Bulletin of the Chemical Society of Japan

Yoshida, Tadashi; Ohsaka, Tetsuya; Nomoto, Shigemitsu

doi: 10.1246/bcsj.45.1585pmid: N/A

Subsequently to the previous work with a dropping mercury electrode (DME), the diffusion coefficient (D) and the maximum surface concentration (Γm) for polyvinylpyrrolidone (PVP) were determined in a In sulfuric acid solution by means of a hanging mercury drop electrode (HMDE). The values of D and Γm for PVP were obtained separately by means of the equation for a semi-infinite spherical diffusion for HMDE. The results for D were compared with the values evaluated from the Stokes-Einstein equation or with those previously published. The results for Γm are also shown in comparison with those values to be expected from the data obtained by the use of DME or HMDE on the assumption of linear diffusion and D, or in comparison with the results published by Jehring. It was also confirmed that the HMDE used by the authors is almost satisfactory for the determination of D and Γm in this case.

Kamiya, Mamoru

doi: 10.1246/bcsj.45.1589pmid: N/A

Systematic studies were made on thianthrene, phenoxathiin, diphenylene dioxide, phenothiazine, and phenoxazine for the correlation between the folded structure and electronic spectra in terms of the semiempirical SCF–MO–CI method. The calculated results are in good agreement with the experimental results, the folded structure being prominent in the sulfur-containing molecules. The dihedral angle dependency of the all valenceelectronic energy and ionization potential was also studied by the extended Hückel method.

Kanesaka, Isao; Hase, Yoshiyuki; Kawai, Kiyoyasu

doi: 10.1246/bcsj.45.1595pmid: N/A

The infrared spectra of addition compounds of hydrogen and deuterium cyanides with boron tribromide have been measured in the frequency region from 4000 to 200 cm−1, and the normal frequencies have been proposed on the basis of the C3υ symmetry for four isotopic compounds, HCN·10BBr3, HCN·11BBr3, DCN·10BBr3, and DCN·11BBr3. The force constants have been calculated on the assumption of a modified Urey-Bradley force field, and the shift of the vibrational frequencies by the coordination has been discussed.

Johnson, Oliver

doi: 10.1246/bcsj.45.1599pmid: N/A

Application of the Hellmann-Feynman Theorem to Metals has led to an interstitial-electron model in which there is some localization of itinerant electron density in octahedral or tetrahedral interstices of close-packed metal ion cores. A flat maximum of electron density at centers of interstices is proposed as well as preferential occupancy of either octahedral or tetrahedral interstices. Such occupancy is rather precisely determined by the requirements of minimum electron-electron repulsion and of opposite spins for electrons in adjacent interstices. Writing the interstitial-electron structure of a metal in terms of interstice occupancy thus includes electron correlation effects. The interstitial-electron structures are instantaneous pictures of electron density which are representative of the highly dynamic situation of electrons in metals. The model leads to localization of d-electrons on the metal-ion core when interstices are fully occupied by itinerant electrons, i.e. at M6+. The presence of vacant interstices is required for metallic properties. On the basis of the model, chemical binding in metals differs from that in polyhedral molecules or metal cluster compounds only in the greater delocalization of electron density in metals. The concepts of the interstitial-electron model are closer to those of the method of pseudopotentials than to the Bloch Band Theory although all of these descriptions of metals can be considered equivalent.

Johnson, Oliver

doi: 10.1246/bcsj.45.1607pmid: N/A

The interstitial-electron model leads to metal structures which are instantaneous pictures of electron distribution written in terms of metal ion core charge Mn+ (n=valency) and numbers of electrons in octahedral or tetrahedral interstices. On the average there are \bare in all interstices, and the degree of electron localization is small in metals. Decisions as to electron occupancy of interstices are primarily based on considerations of \bare spin and of screening of \bare by ion cores, but electronic heat capacity, Hall coefficient and anisotropy in magnetic susceptibility are of use in making decisions on electron occupancy of interstices. For univalent metals there is little localization of \bare because of the large excess of vacant interstices. This is also true when interstices approach full occupancy by (\bare)2 as in M4+ and M5+. Among divalent and trivalent metals the preferential occupancy of interstices leads to considerable localization of \bare density for Be, Sc, Y, and Tl. This high degree of localization is a consequence of mutual polarization of ion cores and \bare; it accounts for the lattice distortion in these metals and leads to other unusual properties.

Gondo, Yasuhiko; Kanda, Yoshiya

doi: 10.1246/bcsj.45.1612pmid: N/A

The coefficients in the Pariser-Parr-type quadratic formulas for the two-center Coulomb repulsion integrals encountered in the planar as well as the non-planar conjugated systems have been expressed as linear functions of the effective nuclear charges of the 2p atomic orbitals involved. The formulas thus obtained are applicable to those conjugated systems consisting of carbon, nitrogen, and oxygen atoms, and may well be useful in variable electronegativity self-consistent field calculations on these systems. With some illustrative applications to spin densities and phosphorescent-state energies, it has been shown that the Pariser-Parr approximation gives better results than the Nishimoto-Mataga one, although the latter is successful in the prediction of electronic transitions within the singlet manifold. Incidentally, this was also the case for the phosphorescent-state zero-field splittings (Y. Gondo and Y. Kanda, This Bulletin, 43, 3943 (1970)). The electric dipole moments have also been discussed.

Inoue, Shigeru; Kanai, Kazumichi; Otsuka, Eiji

doi: 10.1246/bcsj.45.1616pmid: N/A

In the preceding paper (This Bulletin, 45, 1339 (1972)) it was reported that the existence of the maximum equilibrium conversion was not due to the experimental method. For this phenomenon, we have presented the following interpretation. While NH4CO2NH2 is converted to urea and water, it dissociates into NH3 and CO2 in the solution (not in the gas phase), and the degree of the dissociation increases exponentially as the temperature becomes higher, while the conversion to urea gradually increases. Therefore, at a certain temperature, the equilibrium conversion reaches its maximum value. Although it is nearly impossible to prove analytically the dissociation of NH4CO2NH2 in the solution, we are sure of it from the following facts: 1) The dissociation of NH4-CO2NH2 is a great endothermic reaction, even under the conditions of urea synthesis. 2) The value of NH3/CO2which gives the minimum equilibrium pressure at a usual temperature is not always equal to 2.0, but varies with the temperature. 3) The effect of H2O/CO2 on the equilibrium pressure varies with the temperature; that is, when the temperature is lower than about 200°C, an increase in H2O/CO2 reduces the equilibrium pressure, but when the temperature is higher than 200°C, an increase in H2O/CO2 makes the equilibrium pressure higher.

Sekine, Tatsuya; Tetsuka, Toshihiro

doi: 10.1246/bcsj.45.1620pmid: N/A

Iron(III) in aqueous solutions, in which [H+]=1.0m, [Na+]=3.0m, and [L−]+[ClO4−]=4.0m, where L− is a chloride or bromide ion, was extracted with thenoyltrifluoroacetone (TTA) in carbon tetrachloride or with trioctylphosphine oxide (TOPO) in hexane. From the TTA extraction, it was concluded that iron(III) formed the first and the second complexes with both chloride (β1=100.88 and β2=100.80) andbromide (β1=10−0.10 and β2=100.00) ions in the aqueous phase. The distribution data of iron(III) with TOPO were then explained in terms of the extraction of the ion-pairs, Fe(ClO4)3, FeL(ClO4)2, and FeL2(ClO4), by using these stability constants. When the aqueous phase contained only chloride or bromide ions, and no perchlorate ion, the increase in the extraction with the increase in the halide ion concentration was much larger than that observed when the aqueous phase contained both halide and perchlorate ions. From the determination of the extraction of hydrogen ions and halide ions with TOPO, the extracted species in the absence of a perchlorate ion were identified as FeL3 and/or HFeL4. It was concluded that the difference in the extraction of iron(III) when a perchlorate ion was present and when it was absent is mainly caused by (i) the extraction of perchloric acid, which combines with TOPO in the organic phase and interferes with the extraction of the iron(III) halide complexes, and (ii) the extraction of iron(III) species containing one or more perchlorate ions which are large enough to be extractable with TOPO in the organic phase.

Moriya, Hiromitsu; Sekine, Tatsuya

doi: 10.1246/bcsj.45.1626pmid: N/A

The solvent extraction of zinc(II) in 1m sodium perchlorate ionic media containing chloride, bromide, or iodide ions at 25°C was determined as a function of the halide-ion (X−) concentration by using the zinc-65 tracer. From the extraction data with isopropyltropolone (IPT) in chloroform, the formation of the ZnX+ complex was observed, but the stability constants of these complexes were not large (ZnCl+: β1 is 100.00, ZnBr+: β1 is less than 10−0.5and the formation of ZnI+ is negligible), and the higher complexes were negligible in all cases. The extraction of zinc(II) from these media with methylisobutylketone (MIBK) was not effective, although the extracted species could be identified as ZnX2. The extraction with trioctylphosphine oxide (TOPO) in hexane, on the other hand, was much better than that with MIBK. From the distribution ratio determined as a function of the halide and TOPO concentrations, the extracted species were concluded to be Zn(ClO4)2(TOPO)4, ZnX(ClO4)(TOPO)3, and ZnX2-(TOPO)2. The extraction constants for these species were determined by a graphic analysis of the data, and it was concluded that the extractabilities are larger in the order: iodide>bromide>chloride. From these data, it is clear that, if a suitable and effective neutral extractant is employed, the extractions of the above complexes are possible, even from aqueous solutions in which practically no complex is formed.

Shibata, Shuzo

doi: 10.1246/bcsj.45.1631pmid: N/A

A new least-squares method has been devised for interpreting electron-diffraction data by comparison of an experimental background with a calculated background. The former is derived from an experimental total intensity by assuming a molecular model. The latter is approximated by a polynomial function. A computer program is written to refine structural parameters of a molecule so as to yield a smooth background. The characteristic of the present method is that it does not need any bias depending upon human judgement throughout an analysis. The distinctive features of the procedure are discussed, and the application of this method to structure determination of several molecules is also described.