Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 74 , Issue 2
Showing 1-26 articles out of 26 articles from the selected issue
  • Fumihiko Tanaka, Tsuyoshi Koga
    Type: scientific monograph
    2001 Volume 74 Issue 2 Pages 201-215
    Published: 2001
    Released: July 01, 2002
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    This paper reviews recent theoretical and computational studies of thermoreversible gelation with multiple cross-link junctions in associating polymers. Paying special attention to the multiplicity and sequence length of the network junctions, we derive phase diagrams with coexisting gelation and phase separation. Local and global structures of the gel networks are studied. The conventional Eldridge–Ferry method is extended to allow for simultaneous evaluation of multiplicity and sequence length (or enthalpy of the cross-links), and applied to the experimental gel melting curves of poly(vinylalcohol) in water. On the basis of the Scanlan–Case criterion, we calculate the number of elastically effective chains and of dangling ends in the network as functions of polymer concentration and temperature. The effect of added surfactants on the formation of thermoreversible gels (surfactant-mediated gelation) in hydrophobically modified associating polymer solutions is also studied under the assumption of the existence of a minimum multiplicity required for stable cross-links. Competition between intramolecular micellization and intermolecular cross-linking is also studied with special attention to the formation of flower micelles.
  • Shigeori Takenaka
    Type: scientific monograph
    2001 Volume 74 Issue 2 Pages 217-224
    Published: 2001
    Released: July 01, 2002
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    Electrochemically active DNA ligands, including ferrocenyl DNA oligonucleotides and ferrocenyl naphthalene bis(carboximide), are reviewed in connection with development of an electrochemical DNA sensor. Ferrocenyl oligonucleotides are used as an electrochemical probe DNA detectable by high performance liquid chromatography with the electrochemical detector (HPLC-ECD) system and they enable the target DNA analysis at femto mole level. Ferrocenyl oligonucelotides are useful also as a polymerase chain reaction (PCR) primer to realize quantitative PCR. Ferrocenyl naphthalene bis(carboximide) is a general DNA detecting ligand. When coupled with a probe DNA immobilized on an electrode, the target DNA from plasmid, chromosomal DNA, and total RNA extracted from several sources can be analyzed with very high sensitivity. Ferrocenyl naphthalene bis(carboximide) bound to the DNA duplex serves as a pseudo-polyferrocene array and this unique architecture leads to enhanced electron transfer between reduced glucose oxidase and the electrode. Unpaired base(s) present on the mismatched base(s) of the DNA duplex can be detected by observation of a decrease in the amount of ferrocenyl naphthalene bis(carboximide) bound to such a mismatched DNA duplex. Hybridized DNA on the DNA microarray was visualized electrochemically in the aqueous solution by the scanning electrochemical microscope (SECM) coupled with the ferrocenyl naphthalene bis(carboximide).
  • Hideki Yorimitsu, Hiroshi Shinokubo, Koichiro Oshima
    Type: technical report
    2001 Volume 74 Issue 2 Pages 225-235
    Published: 2001
    Released: July 01, 2002
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    Treatment of various organic halides with phosphinic acid (hypophosphorous acid) in aqueous ethanol in the presence of a radical initiator and a base gave the corresponding reduced products in high yields. Addition of a base is indispensable for the reduction of halides by phosphinic acid. Allylic ether of o-iodophenol or 2-haloalkanal allylic acetal underwent radical cyclization under the same conditions to afford the corresponding cyclic product in excellent yield. Deuterated phosphinic acid was found to be an efficient chain carrier for the radical deuteration of organic halides. For example, a deuterium oxide solution of deuterated phosphinic acid, potassium carbonate, 2,2′-azobis(isobutyramidine) dihydrochloride as an initiator, and p-iodobenzoic acid was heated at reflux to give p-deuteriobenzoic acid in 94% yield. A mixed dioxane/D2O solvent system combined with DBU and potassium peroxodisulfate was crucial to deuterate hydrophobic substrates in high yields and with high deuterium incorporation. Complete deuterium incorporation was accomplished only by the reaction in D2O without an organic cosolvent and an organic base.
  • Yoshihisa Fujiwara, Yoshito Taga, Taro Tomonari, Yukimi Akimoto, Takes ...
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 237-244
    Published: 2001
    Released: July 01, 2002
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    The microviscosity dependences of the magnetic field and magnetic isotope effects on disappearance of radical pairs (RPs) comprising benzophenone ketyl and alkyl radicals were investigated in sodium dodecyl sulfate (SDS) micellar solutions. The increase in microviscosity of the SDS micelle by adding MgCl2 caused not only a deceleration in the escape rate of the component radicals from the micelle but also a small magnetic isotope effect on the RP decay rate. The small magnetic isotope effect was explained by an increase in the correlation time of the radical motion, which is coupled with the anisotropic hyperfine interaction modulating the spin-lattice relaxation of RP.
  • Yuji Naruse, Akihiro Hayashi, Shin-ichiro Sou, Hirotaka Ikeda, Satoshi ...
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 245-254
    Published: 2001
    Released: July 01, 2002
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    Structures and reactions of CH3OCH2M (M = Li, Na, K) were investigated in a theoretical manner. CH3OCH2M has the acute bond angle of ∠M-C-O due to a strong coordination of the oxygen to the alkali metals. The nucleophilic substitution reaction of the substrate CH3OCH2Li by the nucleophile CH3OCH2Li is more preferred than the carbene generation by α-elimination and a nucleophilic substitution of CH3OCH2Li by CH3Li. The resulting 2-methoxyethyllithium readily liberated lithium methoxide to afford ethylene, which added to the anion species to give an ethylated product. Among the CH3OCH2M (M = Li, Na, K), CH3OCH2K is the most nucleophilic, due to the high σC–K level, while CH3OCH2Li is the most nucleophilic because of the lowest σ*C–O level. This supports a previously proposed mechanism for the ethylation of indole derivatives by methyl ethers in the presence of BuLi - t-BuOK.
  • Maria Olea, Maki Kunitake, Takafumi Shido, Kiyotaka Asakura, Yasuhiro ...
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 255-265
    Published: 2001
    Released: July 01, 2002
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    The adsorption kinetics on Au/Ti(OH)4* (a newly developed Au catalyst, active for low-temperature CO oxidation) for CO, O2, and CO2 in the temperature range 298–473 K was determined by temporal analysis of products (TAP) technique. The response signals from the single-pulse TAP experiments were analyzed using a statistical approach, and they were fitted to analytical models in order to establish the adsorption/desorption parameters. The pulse response of a non-adsorbing gas (argon) was used as a “reference”. The experiments revealed that: CO molecules reversibly adsorbed on the catalyst surface; O2 molecularly adsorbed , irreversibly for high pulse intensities and reversibly for low pulse ones; CO2 molecules irreversibly adsorbed on the surface, probably as carbonates. This catalyst exhibited an apparent negative activation energy for irreversible adsorption of O2.
  • Seiko Nakagawa, Toshinari Shimokawa
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 267-271
    Published: 2001
    Released: July 01, 2002
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    The formation of negative ions from halogenated acetonitriles XCH2CN (X = F, Cl, Br, I) and C6F4(CN)2 was studied using negative chemical ionization mass spectrometry. The halide ion was observed for XCH2CN (X = Cl, Br, I). While the intensity of the ion increased with increasing temperature for ICH2CN, the temperature dependence for the production of ions was only slightly observed over the temperature range of 393–537 K for ClCH2CN and BrCH2CN. The parent anions were observed for C6F4(CN)2. The intensity of the parent anions increased in the order 1,3-C6F4(CN)2- < 1,2-C6F4(CN)2- < 1,4-C6F4(CN)2-. A temperature dependence for the parent anions was not observed. The difference in the intensity can be explained by a recombination reaction with the positive ions.
  • Jing Ma, Hirotaka Ikeda, Satoshi Inagaki
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 273-278
    Published: 2001
    Released: July 01, 2002
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    Orbital phase theory was applied to predict that the cross σ-conjugated isomers of acyclic Group 14 triplet diradicals E4H8 1 and E5H10 3 (E = C, Si, Ge, Sn) are more stable than the linear ones, 2 and 4, respectively. This prediction was confirmed by ab initio molecular orbital (MO) and density functional theory (DFT) calculations. It was also found that the radicals are preferentially in conjugation with the C-H bond for E = C (1a and 2a), but with the E-E bond for E = Si, Ge, Sn.
  • Keisuke Tominaga, Hiroaki Maekawa
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 279-286
    Published: 2001
    Released: July 01, 2002
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    We have theoretically investigated two-dimensional vibrational spectra for a two-mode system in terms of a diagrammatic approach. The two vibrational modes are anharmonically coupled. The perturbed stationary states are obtained by treating the cubic anharmonicity as a perturbation, and expressions for the third order response functions are derived. A physical origin of cross peaks in the spectrum is discussed. It is found that the vibrational dephasing time as well as the anharmonicity is important for the appearance of cross peaks.
  • Champika Vithana, Hidehiro Uekusa, Yuji Ohashi
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 287-292
    Published: 2001
    Released: July 01, 2002
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    The 4-cyanobutyl group bonded to the cobalt atom in a cobaloxime complex crystal was isomerized to the 2-cyanobutyl group through the 3-cyanobutyl group on exposure to a xenon lamp with retention of the single crystal form. The X-ray crystal structure analysis of the initial crystal, (I), and the crystal after 66 hours exposure, (II), revealed that the produced 3-cyanobutyl group at one site in (II) is not disordered racemates but one enantiomer. The occupancy factors of the 4-cyanobutyl and the produced 3-cyanobutyl group were 0.786(7) and 0.214(7), respectively in (II). Although the structure of the produced 2-cyanobutyl group was not located on the difference electron density map, the NMR measurement clearly indicated that a small amount of the 2-cyanobutyl complex (ca. 6%) was produced.
  • Yukie Mori, Yoshio Sakaguchi, Hisaharu Hayashi
    Type: Others
    Subject area: TP
    2001 Volume 74 Issue 2 Pages 293-304
    Published: 2001
    Released: July 01, 2002
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    Photo-induced intramolecular electron transfer (ET) and subsequent back ET have been studied for phenothiazine-bridge-pyromellitdiimide (D-B-A) and phenothiazine-bridge-pyromellitdiimide-nitroxide radical (D-B-A-R•) in various solvents by nano-second transient absorption spectroscopy. Upon excitation of the phenothiazine (D) moiety in these compounds, ET from 1D* to A took place at a rate of ca. 5 × 109 s-1 to give charge-separated (CS) states, 1[D•+-B-A•-] or 2[D•+-B-A•--R•], in high quantum yields. The decay dynamics of the CS states was determined by the interplay between the spin conversion and the back ET to the ground state. The efficiency of the interconversion between states with different spin multiplicities was strongly affected by the presence of R• and external magnetic fields. A faster spin conversion of [D•+-B-A•--R•] resulted in a slower initial decay of the CS state generated from the excited singlet state of D compared with [D•+-B-A•- ]. Such a spin effect manifested most markedly in dioxane. On the other hand, the back ET rate (kBET) varied by more than two orders of magnitude with the solvent polarity. In dimethyl sulfoxide, the back ET was predicted to be almost barrierless, kBET ≥ 109 s-1, while in benzene, this process fell in the inverted region, kBET = 6.5 × 106 s-1.
  • Ok-Sang Jung, Young-A Lee, Sung Ho Park, Yun Ju Kim, Kyung Ho Yoo, Don ...
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 2 Pages 305-309
    Published: 2001
    Released: July 01, 2002
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    A series of cobalt-benzoquinone complexes containing piperidine derivatives as a coligand, [Co(3,6-dbq)2(N-N)], (N-N = 1,1′-methylenedipiperidine (mdp), 1,1′-methylenebis(3-methylpiperidine) (mbmp), 1-methyl-4-(methylamino)piperidine (mmap); 3,6-dbq = 3,6-di-tert-butyl-1,2-benzoquinone) have been prepared and characterized. The crystal structure of [Co(3,6-dbq)2(mmap)]•0.5Me2CO (P1-, a = 11.524(2) Å, b = 12.565(4) Å, c = 14.160(3) Å, α = 80.65(2)°, β = 82.15(2)°, γ = 87.39(2)°, V = 2003.6(8) Å3, R = 0.0763) proves that the molecule exists as low-spin [CoIII(3,6-dbsq)(3,6-dbcat)(mmap)] (3,6-dbsq = 3,6-di-tert-butyl-1,2-semiquinonato; 3,6-dbcat = 3,6-di-tert-butylcatecholato) in the solid state. According to magnetic, spectroscopic, and thermal analyses, [CoIII(3,6-dbsq)(3,6-dbcat)(mmap)] is locked up to 431 K while [CoII(3,6-dbsq)2(mdp)] and [CoII(3,6-dbsq)2(mbmp)] are changed to their corresponding low spin CoIII forms at (below) T1/2 = 215 K and 271 K, respectively. The transition temperature (T1/2) between CoIII/CoII varies as mbmp < mdp << mmap, which appears to be associated with electronic versus steric effects of the piperidine coligands. In particular, [Co(3,6-dbq)2(mdp)] reveals a two-step spin conversion centered at 208 K and 298 K with a plateau of 90 deg.
  • Shoichi Katsuta, Takako Motoyama, Yasuyuki Takeda, Mikio Ouchi
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 2 Pages 311-315
    Published: 2001
    Released: July 01, 2002
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    The stability constants of 1 : 1 complexes of 15,15-dimethyl-16-crown-5 (DM16C5) with Li+, Na+, K+, Ag+, Tl+, Sr2+, Ba2+, and Pb2+ and of 16-crown-5 (16C5) with Li+ have been determined by conductometry in water at 25 °C. The transfer activity coefficients (sγ H2O) of the alkali metal ion complexes between nonaqueous solvents (s: acetonitrile, propylene carbonate, and methanol) and water have been calculated. These values have been compared with the literature values for 16C5 and 15-(2,5-dioxahexyl)-15-methyl-16-crown-5 (L16C5). In water, 16C5 and DM16C5 selectively complex Li+ over Na+ and K+. The complexing ability of DM16C5 for a given metal ion is generally lower than that of 16C5 and L16C5. The alkali metal ion complexes of all the crown ethers are much less stable in water than in s, and the selectivity and the substituent effects also depend upon the solvent. The sγ H2O values provide the following information: the alkali metal ion and the ether oxygen atoms are greatly dehydrated upon complexation in water; the dehydration is most drastic for Na+; the dehydration for Na+ is hindered by the methyl groups of DM16C5 and facilitated by the electron-donating side arm of L16C5. The solvent effects upon complexation are explained in terms of solute-solvent interactions.
  • Shigeru Ito, Yoshitomo Omomo, Takashi Fujii
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 2 Pages 317-321
    Published: 2001
    Released: July 01, 2002
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    The chemical lithiation⁄delithiation of K+-β-ferrite has been performed using butyllithium, lithium naphthalide (for lithiation), and iodine (for delithiation). In lithiation using butyllithium, the lithium content (y) in K1+xLiyFe11O17 was dependent on the average grain size of K+-β-ferrite single crystals; small grains (5 μm) largely reacted with lithium to form K0.99Li1.65Fe11O17. Lithiation was performed by the reduction of Fe3+ to Fe2+. Since the same X-ray diffraction (XRD) patterns were obtained before and after lithiation, the reaction seemed to be restricted to only near the grain surfaces. In lithiation using lithium naphthalide, the lithium content (y), which attained to be 36, was independent of the average grain size of K+-β-ferrite single crystals. This lithium content was remarkably large, compared to y = ca.1.6 in lithiation using butyllithium. A large amount of Fe0 (metal) was detected in the samples. According to scanning electron microscope (SEM) and XRD studies, not only pulverization of grains, but also destruction of the β-structure, occurred upon lithiation. On the other hand, delithiation of deeply lithiated samples was achieved by using iodine as an oxidant.
  • Takako Kawahashi, Masahiro Mikuriya, Ryoji Nukada, Jong-Wan Lim
    Type: Others
    Subject area: AI
    2001 Volume 74 Issue 2 Pages 323-329
    Published: 2001
    Released: July 01, 2002
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    Palladium(II) complexes with 2-[(2-aminoethyl)amino]ethanethiol (HL1), 2-[(3-aminopropyl)amino]ethanethiol (HL2), 2-[(2-pyridylmethyl)amino]ethanethiol (HL3), and 2-{[2-(2-pyridyl)ethyl]amino}ethanethiol (HL4), [Pd4(L1)4]Cl4 (1), [Pd4(L2)4]Cl4 (2), [Pd4(L3)4](ClO4)3Cl (3), [Pd4(L4)4][Pd(SCN)4]Cl2 (4), and [Pd4(L4)4](ClO4)4 (5), were synthesized and characterized by measurements of the infrared, electronic, and NMR spectra. X-ray crystal structure analyses of 1, 2, 3, and 4 show that these complexes have a thiolato-bridged tetranuclear structure, where each palladium(II) center takes a square-planar N2S2 coordination environment.
  • Masahiro Mikuriya, Kenichi Minowa, Jong-Wan Lim
    Type: Introduction
    Subject area: AI
    2001 Volume 74 Issue 2 Pages 331-332
    Published: 2001
    Released: July 01, 2002
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    A palladium(II) complex with 2-hydroxy-N,N′-bis(1-methyl-3-hydroxy-3-phenol-2-propene-1-ylidene)-1,3-propanediamine (H3L), [Pd(HL)]2, was synthesized and characterized by measurements of the magnetic moment and the electronic spectra. The X-ray crystal structure shows that the compound has a dimeric structure with two planar N2O2 coordination environments, which is formed by hydrogen-bonds between the alkoxy groups and the coordinating keto groups.
  • Joe Otsuki, Toshihiro Yamagata, Koji Ohmuro, Koji Araki, Toshio Takido ...
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 333-337
    Published: 2001
    Released: July 01, 2002
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    Phthalimide-fused mono(crown ether)s (1 and 2) and bis(crown ether)s (3 and 4) were prepared. These imide derivatives strongly fluoresce in methanol, and the fluorescence intensity is affected by alkali metal ions due to crown-ion interactions. While fluorescence increases upon complexation involving a single macrocycle, it decreases when the fluorophores take a face-to-face arrangement. This property was used to monitor the process of ion complexation and concomitant conformation changes. With the incremental addition of cesium ions (M) to the bis(crown ether)s (L), a folded sandwich complex (LM) initially formed, which subsequently transformed into a more extended LM2-type complex. This behavior, which was independently confirmed by 1H NMR spectroscopy, is clearly manifested in the fluorescence intensity.
  • Hiroki Itoh, Ichiro Kato, Kei Unoura, Yasuhisa Senda
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 339-345
    Published: 2001
    Released: July 01, 2002
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    A competitive transannular reaction occurred to give 7-methyltricyclo[3.3.1.03,7]nonan-3-ol (5) and 1-adamantanol (6) in the non-mediated electroreduction of 7-methylenebicyclo[3.3.1]nonan-3-one (1) in N,N-dimethylformamide. The apparent temperature dependence of the regioselectivity of the reaction may be attributed to the competitive operation of both kinetic and thermodynamic controls in the cyclization of the ketyl radical anion. The differences in the parameter of activation between the 5-exo- and 6-endocyclizations of 1•-, ΔΔH(5-exo - 6-endo) and ΔΔS(5-exo - 6-endo), were evaluated to be -3.1 kcal mol-1 and -11 cal mol-1 K-1, respectively. Semiempirical PM3 (RHF and UHF) calculations were also carried out to elucidate the reaction mechanism.
  • Kenji Arakawa, Tadashi Eguchi, Katsumi Kakinuma
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 347-356
    Published: 2001
    Released: July 01, 2002
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    Described in this paper is the biophysical significance of the archaeal 36-membered macrocyclic diether phospholipid 36MPC as a function of temperature, which was studied by measuring of membrane fluidity, liposomal proton permeability, and liposomal thermostability in comparison with its acyclic counterpart, DPhyPC, their glycolipid derivatives, 36MGen and DPhyGen, egg yolk lecithin eggPC, and a mixed lipid of DMPC–cholesterol (2 : 1). Fluorescence anisotropy measurements indicated that the macrocyclic structure led to a decrease in the fluidity in the inter-membrane hydrophobic part more than in the membrane surface by limiting the motional freedom of the alkyl chains. The proton permeability was also significantly reduced by introducing a macrocyclic structure. Liposomal thermostability measurements using 6-carboxyfluorescein (CF) suggested that 36MPC formed liposomes with greater thermal stability than these of DPhyPC. The presence of glycolipids to the corresponding phospholipids greatly reduced the CF leakage from liposomes. Most importantly, DMPC-cholesterol liposome showed less leakage than 36MPC at 40 °C. However, by raising the temperature, this situation was completely reversed. This suggested that the cyclic structure contributed to the formation of stable liposomes, especially at higher temperatures. These findings clearly demonstrate that the 36-membered macrocyclic lipid membrane plays an important role for the thermophilic archaea to adapt to extreme environments.
  • Michinori Oki, Masahiro Nishino, Kazuihiro Kaieda, Takafumi Nakashima, ...
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 357-361
    Published: 2001
    Released: July 01, 2002
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    9-(3-Acetoxy-1-methylpropyl)-8,13-difluoro-1,4-dimethyltriptycene and 9-(1-methyl-2-propenyl)-8,13-difluoro-1,4-dimethyl- and 1,2,3,4-tetrachloro-triptycenes were prepared. Their barriers to internal rotation around the C(9)–C(alkyl) bonds were measured by the classical kinetics. The barrier was affected a little by the substituent, being ca. 25–26 kcal mol-1. Rotamer distributions in these compounds and possible causes for these indifferent barriers to rotation are discussed.
  • Ken’ichi Takeuchi, Takuhiro Ushino, Takao Okazaki, Toshikazu Kit ...
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 363-370
    Published: 2001
    Released: July 01, 2002
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    The rates of solvolysis in various solvents were determined for 1,1,3,3-tetramethyl-2-oxobutyl tosylate (1OTs) and 1,3,3-trimethyl-2-oxocyclopentyl mesylate (4OMs). The rate data for 1OTs reinforced that the linear Grunwald-Winstein (GW) relationship of 1OMs previously reported by Creary for non-aqueous solvents must also hold for aqueous organic solvents. 4OMs showed a markedly dispersed GW relationship that is, on the other hand, well correlated with an extended GW equation involving a nucleophilicity parameter. Such solvent dependence, such marked effects of added sodium azide on rates, and the 100% inversion of configuration of the solvolysis product showed that the solvolysis of 4OMs would be categorized to SN2(intermediate), whereas 1OMs and 1OTs solvolyze via limiting SN1. The negligible susceptibility of 1OTs toward nucleophilicity of solvent and azide probe indicates that the nucleofuge leaves along the C=O axis in such a manner that the back-strain (B-strain) in the ground state is efficiently relieved in the transition state. Comparison of solvolysis rates of 1OMs and 4OMs with those of the corresponding parent substrates suggests that the transition states of these substrates would not be stabilized by carbonyl π conjugation. The origin of the unexpectedly fast rates of solvolysis of 1OMs has been discussed.
  • Ryuki Kakino, Isao Shimizu, Akio Yamamoto
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 371-376
    Published: 2001
    Released: July 01, 2002
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    Cross-coupling reaction of aryl trifluoroacetates with organoboron compounds catalyzed by palladium complexes gives trifluoromethyl ketones in moderate to excellent yields under mild conditions. The catalytic process has been designed on the basis of fundamental studies dealing with oxidative addition of phenyl trifluoroacetate to a Pd(0) complex to give a (phenoxo)(trifluoroacetyl)palladium(II) complex and its subsequent reaction with phenylboronic acid to liberate phenyl trifluoromethyl ketone. The catalytic cycle is proposed to be composed of (a) oxidative addition of the ester to give acyl(aryloxo)palladium intermediate, (b) the subsequent transmetallation with arylboron compounds, and (c) reductive elimination. Palladium(0) complexes, as well as catalysts prepared in situ from palladium acetate and 3 molar amounts of tributylphosphine or phosphite at room temperature, serve as convenient and effective catalysts. The process is applicable to a wide range of phenyl- and naphthylboronic acids to give various aryl trifluoromethyl ketones under mild conditions. Aryl perfluoroalkyl ketone derivatives can be similarly prepared in high yields from various phenyl perfluoroalkanecarboxylates and arylboronic acids.
  • Yuefa Gong, Katsuya Kato, Hiroshi Kimoto
    Type: Others
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 377-383
    Published: 2001
    Released: July 01, 2002
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    Phenol did not react directly with trifluoroacetaldehyde ethyl hemiacetal. In the presence of catalytic amounts of anhydrous potassium carbonate, however, the reaction readily occurred. The p-substituted product 4-(2,2,2-trifluoro-1-hydroxyethyl)phenol predominated. In contrast, the reaction catalyzed by zinc halide predominantly produced the o-substituted product. Corresponding reactions of several phenols were studied under the same catalytic conditions.
  • Yozo Miura, Hiroyuki Oka, Yoshio Teki
    Type: Introduction
    Subject area: OB
    2001 Volume 74 Issue 2 Pages 385-386
    Published: 2001
    Released: July 01, 2002
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    4-t-Butyl-2,6-diphenylphenylnitrene and 2,2′-(1,3-phenylene)bis(4-t-butyl-6-phenylphenylnitrene) were generated by the phyolysis of the corresponding mono- and diazides and studied by ESR spectroscopy.
  • Masamitsu Matsumoto, Yuji Wada, Takayuki Kitamura, Kouichiro Shigaki, ...
    Type: Others
    Subject area: AM
    2001 Volume 74 Issue 2 Pages 387-393
    Published: 2001
    Released: July 01, 2002
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    A solid-state dye-sensitized TiO2 solar cell has been fabricated with a polymer electrolyte constructed with α-methacryloyl-ω-methoxyocta(oxyethylene) or 2-(2-methoxyethoxy)ethyl acrylate as a base polymer, α-acryloyl-ω-acryloyloxyocta(oxyethylene)octa(ethylene glycol) dimethacrylate as a cross-linking agent and 3-methoxypropiononitrile as a plasticizer. The polymer is in-situ polymerized at the porous TiO2 film by photo-irradiation and the resulting film is immersed into the liquid electrolyte in order to introduce the electrolyte to the polymer phase. The conductivity of the polymer electrolyte reached 2.67 mS cm-1. The energy conversion efficiency of the solid-state cell was 2.62% under irradiation of simulated sunlight (AM 1.5, 1 kW m-2), achieving 86.4% of the cell efficiency using the liquid electrolyte.
  • Hiroki Itoh, Masayo Ishikawa, Akiomi Takada, Hideaki Kudo, Yasuhisa Se ...
    Type: Others
    Subject area: AM
    2001 Volume 74 Issue 2 Pages 395-405
    Published: 2001
    Released: July 01, 2002
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    In order to get insight into the effect of the different fixations of the conjugated systems of the aminochalcone-dyes on both the photophysical behavior and the quenching scheme of photoinitiation systems in a film, photophysical behavior of 2-benzoyl-6-(dimethylamino)benzo[b]furan (A) on 355 nm excitation with or without a radical-generating reagent, 2,4,6-tris(trichloromethyl)-1,3,5-triazine (TRI), in poly(methyl methacrylate) (PMMA) film has been investigated by laser flash photolysis using a total reflection cell. Dye A showed characteristic dual fluorescences of which the lifetimes, τSs, of shorter- and longer-wavelength components were evaluated to be 3.2 and 5.4 ns, respectively. The fluorescences were quenched by TRI with different static quenching distances, (Rs)Ss, of 1.3 and 1.5 nm for Ashort and Along, respectively. The static quenching distance of the initial triplet absorption of A, (Rs)T, was evaluated to be 1.5 nm. In addition, deconvolution analysis of the lifetimes of fluorescent dyes has been carried out to clarify the property of nonstatic quenching of the dyes: A, 10-benzoyl-2,3,6,7-tetrahydro-1H,5H-furo[3,2-g]pyrido[3,2,1-i,j]quinoline (B), 4-(dimethylamino)chalcone (C), and (E)-3-(9-julolidinyl)-1-phenyl-2-propen-1-one (D), with TRI in the film.
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