Electron Spin Resonance of Anion Radicals of N-Alkyl Phthalimides and Aromatic Acid AnhydridesHirayama, Masatoshi
doi: 10.1246/bcsj.40.1557pmid: N/A
The ESR spectra of anion radicals of N-methyl, N-ethyl, and N-n-butyl phthalimides, naphthalic acid anhydride, and pyromellitic acid anhydride were measured in acetonitrile. Both the electrolytic and alkali metal reduction methods were used for the radical generation. The spin densities of these anion radicals were then calculated by McLachlan’s method; the calculated results were partly in agreement with the experimental data. Satellite lines due to three kinds of 13C nuclei in the pyromellitic acid anhydride anion radical were observed; one of these splitting constants was assigned to the position 1.
NMR Spectra of Some Metal AcetylacetonatesKawasaki, Yoshikane; Tanaka, Toshio; Okawara, Rokuro
doi: 10.1246/bcsj.40.1562pmid: N/A
The NMR spectra of a series of complexes, XX′Sn(acac)2 (X, X′ =alkyl, aryl and halogen), (CH3)2Pb(acac)2, Cl2Ti(acac)2, Cl2Ge(acac)2, Cl4Sb(acac) and (C6H5)Cl3Sb(acac), have been studied in chloroform. A linear relationship has been found between the chemical shifts of the γ proton and those of the methyl protons of acetylacetone for various type of complexes. In XX′Sn-(acac)2, both τ values decrease with an increase in the electron-attracting power of the substituents, X and X′, and the chemical shifts of these protons are found to be correlated with the Sn–O and C=O stretching frequencies. This behavior can be explained in terms of the inductive effect of the substituents on the tin atom.
Solvent Effect on the Proton Magnetic Resonance Spectra of Dimethyltin Dichloride, Trimethyltin Chloride and Trimethyllead ChlorideMatsubayashi, Gen-etsu; Kawasaki, Yoshikane; Tanaka, Toshio; Okawara, Rokuro
doi: 10.1246/bcsj.40.1566pmid: N/A
The chemical shifts of methyl protons (τ(M–CH3) values) and the coupling constants between the methyl protons and the metal atom JM–CH3 values for dimethyltin dichloride, trimethyltin chloride, and trimethyllead chloride have been measured in thirty-two organic solvents. From the relation between the τ(M–CH3) and the JM–CH3 values, the solvents used here have been classified into four groups. Carbon tetrachloride is representative of the first groups. The second group consists of usual polar organic solvents which can coordinate to the metal atom. The third consists of nitrobenzene, benzonitrile, pyridine, and its derivatives among the solvents studied here. The fourth consists of alkyl- or halogen-substituted aromatic solvents. The configurations of trimethyltin chloride in these solvents have been discussed on the basis of the J119Sn−CH3 values and the intensity of the Sn–C symmetric stretching band relative to that of the asymmetric one. The effects of the temperature and the concentration of the solute on the τ(Sn–CH3) and the J119Sn−CH3 values of trimethyltin chloride have been examined in several solvents.
The Crystal Structure of 2-Anilino-3-bromo-tetrahydro-exo-dicyclopentadieneTanaka, Nobuo; Ashida, Tamaichi; Sasada, Yoshio; Kakudo, Masao; Kasai, Nobutami
doi: 10.1246/bcsj.40.1574pmid: N/A
2-Anilmo-3-bromo-tetrahydro-exo-dicyclopentadiene, C16H20NBr, crystallizes in the monoclinic space group P21⁄c, with four molecules in a unit cell of dimensions a=9.15, b=17.36, c=9.56 Å, β=108.45°. The structure was solved by superimposing the minimum function upon the first Fourier map based on the Br atom only. The atomic parameters were refined by the block-diagonal least-squares method. Most of bond-angles of carbon atoms forming a tricyclic system in the molecule are somewhat smaller than the ordinary tetrahedral angle, particularly on the bridged carbon atom. The Br atom is bonded to the endo side of the ring and the N atom to exo.
An MO Interpretation of the Methylation of Olefins by the Methylsulfinyl CarbanionYamamoto, Osamu; Kato, Hiroshi; Yonezawa, Teijiro
doi: 10.1246/bcsj.40.1580pmid: N/A
Recently the reaction of the methylsulfinyl carbanion with a number of olefins (quinoline, acridine, anthracene, butadiene, etc.) has been reported on by several authors. The superdelocalizability for the nucleophilic attack, Sr(N), is used as a theoretical index for discussing the intermolecular reactivity. It is pointed out that the calculated values of Sr(N) are useful in predicting the relative reactivity as well as the orientation in the nucleophilic aromatic methylation. In addition, the mechanism of the ring-opening reaction taking place with regard to benzofuran is discussed briefly.
Magnetic Properties of Aromatic Hydrocarbon-Alkali Metal Ion-Pair Salts. INishiguchi, Hiroaki
doi: 10.1246/bcsj.40.1587pmid: N/A
Measurements of magnetic susceptibility and electron paramagnetic resonance absorptions have been carried out on biphenyl (Bp)-potassium (K), -rubidium (Rb), and -cesium (Cs) ion-pair salts. These powder salts were prepared by the evaporation of the solvent from the corresponding anion radical solutions in vacuo. The magnetic susceptibility of the Bp-K system is paramagnetic and exhibits a maximum at 130±4°K. This susceptibility can be fitted approximately to the expression:χM=\frac2Ng2β2kT·\frac13+eδ⁄kT,which leads to a singlet-triplet dimer model consisting of a singlet ground state and a triplet state lying slightly above the ground state. The line width of the electron paramagnetic resonance (EPR) spectrum is also temperature-dependent and becomes broader as the temperature decreases. The Bp-Rb and Bp-Cs systems also exhibit susceptibilities which monotonously increase as the temperature decreases. These can be fitted to the higher temperature range (kT⁄δ>1) of the above equation rather than to the Curie-Weiss law. For these compounds single absorption lines have also been observed at g=2.002 in the EPR spectra at room temperature. The results suggest that these salts may be interpreted generally by means of the singlet-triplet dimer model proposed for the organic salts based on the anion radical of tetracyanoquinodimethane (TCNQ). However, one marked difference is that the singlet-triplet separations of these compounds are very small in comparison with those of the TCNQ radical salts.
Krafft Temperatures of Perfluoro-Octanoic Acid and of Its SaltsNakayama, Haruo
doi: 10.1246/bcsj.40.1592pmid: N/A
The Krafft temperatures of perfluoro-octanoic acid and of its alkali metal and ammonium salts have been determined from the solubility measurements. The heats of solution and of wetting of dry solid surfactants have also been measured. The solubility decreases in the order; Li-salt>Na-salt>K-salt, and then increases in the sequence; Rb-salt<Cs-salt. Ammonium salt is more soluble than sodium salt. Acid is least soluble. The heats of wetting depend markedly on the kind of counterions, but the heats of solution of hydrated solids, which are calculated from the temperature-dependence of single-dispersion solubility, are almost independent of the counterions. The order of Krafft temperatures for alkali metal salts is; Li<Na<K>Rb>Cs, just the reverse of that of the solubility. It is concluded that the Krafft temperature of each substance is mainly determined by the magnitude of the non-micellar solubility, and that the increasing order of the solubilities of salts can reasonably be estimated by comparing it with the solubility order of ordinary organic or inorganic salts which have the same chemical properties as the surfactants. This sequence of solubility is markedly determined by the strength of the acids from which the salts are derived.
Studies of the ζ-Potential of Natural and Synthetic Fibers in Dye Solutions. XVII. ζ-Potential and Surface Dyeability of Drawn Nylon 6 Fiber in an Acid Dye SolutionSuzawa, Toshiro; Saito, Tomoyuki; Shinohara, Hideki
doi: 10.1246/bcsj.40.1596pmid: N/A
In order to ascertain the relation between the change in the fine structure and the dyeability of the nylon 6 fiber with its drawing, the ζ-potential, the surface dye adsorption, and the total dye adsorption of the drawn nylon 6 fiber in an acidic solution (pH 3.0) of acid dye—Orange II and Orange I were determined. The crystallinity and the birefringence of the fiber increase as the draw ratio increases. The isoelectric points of the fibers with the draw ratios of 1 (undrawn), 3, and 4 are pH 5.2, pH 5.4, and pH 5.4 respectively. The increase in the dye concentration changed the sign of the ζ-potential of these fibers in a dye solution from positive to negative and increased the absolute values of the ζ-potential. Moreover, it was suggested that these fibers combine with dye by electrostatic bonds. The surface dye adsorption as calculated from the difference between the surface charge density, Δσ, of the system with dye and that without dye increased in any case as the dye concentration increased. These values became smaller in the order of draw ratios: 1 (undrawn), 3, and 4. The total dye adsorption as well as the surface dye adsorption increased with the increase in the dye concentration and decreased with the drawing. Moreover, the surface areas covered by adsorbed dye molecules, which were calculated from the slope of the graph between the surface dye adsorption and the total dye adsorption, were 4.4, 2.9, and 1.8×106cm2/g fiber in the order of draw ratios: 1 (undrawn), 3, and 4. Also, the effect of the molecular structure of the dye on the ζ-potential, the surface dye adsorption, and the total dye adsorption was discussed.