Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 64 , Issue 7
Showing 1-50 articles out of 51 articles from the selected issue
  • Kozo Kozawa, Taketoshi Hoshizaki, Tokiko Uchida
    1991 Volume 64 Issue 7 Pages 2039-2044
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Donor-acceptor complexes were prepared, and their structures and electronic properties were observed. Donors were phenothiazine and its four derivatives, and acceptors were metallic chlorides (Lewis acids), iodine, and two π-type acceptors. By the absorption edge of diffuse reflection spectra (λE) and crystal structure, the complexes were classified into four groups. Groups I, II, and III correspond to the complexes with Lewis acids or iodine, and group IV consists of complexes with π-type acceptors. The summarized characteristics of each group are as follows. Group I: λE950 nm, complete charge transfer, insulator, and alternate arrangement of cations and anions. Group II: 1200 nmλE1700 nm, complete charge transfer, semiconductive behavior, and oligomeric or columnar arrangement of cation radicals. Group III: λE>2500 nm, partial charge transfer, metallic conductor or semiconductor with small activation energy, and columnar arrangement. Group IV: λE1700 nm, and semiconductive behavior. Based on these classifications, we have proposed a mechanism for controlling the aggregate manner of cation radicals.
  • Yoshihiko Tezuka, Shigeru Ohyama, Tadahiro Ishii, Koichi Aoki
    1991 Volume 64 Issue 7 Pages 2045-2051
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    According to the propagation theory of a conductive zone for the electrochemical doping process of conducting polymer films, an oxidized conductive zone works as an electrode for oxidizing the reduced non-conductive region and is propagated throughout the film under charge transfer control. This theory was verified for polypyrrole films by tracing the temporal and spatial variations of conductive regions in a film. An exhaustively reduced polypyrrole film was laid on an insulating glass plate and connected electrically to an ITO electrode at the marginal part. The film absorbance to a monochromatic light beam was monitored with a photodiode array detector at 14 segments of the film. When the potential of the ITO electrode was stepped to an oxidation potential of the film, an electrochemically oxidized conductive zone was propagated through the film with a manifest phase boundary. The distance from the edge of the ITO electrode to the front of the conductive zone increased linearly with time. The logarithmic slope of the propagation speed exhibited a linear relation to the applied potential.
  • Susumu Matsuzaki, Toshihiro Hiejima, Mizuka Sano
    1991 Volume 64 Issue 7 Pages 2052-2057
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The pressure dependence of IR spectra measured for a mixed-stack neutral charge-transfer (CT) crystal, tetrathiafulvalene–iodanil (TTF–IA), showed an occurrence of a neutral–ionic (NI) transition at 1.9 GPa. The N-I transition is accompanied by gradual dimerization of the crystal lattice and a small ionicity jump, in contrast to the case of TTF–chloranil (TTF–CA). Such a quasi-continuous NI transition is attributable to stronger electron–lattice interaction in TTF–IA than that in TTF–CA.
  • Sumio Kaizaki, Norio Koine, Narumi Sakagami
    1991 Volume 64 Issue 7 Pages 2058-2064
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The solvatochromism of the first ligand field absorption bands and/or the solvent dependence of 13C and 59Co NMR shifts for trans- and cis-[M(N)2(O)4] type complexes of cobalt(III) or chromium(III) with various kinds of polyamine-N-polycarboxylato ligands was elucidated in terms of the angular overlap model (AOM) parametrization. On the basis of the difference in the solvent-dependence of spectroscopic data of the complexes studied in various solvents, it was found that the solvatochromism could result from variations of the metal-ligand σ and/or π bond interactions (expressed by the eσ(O), eσ(N), and anisotropic eπ(O) AOM parameter values) due to the preferential solvation toward the oxygen Pπ orbitals coplanar with the M(O)2 coordinate planes.
  • Kazushi Mashima, Kouki Jyodoi, Akira Ohyoshi, Hidemasa Takaya
    1991 Volume 64 Issue 7 Pages 2065-2076
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    A family of titanoxycarbene–metal carbonyl complexes of formula Cp*2TiOC(=MLn)CH2CH2 (3), where Cp*5-C5Me5 and MLn=Cr(CO)5, Mo(CO)5, W(CO)5, Mn2(CO)9, and Re2(CO)9, has been prepared by the treatment of titanocene-ethylene complex 1 with metal carbonyls of group 6 and 7. Complex 3b crystallizes in space group P2⁄a (Z=8) with cell constants a=30.401(1), b=9.251(1), c=27.561(5) Å, β=105.73(1)°, and V=7460(2) Å3 (data taken at −40 °C, 6715 reflections, R=0.069). Two independent molecules of 3b in crystal make an enantiomorphic pair. A notable feature of the structure is the long distance of Ti–O bond coupled with the short distance of C(2)–O bond, which is characterized by a large contribution of zwitterionic canonical form 7. Thermal decomposition of 3 affords ethylene and the corresponding metal carbonyls, indicating that the C(carbenic)–C(3) bond fission occurred selectively, which is rather unusual for conventional Fischer-type carbene complexes. Complexes 3 react rapidly with atmospheric pressure of carbon monoxide below −30°C to produce cyclic acyltitanium complexes 12. The reverse reactions occur even below −30°C upon replacement of carbon monoxide by argon. Complex 3b also reacts with t-butyl isocyanide with a cleavage of the Ti–O bond to give 1 : 2 adduct 17, whose molecular structure has been elucidated by X-ray crystallography [P21n with cell constants a=14.964(2), b=26.207(4), c=14.719(3) Å, β=100.30(1)°, and V=5679(2) Å3 (measured at −120°C, 5311 reflections, R=0.068)], revealing that it has a novel zwitterionic structure possessing (η2-imidoyl)titanium cation and anionic acyldirhenium carbonyl moieties linked by an ethylene bridge. The controlled experiments show that complex 16 in which acyl ligand is trans to the Re–Re bond is the precursor of complex 17. Complex 18, a tungsten analogue of 17, has also been prepared. Reactions of 3b and 3e with acetylenes are also described.
  • Hiromu Imai, Hiroshi Tamura
    1991 Volume 64 Issue 7 Pages 2077-2080
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The stability constants of imidazole (HIm)– and alkylimidazoles–copper(II) acetate complexes were calculated from the potentiometric titration data with the aid of the SUPERQUAD computer program. The stability constants of ionic species of [CuALr]+ type (A : CH3COO, L : HIm a, 1-CH3·Im b, 2-CH3·HIm c, 4-CH3·HIm d, 2-C2H5·HIm e, 2-(CH3)2CH·HIm f, r=1, 2, 3, and 4) detected from the complexes were ascertained to be decreased in the order of b(1-substituted)d(4-substituted)>c(2-substituted) relating to the position of methyl group bonded to the imidazole ring, and c(2-CH3)>e(2-C2H5)>f(2-(CH3)2CH) relating to the kinds of alkyl group substituted on 2-position, respectively. The stability of these ionic species was discussed from the neutralization effect of the charge and the steric effect of alkyl group or acetate ion. The stability constants of the hydroxo species of [CuL2(OH)2] type indicated the extremely small values, and its order did not indicate a similar tendency with those of ionic species of [CuALr]+ types. The distribution of these complex species was investigated as a function of pH.
  • Masahiko Kato, Masaru Mitsuda, Takuji Shibuya, Kimiaki Furuichi
    1991 Volume 64 Issue 7 Pages 2081-2087
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    6,7,12,13-Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione has been synthesized starting from the [4+6]-cycloaddition product of the reaction of 3,4-bis(methylene)-7,7-dibromobicyclo-[4.1.0]heptane with tropone. The adducts were transformed to their epoxides, which were treated with trifluoroacetic acid to give the 3,14-dione. This was transformed to benzo[1,2:4,5]dicycloheptene-1,9-dione, bis(tropono)benzene, by two different methods: (1) by heating it with trichloroacetic acid and DDQ in toluene or (2) through bromination followed by heating in DMF. The 1,9-dione is protonated in coned sulfuric acid to give bis(hydroxytropylium) dication, while it is protonated mainly (>80%) on the C-9 carbonyl oxygen and less (<40%) on the C-1 carbonyl oxygen in deuteriochloroform containing trifluoroacetic acid.
  • Kiyoshi Yamauchi, Katsu Yamada, Masayoshi Kinoshita, Tadao Kamikawa
    1991 Volume 64 Issue 7 Pages 2088-2090
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    1,1′-(1,32-Dotriacontanediyl)bis[2-[(3RS,1R,11R)-3,7,11,15-tetramethylhexadecyl]-sn-glycero-3-phosphocholine] (the tetramethylhexadecyl group=phytanyl) was synthesized conveniently by reactions involving etherification of 1,1′-(1,32-dotriacontanediyl)bis(3-benzyl-sn-glycerol) (1) with (7R,11R)-3,7,11,15-tetramethyl-2-hexadecenyl bromide and hydrogenation of the resulting unsaturated ether with p-tolylsulfonylhydrazine; a total yield from 1, 7–10%. Unlike usual monopolar double-chain-amphiphiles, the bipolar lipid bent into a U-form in a water–air interface to produce the Langmuir membrane, exhibiting peculiar surface pressure–surface area isotherms.
  • Kazuo Takimiya, Yoshio Aso, Tetsuo Otsubo, Fumio Ogura
    1991 Volume 64 Issue 7 Pages 2091-2102
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The dimethyl and tetramethyl derivatives of a series of anthra[1,9-cd : 4,10-cd′]bis[1,2]dithiole, diselenole, and ditellurole have been prepared as a new type of electron donor. The introduced methyl groups serve to enhance not only the donor strength, but also the solubility, enabling a ready formation of their charge-transfer complexes with various electron acceptors such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), its 2,3,5,6-tetrafluoro derivative, 2,5-dimethyl derivative (DMTCNQ), 2,5-dimethoxy derivative (DMOTCNQ), 2,6-bis(dicyanomethylene)-2,6-dihydronaphthalene (TNAP), 3,3′-dichloro-5,5′-bis(dicyanomethylene)-Δ2.2′-bi(3-thiolene) (DCBT), and 3,3′-dibromo-5,5′-bis(dicyanomethylene)-Δ2.2′-bi(3-selenolene) (DBBS). Although the resulting complexes are mostly 1:1 stoichiometrical, the TCNQ complexes tend to favor a composition rich in acceptors; on the contrary, the DMTCNQ and DMOTCNQ complexes tend to favor a composition rich in donors. Their electrical conductivities range widely from 8 to 10−9 S cm−1, being apparently dependent on appropriate combinations of the donors and the acceptors. In general, the present donors have a tendency to form highly conductive complexes with TCNQ, TNAP, DCBT, and DBBS. These highly conductive complexes mostly show a broad electron absorption in the infrared region, being characteristic of a segregated stacked structure in a mixed valence state. On the other hand, the X-ray analyses of DMTCNQ complexes of 3,4-dimethyl, 8,9-dimethyl, and 3,4,8,9-tetramethylanthra[1,9-cd : 4,10-cd′]diselenoles and 3,4,8,9-tetramethylanthra[1,9-cd : 4,10-cd′]dithiole have revealed that all of the crystal structures have mixed stack columns of donor–donor–acceptor type. Of them, the 3,4-dimethyl derivative complex shows an unusually high conductivity (0.53 S cm−1) for a mixed stacked structure, which is considered to be due to strong heteroatomic interactions of the intra- and inter-columns.
  • Hiroshi Matsubara, Takanori Tanaka, Yoshio Takai, Masami Sawada, Koji ...
    1991 Volume 64 Issue 7 Pages 2103-2108
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The crystal and molecular structure of the title nematogen (1), has been determined by an X-ray analysis. Compound 1 belongs to the triclinic system with space group P-1, a=9.798(2), b=11.579(2), c=9.716(2) Å, α=74.081(13), β=117.766(14), γ=108.179(13)°, and with two molecules in the unit cell. The geometry around the boron atom is planar, and the plane defined by O2BC is parallel to the phenyl ring bonded to the boron atom. The angle between two phenyl rings is 74.3°. The molecules are in their most extended conformation, with nearest neighbors oriented antiparallel to each other. The 1H NMR studies have indicated that the half-chair conformation of the dioxaborinane is kept in a solution even at 125°C where 1 forms a nematic phase, and the rigidity is essential for the formation of mesophases.
  • Tohru Yamada, Toshihiro Takai, Oliver Rhode, Teruaki Mukaiyama
    1991 Volume 64 Issue 7 Pages 2109-2117
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    In the presence of a bis(1,3-diketonato)nickel(II) complex, various olefins are directly monooxygenated into the corresponding epoxides on treatment with atmospheric pressure of oxygen or air and aldehydes. Especially, it is noted that bis[1,3-bis(p-methoxyphenyl)-1,3-propanedionato]nickel(II) behaves as an excellent catalyst in the present epoxidation.
  • Noritaka Chida, Masami Ohtsuka, Katsuyuki Ogura, Seiichiro Ogawa
    1991 Volume 64 Issue 7 Pages 2118-2121
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Conversion of hex-5-enopyranosides into substituted cyclohexanones (Ferrier rearrangement) was found to proceed efficiently with a catalytic amount of various mercury(II) salts at room temperature in a neutral solvent system. Among the mercury(II) salts tested, mercury(II) trifluoroacetate showed the highest activity. Four optically active cyclohexenones were prepared from hex-5-enopyranosides utilizing this method.
  • Yujiro Hayashi, Ken Otaka, Nobuo Saito, Koichi Narasaka
    1991 Volume 64 Issue 7 Pages 2122-2127
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Asymmetric Michael and [2+2] cycloaddition reactions between enamines and methyl (E)-4-oxo-4-(2-oxo-1,3-oxazolidin-3-yl)-2-butenoate proceed with a chiral titanium reagent generated in situ from dichlorodiisopropoxytitanium and a tartrate-derived chiral 1,4-diol. In the presence of excess amounts of the chiral titanium reagent, good to moderate enantioselectivity is attained. The reactions are also well catalyzed even with a catalytic amount of the titanium reagent.
  • Hidenori Okamoto, Shozo Kato
    1991 Volume 64 Issue 7 Pages 2128-2130
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    We have found that the treatment of a Schiff base (2) with trichlorosilane and chloroacetyl chloride results in a highly active chloroacetamide herbicide (1) in an excellent yield. This one-step hydroamidation reaction of a Schiff base is a useful synthetic method.
  • Hidetsugu Wakabayashi, Teruo Kurihara, Sumio Ishikawa, Joji Okada, Tet ...
    1991 Volume 64 Issue 7 Pages 2131-2139
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Five isomeric benzo[b]cyclohept[e][1,4]oxazin-6∼10-ones (hereafter refered to as benzoxazinotropones) and bromobenzoxazinotropones were prepared almost quantitatively by the hydrolysis of the corresponding mono-, di-, and tribromobenzo[b]cyclohept[e][1,4]oxazines with refluxing acetic acid. On the basis of spectral data and theoretical calculations, benzo[b]cyclohept[e][1,4]oxazin-6∼9(11H)-ones are believed to exist in the keto form. These compounds gave respective methoxy- and acetoxybenzo[b]cyclohept[e][1,4]oxazines when reacted with diazomethane and acetic anhydride. On the other hand, benzo[b]cyclohept[e][1,4]oxazin-10(11H)-one was found to exist in a stable, intermolecularly hydrogen-bonded form and did not form acetoxylated or methylated compounds. Possible reaction pathways for the formation of these products are discussed.
  • Tadamitsu Sakurai, Hisashi Mizuno, Tsuneari Kubota, Hiroyasu Inoue
    1991 Volume 64 Issue 7 Pages 2140-2147
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Title hydroxylamines (1) undergo benzophenone-sensitized photolysis to give N-benzylidenebenzylamine (2), p-substituted benzoic acids (3), and monosubstituted benzenes (4) derived from decarboxylation of p-substituted benzoyloxyl radicals. Analysis of the linear Stern–Volmer plots, both for the sensitized photolysis of 1 and for the phosphorescence quenching of benzophenone by 1, demonstrates the participation of triplet 1 in this photolysis. The logarithm of the ratio (krkd), where kt is the rate constant for homolytic cleavage of the N–O bond in triplet 1 and kd is that for its deactivation, used as a measure of the triplet-state reactivities of 1, exhibited a good Hammett-type relationship against the substituent constant (σ) with a slope (ρ) of −0.75. This indicates the exclusive occurrence of homolysis of the N–O bond in the first excited triplet state of 1. Thus the decomposition of 1 activated by triplet benzophenone is classified as an imine-forming radical elimination. The results of deuterium isotope and micellar effects on the sensitized photolysis suggest that the “out-of-cage” products 4 are obtained by decarboxylation and subsequent hydrogen abstraction of p-substituted benzoyloxyl radicals which escaped from the triplet cage in competition with spin inversion to the singlet cage. In this singlet cage, hydrogen abstraction giving 2 and 3 and recombination affording the starting 1 were found to take place exclusively.
  • Akio Toshimitsu, Takehiro Kusumoto, Tatsuo Oida, Shigeo Tanimoto
    1991 Volume 64 Issue 7 Pages 2148-2152
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The reaction of olefins, benzeneselenenyl chloride, and p-toluenesulfonamide in the presence of zinc(II) chloride affords N-[2-(phenylseleno)alkyl]-p-toluenesulfonamides in good to excellent yields. When combined with alkylation on the carbon atom bearing the phenylseleno group thus introduced and subsequent oxidative or reductive removal of the selenium moiety, this reaction can be utilized in the preparation of a wide range of allylic or saturated amides.
  • Tsuyoshi Satoh, Yasumasa Hayashi, Koji Yamakawa
    1991 Volume 64 Issue 7 Pages 2153-2158
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxide to carbonyl compounds gave the adducts, which were heated in refluxing toluene or xylene to give vinyl chlorides in high overall yield. Dehydrochlorination of the vinyl chlorides with excess n-BuLi afforded propargylic alcohols in high yields. Asymmetric synthesis of both enantiomers of the propargylic alcohols was realized using optically active 1-chloroalkyl p-tolyl sulfoxide and aldehyde.
  • Kenichi Imaeda, Takehiko Mori, Chikako Nakano, Hiroo Inokuchi, Naoko I ...
    1991 Volume 64 Issue 7 Pages 2159-2168
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The crystal structures and the electrical conductivities have been studied for tetrakis(alkylchalcogeno)tetrathiafulvalene (TXCn-TTF (X=sulfur, selenium, tellurium; n=2,3)) complexes with tetracyanoquinodimethane (TCNQ). All the complexes with a composition of 1 : 1 had the same crystal system (triclinic) and the same space group (P\bar1). The donor and acceptor molecules were alternately stacked in their crystals. (TSeC2-TTF)TCNQ was obtained as plate and needle crystals. The molecular structure of TSeC2-TTF and the overlapping mode between TSeC2-TTF and TCNQ molecules of the two complexes were subtly different. All the complexes were semiconductors because of their mixed-stack structures. (TTeC2-TTF)TCNQ showed the lowest resistivity (5 Ω, cm at room temperature). Its good conductivity was brought about by the effective degree of charge-transfer and the favorable overlap between TTeC2-TTF and TCNQ molecules. An overall discussion on the structural and physical properties of a series of TCNQ complexes with TXCn-TTF (X=sulfur, selenium, tellurium; n=1,2,3) is presented.
  • Tatsuo Arai, Yoshinobu Nishimura, Masako Sasaki, Hitoshi Fujita, Itsur ...
    1991 Volume 64 Issue 7 Pages 2169-2173
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The mechanism and active species of drug-induced photosensitive reactions were investigated by measuring the absorption spectra of the transient species on photoexcitation as well as by determining the efficiency of singlet oxygen production on quenching by oxygen of the excited state of drugs. The quantum yields of singlet oxygen production were determined for chlorpromazine hydrochloride, mequitazine, and afloqualone as 0.27, 0.28, and 0.14, respectively. These rather high yields of singlet oxygen suggest its important role in photosensitivity of the drugs. On the basis of the transient-spectroscopic investigations the quenching mechanism of excited-state drugs by oxygen was discussed.
  • Tsutomu Ishioka
    1991 Volume 64 Issue 7 Pages 2174-2182
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The structural transition behavior of potassium soaps (99% purity), CH3(CH2)nCO2K (n=14, 16, 18, 20), having low water contents of less than 10 wt% was investigated by both DSC and vibrational spectroscopies. Nine phases from crystal (I<80°C) to liquid crystal (260°C<IX) were observed for n=14 and 16 by thermal measurements. An additional phase I′ (I<I′<II) was found for n=18 and 20. The structural changes of the alkyl chains accompanied by these transitions were investigated by using IR and Raman methods. With increase in temperature, the itensities of the IR methylene progressive bands which were characteristic of all-trans conformation decreased and conformational defect bands ascribed to gt-, gg-, and gtg′ conformations, were observed in phases I′, II, and III for n=14–20. These indicate the onset of a partial melting of the chains in these phases. At the transition from phase III to IV, the chains entered liquid-like conformations. The result was also confirmed by the Raman spectra.
  • Akiko Sekine, Yuji Ohashi
    1991 Volume 64 Issue 7 Pages 2183-2187
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The crystal structures of two cobaloxime complexes with different axial base ligands have been determined by X-ray analysis at room temperature. I: (3-Aminopyridine)(2-cyanoethyl)bis(dimethylglyoximato)cobalt(III); the cystal is monoclinic, the space group being C2⁄c, Z=8 with a=28.849(8), b=7.746(2), c=18.429(5) Å, and β=105.71(3)°. II: (Aniline)(2-cyanoethyl)bis(dimethylglyoximato)cobalt(III) aniline solvate; the crystal is monoclinic, the space group being P21c, Z=4 with a=14.228(7), b=11.426(4), c=14.178(3) Å, and β=91.92(3)°. Both structures were refined by a full-matrix least-squares method to final R values of 0.070 and 0.074 for 3886 and 3311 observed reflections, respectively. Their photoisomerization rates in the solid state obtained from changes in the IR spectra, 3.2 and 4.2×10−4 s−1, respectively, are significantly greater than those of the related compounds. The hydrogen bonds between the reactive 2-cyanoethyl groups and the atoms of the neighboring molecules in the two crystals should be responsible for the greater reaction rates. Taking into account the role of the hydrogen bonds, a probable isomerization mechanism is proposed.
  • Yoshimi Sueishi, Masahiro Kuzukawa, Shunzo Yamamoto, Norio Nishimura
    1991 Volume 64 Issue 7 Pages 2188-2191
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Pressure effects on the rate of spin–spin exchange of some nitroxide radicals in acetone and hexane at 298.2 K have been studied by means of a high-pressure ESR technique. It was found that this exchange reaction is diffusion-controlled. The rate of the spin exchange is related to that of diffusion, the probability of the spin exchange, P=f(J, τ1), and steric factor fs. The values of P and hence τ1 were estimated as a function of pressure. A method for evaluating the steric factor and the exchange integral is proposed.
  • Tatsuya Masuda, Yoshio Matsunaga
    1991 Volume 64 Issue 7 Pages 2192-2195
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The mesomorphic properties of a homologous series of 4-[3,4-bis(4-alkoxybenzoyloxy)benzylideneamino]azobenzenes have been studied by differential scanning calorimetry and microscopy. While the nematic phases exhibited by the ethoxy and propoxy homologues are metastable, those exhibited by all of the butoxy-to-hexadecyloxy homologues exhibit the temperature range of stable existence. A metastable smectic A-phase is observed for the tetradecyloxy and hexadecyloxy homologues. Among the examined 4-[2,4-bis(4-alkoxybenzoyloxy)benzylideneamino]azobenzenes, only the dodecyloxy and tetradecyloxy members are nematogenic. Their clearing points are located at more than 30 °C below the melting points. 4-(Benzylideneamino)azobenzene and its 3-(4-dodecyloxybenzoyloxy) derivative are nonmesogenic; however, the phase diagrams of binary systems with 4-(4-nonyloxybenzylideneamino)azobenzene revealed that the addition of a 3-(4-dodecyloxybenzoyloxy) group to the former molecule depresses the virtual nematic behavior, but promotes the smectic A behavior. A further addition of the same group at the 4-position drastically raises the nematic-isotropic transition temperature.
  • Hiroshi Kashiwagi
    1991 Volume 64 Issue 7 Pages 2196-2201
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    A decationated Y-type zeolite (HY) was adsorbed by a single organic compound from a heptane solution, and dried in vacuo. The numbers of the radicals in these binary systems before, during, and after irradiating with ultraviolet (UV) light or heating were followed by electron paramagnetic resonance spectroscopy and then compared. During UV irradiation, the number of radicals increased from the constant number of spins before illumination (C1) to the second constant number of spins (C2). After stopping the illumination, the C2 decreased up to the third constant number of spins (C3). The C3 value was smaller than C2, but was significantly greater than C1. The enhancement of radicals induced by UV light, expressed quantitatively in terms of the C3/C1 ratio, was pronounced when either a weak donor or a weak acceptor was adsorbed on HY calcined at a low temperature. C1 was proportional to the amount of adsorption up to the maximal amount of adsorption, whereas C2 and C3 were proportional only at a considerably decreased amount of adsorption. A similar tendency was observed when the binary systems were heated at 40 or 80 °C. A quantitative determination of the mechanically induced enhancement of radicals would prompt either an improvement in the reproducibility of physicochemical data or an elucidation of the solid acidity or basicity.
  • Seiji Yamamoto, Nobuhisa Hashimoto, Mitsuo Ito
    1991 Volume 64 Issue 7 Pages 2202-2206
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The S1(n,π*)←S0 and T(n,π*)←S0 sensitized phosphorescence excitation spectra of jet-cooled o- and m-substituted (fluoro- and methyl-) acetophenones have been measured. The two rotational isomers (O-cis and O-trans isomers) of each molecule arising from the orientation of the acetyl group with respect to o- or m-substituent have been discriminated. The energy difference in the 0–0 transition between the two isomers is less than 100 cm−1 for m-substituted acetophenone but more than 300 cm−1 for o-substituted acetophenone. The characteristic energy difference can be explained from the fact that the electronic excitation is localized on the C=O group.
  • Masana Arimura, Yozaburo Yoshikawa
    1991 Volume 64 Issue 7 Pages 2207-2213
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Ionization efficiency curves of N,N-dimethylformamide (DMF) ion and of its fragment ions, C3H6NO+, C2H4NO+, and C2H6N+ were obtained by use of vacuum ultraviolet photoionization method. The appearance energy of the parent ion was 9.12±0.06 eV. The appearance energies of C3H6NO+, C2H4NO+, and C2H6N+ were very close (10.77±0.08 eV for C3H6NO+ and C2H4NO+, 10.59±0.08 eV for C2H6N+). The relative intensity curve of C2H6N+ normalized by the sum of fragment ions vs. photon energy has the second rise at 12.2±0.3 eV, which implies that another fragmentation process appears at the photon energy above 12.2 eV. The second fragmentation process is ascribed to a channel through DMF cation in an excited electronic state.
  • Satoshi Sato, Masahiro Hiratsuka, Toshiaki Sodesawa, Fumio Nozaki
    1991 Volume 64 Issue 7 Pages 2214-2219
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The chemical vapor deposition (CVD) of silica onto an amorphous silica–alumina was investigated using tetraethoxysilane in order to create Brønsted acid sites on the surface of original silica-alumina. Silica loading could be readily controlled by the CVD time at 160 °C; the silica covered an internal wall of mesopore of the support of silica–alumina. The resulting CVD silica–alumina was catalytically more active than the original silica–alumina support for such test reactions as the cracking of cumene and the isomerization of 1-butene. The characteristic changes in the amount of Brønsted acid sites were clarified by means of the temperature-programmed desorption of adsorbed 2,6-dimethylpyridine. Strong Lewis acid sites of the original silica–alumina were converted into strong Brønsted acid sites upon depositing the silica component.
  • Ichiro Tanahashi, Hiroto Nakama, Atsushi Nishino, Jun Takeda
    1991 Volume 64 Issue 7 Pages 2220-2223
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Molecular sieving carbon (MSC) has been characterized for CO2-adsorbers in a controlled atmosphere storage (CA storage) system by a gas-adsorption method. Experimental data were analyzed by means of the Dubinin-Astakhov equation, the t-method, and the micropore analysis method. The BET surface area of MSC was 592 m2 g−1. In the pore size distribution curve of MSC, the most common pore diameter was 0.68 nm. The temperature and the space velocity dependence of adsorbers with MSC have been investigated. The CO2 adsorption capacity of adsorbers was determined by the gas-flow method. The capacity of the adsorbers at 60°C decreased to 55%, compared with that at 20°C; it decreased with increasing space velocity.
  • Yutaka Ikushima, Norio Saito, Masahiko Arai, Kunio Arai
    1991 Volume 64 Issue 7 Pages 2224-2229
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The solvent polarity parameters of supercritical carbon dioxide were determined as a function of the temperature and pressure within the ranges 318–353 K and 5.85–28.5 MPa. An infrared (IR) spectroscopic technique has been employed to determine the values of π* dipolarity/polarizability and the Lewis basicity parameter BMeOD by measuring the transitions in the IR absorption wavelength of functional groups (such as C=O and O–H···BA, where BA is a hydrogen-bond acceptor), in supercritical carbon dioxide. Ultraviolet/visible (UV/vis) spectroscopy was used to determine the value of the Kamlet-Taft’s solvatochromic acidity partameter, α. The BMeOD-value was enhanced with density, but was very small at the temperatures and pressures examined, almost the same as that for hexane. The α-value tended to be dependent on density at lower pressures, but was remarkably smaller compared with those for alcohols. The π*-value significantly increased with an increase in the density, becoming more negative at higher temperatures above 10 MPa. Furthermore, the ET(30)-value was estimated by using the determined π*-value. A reliable ET(30)-value for supercritical carbon dioxide has been obtained.
  • Keiichi Yokoyama, Shin-ya Takane, Takayuki Fueno
    1991 Volume 64 Issue 7 Pages 2230-2235
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Paths of isomerizations of isocyanic acid HNCO into various chain isomers via ring intermediates have been investigated by ab initio MO calculations with the MRD-CI procedure employing the 6-31G** basis sets. Geometry optimizations were accomplished at the RHF, UHF, or CASSCF level of theory. It is found that the isomerization from HNCO to cyanic acid HOCN is energetically the most favorable and that it should proceed via successive 1,2-hydrogen migrations rather than by a single 1,3-hydrogen migration. The overall barrier height is calculated to be 423 kJ mol−1, which is ca. 60 kJ mol−1 higher than the critical energy for the main decomposition channel, HNCO→NH(3Σ)+CO. Implications of the results to the kinetics of the thermal decompostion of HNCO at high temperatures are discussed.
  • Yasumasa Sakakibara, Isao Yamamoto, Ken Sasaki, Mutsuji Sakai, Norito ...
    1991 Volume 64 Issue 7 Pages 2236-2241
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The isomerization of 1,5-cyclooctadiene (1,5-COD) with Ni(acac)2–Et3Al2Cl3–phosphorus ligand (Ni : Al2 : P=1 : 10 : 3) was first examined with varying P ligands in toluene in order to find suitable conditions for the formation of 1,4-COD. The product distribution depended largely on the P ligands. For several phosphites possessing very strong π-acceptor properties, the main product was 1,4-COD. In particular, the less-bulky bicyclic phosphite, 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (L-3) was very effective and gave 1,4-COD in a high selectivity of 93% at 66% conversion (1,5-COD/ Ni=500, molar ratio) by employing a low temperature of −30°C. However, the reaction stopped before reaching completion because the catalyst was deactivated by the accumulation of 1,4-COD product. The conversion, depending on the 1,5-COD/toluene ratio (volume) rather than the 1,5-COD/Ni ratio, increased with a decrease in the 1,5-COD/ toluene ratio and was 66–69% at a ratio of 0.19. On the other hand, the catalyst (P: L-3) was much less active for 1,4-COD than for 1,5-COD and was deactivated quickly under the same reaction conditions. This appeared to result in a high selectivity of 1,4-COD in the isomerization of 1,5-COD. The mechanistic implications of the experimental results are discussed.
  • Makoto Sakakibara, Tetsuya Ishida, Yoshihiko Watanabe, Takeshi Toru, Y ...
    1991 Volume 64 Issue 7 Pages 2242-2248
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Selenation of 2-chloro- and 2,6-dichloro-1,5-naphthoquinones with benzeneselenolate ion, generated from diphenyl diselenide and tributylphosphine in an alkaline medium, afforded 2-phenylseleno- and 2,6-bis(phenylseleno)-1,5-naphthoquinones in excellent yields. Reaction of halo-1,4-naphthoquinones with 3-amino-2-pyridineselenolate ion generated from bis(3-amino-2-pyridyl) diselenide gave naphtho[2,1-b]pyrido[3,2-e][1,4]selenazines and pyrido[2,3-b]pyrido[3″,2″:5′,6′][1,4]selenazino[2′,3′:3,4]naphtho[1,2-e][1,4]selenazines in high yields.
  • Nobujiro Shimizu, Shin-ichiro Watanabe, Yuho Tsuno
    1991 Volume 64 Issue 7 Pages 2249-2254
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Solvolysis rates have been measured in various solvents at 25°C for 1-(substituted phenyl)-2-(trimethyl-silyl)ethyl trifluoroacetates (1a1g; R=H, 4-Me, 4-Cl, 4-Br, 3-Cl, 3,4-Cl2, and 3,5-Cl2, respectively) and structurally related compounds, 1-phenylethyl-, 3,3-dimethyl-1-phenylbutyl-, and 1-(4-methylphenyl)ethyl trifluoroacetates (3a, 4, and 5). In dioxane/water mixtures 1g solvolyzes with the same sensitivity to the change in solvent ionizing power as that for a kc substrate 5. The solvolyses of 1e and 5 exhibit almost identical α-deuterium kinetic isotope effects (kHkD) of 1.18–1.19 in aq dioxane. Substituent effect on the solvolysis of 1 in 90% aq dioxane is expressed by an LArSR equation: logkXkH=−3.05 (σ°+1.05Δ\barσR+) (R=0.9997). These findings are consistent with kc mechanism for the solvolysis of 1. Relative rates for the solvolysis of 1a, 3a, and 4 in 30% aq dioxane are 2.99×105 : 2.84 : 1.0 indicating solvolytic generation of α-(trimethylsilylmethyl)benzyl cation to be about 7 kcal mol−1 energetically more favorable than that of the corresponding α-alkylbenzyl cations.
  • Masakazu Nishida, Hiroshi Kimoto, Shozo Fujii, Yoshio Hayakawa, Louis ...
    1991 Volume 64 Issue 7 Pages 2255-2259
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The title reaction was achieved by UV (254 nm) irradiation with CF3I. The methylthio group was introduced to increase electron density and to limit available reactive sites in the rings. Following trifluoromethylation, the methylthio groups were readily removed by hydrogenolysis (Raney Ni) to give the desired trifluoromethyl heterocycles.
  • Yasufumi Tamai, Yutaka Matsuzaka, Shuichi Ôi, Sotaro Miyano
    1991 Volume 64 Issue 7 Pages 2260-2265
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Optically active polyamides 4a4c were synthesized from the polycondensation of axially dissymmetric 1,1′-binaphthalene-2,2′-dicarbonyl dichloride (2) with 1,4-benzenediamine, 1,6-hexanediamine, and 1,10-decanediamine, respectively. CD spectra of the polyamides 4a4c are essentially the same as those of the corresponding model diamides 6a6c prepared from 2 and benzenamine, 1-hexanamine, and 1-decanamine, respectively. This similarity indicates that the conformation of the 1,1′-binaphthalene-2,2′-dicarboxamide moieties of the polyamides 4a4c in solution state are rather similar to those of the corresponding model diamides 6a6c. Several axially chiral biaryl compounds and 3,5-dinitrophenylcarbamates (3,5-DNPCs) derived from 1-aryl-1-alkanols were resolved by HPLC equipped with the columns packed the chiral stationary phases (CSPs) prepared from 4a4c adsorbed on spherical silica gel. A main control factor for the chiral discrimination seems to be the hydrogen bonding between the amide groups of the CSPs and the hydrogen-bonding sites of the atropisomeric biaryls. The donor–acceptor interaction between the binaphthalene moiety of the CSPs and the 3,5-dinitrobenzene moiety of the 3,5-DNPCs may also be important for the chiral discrimination of the 3,5-DNPCs.
  • Takahiko Akiyama, Yasuhiro Takesue, Masahiro Kumegawa, Hiroyuki Nishim ...
    1991 Volume 64 Issue 7 Pages 2266-2269
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    5′-O-Acryloyl-5-fluorouridine was prepared by use of p-methoxybenzyl (PMB) group as an N3-imide protecting group of 5-fluorouridine. PMB group was introduced chemoselectively by use of N,N-diisopropylethylamine or DBU as a base. A new deprotection method was developed by means of AlCl3–anisole system at room temperature.
  • Byong-tae Chang, Sung-jin Kim
    1991 Volume 64 Issue 7 Pages 2270-2274
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The properties of TiO2 supports and the H2 reduction temperature of Fe3O4/TiO2 catalysts were found to play imortant roles in determining their activity and light olefin selectivity. For each catalyst, a good linear relationship was observed between the CO conversion and the light olefin selectivity. The sequence of the latter under identical conditions was JRC-TIO-5>TIO-3>TIO-4.
  • Kaoru Fujimoto, Ikusei Nakamura, Kohshiroh Yokota, Kohjiroh Aimoto
    1991 Volume 64 Issue 7 Pages 2275-2280
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    H–ZSM-5 showed a high selectivity of propane and low selectivity of aromatic hydrocarbons in butane conversion at 450°C, whereas Ga-supportd ZSM-5 (Ga–ZSM-5) showed higher selectivities of aromatic hydrocarbons and hydrogen. A small amount of oxygen in the feed promoted butane conversion to aromatic hydrocarbons on H–ZSM-5. Hybrid catalysts composed of the physical mixture of Ga/Al2O3 and H–ZSM-5 showed comparable activities and aromatic selectivities to those of the Ga-supported ZSM-5 zeolite (Ga–ZSM-5). Hydrogen was adsorbed quickly on the Ga–ZSM-5 and on the hybrid catalyst at 400°C and the adsorbed hydrogen was desorbed at around 450°C during the temperature programmed desorption experiment from both catalysts. However, little hydrogen was adsorbed on H–ZSM-5 and was desorbed from it. It was pointed out that the supported Ga promoted the zeolite-catalyzed aromatization of lower paraffins by promoting hydrogen desorption via the “reverse spillover” effecct.
  • Ichiro Tanahashi, Masaru Yoshida, Tsuneo Mitsuyu
    1991 Volume 64 Issue 7 Pages 2281-2283
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Al2O3 thin films containing CdS microcrystallites were successfully prepared by an rf-magnetron sputtering technique. Photoluminescence spectra of films exhibited blue band-edge emission at a higher energy than that of bulk CdS. The spectral change seems to arise from a zero-dimensional confinement of electrons and holes in CdS microcrystallites.
  • Makoto Isihara
    1991 Volume 64 Issue 7 Pages 2284-2285
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The hyperivial condition upon p-densities is applied to the simple Hiickel model of linear chains. The invariance of the modified p-density is derived in fully generalized form. Any bond order between nonadjacent sites is shown expressible in terms of two electron densities or two bond orders between adjacent sites.
  • Masahiko Maekawa, Megumu Munakata, Susumu Kitagawa, Teijiro Yonezawa
    1991 Volume 64 Issue 7 Pages 2286-2288
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The dicopper(I) complex with 2-(diphenylphosphino)pyridine (Ph2Ppy), [Cu2(μ-Ph2Ppy)2(CH3CN)2](PF6)2 has been prepared. The crystal structure has been determined crystallographically: Space group P\bar1, a=10,807(6), b=11.756(8), c=8.606(7) Å, α=90.36(6), β=95.98(5), γ=92.90(5)°, Z=1, R=0.067. The two copper atoms are bridged by two Ph2Ppy molecules in a head-to-tail arrangement, resulting in a rare staggered conformation of the eight-membered ring CU2P2N2C2, whose factor is concerned with the coordination numbers of the central metal atoms. 1H NMR studies show that the ligand of a CH3CN in the titled compound undergoes dissociation in acetone solution.
  • Etsuo Hasegawa, Eriko Matsubuchi, Eishun Tsuchida
    1991 Volume 64 Issue 7 Pages 2289-2291
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The demetalation of a series of (5,10,15,20-tetrahenylporphyrinato)iron(III) complexes having bulky substituents at the o-positions of phenyl rings was studied in acetic acid in the presence of iron(II) chloride and HCl. The reaction occurred simultaneously with the reduction of Fe(III) porphyrin to Fe(II) porphyrin, since no demetalation was observed without iron(II) chloride. The pseudo-first-order rate constants, which were determined spectrophotometrically, decreased with an increase in the bulkiness of the o-substituents on the phenyl rings. The atropisomeric structures of the products were determined by high-resolution NMR measurements.
  • Yasushi Kanzaki, Mitsuo Abe
    1991 Volume 64 Issue 7 Pages 2292-2294
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The intercalation of enzymes with molecular weights of 23000–240000 was examined for layered inorganic compounds. The intercalation of papain and catalase into γ-type titanium(IV) phosphate was achieved by coexisting pro-pylamine in an aqueous medium. The intercalation compound of papain was enzyme active for N-benzoyl-L-arginine ethyl ester and a catalase intercalation compound for H2O2 decomposition.
  • Yasuhiro Tanoue, Akira Terada
    1991 Volume 64 Issue 7 Pages 2295-2297
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The structures of the products in our previous report “One-Pot Ortho Hydroxylations of 2-(1-Hydroxyalkyl)-naphthalenes and (1-Hydroxyalkyl)benzenes” were reexamined by 13CNMR spectra and part of our previous interpretation will be corrected here. The lithiations of 2-(1-hydroxyalkyl)-1,4,5,6,8-pentamethoxynaphthalenes occurred at the 7-position, and not at the 3-position as we reported.
  • Hideo Kojima, Kazuyoshi Ozaki, Noboru Matsumura, Hiroo Inoue
    1991 Volume 64 Issue 7 Pages 2298-2299
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The reaction of tris(t-butylthio)cyclopropenylium perchlorate with phenyl-, o-tolyl-, or 1-naphthylmagnesium bromide in tetrahydrofuran at room temperature gave t-butylthio-substituted allenes and indenes. The reaction with 2,6-xylylmagnesium bromide gave only the corresponding allene derivative.
  • Hiroyoshi Kamogawa, Takuharu Nakata, Sei Komatsu
    1991 Volume 64 Issue 7 Pages 2300-2302
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    5,10,15,20-Tetraphenylporphyrins (Por) with a styrenic double bond-bearing substituent attached at the pyrrole residue with an amide or ester spacer were synthesized starting with 3-substituted pyrroles. Free radical copolymerization of ZnPor, prepared from Por, with 1-vinyl-2-pyrrolidone gave more favorable results than did Por.
  • Motoo Tori, Takeshi Hasebe, Yoshinori Asakawa, Keiichiro Ogawa, Shin Y ...
    1991 Volume 64 Issue 7 Pages 2303-2305
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The X-ray analysis of the title compound has been carried out to give unambiguous assignment of the absolute configurations of the liverwort sesquiterpenoids (−)-chiloscyphone and (+)-chiloscypholone, each for which the enantiomerically opposite configurations had been assigned in the previous report.
  • Masataka Yokoyama, Toshihiro Ikuma, Sadataka Sugasawa, Hideo Togo
    1991 Volume 64 Issue 7 Pages 2306-2308
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    Several nucleosides bearing pyazole ring as the base moiety were synthesized by the reaction of D-ribofuranosylhydrazine or 2-deoxy-D-ribosuranosylhydrazine with easily available acylketene ditioacetal derivatives.
  • Katsuya Matsumoto, Takashi Ebata, Koshi Koseki, Hiroshi Kawakami, Haji ...
    1991 Volume 64 Issue 7 Pages 2309-2310
    Published: 1991
    Released: June 07, 2006
    JOURNALS FREE ACCESS
    The stereoselective reduction and cis-dihydroxylation of levoglucosenone (1,6-anhydro-3,4-dideoxy-β-D-glycero-hex-3-enopyranos-2-ulose), gave D-altrosan (1,6-anhydro-β-D-altropyranose), which could be converted to D-altrose in high yield.
feedback
Top