Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 61 , Issue 5
Showing 1-50 articles out of 69 articles from the selected issue
  • Jun-ichi Aihara
    1988 Volume 61 Issue 5 Pages 1451-1454
    Published: 1988
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Various polycyclic aromatic hydrocarbons (PAHs) are distributed widely in our environment. Diesel particulate extract contains many larger PAHs. All these PAHs have a percent resonance energy larger than 2.50. Dibenzo[def,mno]chrysene and anthracene constitute the most unstable PAHs among them. A couple of reaction paths to the formation of ovalene are discernible in flames by inspecting the combustion products. It seems likely that a similar type of reactions take place in the envelopes of carbon stars to give large compact PAHs and graphite.
  • Michiko Konno, Hirotoshi Sano
    1988 Volume 61 Issue 5 Pages 1455-1461
    Published: 1988
    Released: June 27, 2006
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    The crystal structure of 1′,1'″-diethylbiferrocenium triiodide, (EtFcFcEt)+ I3, was determined by means of X-ray diffraction. The crystals at 298 and 140 K are found to be monoclinic, with the P21c space group and with Z=2. At 298 K, a=9.7557(10), b=9.9772(12), c=13.8216(13) Å, β=107.625(9)°, and U=1282.18(23) Å3, while at 140 K, a=9.6931(17), b=9.8065(22), c=13.7373(19) Å, β=107.642(15)°, and U=1244.4(4) Å3. The structures are refined to R=0.049 at 298 K and R=0.036 at 140 K. The (EtFcFcEt)+ cations and I3 anions sit on a crystallographic center of symmetry both at 298 and at 140 K, and the two ferrocenyl(Fc) units are crystallographically equivalent. The ethyl group in each ethylcyclopentadienyl(EtCp) group is not parallel to the fulvalene moiety, but the terminal CH3 group moves away with the 60° inclination from the Cp plane. An appreciable interaction seems to exist between the Cp ring of the cation and the I3 anion along the a+c⁄2 direction, but the interaction among the cations along the a axis seems to be so weak as to be negligible.
  • Mitsuo Mishima, Tsutomu Okuda
    1988 Volume 61 Issue 5 Pages 1463-1469
    Published: 1988
    Released: June 27, 2006
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    NQR spectra due to 35Cl, 127I, and 121Sb in I3Cl2SbCl6 and ICl2SbCl6 have been observed in the temperature range 77 K to melting point. The Zeeman effect on the single crystals of these complexes has been examined. In I3Cl2SbCl6 the η-values for the I atoms contributing to the higher and the lower NQR frequencies are 0.73 to 0.09, respectively, whereas in ICl2SbCl6 the η-value for the I atom is 0.15. In these complexes the 35Cl NQR lines which yield large η-values (0.42 to 0.56) are assigned to the bridging Cl atoms. The η-values for the other Cl atoms, except the Cl atoms in the ICl2+ ion which have η-values of 0.13 to 0.15, are negligibly small. The Sb atoms in both complexes have considerably large η-values (0.39). The orbital populations have been calculated from the NQR parameters. The bonding in the cations is explained on the basis of an approximation using only p orbitals of the I atom.
  • Masako Yamamoto, Shoji Harada, Thoru Nakatsuka, Takayuki Sano
    1988 Volume 61 Issue 5 Pages 1471-1474
    Published: 1988
    Released: June 27, 2006
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    The hydrodynamic behavior of amylose with and without sodium dodecyl sulfate (SDS) has been examined by viscosity measurements. Two distinct viscosity phenomena have been observed by complexation; one is the increase at the first stage of binding of SDS, which disappears by an addition of salt, and the other is the subsequent decrease in the region of further binding of SDS. These results are interpreted by an idea that the expansion of the complex occurs by an electrostatic repulsion of the bound SDS molecules and the contraction of the complex by a hydrophobic interaction of cooperatively bound SDS molecules. This idea was confirmed further by experiments using amyloses of different length and homologous surfactants of SDS.
  • Kunio Esumi, Yuichi Sakamoto, Keiko Yoshikawa, Kenjiro Meguro
    1988 Volume 61 Issue 5 Pages 1475-1478
    Published: 1988
    Released: June 27, 2006
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    The properties of mixed surfactant bilayers on monodispersed ferric hydro sol were studied by measuring the amount of surfactant adsorbed, particle size, and pyrene fluorescence spectra. The positively charged sols flocculated upon addition of sodium dodecyl sulfate (SDS) or lithium perfluoro-1-octanesulfonate (LiFOS) were redispersed by further addition of poly(oxyethylene) nonyl phenyl ether (NP7.5) due to the formation of a mixed surfactant bilayer on the sols. The mixed surfactant bilayer of SDS–NP7.5 on the sols was more easily formed than LiFOS–NP7.5. Fluorescence fine structure of pyrene gave information on the polarity of the microenvironment in the mixed surfactant layer on the sols.
  • Yoshihiro Sasaki
    1988 Volume 61 Issue 5 Pages 1479-1483
    Published: 1988
    Released: June 27, 2006
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    The oscillation behavior of the bromate–cerium–oxalic acid system was simulated within the FKN framework with bromine-hydrolysis control, where a radical-chain reaction of HOBr with oxalic acid and the formation of HCO2· by the reduction of Ce(IV) were assumed. When [(COOH)2]=0.03 mol dm−3 and k13=0.075 s−1 (k13: the rate constant of bromine removal), the oscillation behavior was qualitatively consistent with the experimental results. Excitability in the reduced and oxidized steady states, induced by a sudden change in the concentration of bromine, was simulated. No bistability was found. When [(COOH)2]=0.03 mol dm−3, no hysteresis near the bifurcation points was observed. However, when [(COOH)2]=0.001 mol dm−3, hysteresis was observed in the transition between the oxidized steady state and the oscillatory state.
  • Kenji Okuyama, Yoshie Soboi, Naomi Iijima, Kiyoshi Hirabayashi, Toyoki ...
    1988 Volume 61 Issue 5 Pages 1485-1490
    Published: 1988
    Released: June 27, 2006
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    Dioctadecyldimethylammonium bromide monohydrate (2C18N+2C1Br·H2O), C38H80NBr·H2O, was crystallized from its solution in chloroform and hexane. The crystals are triclinic with the space group P\bar1, Z=2, a (normal to the bilayer surface)=3.811(2), b=0.7890(2), c=0.7418(2) nm, α=104.37(3), β=103.06(4), and γ=74.93(3)°. The structure was solved by the direct method and refined by the block-diagonal least-squares procedure: R=0.08 for 3121 observed reflections. The crystal structure consists of bimolecular layers stacking regularly along the a-direction. The two amphiphile molecules in the unit cell are related by centrosymmetry and pack tail to tail in a bilayer structure with tilting hydrocarbon chains by about 45° to the bilayer surface. The packing cross section per molecule in the layer plane is 0.567 nm2. The hydrocarbon chains pack with an triclinic (T//) subcell with dimensions of as=0.42, bs=0.49, cs=0.26 nm, αs=88, βs=104, and γs=111°. One of the two alkyl chains bends near the nitrogen atom and conforms a part of a head region. Two water oxygen atoms with half occupancies were found in an asymmetric unit and accomodated statistically in a unit cell. These water molecules are linked with bromide anions by hydrogen bonds with the distance of about 0.34 nm. Bromide anions and ammonium cations are on the same plane parallel to the bilayer surface.
  • Yoshiya Kera, Takahiro Kawashima
    1988 Volume 61 Issue 5 Pages 1491-1499
    Published: 1988
    Released: June 27, 2006
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    SnO2 and Nb2O5-supported monolayer or sub monolayer vanadium oxide catalysts were prepared by an impregnation method such as the column-exchange adsorption of oxovanadium ion at various pH(=2, 4, and 7). The deposited states of the vanadia species on SnO2 and Nb2O5 surfaces were examined by ESR spectrometry using V4+ ion as a probe. The catalytic features were studied by measuring the 2-propanol decomposition rate as a test reaction. The deposited states of the vanadia species differed to a small extent between SnO2 and Nb2O5 carriers depending upon the difference in the symmetry of the surface field. The deposited states, however, did not vary with pH upon impregnation, although the amounts of vanadium oxide deposited (coverage, θ) were much affected by the pH. The activation energy (Ea) for the dehydration of 2-propanol over these catalysts was linearly related to the reciprocal of the coverage (1⁄θ). When both curves were extended to 1⁄θ=0, they crossed at around 5–6 kcal·mol−1 which was the minimum value, although the inclination differed largely between the carriers. This low activation energy was regarded as an intrinsic value that was caused by the multi-layered vanadium oxide deposited on the carriers. Through the discussion it is clearly shown that the most effective catalyst, a monolayer catalyst, was prepared on impregnation at pH=2 and the vanadia species were dispersed widely, keeping a weak interaction with the SnO2 and Nb2O5 surfaces.
  • Masatoshi Hirayama, Masaaki Kobayashi, Hiroshi Yamamoto
    1988 Volume 61 Issue 5 Pages 1501-1504
    Published: 1988
    Released: June 27, 2006
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    The formation of 9,10-bis(phenylethynyl)anthracene dianion by contact of tetrahydrofuran-d8 solution of its precursor with sodium in vacuo, is confirmed by the 1H and 13C NMR spectra and its reactivity. The excess π-charge-density distribution estimated by the CNDO/2 calculation for the dianion, is consistent with the observed 1H and 13C chemical shift values.
  • Tadahiko Kidokoro, Kotaro Matsui, Satoshi Ishiwata, Toshiyuki Sasaki, ...
    1988 Volume 61 Issue 5 Pages 1505-1508
    Published: 1988
    Released: June 27, 2006
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    Adsorbing-particle flotation of Hg2+ ions by using active charcoal as an adsorbent, Polyacrylamide (PAA) as a coagulant, and hexadecyltrimethylammonium chloride (HTAC) as a frother was carried out. The floatability exceeded 90% in a wide range of pH and nearly 98% of Hg2+ ions was floated from 2.1×10−4 mol dm−3 solution by adding 2500 ppm of active charcoal, 24 ppm of PAA, 81 ppm of HTAC and with shaking. Stepwise and double flotations were further attempted which proved to distinctly increase the floatability, while sodium sulfide treatment of active charcoal showed only a slight increase and the coexistence of chloride ions showed no effect. The mechanism of adsorbing-particle flotation was discussed.
  • Masahiro Kohno
    1988 Volume 61 Issue 5 Pages 1509-1515
    Published: 1988
    Released: June 27, 2006
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    The title reactions in aerated benzene solutions were investigated by using ESR and optical-absorption spectrometers. It was found that (1) a benzyl peroxide radical, bpox·, generated photochemically from dibenzoyl peroxide (DBPO) oxidizes [CoII(tpp)] to produce, successively, a five-coordinate cobalt(III) complex, [CoIII(bpox)(tpp)]; a π cation radical, [CoIII(tpp)\underset.+](bpox)2, and isoporphyrin; (2) a t-butyl peroxide radical, bupox·, generated from di-t-butyl peroxide (DBuPO) oxidizes [CoII(tpp)] to give only a six-coordinate cobalt(III)complex, [CoIII(bupox)(tpp)(dbupo)]; (3) lipid peroxide radicals (lpox·: oapox·, lapox·, lnapox·, and aapox·) produced from unsaturated fatty acids, oleic acid (OA), linoleic acid (LA), linolenic acid (LNA), or arachidonic acid (AA), do not react with [CoII(tpp)]; (4) all the peroxide radicals (pox·: lpox·, bpox·, bupox·) react with [CoIII(Cl)(tpp)] to produce π cation radicals, [CoIII(tpp)\underset.+](Cl)(pox), and (5) bpox· and lapox· react further with the π cation radicals to give isoporphyrins. Finally, the present reactions were compared with the reactions of horseradish peroxidase.
  • Kozue Kaibara, Hiroyoshi Inoue, Shigeru Tsuruyama, Hideo Kimizuka
    1988 Volume 61 Issue 5 Pages 1517-1525
    Published: 1988
    Released: June 27, 2006
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    Ion-transport processes across an amphoteric ion-exchange membrane were investigated by means of estimating the membrane permeability matrix, a set of modified linear phenomenological coefficients, from the electrochemical and the ion flux data. Systematic comparisons of phenomenological analyses on an amphoteric ion-exchange membrane system with those on an ordinary cation-exchange membrane system were carried out to investigate the correlations of singly- and binary-charged membrane structures to characteristic transport properties. The modes of ion permselectivity of an amphoteric ion-exchange membrane in the metal chloride concentration-cell systems are characterized by the potentiometric selective response due to the ion-sieve effect, the low membrane conductance, and the large ion flux, while those of an ordinary cation-exchange membrane are characterized by the totally charge-dependent potential response, the high conductance, and the extremely small ion flux. The cross elements of the membrane permeability matrix, which represent the partial contributions of cation-anion interactions to the membrane permselectivity, are positive for an amphoteric membrane and negative for a cation-exchange membrane. The positive cross matrix elements act deceleratively on the membrane permeability, whereas the negative elements do acceleratively. It was pointed out based on the nonequilibrium thermodynamic theory that the preferable and efficient permeation mechanism is the simple diffusion process in an amphoteric ion-exchange membrane, whereas the electroconductive process in a cation-exchange membrane.
  • Jun Fujisawa, Toshiyuki Takayanagi, Shin Sato, Kazuo Shimokoshi
    1988 Volume 61 Issue 5 Pages 1527-1534
    Published: 1988
    Released: June 27, 2006
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    The reactions of the cation radicals of 1,3-butadiene, cis- and trans- 1,3-pentadienes, 2-methyl-1,3-butadiene, and 2,3-dimethyl- 1,3-butadiene have been investigated by low-temperature matrix ESR. The cation radicals produced in the irradiated solid solutions of CCl2FCCl2F were found to react with their neutral parents at temperatures above ca. 110 K, forming radicals with allylic ends. On the other hand, 1,3-pentadiene cation radicals in the matrices of CCl4, CCl3F, and CCl3CF3 were found to isomerize into cyclopentene cation radicals, irrespective of the cis and trans forms. The possible mechanisms for the reactions and their implications in the cationic polymerization of dienes are discussed.
  • Akihiko Kudo, Kazunari Domen, Ken-ichi Maruya, Takaharu Onishi
    1988 Volume 61 Issue 5 Pages 1535-1538
    Published: 1988
    Released: June 27, 2006
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    The reduction of H2O (or H+) to form H2 by reduced TiO2 and Pt–TiO2 was studied in distilled water and aqueous solutions of HCl, H2SO4, HNO3, and NaOH. Over the reduced TiO2 powder, H2 evolved moderately in distilled water and Ti3+ ions on the surface were presumed to be active sites for the reaction. The reaction in aqueous NaOH solution proceeded similarly to that in water while it was strongly suppressed in aqueous HCl and H2SO4 solutions. It was found that the suppression of H2 evolution is due to protons in the solution. Over reduced Pt–TiO2, H2 evolved rapidly from all solutions, except HNO3. In aqueous HNO3 solution, NO3 was reduced to NH3 over reduced TiO2 and Pt–TiO2.
  • Koji Tamura, Masanori Owari, Yoshimasa Nihei
    1988 Volume 61 Issue 5 Pages 1539-1544
    Published: 1988
    Released: June 27, 2006
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    Platinum atoms deposited on a TiO2 (110) surface were studied by X-ray photoelectron diffraction, and the structure of the platinum particles was clarified. It was found that after annealing at 823 K for 30 min the platinum particles coalesced and that the structural model of platinum particles based on the (111) surface of the fcc crystal explained the experimental XPED patterns very well.
  • Takashi Kakiuchi, Miki Kobayashi, Mitsugi Senda
    1988 Volume 61 Issue 5 Pages 1545-1550
    Published: 1988
    Released: June 27, 2006
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    The effect of counterions, F, Cl, and Br on the adsorption of the hexadecyltrimethylammonium ion (HTMA+) at the polarized nitrobenzene–water interface has been studied by measuring electrocapillary curves. The interfacial tension in the negative branch of the electrocapillary curve, where the interface is polarized such that the potential in the aqueous phase is negative with respect to that in the nitrobenzene phase, was lowered due to the specific adsorption of HTMA+ ion at the interface. The magnitude of interfacial tension depression in the negative branch became larger in the order F, Cl, and Br, indicating a specific counterion binding at the interface in this order. The adsorption free energy of the HTMA+ ion, ΔGa0, for the adsorption of HTMA+ ion at the interface from the nitrobenzene phase was found to depend markedly on the anionic species present in the aqueous side of the interface. This ΔGa0 values can be taken as a quantitative measure of the counterion specificity at the interface. The meaning of the fact that the change in the shape of the electrocapillary curves depends on the counterion species is discussed in detail in terms of the thermodynamics of the oil–water interface.
  • Masahiro Manabe, Hideo Kawamura, Gohsuke Sugihara, Mitsuru Tanaka
    1988 Volume 61 Issue 5 Pages 1551-1555
    Published: 1988
    Released: June 27, 2006
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    The critical micelle concentration, cmc, of sodium perfluorooctanoate, SPFO, and sodium dodecyl sulfate, SDS, in the presence of two homologous series of alkanols (l-alkanols and ω-phenyl-l-alkanols) at very low concentrations of the alkanols Ca, was measured by a differential specific conductivity method. The free energy of transfer per CH2 group in the alkanols from water to the respective micelles, ΔG°(CH2), has been estimated from a linear relation of the rate of cmc-decrease, Δcmc/ΔCa, with the number of carbon atoms in the alkyl chain of alkanols. The respective values of ΔG°(CH2) obtained for two series of homologues added to a given surfactant are in good agreement with each other: ΔG°(CH2) is −1.73 kJ mol−1 in the SPFO system and −2.30 kJ mol−1 in the SDS system. The former has been found to be smaller in magnitude than the latter. On the basis of ΔG°(CH2), a thermodynamic parameter has been proposed which characterizes the degree of modification of a medium from its pure liquid state to surfactant micelles or to interfaces composed of a hydrocarbon or a fluorocarbon.
  • Yukihiro Yokoyama, Masahiro Ushio, Kenji Goto, Mikio Takaki, Kensuke T ...
    1988 Volume 61 Issue 5 Pages 1557-1563
    Published: 1988
    Released: June 27, 2006
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    1H and 13C NMR spectra have been observed for the carbanions produced from 1,1-diphenylethylene derivatives. Among five precursors, three have been reduced to corresponding dimer dianions in contact with alkali metal in THF; however, the rest could not be dimerized. Failure in dimerization is controlled by a steric effect of substituents at the 2-position. DNMR measurements were also carried out for 1,1-di-p-tolylpropene dimer dianions. The results are discussed in terms of two internal rotations around the bonds between the C1 and C2, and the C1 and Ci atoms.
  • Tohru Inoue, Kohsuke Fukushima, Ryosuke Shimozawa
    1988 Volume 61 Issue 5 Pages 1565-1569
    Published: 1988
    Released: June 27, 2006
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    The gel-to-liquid-crystalline phase transition temperature of a dipalmitoylphosphatidylcholine vesicle membrane was measured in the presence of polyethylene glycol monoalkyl ethers (CnEm) of various chain lengths of hydrophobic (n) and hydrophilic (m) groups. All of the surfactants, except of C12E1, depressed the transition temperature almost linearly with the concentration. The depression of the phase-transition temperature was analyzed by applying the van’t Hoff model for the freezing-point depression; also, the partition coefficients of the surfactants between bulk water and the membrane phase were estimated. Discussions were given concerning the dependence of the partition coefficients on the chain lengths of both oxyethylene and alkyl groups.
  • Kyuya Yakushi, Michiko Yoshitake, Haruo Kuroda, Atsushi Kawamoto, Jiro ...
    1988 Volume 61 Issue 5 Pages 1571-1576
    Published: 1988
    Released: June 27, 2006
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    Single crystals of a (tetrabenzoporphyrinato)nickel hexafluoroarsenate, (NiTBP)3(AsF6)2 were prepared by the use of an electrochemical technique. NiTBP is stacked one-dimensionally with a periodic unit composed of three macrocycles. This stacking mode is a new type among the one-dimensionally stacked macrocyclic complexes. The experimental results on reflectance spectrum and ESR indicate that this material is a one-dimensional semiconductor with a small electron correlation.
  • Yoshihiro Sumiyoshi, Masumi Ushio, Sadao Suzuki
    1988 Volume 61 Issue 5 Pages 1577-1585
    Published: 1988
    Released: June 27, 2006
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    Graphite single crystals with maximum dimensions of 40 mm in diameter and 0.04-mm thick were prepared from an iron solution by a slow-cooling method. The cell parameters of the product were ao=2.462±0.002 and co=6.708±0.001 Å. A flux of 200 g of electrolytical iron and 8 g of graphite were charged in the graphite crucible. The iron melt, saturated with carbon, was slowly cooled from maximum temperatures ranging between 1800 and 2500 °C to near 1150 °C at cooling rates ranging from 5 to 30 °C min−1. Large graphite single-crystal films of better quality were formed after quick cooling rather than slow cooling. Large graphite crystal films were formed at above 1850 °C; temperatures greater than 1950 °C were needed in order to grow the crystal films with good quality. From in-situ observations through a hole, the growth of the small graphite crystals was seen to occur on the surface of the melt at about 1550 °C; these were gathered in a constant direction, initiating the incorporation of small crystals. The incorporation of the small crystals was promoted at about 1700 °C and the surface of the melt was covered with a single-crystal film. For the formation mechanism of the graphite single-crystal film, a heating process was played an important role.
  • Eiichi Sekido, Hideo Kawahara, Kaoru Tsuji
    1988 Volume 61 Issue 5 Pages 1587-1591
    Published: 1988
    Released: June 27, 2006
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    The liquid–liquid extraction of various metal ions, especially of soft class b metal ions with a thiacrown compound, 1,4,7,10,13,16-hexathiacyclooctadecane (HTCO) using picrate ion (Pic) was examined and compared with that of 1,4,8,11-tetrathiacyclotetradecane (TTCT). Although the extraction behavior of the class a, ab, and b metals with HTCO is fundamentally similar to that with TTCT, that of some metals belonging to class b metals with HTCO is different from that with TTCT. The extraction percentages of copper(II) and palladium(II) with HTCO are a few times larger than those with TTCT. Copper(I) and silver(I) are extracted with HTCO as the 1 : 1 complexes such as [Cu(htco)]+Pic and [Ag(htco)]+Pic, respectively, regardless of the relative concentration of the ligand to the metal. On the other hand, copper(I) and silver(I) complexes with TTCT are extracted with different compositions depending upon the relative concentration of the ligand to the metal.
  • Hiromasa Hashimoto, Seichi Okeya, Yukio Nakamura
    1988 Volume 61 Issue 5 Pages 1593-1600
    Published: 1988
    Released: June 27, 2006
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    The reactions of [M(β-dik)2] (M=Pt(II), Pd(II); β-dik=acetylacetonate (acac), dipivaloylmethanate (dpm), hexafluoroacetylacetonate (hfac) ions) with dppm (dppm=Ph2PCH2PPh2) and mdppm (mdppm=Ph2PCH(Me)PPh2) have been investigated. [M(hfac)2] complexes react with dppm to afford the stable cationic complexes, [M(dppm)2](hfac)2. By contrast, [M(acac)2] complexes react to give the homoleptic bis(diphenylphosphino)methanido complexes, [M(Ph2PCHPPh2)2], through deprotonation of dppm by the displaced acac anions. The analogous complexes, [M(Ph2PC(Me)PPh2)2], are obtained using mdppm, instead of dppm. A complete reaction scheme leading to these products is proposed, based on the IR and 1H, 13C, and 31P NMR spectral data. Some consideration is given to the dependence of these reactions on the metals and the β-diketonate ligands, employed.
  • Sen-ichi Aizawa, Ken-ichi Okamoto, Hisahiko Einaga, Jinsai Hidaka
    1988 Volume 61 Issue 5 Pages 1601-1606
    Published: 1988
    Released: June 27, 2006
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    Three trinuclear complexes with ΔLLL- and/or ΛLLL-fac(S)-[Co(L-cys-N,S)3] terminals, and ΔLLLΔLLL-,ΔLLLΛLLL-, and ΛLLLΛLLL-[Fe{Co(L-cys-N,S)3}2]3−, ΔLLLΛLLL-[Co{Co(L-cys-N,S)3}2]3− and ΔLLLΔLLL-[Ni{Co(L-cys-N,S)3}2]4−, were newly prepared. These complexes were characterized from their electronic absorption, CD, and 13C NMR spectra. Each reaction of ΔLLL-fac(S)-[Co(L-cys-N,S)3]3− with Fe(II) and Co(II) was accompanied by the inversion of the absolute configuration of the one or both terminals to give the ΔLLLΛLLL and ΛLLLΛLLL isomers, while the reaction with Fe(III), Co(III), or Ni(II) proceeded with the retention of the terminal to give the ΔLLLΔLLL isomer. The voltammetric study revealed that the formal potential of ΔLLLΔLLL-[Fe{Co(L-cys-N,S)3}2]3− (−0.16 V) is more anodic than that of ΔLLLΔLLL-[Co{Co(L-cys-N,S)3}2]3− (−0.43 V). These redox potentials are discussed in relation to the formation ratios of the isomers for the trinuclear complexes.
  • Yoshihiko Sugita, Akira Ouchi
    1988 Volume 61 Issue 5 Pages 1607-1612
    Published: 1988
    Released: June 27, 2006
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    The crystal and molecular structures of the chloroacetato–dimethyl sulfoxide (dmso) mixed complex of neodymium(III) indicated in the title were determined by the single-crystal X-ray diffraction method. The crystal is monoclinic, space group P21n, a=21.106(21), b=15.871(8), c=15.748(7) Å, β=93.29(5)°, Z=4 (including 12 metal atoms in a unit cell). There are three kinds of crystallographically independent metal atoms, Nd(1), Nd(2), and Nd(3): Nd(1) and Nd(3) are ennea-coordinated (approximately tricapped trigonalprism geometry), and Nd(2) is deca-coordinated (approximately bicapped square-antiprism geometry) including a slightly long M–O bonding. All dmso molecules are directly coordinated to the metal atoms as unidentate, while all the carboxylate ions bridge metal atoms acting as bidentate or tridentate ligands. The bridging atoms are arranged in a chain which is approximately formed along the [101] axis. Also, the isomorphous lanthanum(III) and praseodymium(III) complexes were obtained and their structures were elucidated.
  • Masatomi Sakamoto, Minoru Takagi, Tomitaro Ishimori, Hisashi Okawa
    1988 Volume 61 Issue 5 Pages 1613-1618
    Published: 1988
    Released: June 27, 2006
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    Heterometal binuclear complexes, [CuLn(fsaen)(H2O)n](NO3) (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu; n=4–5) and [CuLn(fsapn)(H2O)4](NO3) (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, or Dy) have been synthesized and characterized, where H4fsaen and H4fsapn denote N,N′-bis(3-carboxysalicylidene)ethylenediamine and N,N′-bis(3-carboxysalicylidene)-1,2-propanediamine, respectively. The ligand field band due to the copper(II) ion bound to the N2O2-site is at 18.5×103–19.5×103 cm−1 for [CuLn(fsaen)(H2O)n](NO3) and 18.4×103–19.2×103 cm−1 for [CuLn(fsapn)(H2O)4](NO3), which are higher frequencies than those of the mononuclear complexes, [Cu(H2fsaen)](H2O)0.5 and [Cu(H2fsapn)](H2O)0.5 (18.3×103 and 18.4×103 cm−1, respectively). When the complexes are dissolved in pyridine (Py), dimethyl sulfoxide (DMSO), or N,N-dimethylformamide (DMF), the d–d band frequency decreases in the order of the solvent DMSO>DMF>Py for the binuclear complexes, whereas it decreases in the order of DMF>DMSO>Py for the mononuclear complexes. These trends were discussed in terms of the different affinities of solvent molecules for copper(II) and lanthanoid(III) ions. No significant magnetic spin-exchange interaction occurred between metal ions.
  • Renji Okazaki, Jun Niwa, Shigeki Kato
    1988 Volume 61 Issue 5 Pages 1619-1624
    Published: 1988
    Released: June 27, 2006
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    Ab initio calculations have been carried out for 2,4-dithia- (5), 2,4-dioxa- (6), 6-oxa- (8), 6-thiabicyclo[3.1.0]hexanes (9), bicyclo[3.1.0]hexane (7), and some of the corresponding cyclohexane derivatives 10–12 using 3-21G, 3-21 G(*) and 6-13G* basis sets. Relative total energies and geometries have been obtained for both boat and chair forms of these compounds. The calculated geometries are in good agreement with observed ones for 7–9. The boat form is more stable than the chair form in the bicyclic systems 7–9, while both the forms have almost equal stability for 5 and the chair form of 6 is slightly more stable than the boat form. The relative stability of the boat form in the bicyclic systems compared with that in the monocyclic cyclohexane derivatives can be explained in terms of the stabilizing orbital interaction. Inversion barriers between the boat and chair forms for 5–7 have also been estimated and are briefly discussed. A similar calculation for bicyclo[3.2.0]hept-6-ene also shows that the boat form is much more stable than the chair form contrary to the conclusion derived from the analysis of experimental results.
  • Kazuo Kodaira, Kunio Okuhara
    1988 Volume 61 Issue 5 Pages 1625-1631
    Published: 1988
    Released: June 27, 2006
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    Phenylacetylenes (ArC≡CH) having fluoro- or trifluoromethyl substituents (o-, m-, p-F; o-, m-, p-CF3; 2,4-, 2,5-, 2,6-, 3,5-(CF3)2) have been prepared from bromobenzenes (ArBr) and benzenes (ArH) using 1,1-dichloro-2,2-difluoroethene (1) by a two-step route: ArLi or ArMgBr→ArCF=CCl2→ArC≡CLi. Upon careful treatment at −70 °C with 1, o-fluorophenyllithium gave o-FC6H4CF=CCl2 in good yield, together with benzyne-derived products, such as o-(o-FC6H4)C6H4CF=CCl2. Lithiation of m-bis(trifluoromethyl)benzene at 0 °C for 9 h (24 h) followed by treatment with bromine gave 1-bromo-2,4-, 2,6-, and 3,5-bis(trifluoromethyl)benzene in 35 (38), 31 (36), and 8% (6%) yield, respectively.
  • Bin Zhou, Koji Kano, Shizunobu Hashimoto
    1988 Volume 61 Issue 5 Pages 1633-1640
    Published: 1988
    Released: June 27, 2006
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    The photoreduction of 10-methyl-9-phenylacridinium chloride in methanol containing K2CO3 involves the nucleophilic addition of methanol to the 9-position of the acridinium cation, the photoinduced heterolysis of the methanol adduct, and the hydride transfer from the alkoxide anion to the acridinium cation in the nonrelaxed ground states to give 9,10-dihydro-10-methyl-9-phenylacridine.
  • Takeshi Komai, Kazuo Matsuyama, Masaru Matsushima
    1988 Volume 61 Issue 5 Pages 1641-1646
    Published: 1988
    Released: June 27, 2006
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    Decomposition rates and products of t-alkyl 2,2-dimethylperoxypropionates were measured in cumene at several temperatures. The peroxyesters decomposed homolytically, depending on the structure of the t-alkyl moiety. The relative rates of the t-alkyl moieties to the 1,1-dimethylethyl one were: 1,1-dimethylbutyl (1.14), 1,1-dimethylpropyl (1.19), 1,1,2-trimethylpropyl (1.85), 1,1,3,3-tetramethylbutyl (2.10), and 1,1-dimethyl-2-phenylethyl (2.34). The decomposition showed an isokinetic relationship and the importance of stabilization by hyperconjugation. Based on these data, the decomposition mechanism, which contains a slight stretching of the Cα–Cβ bond to the peroxyl oxygen at the transition state is, discussed.
  • Ryu Sato, Satoru Saito, Hiroshi Chiba, Takehiko Goto, Minoru Saito
    1988 Volume 61 Issue 5 Pages 1647-1651
    Published: 1988
    Released: June 27, 2006
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    Many cyclic polysulfides, i.e., benzopentathiepins (3a–d), 6H-1,2,3,4,5-benzopentathiocin, 5H-1,2,3,4-benzotetrathiepin, 3H-1,2-benzodithiole, 1,5-dihydro-2,3,4-benzotrithiepin, 1,4-dihydro-2,3-benzodithiin, naphtho[1,8-cd]-1,2-dithiole, 1,2,3-trithiane, 1,2-dithiane, 2,3,4,5-tetrathiabicyclo[4.4.0]decane, and 2,3,4,5,6-pentathiabicyclo[5.4.0]undecane, were synthesized in high yields by new reactions of their corresponding dithiols and related compounds, 1,3-benzodithiole-2-thiones (5) and 1,3-dithiolane-2-thione, with elemental sulfur in liquid ammonia at ambient temperature. In the synthesis of 3a–d from 1,2-benzenedithiol or 5, considerable increase in the product yield was observed upon adding 1,3-dinitrobenzene to the solvent used in work-up.
  • Masatoshi Motoi, Hiroshi Suda, Katsuhiko Shimamura, Shinsuke Nagahara, ...
    1988 Volume 61 Issue 5 Pages 1653-1659
    Published: 1988
    Released: June 27, 2006
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    3-(6-Bromo-2-oxahexyl and 8-bromo-2-oxaoctyl)-3-methyloxetanes, and 1,8- and 1,10-bis(3-methyl-3-oxetanyl)-2,7-dioxaoctane and -2,9-dioxadecane were readily prepared in fairly good yields by the reaction of 3-hydroxymethyl-3-methyloxetane (1) with tetra- and hexamethylene dibromides in the presence of a phase-transfer catalyst. The formation of the mono- and disubstituted products depends upon the molar ratios of the dibromide to 1. The optimum reaction conditions for the etherification of 1 with tetramethylene dibromide were searched. The (ω-bromo-2-oxaalkyl)oxetanes were polymerized to give soluble polyoxetanes (\barMn 3500–5500) by cationic ring-opening polymerization. The use of the bisoxetanes, a new cross-linking agent, as a comonomer gave insoluble elastic polyoxetane resins having a pendant bromide at the spacer end.
  • Tsunehisa Fujita, Yoichi Inaba, Kenji Ogino, Waichiro Tagaki
    1988 Volume 61 Issue 5 Pages 1661-1667
    Published: 1988
    Released: June 27, 2006
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    The catalytic effects of bivalent metal ion (Zn2+ and Cu2+) complexes of N-alkyl-2-hydroxymethylimidazoles on the hydrolysis of p-nitrophenyl picolinate (PNPP) have been studied kinetically in the reverse micelles of AOT/hexane/water at 25 °C. The results were compared with those obtained in the non-micellar aqueous media and aqueous micelles. The hydrolysis was observed to occur through the acyl group transfer from PNPP to the ligand hydroxyl group in both cases of Zn2+ and Cu2+ ions and in all three non-micellar and micellar systems. However, the ligand:metal ion ratio in the kinetically active complexes was found to differ significantly in the three systems: there seems to exist general trends of 1 : 1, 2 : 1, and 4 : 1 stoichiometry in the ligand:metal ion ratio, depending on non-micellar aqueous media, aqueous micelles and reverse micelles, respectively. It was also noticed that the hydrolysis is always faster in micellar systems than in non-micellar aqueous media. Furthermore, a lipophilic ligand (N-dodecyl, Lig-12) was found to be more active than a hydrophilic ligand (N-methyl, Lig-1) under two micellar conditions.
  • Mitsuo Sekine, Reiko Iwase, Narihiro Masuda, Tsujiaki Hata
    1988 Volume 61 Issue 5 Pages 1669-1677
    Published: 1988
    Released: June 27, 2006
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    Two kinds of substituted trityls, i.e., 4,4′,4″-tris(benzoyloxy)trityl (TBTr) and 4,4′,4″-tris(p-anisoyloxy)trityl (TAnTr), have been examined as protecting groups of the amino group of adenosine in oligoribonucleotide synthesis. The former was used for a 3′-terminal adenosine unit and the latter was introduced into an building block of internal adenosine. These protecting groups were successfully applied to the liquid-phase synthesis of pGUA and pGUAUUA which were the 5′-terminal oligoribonucleotide fragments of brome mosaic virus mRNA 4.
  • Toshihide Kawashima, Yutaka Shiomi, Yasuo Tohda, Masahiro Ariga, Yutak ...
    1988 Volume 61 Issue 5 Pages 1679-1681
    Published: 1988
    Released: June 27, 2006
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    Several viologen analogs having good coplanarity were synthesized and their redox potentials were measured by cyclic voltammetry.
  • Yoshiyuki Hama, Yukikazu Nobuhara, Yoshio Aso, Tetsuo Otsubo, Fumio Og ...
    1988 Volume 61 Issue 5 Pages 1683-1686
    Published: 1988
    Released: June 27, 2006
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    Bis(tetrapropyl- and tetrabutylammonium) 1,1′-(2,5-pyridinediyl)bis[dicyanomethanide] (4a and 4b) were prepared in order to investigate the properties of pyridine-analogue 3 of TCNQ as a new electron acceptor and its complexation with TTF. Although 3 was not isolated, the cyclic voltammetry of the salt 4 indicated that 3 was a stronger electron acceptor than TCNQ. The charge-transfer complex of TTF and 3 was prepared by mixing TTF with 3 which was generated in situ from the electrolytic oxidation of 4 or from the oxidation of 2,5-bis(dicyanomethyl)pyridine, a precursor of 4, with hydrogen peroxide. It consisted of 1 : 1 composition of donor and acceptor and showed a high electrical conductivity of 19 S cm−1. The 2 : 1 complex was prepared by metathesis of (TTF)3(BF4)2 and 4, and also highly conductive.
  • Masao Hisatome, Rin-ichi Yamashita, Jun Watanabe, Koji Yamakawa, Yoich ...
    1988 Volume 61 Issue 5 Pages 1687-1694
    Published: 1988
    Released: June 27, 2006
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    The title compound bridged with four pentamethylene chains has been synthesized by stepwise construction of a pentamethylene bridge via formation of a three-carbon bridge followed by insertion of two carbon units. Crystal structure of the phane has been determined by X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21n with unit cell parameters a=16.691(10), b=9.858(5), c=15.237(8) Å, β=112.43(6)°, and z=4. The structure parameters of the ferrocene moiety fall in normal ranges. Characteristic features are noted in the methylene bridges. The γ-methylene carbons undergo large thermal vibration, and apparent shortening of the bond lengths by oscillatory motions of atoms is seen.
  • Sadatoshi Akabori, Sadao Sato, Kayoko Kawazoe, Masaru Sato, Yoichi Hab ...
    1988 Volume 61 Issue 5 Pages 1695-1700
    Published: 1988
    Released: June 27, 2006
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    Dichlorobis(4,7,10-trioxa-1,13-dithia[13](1,1′)ruthenocenophane)palladium(II) (6) was obtained by the reaction of 4,7,10-trioxa-1,13-dithia[13](1,1′)ruthenocenophane (5) with dichlorobis(acetonitrile)palladium(II) in 72% yield. The crystal structures of the complex 6 and its metal free ligand 5 were determined by the X-ray method. The crystal data: 5, monoclinic, P21a, a=18.783(2), b=7.895(1), c=12.892(1) Å, β=93.53(1)°, U=1908.2 Å3, Z=4, Dc=1.58 g cm−3, μ(Mo Kα)=10 cm−1. 6, triclinic, P\bar1, a=13.956(2), b=9.174(1), c=8.770(1) Å, α=86.61(1), β=75.54(1), γ=94.37(1)°, U=1080.6 Å3, Z=2, Dc=1.94 g cm−3, μ(Mo Kα)=20 cm−1. The Pd atom of 6 bonded to the two sulfur atoms of the ligand and the torsion angle (69.2°) around the z-axis of the ruthenocenophane nucleus in the metal-free ligand is much larger than the corresponding one (0.4°) in the complex. These results are completely opposite of the case of 1,4,7,10-tetrathia[10](1,1′)ruthenocenophane and its Pt complex. Furthermore, the intramolecular atomic distance (3.697 Å) between the Ru and Pd atoms in 6 suggests the absence of the Ru–Pd dative bond.
  • Shinji Yamasaki, Yuji Hidaka, Hideaki Ito, Yoshifumi Takeda, Yasutsugu ...
    1988 Volume 61 Issue 5 Pages 1701-1706
    Published: 1988
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The heat-stable enterotoxin (STh) of enterotoxigenic Escherichia coli consists of 19 amino acid residues and is linked intramolecularly by three disulfide bonds between Cys6 and Cys11, Cys7 and Cys15, and Cys10 and Cys18 (Y. Shimonishi et al., FEBS Lett., 215, 165 (1987)). The syntheses and biological assays of various analogs of STh with one or two of the three disulfide bonds showed that a disulfide bond between Cys7 and Cys15 and another between Cys6 and Cys11 or Cys10 and Cys18 are necessary for construction and stabilization of the spatial structure of STh to express its toxicity.
  • Yasuo Butsugan, Kenji Nagai, Fumitoshi Nagaya, Hiroki Tabuchi, Katsuhi ...
    1988 Volume 61 Issue 5 Pages 1707-1714
    Published: 1988
    Released: June 27, 2006
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    Pyrophosphate tetraesters possessing allylic and homoallylic side chains were synthesized. Reaction of alkyl allyl (and 3-methyl-3-butenyl) phosphorochloridates with sodium hydrogencarbonate gave P1,P2-dialkyl P1,P2-diallyl [and P1,P2-bis(3-methyl-3-butenyl)] pyrophosphates. Condensation of alkyl allyl (and 3-methyl-3-butenyl) phosphorochloridates with dialkyl phosphates gave trialkyl allyl (and 3-methyl-3-butenyl) pyrophosphates. Reactions of crotyl (2-butenyl) pyrophosphates with various nucleophiles such as phenolic ethers, aromatic amines, and nitrogen-containing heterocycles in the presence of boron trifluoride etherate gave good to moderate yields of crotylated products. The crotyl pyrophosphates were found to be much more reactive than the corresponding orthophosphate esters.
  • Shunsuke Izumi, Takayuki Suga
    1988 Volume 61 Issue 5 Pages 1715-1720
    Published: 1988
    Released: June 27, 2006
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    A method for the simulation of the time courses in the oxidation of cycloalkanols and the reduction of cycloalkanones in the cultured cells of Nicotiana tabacum was developed on the basis of the permeability of these compounds into the cultured cells and the 13C NMR chemical shift of the carbonyl carbon of the cycloalkanones. Further, the method has been applied to the simulation of the time courses in the oxidation of (+)-borneol and (+)-isopinocampheol and the reduction of (−)-carvomenthone in the cultured cells of N. tabacum.
  • Atsuyoshi Ohno, Masato Higaki, Shinzaburo Oka
    1988 Volume 61 Issue 5 Pages 1721-1724
    Published: 1988
    Released: June 27, 2006
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    1H NMR spectra were studied for a carbanion derived from t-butyl phenylmethyl sulfoxide in tetrahydrofuran. It has been concluded that the conformation of the carbanion in solution is the same as that in a crystal. The carbanion exists in two diastereomeric dimeric forms in the presence of an equivalent amount of countercation, but it becomes a monomer when excess base exists in the solution.
  • Jun Tamaki, Masashi Yamamura, Toshinobu Imanaka
    1988 Volume 61 Issue 5 Pages 1725-1729
    Published: 1988
    Released: June 27, 2006
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    Pd–(B, P) thin film alloys have been prepared by an RF sputtering method. Before heat treatment, the selectivity for the partial hydrogenation of olefins increased with the increase in the B or P concentration in the Pd–(B, P) films. After the heat treatment, on the other hand, the selectivity for the partial hydrogenation was reduced over the Pd films with a low B or P concentration. However, in the case of the Pd films with a high B or P concentration, the selectivity was enhanced by the heat treatment. The high selectivity after the heat treatment was explainable in terms of the small ensemble size, the low electron density of Pd, and the appearance of a Pd3B, Pd4.8P, or Pd5P2 phase in the Pd films with a high B or P concentration. A sputtered film is known to have a columnar structure. This columnar structure was deduced to be controlled both by the alloying of Pd with B or P and by the heat treatment, so as to exhibit the high selectivity for the partial hydrogenation of olefins.
  • Kimihisa Yamamoto, Toshio Asada, Hiroyuki Nishide, Eishun Tsuchida
    1988 Volume 61 Issue 5 Pages 1731-1734
    Published: 1988
    Released: June 27, 2006
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    The electro-oxidative polymerization of benzene in the presence of strong acids yields poly(p-phenylene) efficiently. A strong protonic acid such as trifluoromethanesulfonic acid or Lewis acid such as an aluminum trichloride forms a complex with benzene and reduces the oxidation potential of benzene to 1.7 V, which brings about the high current efficiency. The acids act both as an electrolyte and as a catalyst in this polymerization of benzene.
  • Jayati Datta, Abhijit Bhattacharya, Kiron Kumar Kundu
    1988 Volume 61 Issue 5 Pages 1735-1742
    Published: 1988
    Released: June 27, 2006
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    Standard potentials of I3/I and I2/I3 redox couples relative to that of aqueous saturated calomel reference electrode SCE (W), ESCE(w) have been determined in propylene carbonate (PC), N,N-dimethylformamide (DMF), acetonitrile (ACN), and their binary mixtures at 25 °C from potentiometric measurements. The results helped evaluate the standard potentials of the redox couple I2/I relative to ESCE(w) as well as the related formation constant (Kf) of I3 in these solvent systems. The solvent effects on the formation equilibrium I2+I\ ightleftharpoonsI3 were analyzed in the light of the transfer free energies of I2, ΔGt°(I2), as obtained from solubility measurements of I2 in the solvents, that of I, ΔGt°(I), as obtained earlier by use of the widely used TATB reference electrolyte assumption and that of I3, ΔGt°(I3), as obtained by subtracting these two contributions from the respective transfer free energies of formation equilibrium in the mixed solvents relative to a chosen reference solvent in each solvent system. The solvation behavior of these individual iodine species viz. I2, I, I3 was interpreted in terms of involved interaction viz. Born, ion-dipole, ion-induced dipole, dispersion type soft–soft interactions, CTTS complexation and also the cavity effect as computed by the scaled particle theory (SPT).
  • Ali Boushehri, A. Mohammad Attaran
    1988 Volume 61 Issue 5 Pages 1743-1747
    Published: 1988
    Released: June 27, 2006
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    The paper presents a contribution to the second virial coefficient due to the asphericity of the molecular charge distribution. This contribution is conveniently divided into terms representing the classical electrostatic interaction between the two charge distributions, the anisotropy of dispersion forces, and the shape of the molecular core. These are considered quantitatively. Results from recalculating the nonspherical contributions to the second virial coefficients with a good spherical core are obtained from statistical mechanics and applied to the CO2 gas. Explilcit formulas are given for the simple cases of axially symmetric molecules.
  • Sukanta K. Pal, Archana Das Gupta, Nanda K. Das Gupta
    1988 Volume 61 Issue 5 Pages 1749-1753
    Published: 1988
    Released: June 27, 2006
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    Benzo[3′,4′]cyclobuta[1′,2′:6,7]cycloocta[1,2,3,4-def]biphenylene (1), benzo[6,7]cycloocta[1,2,3,4-def]biphenylene (2), dibenzo[a,c]benzo[3,4]cyclobuta[1,2-f]cyclooctene (3), and biphenyleno[8′,1′:4,5,6,7]cycloocta[1,2-l]phenanthrene (4) have been studied by semiempirical SCFMO method of Pariser and Parr and Pople. Core resonance intergral values of Lo and Whitehead, Dewar et al. and Yamaguchi et al. have been used. It has been observed that π*←π spectra predicted by the methods of Lo and Whitehead and Chung and Dewar suitable for the prediction of ground state properties are in good agreement with experimental results and comparable to those predicted by the method of Yamaguchi et al. developed for the prediction of spectral transitions. For comparison values obtained by configuration interaction method has also been included. Resonance stabilization of the molecules has been studied along with other properties such as bond length, ionization potential, electron affinity, and half-wave reduction potential.
  • Manuel A. V. Ribeiro da Silva, Maria Luisa C. C. H. Ferrão
    1988 Volume 61 Issue 5 Pages 1755-1759
    Published: 1988
    Released: June 27, 2006
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    The standard molar enthalpies of formation of the crystalline complexes of cobalt(III) with 1-phenyl-1,3-butanedione (Hbzac), 2,2,6,6-tetramethyl-3,5-heptanedione(Hdpm), and 1,1,1-trifluoro-2,4-pentanedione (Htfac) were determined, at 298.15 K, by solution-reaction calorimetry:
    ΔfH°m[Co(bzac)3,cr]=−877.1±8.7kJ·mol−1
    ΔfH°m[Co(dmp)3,cr]=−1708±12kJ·mol−1
    ΔfH°m[Co(tfac)3,cr]=−3191±15kJ·mol−1
    The enthalpies of sublimation of Co(dpm)3 and Co(tfac)3, at 298.15 K, determined by high-temperature microcalorimetry were 126±3 and 114±2 kJ·mol−1, respectively. From the enthalpies of formation of the gaseous complexes, the average molar bond-dissociation enthalpies, ⟨D⟩(Co–O), were derived.
  • Mohamed Tarek Mohamed Zaki, Wageh Georgy Hanna, Mohamed Hossam Fawzy
    1988 Volume 61 Issue 5 Pages 1761-1765
    Published: 1988
    Released: June 27, 2006
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    A simple and sensitive conductometric method for the determination of copper(II), iron(II) and (III), aluminum(III), chromium(III), gold(III), platinum(IV), vanadyl, zirconyl, and uranyl ions with oxine solution in ethanol–water system is described. An average recovery of 100.3% with standard deviation not exceeding 0.4% is observed. The effect of solvent, shape of titration curves and molar ratio of the chelates are studied. The proposed method shows good agreement with the conventional EDTA titration using metallochromic indicators. The advantage over the conventional method is discussed.
  • Suman Jain (nee Mittal), Kalyan K. Banerji
    1988 Volume 61 Issue 5 Pages 1767-1771
    Published: 1988
    Released: June 27, 2006
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    The kinetics of the oxidation of twenty-four monosubstituted benzyl alcohols by ethyl chlorocarbamate (ECC) have been studied in aqueous acetic acid solution, in the presence of perchloric acid. The main product of the oxidation is the corresponding benzaldehyde. The reaction is first order with respect to the alcohol, ECC, and hydrogen ion. The oxidation of [α,α-D2]benzyl alcohol indicated a primary kinetic isotope effect, kHkD=5.40 at 298 K. The value of solvent isotope effect, k(H2O)/k(D2O), is 1.85 at 298 K. Addition of ethyl carbamate does not affect the reaction rate. [EtOC(OH)NHCl]+ has been postulated as the reactive oxidizing species. The rates of oxidation of para- and meta-substituted benzyl alcohols show excellent correlation in Taft’s dual substituent parameter equation, with negative reaction constants. The rates of the ortho-substituted compounds correlate well in Charton’s equation of inductive, resonance and steric substituent parameters. A mechanism involving simultaneous transfer of a hydride ion from the C–H bond and of a proton from the O–H bond to the oxidant is proposed.
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