Bulletin of the Chemical Society of Japan

Kobayashi, Michio; Tokunaga, Hitoshi; Okubo, Jun; Hoshi, Toshihiko; Tanizaki, Yoshie

doi: 10.1246/bcsj.61.4171pmid: N/A

Polarized ATR spectra have been measured for the dye layers adsorbed on stacked, thin glass plates. For the adsorbed Crystal Violet (CV) layer, the metachromasy band in the || polarized ATR spectrum is blue-shifted and intensified in comparison with that in the ⊥ polarized ATR spectrum. This is in marked contrast to the observation for the adsorbed Methylene Blue (MB) layer that the || polarized ATR spectrum is similar in shape and position to the ⊥ polarized ATR spectrum. The blue shift and the enhancement of the metachromasy band in the || polarized ATR spectrum for the adsorbed CV layer is ascribed to an optical property characteristic of the adsorbed CV layer; the adsorbed CV layer exhibits an extra electronic transition band located at the high-energy side of the metachromasy band and polarized normal to the glass plane. Two possible explanations for the occurrence of this extra band are presented.

Kaneko, Tetsuo

doi: 10.1246/bcsj.61.4177pmid: N/A

A layer formed by the aggregation of polyelectrolyte molecules is charged according to the ionic dissociation of the layer in a simple salt solution. The charge carried by the layer is estimated on a basis of solutions of the Poisson-Boltzmann equation. It has been found that this charge is independent of the concentration, ns, of a salt, in spite of the permanence of the layer to counter ions when the density, ng, of charged groups in the polyelectrolyte molecules is much higher than the concentration ns. As the result, the charge may be given as a function of three parameters (temperature, density ng, and thickness of the layer) except for ns. Moreover, it has been found that the distribution of counter ions within the layer and their distribution in the vicinity of the layer may be independent of ns and that these distributions of counter ions may agree with that in a salt-free solution.

Ogumi, Zempachi; Mizoe, Toshiyuki; Takehara, Zen-ichiro

doi: 10.1246/bcsj.61.4183pmid: N/A

Fe3+ has been incorporated into Pt–Nafion. The behavior of Fe3+ as a mediator was examined in detail in a system comprising the oxidation of l-ascorbic acid (AA) to dehydroascorbic acid (AD). The diffusion of AA in Nafion is slower than that of Fe3+. The concentration profiles of Fe3+ and AA in Pt–Nafion have been clarified and a reaction of the mediator with AA took place within a very narrow zone close to the surface. The averaged diffusion coefficients of Fe3+ and AA are 1.5×10−7 cm2 s−1 and 4.7×10−8 cm2 s−1, respectively.

Fujita, Shinsaku

doi: 10.1246/bcsj.61.4189pmid: N/A

A novel method of enumerating reaction types is presented. The reaction types are formulated as reaction center graphs (RCGs) that are derived from a parent basic reaction graph (BRG) or from a parent reaction graph (RG) by the substitution of various atoms on the vertices and/or by the attachment of single, double, or triple par-bonds to the edges. The counting of the isomeric RCGs is solved by applying Pólya’s theorem to the derivation of a cycle index, in which different variables are introduced to the different orbits of the permutation group of a parent BRG (or RG). Various atom-figure and bond-figure inventories are described in order to count the isomers of RCGs. The numbers of the RCGs are given in the form of the coefficients of a generating function called an RCG-counting polynomial series.

Hoshino, Naomi; Inabe, Tamotsu; Mitani, Tadaoki; Maruyama, Yusei

doi: 10.1246/bcsj.61.4207pmid: N/A

A thermochromic derivative of salicylideneaniline, N,N′-bis(salicylidene)-p-phenylenediamine (BSP), has been prepared and subjected to structural and optical studies in the crystalline state. An X-ray crystallographic analysis has shown that the molecules are planar and are stacked in a parallel fashion to form one-dimensional columns. The interplanar spacing has been found to be quite short, suggesting the existence of an intermolecular charge-transfer interaction. The molecule contains fairly short O–H··· N hydrogen bonds, the strength of which is manifested in an OH stretching absorption band in the infrared region, showing considerable broadening and a low-frequency shift. The BSP crystals are remarkably thermochromic, and visible absorption and emission spectral changes with temperature have been interpreted in terms of an intramolecular proton transfer from the hydroxyl oxygen to imine nitrogen through the O–H··· N hydrogen bond. The emission spectra have also been examined under high pressures.

Inabe, Tamotsu; Mitsuhashi, Tsutomu; Maruyama, Yusei

doi: 10.1246/bcsj.61.4215pmid: N/A

Charge transfer complexes of OCNAQ with pyrene, PT (phenothiazine), TMTTF (tetramethyltetrathiafulvalene), TTF (5,6 : 11,12-bis(epidithio)naphthacene), and TTF (tetrathiafulvalene) have been prepared. The pyrene and PT complexes are electrically insulating and the ground state is neutral. In most of the other complexes OCNAQ is fully charged. One of the TTT complexes, (TTT)2OCNAQ(DMF), where DMF is N,N-dimethylformamide, has been found to show metallic conductivity. A structural study has revealed that short S···N contacts exist between TTT and OCNAQ, in addition to one-dimensional TTT stacks. This transverse interaction has been demonstrated by the small anisotropy of the conductivity. The 2 : 1 TTF complex is also metallic down to 43 K, at which point a metal-to-insulator transition occurs. A structure analysis and thermoelectric power data suggest that the charge conduction in this crystal takes place not only through the TTF stacks but also through a two-dimensional network of the OCNAQ molecules.

Kitagawa, Masaki; Hoshi, Hajime; Sakurai, Minoru; Inoue, Yoshio; Chûjô, Riichirô

doi: 10.1246/bcsj.61.4225pmid: N/A

The dipole moments of α-cyclodextrin(α-CD)-aromatic guest systems have been calculated by means of the CNDO/2 molecular orbital (MO) method in order to investigate the role of electrostatic interaction in the stabilization of the inclusion complexes. It is found that α-CD has a remarkably large dipole moment which amounts to 13.5 D and is directed from its secondary hydroxyl side (the wider rim) towards the primary hydroxyl side (the narrower rim). The dipole moments of the guests, benzene derivatives, run antiparallel to that of α-CD in the complexed state. The MO total energy of the α-CD-guest supermolecular complexes shows that these antiparallel-orientations are energitically more favorable than the reversed one. It is concluded that the electrostatic interaction, mainly dipole–dipole interaction, between the α-CD and the guest molecules plays an essential role in determining the guest orientation. On the basis of these results, it is deduced that during complexation the CD molecule undergoes appreciable amount of conformational change, suggesting that the “induced-fit” mechanism is operating when the guest molecule is admitted into the host cavity.

Miyasaka, Taira; Yoshida, Takaichi

doi: 10.1246/bcsj.61.4231pmid: N/A

Several model compounds of poly(thiotrimethylene), including one to four thiotrimethylene units, were studied by means of a molecular mechanics method. The geometric and statistical weight parameters were directly derived from the results of molecular mechanics calculations concerning several conformers of these model compounds. Although the first-order interactions of poly(thiotrimethylene) were significantly larger than those of poly(oxyalkylenes), the second-order interactions of this polymer were much smaller. The “gauche effect” by sulfur atoms seemed to be mainly caused by small second-order interactions. By means of the model, compounds including more than three repeating units, the calculated configuration-dependent properties were in better agreement with the experimental ones than that calculated earlier. The better agreement was obtained by varying some of the geometric parameters. Compounds including more than three repeating units of the polymer were available as model compounds. Since this was also true in poly(oxyalkylenes), it was found that a combination of the methods of molecular and statistical mechanics was sufficiently effective to investigate the configurational properties of poly(thiotrimethylene).

Kimura, Minoru; Kawabe, Hiroyuki; Nakajima, Akihiko; Nishikawa, Kiyoshi; Aono, Shigeyuki

doi: 10.1246/bcsj.61.4239pmid: N/A

The effective electron–electron interaction in the high polymers of polyacene carbon skeleton is investigated. The appearance of various phases in this system depends on associated parameters characterizing the electron–electron interactions near the Fermi level. The main purpose of this work is to estimate these parameters under the random phase approximation and to presume whether this polymer may or may not be superconductor at room temperature.

Kimura, Minoru; Kawabe, Hiroyuki; Nishikawa, Kiyoshi; Aono, Shigeyuki

doi: 10.1246/bcsj.61.4245pmid: N/A

The electron–electron interaction which is crucial in determining whether new phases will arise or not in polyacene is investigated by means of the renormalization group. This approach is valuable to effectively include, from the view-point of the group theory, the higher order diagrams not taken into account in the random phase approximation of the previous work. It is found that there is a range of coupling constants where the singlet superconducting phase without simultaneous CDW ordering can be expected.