8-endo-ol (1b), 1,5,8-trimethyltricyclo[3.2.1.02,7]oct-3-en-8-endo-ol (1c), and 5,8-dimethyl-9-methylenetricyclo[3.3.1.02,8]non-3-en-7-one (2) were investigated in order to study the origin of its stereoselectivity or site selectivity. The reaction of 2,4,6-trimethylbenzonitrile oxide (mesitonitrile oxide, MNO) with 1a, b occurs on the exo-mthylene group from the exo-side, but on the endocyclic double bond in the case of 1c. The compound 2 undergoes the addition of MNO on both the exocyclic and endocyclic double bonds to give a corresponding bis-adduct. On the other hand, the reaction of phenyl azide (PA) with 1ac occurs on the endocyclic double bond from the endo-side to give a single adduct. The reaction of 6-exo-methoxy-1,5,6-trimethyltricyclo[3.2.1.02,7]oct-3-en-8-one with MNO or PA was also studied to prove the regioselectivity of the cycloadditions of constrained vinylcyclopropane moiety.
  • Munehiro Nakatani, Kimi Takahashi, Sumie Watanabe, Atsuko Shintoku, Ts ...
    1984 Volume 57 Issue 6 Pages 1510-1514
    Published: 1984
    Released: June 27, 2006
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    The reaction of 2,6-dimethyl-4-methoxybenzyl alcohols, ethyl ethers, and acetates, possessing electrondonating and -withdrawing groups at the benzylic position, with bromine water was studied at different temperatures. The reaction was strongly affected by the electronegativity of a benzyl substituent to afford bromination products of aromatic nuclei and 2,4-dibromo-3,5-dimethylmethoxybenzene along with 2,4,6-tribromo derivatives formed by the cleavage of C–C bond.
  • Kensuke Shima, Kimiko Tanabe, Shinpei Furukawa, Jouji Saito, Kazuhiro ...
    1984 Volume 57 Issue 6 Pages 1515-1517
    Published: 1984
    Released: June 27, 2006
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    The photoreactions of N,N-dimethylpyruvamide (DMPA) in methanol and ethanol were investigated. Irradiation of DMPA in methanol gave three products (3,5-dimethyl-4-oxazolidinone, 2-hydroxy-N-methyl-N-(methoxymethyl)propanamide, and 2,3-dihydroxy-2,3-dimethyl-N,N,N′-trimethyl-N′-(methoxymethyl)-butanediamide) in good yields. The product distribution was dependent on the concentration of DMPA and methanol. Similarly, irradiation of DMPA in ethanol gave three products (3,5-dimethyl-4-oxazolidinone, 2-hydroxy-N-methyl-N-(ethoxymethyl)propanamide, and 2,3-dihydroxy-2,3-dimethyl-N,N,N′-trimethyl-N′-(ethoxymethyl)butanediamide). The mechanism for the formation of these products is discussed.
  • Tsutomu Osawa, Tadao Harada
    1984 Volume 57 Issue 6 Pages 1518-1521
    Published: 1984
    Released: June 27, 2006
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    The enantioface-differentiating (asymmetric) hydrogenation of various methyl ketones (R–COCH3) was carried out over the Raney nickel catalyst modified with (R,R)-tartaric acid and sodium bromide. The presence of an appreciable amount of carboxylic acid in the reaction system was indispensable for a high optical yield. The highest optical yield (74%) was obtained in the hydrogenation of 3,3-dimethyl-2-butanone in the presence of pivalic acid.
  • Yosuke Kataoka
    1984 Volume 57 Issue 6 Pages 1522-1527
    Published: 1984
    Released: June 27, 2006
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    Molecular dynamics simulations of a water-like system are performed at many temperatures and densities. A 2-dimensional model of water is used for the system with 144 molecules in a square cell. The calculated self-diffusion coeffcient and the dipole direction relaxation time are in good agreement with the observed values in a wide temperature-pressure plane. Cross correlation function of displacement and local orientational order parameter are computed by the time-averaged configurations, where the average of period is several times longer than the velocity correlation time. The cross correlation is observed even in the third neighbor pairs, which proves the existence of hydrogen-bonded local structure. The lifetime of this local structure is about 2×10 ps at low temperatures and low density, where density maximum is known. The lifetime of the unstable species with a rather high energy is found to be about 0.5–2 ps at low temperatures and low density.
  • Takeshi Ohno, Shunji Kato
    1984 Volume 57 Issue 6 Pages 1528-1533
    Published: 1984
    Released: June 27, 2006
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    Molar absorption coefficients of the phosphorescent states (2E) of [Cr(2,2′-bipyridine)3]3+ and [Cr(4,7-diphenyl-1,10-phenanthroline)3]3+ were determined. The 2E state of [Cr(2,2′-bipyridine)3]3+ was reduced to [Cr(2,2′-bipyridine)3]2+ with the yield of less than 0.2 in the quenching by iron(II) compounds. The reduction yields of [Cr(2,2′-bipyridine)3]3+ and [Cr(4,7-diphenyl-1,10-phenanthroline)3]3+ in the quenching of 2E by aromatic amines increase with the Gibbs energy change (−ΔG) in the reverse electron-transfer process. The weak dependence of the yields on ΔG can not be interpreted in terms of adiabatic reverse electron transfer in the geminate pair, which is formed in the quenching process. The electron transfer from the chromium(II) compounds of triplet spin-multiplicity to the amine radical of doublet spin-multiplicity suffers from spin-restriction.
  • Yasushi Inoue, Hiromichi Yamazaki
    1984 Volume 57 Issue 6 Pages 1534-1538
    Published: 1984
    Released: June 27, 2006
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    In order to elucidate the fundamental properties of hydrous tin(IV) oxide as a cation-exchanger, the stoichiometry of cation exchange and its acid-base property were studied by means of the uptake curves for alkali-metal ions. The results are summarized as follows: 1) The equivalent exchange between the hydrogen ion and either alkali-metal or alkaline-earth-metal ions holds, irrespective of the ionic strength of the solution and the extent of exchange. 2) The water content in the exchanger depends on the ionic composition. 3) This material is an amphoteric ion-exchanger, with at least two kinds of weakly dissociable ion-exchange sites, and the conditional dissociation constant depends on the ionic composition of the exchanger. The stability to various reagents was also examined.
  • Isao Sanemasa, Seiji Arakawa, Masatake Araki, Toshio Deguchi
    1984 Volume 57 Issue 6 Pages 1539-1544
    Published: 1984
    Released: June 27, 2006
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    Salt effects on the solubilities of benzene, toluene, ethylbenzene, and propylbenzene were studied by making use of the solute vapor. The salting coefficients were determined at 25 °C, and the results were compared with the literature values and with those estimated by means of theoretical equations. The McDevit-Long equation did not give satisfactory predictions until the equation was multiplied by a factor of 0.4. The scaled particle theory gave a favorable agreement with the observations in most cases if suitable pair-potential parameters of solutes were used in the calculations.
  • Yoshiyuki Tanizaki, Masao Yamazaki, Sumiko Nagatsuka
    1984 Volume 57 Issue 6 Pages 1545-1550
    Published: 1984
    Released: June 27, 2006
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    Eight kinds of Millipore filters with different pore sizes (8–0.025 μm) were used for the filtration of two water samples taken from the Tama River. The filtrates were analyzed for 31 elements using a neutron activation analysis. Most alkali and alkaline earth elements were distributed in the smallest size fraction (<0.025 μm). The same fractionation pattern was also recognized for As, Se, Mo, Sb, and W, which tend to form oxoanions. But the major transition elements were concentrated in the larger size fractions (>0.45 μm). For the river water sample with higher concentration of total organic carbon, however, most of such elements were found in the smallest size fraction. The solubilities of rare earth elements bacame higher with increasing their ionic potentials.
  • Tadashi Hara, Motohiro Toriyama, Kazuhiko Tsukagoshi
    1984 Volume 57 Issue 6 Pages 1551-1555
    Published: 1984
    Released: June 27, 2006
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    A flow-injection analysis method of protein by direct injection has been established by use of the luminol-hydrogen peroxide luminescence system. The determination of protein is based on the measurement of the decreasing catalytic activity of copper(II) for the chemiluminescent reaction between luminol and hydrogen peroxide. The present flow-injection analysis in which a protein solution is directly injected is quite different from the previous one in which a protein solution is injected after having been previously allowed to react with copper(II) outside the flow-through system. The optimum conditions for the determination of protein were determined with regard to reagent concentration, flow rate, reaction time, and reaction temperature. The present method is simple, rapid, and applicable to the determination of 2×10−4–1×10−1 g dm−3 of protein with 40 ng of detection limit at a rate of about 30 samples per hour. The present method was also applied to the determination of the ratio of albumin to globulin in a sample. The present flow-injection system is expected to be a sensitive detector for the determination of small amounts of protein.
  • Tasuku Ito, Masako Kato, Haruko Ito
    1984 Volume 57 Issue 6 Pages 1556-1561
    Published: 1984
    Released: June 27, 2006
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    X-Ray data of 16 structures having coordination geometry of the trans-MX2N4 type show that (i) an out-of-plane coordination bond length decreases as an in-plane distance increases, (ii) the degree of the correlation is metal ion dependent and varies in the order, Zn2+>Ni2+>Co3+. In the Ni(II) systems, complexes having stronger ligands (X=NCS) at axial positions show the weaker correlation as compared with complexes with weaker axial ligands (Cl). Electronic origin that causes such negative correlations has been investigated in terms of the potential energy surfaces obtained from ab initio MO calculations for model compounds, trans-[MCl2(NH3)4]. A section of the potential surface along the M–Cl and M–N bond axes is an ellipse and the ellipse has a tilt with respect to the metal-ligand bond axes. The dependence of the M–Cl distances on the M–N distances becomes stronger, as the tilt of the ellipse increases, and/or as the ratio of the length of long to short axes of the ellipse is increased. The degree of correlation expected from the potential energy surfaces are consistent, in all respect, with experimentally observed results. The interrelationships, found both experimentally and theoretically, are associated with softness of metal ions. Among the metal ions studied, Co(III) is the hardest, Zn(II) is the softest, and Ni(II) is intermediate.
  • Tadashi Endo, Masao Hashimoto, Toyohiko Orii, Masato M. Ito
    1984 Volume 57 Issue 6 Pages 1562-1566
    Published: 1984
    Released: June 27, 2006
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    The rates of oxidation of 1:1 mixtures of associating thiols, each having the binding site (Remark: Graphics omitted.) and the recognition site [p-(CH3)2NC6H4 or R], with O2 were measured in 80% (v/v) acetonitrile-20% water in the range of 20 to 50 °C. Oxidation of the thiol having the p-(CH3)2NC6H4 group proceeds about 100 times faster than that of the thiols with R. It has been found that oxidation of 1:1 mixtures of the thiols is first-order with respect to thiols and 0.7 th-order with respect to triethylamine by means of the method of initial rates. The k1.7 values for R=C6H5, p-CH3C6H4, and p-C2H5C6H4 were similar to one another; this makes a sharp contrast with our previous work that the selectivity (the logarithmeric ratio of the yield of the unsymmetrical disulfide to twice that of the symmetrical disulfide) changes greatly with the structures of R and temperature. It is concluded that the product ratio does not depend upon the k1.7. The large negative activation entropies (−51 to −45 cal K−1 mol−1) suggest that the oxidation would proceed through a highly ordered transition state.
  • Katsuhiro Saito, Takashi Toda, Toshio Mukai
    1984 Volume 57 Issue 6 Pages 1567-1569
    Published: 1984
    Released: June 27, 2006
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    Tropone tosylhydrazone sodium salt was allowed to react with silver chromate to give 2-tosyl-2H-indazole. The reaction is thought to proceed through the cyclization of the hydrazyl radical intermediate. Under the same conditions, sodium salts of m-nitrobenzaldehyde tosylhydrazone (5), benzylideneacetone tosylhydrazone derivatives (7a and 7b), and β-ionone tosylhydrazone (9) reacted to yield m-nitrobenzonitrile from 5 and pyrazole derivatives from 7a, b, and 9, respectively. m-Nitrobenzonitrile is formed by homolytic fission of nitrogen–nitrogen bond of 5. Formation of the pyrazole derivatives can be explained by intramolecular 1,3-dipolar additions of the corresponding diazo intermediates.
  • Yuji Hiraki, Akira Tai
    1984 Volume 57 Issue 6 Pages 1570-1575
    Published: 1984
    Released: June 27, 2006
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    The enantiomer-differentiating acylation (kinetic resolution) of 1-phenylalkylamines and their derivatives was carried out with (S)-2-phenylbutyric anhydride and its derivatives in aqueous and nonaqueous media. On the basis of the distributions of the two diastereomeric products, the molecular interactions between hydrocarbon residues responsible for the structural recognition of the reacting molecules were studied. In nonpolar media, the (R,S)-isomer was predominantly formed over the (S,S)-isomer. Moreover, the differentiation was mainly controlled by the size of the alkyl substituents of the substrates. In aqueous media, though, the (S,S)-isomer was predominantly formed. By a comparative study of the cyclohexyl analogs of the substrates and the reagents, it was shown that alkyl-phenyl and/or phenyl-phenyl interactions were important in the recognition process. A partitioning process of the substrate into the reagent phase was not effective in the differentiation of the enantiomer by the reaction in suspensions of optically active reagents in highly aqueous media.
  • Naoshi Fujiwara, Hiroshi Tomiyasu, Hiroshi Fukutomi
    1984 Volume 57 Issue 6 Pages 1576-1581
    Published: 1984
    Released: June 27, 2006
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    Kinetics of the ligand exchange reaction between tetrakis(acetylacetonato)thorium(IV) and free acetylacetone in CD3CN and CDCl3 was studied by 1H NMR. The rate law was written as rate =k[Th(acac)4][Hacac]enol, where k=(1.0±0.1)×102 s−1 mol−1 kg at 0 °C in CD3CN and (1.7±0.1)×102 s−1 mol−1 kg at −16 °C in CDCl3. The rates were retarded by addition of bases and the retardation effect well correlated with the donor number of the bases. Under the conditions studied, the activation entropies gave large negative values. A ligand exchange mechanism passing through a nine-coordinate intermediate is proposed to interpret the kinetic law.
  • Akimasa Yajima, Takashi Arai, Ryoko Matsuzaki, Yuzo Saeki
    1984 Volume 57 Issue 6 Pages 1582-1585
    Published: 1984
    Released: June 27, 2006
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    The reaction products of gaseous NbCl5 with ammonia were NbCl5·5NH3 at 200 °C, NbCl5·5NH3, Nb4N5, and NH4Cl at 250–500 °C, Nb4N5 and NH4Cl at 550–950 °C, δ-NbN and NH4Cl at 1000 °C, δ-NbN, Nb2N, NH4Cl, and HCl at 1100 °C, and δ-NbN, Nb2N, Nb4N3, δ′-NbN, ε-NbN, NH4Cl, and HCl at 1200–1300 °C. In the vapor-phase reaction of gaseous NbCl5 with ammonia, the reaction of gaseous NbCl5 with ammonia to form NbCl5·5NH3 occurs first. Above ca. 235 °C, the NbCl5·5NH3 reacts with ammonia to form Nb4N5. Above ca. 1000 °C, the Nb4N5 decomposes to δ-NbN. Above about 1100 °C, in addition to these reactions, the nitriding of niobium, formed by the reduction of gaseous NbCl5 with the hydrogen resulting from the thermal dissociation of ammonia, also occurs to form Nb2N at 1100 °C and Nb2N, Nb4N3, δ′-NbN, and ε-NbN at 1200–1300 °C. When the Nb4N5, formed by the vapor-phase reaction, is heated in an argon atmosphere, it changes to δ-NbN at ca. 1000 °C, to δ-NbN and ε-NbN at 1100–1200 °C, and then to Nb4N3 and δ-NbN at 1300 °C. The niobium nitrides formed above 1200 °C are uniform, ultrafine powders with particle diameters of the order of 1/100 μm.
  • Kazuo Haga, Masayuki Oohashi, Ryohei Kaneko
    1984 Volume 57 Issue 6 Pages 1586-1590
    Published: 1984
    Released: June 27, 2006
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    Condensation of 1,4-cyclohexanedione with N-alkylarylamines gives N-alkyl-N-arylanilines, and that with diarylamines gives triarylamines. A mechanism involving dehydration of monoenamines of the 1,4-dione is proposed for the reaction. Relative rates of substituted N-ethylanilines on competitive reactions plotted vs. Hammet’s σ values gave −2.0 as the ρ value. In separate reactions, however, a different tendency is noted for the yield, that is, the ease of reactions with p-chloro and p-nitro derivatives. This discrepancy is explained in terms of acidities of the conjugate acids of the amines used as the actual catalysts.
  • Tomoji Saeki, Eiichi Narita, Hiroyuki Naito
    1984 Volume 57 Issue 6 Pages 1591-1595
    Published: 1984
    Released: June 27, 2006
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    Kinetic study of the hydrolysis of silicon phosphate, Si3(PO4)4 (hexagonal), was carried out in borax buffer solutions (pH 5–12, temperature 20–50 °C) to investigate how it acts as a hardener for alkali silicate adhesive. The silicon phosphate was found to be hydrolyzed with a resulting release of orthophosphate ion, soluble silicate ions, and colloidal silica under mild conditions; the decomposition rate increased with decreasing the particle size of the phosphate and with increasing the pH and temperature of the buffer solution. From the analysis of the decomposition rate on the basis of the shrinking core model, it was found that the decomposition rate could be adequately expressed by the rate equation based on the mixed control of diffusion through a residual layer and surface chemical reaction. This indicates that a part of the colloidal silica which resulted from the hydrolysis remains on the surface of the silicon phosphate particle and then partially limits the overall rate of the hydrolysis. The dependence of both rate-determining steps for the decomposition rate was quantitatively indicated according to the reaction conditions.
  • Kazuaki Yamanari, Yoichi Shimura
    1984 Volume 57 Issue 6 Pages 1596-1603
    Published: 1984
    Released: June 27, 2006
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    [2]-[[(en)2Co{XCH2S(CH2)nSCH2Y}Co(en)2]Clm]-[α-CDX]-rotaxanes (n=8, 10, and 12 for X=Y=CO2 (m=4); n=10 for X=CO2 and Y=CH2NH2(m=5); α-CDX=α-cyclodextrin) were prepared with partial stereoselectivity and characterized from their visible-UV absorption, circular dichroism(CD), and 13C NMR spectra, and elemental analysis. The rotaxane formation could be identified by the down field shift of the chemical shift due to α-CDX in the 13C NMR spectra and the increase of the CD intensity in the ligand-to-metal charge transfer band region in the CD spectra. The rotaxanes always showed apparently ΔΔ-rich CD spectra, the highest selectivity(10% ΔΔ-rich) being found in the case of n=10.
  • Michikazu Yoshioka, Tsuneji Suzuki, Masashi Oka
    1984 Volume 57 Issue 6 Pages 1604-1607
    Published: 1984
    Released: June 27, 2006
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    Irradiation of 2,2-dimethyl-1-phenyl-1,3-diketones with 3-ethyl or 3-isopropyl substituents gave type II cyclization product, 3-hydroxy-2,2,4-trimethyl-3-phenylcyclobutanone or 3-hydroxy-2,2,4,4-tetramethyl-3-phenylcyclobutanone, along with type I cleavage products. The type II cyclization/type I cleavage ratio is greater with a 3-isopropyl group than with a 3-ethyl group. A similar irradiation of 2,2-dimethyl-1-phenyl-1,3-butanedione gave type I cleavage products and no type II cyclization product. Irradiation of 2,4-dimethyl-1-phenyl-1,3-pentanedione gave 3-hydroxy-2,2,4-trimethy1-3-phenylcyclobutanone and propiophenone. The geometry of 3-hydroxy-2,2,4-trimethyl-3-phenylcyclobutanone which arose from 2,2-dimethyl-1-phenyl-1,3-pentanedione was cis with respect to phenyl and 4-methyl groups and that which arose from 2,4-dimethyl-1-phenyl-1,3-pentanedione was trans.
  • Noriyuki Yonezawa, Yutaka Ikebe, Tsuyoshi Yoshida, Teruhisa Hirai, Kaz ...
    1984 Volume 57 Issue 6 Pages 1608-1611
    Published: 1984
    Released: June 27, 2006
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    The thermal behavior of head-to-head coumarin dimers and twelve lactone-opened derivatives was investigated. Though the lactone rings in coumarin dimers are very susceptible to nucleophilic ring-opening, heating these derivatives reformed six-membered lactone rings except for certain imide and diamide derivatives. The large neiboring group effect allowed the relactonization by the attack of hydroxyphenyl group to carbonyl carbon in preference to the scission of cyclobutane ring.
  • Isao Ikeda, Hiroshi Emura, Mitsuo Okahara
    1984 Volume 57 Issue 6 Pages 1612-1616
    Published: 1984
    Released: June 27, 2006
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    A series of long chain alkyl lariat ethers were synthesized and their aqueous properties in the absence and presence of alkali metal cations were investigated by measuring their cloud points and complex stability constants. In spite of the presence of ether oxygen(s) in the side chain, complexing abilities toward sodium and potassium cations did not significantly differ from those of the corresponding alkyl crown ethers. As the number of ether oxygens in the side chain of lariat ethers was increased, the water solubilities were much improved and showed high cloud points. However, the degree of salting-in effect decreased and the increment of cloud point caused by addition of salts decreased, probably due to the increase of acyclicity of the polyether molecule.
  • Norio Nishimura, Shinya Kosako, Yoshimi Sueishi
    1984 Volume 57 Issue 6 Pages 1617-1625
    Published: 1984
    Released: June 27, 2006
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    The substituent, solvent, and pressure effects on the rate of the thermal cis-to-trans isomerization of 4-dimethylamino-4′-nitroazobenzene(NDAAB) derivatives have been studied. 2-Methyl- and 2′-chloro–NDAAB isomerize faster than NDAAB, and 2′-methyl- and 2-chloro-NDAAB isomerize slower than NDAAB. For 2,2′-dimethyl- and 2,2′-dichloro-NDAAB, the rates are between those of the monosubstituted ones. These findings are very similar to those for 4-(dimethylamino)azobenzene (DAAB) derivatives, and no fundamental difference in the kinetic-substituent effects was observed between NDAAB and DAAB. The volume of activation, which is of a negative value, varies remarkably from solvent to solvent and from substituent to substituent; its magnitude increases generally with an increase in the solvent polarity. Even for DAAB and 4,4′-bis(diethylamino)azobenzene (BDEAAB), the rate is appreciably accelerated by external pressures in polar solvents. It is concluded that the observed results are more consistent with the inversion mechanism than with the rotational mechanism.
  • Ken-ichi Okamoto, Akira Itaya
    1984 Volume 57 Issue 6 Pages 1626-1630
    Published: 1984
    Released: June 27, 2006
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    The carrier-photogeneration efficiency of holes in poly(N-vinylcarbazole) (PVCz) films was investigated by means of the time-of-flight method as a function of applied electric field, temperature, and excitation band. The extrinsic effects on the efficiency were examined; these included photooxidation of film surface and doping with a weak electron-acceptor, dimethyl terephthalate (DMTP). The experimental results were analyzed according to the Onsager theory of geminate recombination of a bound electron-hole pair with an interionic separation of ro. The primary yield of the electron-hole pair, φo, increased from 0.02 to 0.059 with decreasing excitation wavelength. By photooxidation, it increased up to 0.09 for all the excitation bands. The ro was independent of the excitation band, and was identical between fresh and photooxidized films. In DMTP(1.8 mol%)-doped films, both φo and ro were independent of the excitation band, although their values were different from those of undoped films. These results indicate that the extrinsic carrier-photogeneration via nonrelaxed exciplexes formed between singlet excitons and acceptor-like impurities or photooxidation products is predominant in PVCz films for all the excitation bands.
  • Kuninobu Kasuga, Takeo Nagahara, Teruaki Masuda, Shunji Kiyota, Yasuo ...
    1984 Volume 57 Issue 6 Pages 1631-1636
    Published: 1984
    Released: June 27, 2006
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    A number of unsymmetrical tetradentate Schiff base complexes of nickel(II) and copper(II) having only one methine carbon in the ligand were synthesized and characterized by means of UV and 1H NMR spectra. The kinetic studies of the electrophilic substitution reactions on the methine carbon with N-halogenosuccinimide gave no support to an aromatic character of the chelate ring, being consistent with the results of 1H NMR studies for the nickel(II) complexes.
  • Katsuyuki Ogura, Mitsuo Yamashita, Michiyo Suzuki, Shigeko Furukawa, G ...
    1984 Volume 57 Issue 6 Pages 1637-1642
    Published: 1984
    Released: June 27, 2006
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    Cyclization of 1,n-dihalo[or bis(tosyloxy)]alkanes with methyl methylthiomethyl sulfoxide in the presence of a base (n-BuLi or KH) gave three-, four-, five-, and six-membered 1-methylsulfinyl-1-methylthiocycloalkanes. These cyclization products were easily converted to the corresponding ketones by acid hydrolysis except 1-methylsulfinyl-1-methylthiocyclopropane which afforded a complicated mixture. The combination of the cyclization with the acid hydrolysis thus provides a new method for synthesizing four-, five-, and six-membered cycloalkanones. Several representative preparations, such as those of substituted cyclobutanones, 3-cyclopentenone, and tetrahydro-4-pyrone, are described.
  • Tohru Hayakawa, Koji Araki, Shinsaku Shiraishi
    1984 Volume 57 Issue 6 Pages 1643-1649
    Published: 1984
    Released: June 27, 2006
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    The 1,3-dipolar cycloaddition reactions of nitrile oxides with substituted p-benzoquinones are discussed in terms of Frontier Molecular Orbital (FMO) theory. The calculation is carried out by ab initio Self Consistent Field (SCF) method with STO-3G basis set. The site- and regio-selectivities in the reactions are correlated with two types of FMO interactions. Some predictions have been confirmed by experimental results.
  • Galal Eldin Hamza Elgemeie, Hassan Attia Elfahham, Said Ahmed Soliman ...
    1984 Volume 57 Issue 6 Pages 1650-1652
    Published: 1984
    Released: June 27, 2006
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    The reactivity of amino and hydroxy azoles toward nitrilimines and hydrazonoyl halides was investigated. Several novel rotes for synthesis of derivatives of known heterocyclic systems are reported.
  • Mahmoud Zarif Amin Badr, Galal Moustafa El-Naggar, Hassan Ahmad Hassan ...
    1984 Volume 57 Issue 6 Pages 1653-1657
    Published: 1984
    Released: June 27, 2006
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    Reaction of 3-methyl-2(1H)quinoxalinone (1) with alkyl, benzyl, and arenesulfonyl halides in the presence of K2CO3 in dry acetone gave 1-substituted 3-methyl-2(1H)-quinoxalinones (2ag). However 1 reacts with benzoyl chloride under the same conditions to give 3-methyl-2-quinoxalinyl benzoate, while it reacts with P2S5 in dry pyridine to give 3-methyl-2(1H)quinoxalinethione (4). Treatment of 4 with methy iodide in the presence of K2CO3 in dry acetone gave 2-methyl-3-(methylthio)quinoxaline but not 1,3-dimethyl-2(1H)-quinoxalinethione which has been obtained from 2a and P2S5 in dry pyridine. Treatment of 4 with benzyl bromide and/or p-nitrobenzyl bromide in the presence of K2CO3 in dry acetone gave 2-benzylthio and 2-(p-nitrobenzylthio)-3-methylquinoxalines. Syntheses of 1-methyl-3-(substituted styryl)-2(1H)-quinoxalinone (8am) were achieved by condensation of 2a with aromatic aldehydes. Addition of thiophenols and mercaptoacetic acid to 8 gives 1-methyl-3-[2-(substituted phenylthio)ethyl]-2(1H)-quinoxalinones and 1-methyl-3-[2-(substituted phenyl)-2-(carboxymethylthio)ethyl]-2(1H)-quinoxalinones respectively. 1,3-Dimethyl-2(1H)-quinoxalinone (2a) condensed with ketones in the presence of ZnCl2 to give 1-methyl-3-[2-(substituted phenyl)-1-alkenyl]-2(1H)-quinoxalinones. 1-Methyl-3-(substituted styryl)-2(1H)-quinoxalinethiones were produced by refluxing a mixture of 8 with P2S5 in dry pyridine.
  • Stephen R. Landor, Olatunji O. Sonola, Austin R. Tatchell
    1984 Volume 57 Issue 6 Pages 1658-1661
    Published: 1984
    Released: June 27, 2006
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    The asymmetric reduction of selected Schiff ’s bases (ketimines) with the lithium aluminium hydride–monosaccharide complexes derived from 3-O-benzyl-1,2-O-cyclohexylidene-α-D-glucofuranose gives optically active secondary amines. The absolute configuration of N-(1-phenylethyl)aniline was assigned as S by N-phenylation of S-(−)-1-phenylethylamine and hence all the levo-rotatory secondary amines obtained by this asymmetric reduction are assigned the S-configuration.
  • Gabriel Rokicki, Witold Kuran
    1984 Volume 57 Issue 6 Pages 1662-1666
    Published: 1984
    Released: June 27, 2006
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    A study has been carried out on the reaction of alkali metal carbonates with epihalohydrins in the presence of cation complexing agents e.g. crown ethers. 3-Glycidyloxypropylene carbonate was found to be formed as the main product of the reaction of epichlorohydrin with potassium carbonate promoted by 18-crown-6. The effect of various epihalohydrins and alkali metal carbonates on the reaction course was examined. It was found that the reaction of potassium hydrogencarbonate with epichlorohydrin gives 4-hydroxymethyl-1,3-dioxolan-2-one. When the reaction of epihalohydrins with potassium carbonates was carried out in the atmosphere of carbon dioxide the products contained linear carbonate linkage apart from cyclic one. From these results, a plausible mechanism was proposed for the reaction of alkali metal carbonates with epihalohydrins in the presence of crown ethers.
  • Girija Shankar Singh, Surendra Bahadur Singh, Kailash Nath Mehrotra
    1984 Volume 57 Issue 6 Pages 1667-1670
    Published: 1984
    Released: June 27, 2006
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    The reactions of 2-diazo-1,2-diphenylethanone (1) with ketohydrazones (3ac) in equimolecular ratio yield (diphenylacetyl)hydrazones (4ac) of the corresponding benzophenones which on further treatment with 1 in equimolecular ratio leads to 1-diphenylacetylazo-1,1,3,3-tetraaryl-2-propanones (5ac). The product 5a is also obtained in the reaction of 1 with benzophenone hydrazone (3a) in 2 : 1 molecular ratio. The bis(acetylacetonato)copper(II)-catalyzed reaction of 1 and also of diphenyldiazomethane (2) with ketohydrazones (3) affords ketazines (6). The mechanistic route for the formation of products is discussed.
  • Takahiro Wada, Fumiko Yokotani, Yoshihiro Matsuo
    1984 Volume 57 Issue 6 Pages 1671-1672
    Published: 1984
    Released: June 27, 2006
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    The ternary system CH3CO2Na–Na4P2O7–H2O was investigated between 38 and 85°C. No double salt occurs in this temperature range. The saturated CH3CO2Na solutions can contain only small amount of Na4P2O7. The CH3CO2Na solutions have a very strong dehydrating influence on Na4P2O7·10H2O. So, the lowest formation temperature of anhydrous Na4P2O7 is about 47°C.
  • Shozi Mishima, Tsuyoshi Nakajima
    1984 Volume 57 Issue 6 Pages 1673-1674
    Published: 1984
    Released: June 27, 2006
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    Acid strength distributions of silica-alumina, silica-magnesia, and their mixtures were measured by the Benesi method. Overestimation of acidity has been demonstrated by the measurement that the acidity in the range H0≤−3.0 for the mixtures is larger than the value expected from additivity.
  • Tadashi Shiraiwa, Hirofumi Fukuoka, Masahiro Yoshida, Hidemoto Kurokaw ...
    1984 Volume 57 Issue 6 Pages 1675-1676
    Published: 1984
    Released: June 27, 2006
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    A ternary complex, (D-alaninato)(L-isoleucinato)copper(II) (abbreviated as [Cu(D-ala)(L-ile)]), was crystallized selectively at 0°C from an aqueous solution containing DL-alanine (DL-Ala), L-isoleucine (L-Ile), and copper(II) acetate monohydrate (Cu(OAc)2·H2O) in the molar ratio of 1:1:1.
  • Yukio Koizumi, Hiroshi Sawase, Yasuo Suzuki, Mamoru Shimoi, Akira Ouch ...
    1984 Volume 57 Issue 6 Pages 1677-1678
    Published: 1984
    Released: June 27, 2006
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    The crystal and molecular structure of the title complex has been determined by the use of the single-crystal X-ray diffraction method. The crystal of CeC21H17O10, F. W. 569.48, was monoclinic; space group P21c, a=13.401(2), b=19.173(5), c=8.079(1) Å, β=98.94(1)°, U=2050.6(8) Å3, Z=4, Dm=1.84(3), Dx=1.84 Mg m−3, and μ(Mo Kα)=2.31 mm−1. Each cerium(III) atom is ennea-coordinated and is in a tri-capped trigonal-prism geometry. They are in a linear polymer, and each cerium(III) atom is bridged to the next metal atom by three carboxylate ligands.
  • Kazuki Sato, Masato Tanaka, Tetsuo Hayase
    1984 Volume 57 Issue 6 Pages 1679-1680
    Published: 1984
    Released: June 27, 2006
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    CD spectra of many oligopeptides having tri- or tetra-L-prolyl sequences showed that a penta- or hexapeptide having a tetra-L-prolyl sequence took poly(L-proline) II helix irrespective of amino acid residues at N- or C-terminal of a L-prolyl cluster and that as to a size of the cluster, tri-L-prolyl sequence was enough to form the helix, when glycine was used as substituent.
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