Bulletin of the Chemical Society of Japan

Nakada, M; Watanabe, Y; Endo, K; Nakahara, H; Sano, H; Mishima, K; Kubo, M K; Sakai, Y; Tominaga, T; Asai, K; Iwamoto, M; Kobayashi, Y; Okada, T; Sakai, N; Kohno, I; Ambe, F

doi: 10.1246/bcsj.65.1pmid: N/A

The chemical states of 57Fe arising from 57Mn produced by the 54Cr (α, p) 57Mn reaction in the metal and oxides of chromium were studied by 57Fe Mössbauer emission spectroscopy. In chromium metal, all of the 57Fe atoms were found at substitutional sites. Both the iron(II) and iron(III) species were observed in Cr2O3, while only iron(III) ions were detected in CrO3.

Oniki, Takayuki; Takahama, Umeo

doi: 10.1246/bcsj.65.6pmid: N/A

Melanins were synthesized from pyrogallol or β-(3,4-dihydroxyphenyl)alanine (dopa) and their electron spin resonance (ESR) spectra were measured. The pyrogallol melanin had four kinds of ESR signal; main and broad signals under anaerobic conditions, and inner and outer signals under aerobic conditions. The main, inner and outer signals disappeared by the reduction of the melanin by NaBH4 or ascorbic acid but the broad signal did not. By the oxidation of the melanin by hexacyanoferrate(III), the intensity of the signals decreased, and the inner and outer signals were not observed under aerobic conditions. Hydrogen peroxide decreased these signals especially under aerobic conditions at high pH. Superoxide gave the signals similar to that under aerobic conditions, but decreased the signals of the hexacyanoferrate(III)-oxidized melanin. ESR signals of dopa melanin showed similar behavior to that of pyrogallol melanin against redox reagents. The chemical structure around radicals in melanins were proposed from these results.

Gutman, Ivan; Hosoya, Haruo; Urakovic, Gordana; Ristic, Lidija

doi: 10.1246/bcsj.65.14pmid: N/A

The two topological indices σ (recently proposed by Merrifield and Simmons) and Z (put forward by one of the present authors, Bull. Chem. Soc. Jpn., 44, 2332 (1971)) are shown to be both conceptually and numerically related. For alkanes, a linear correlation exists between ln σ and ln Z. For unbranched catacondensed benzenoid hydrocarbons σ and Z are linearly correlated. In any case σ and Z exhibit a reverse dependency on molecular structures: structural transformations having an increasing effect on Z decrease σ and vice versa.

Nakamura, Toshio; Ueda, Takahiro; Fujimori, Kunihide

doi: 10.1246/bcsj.65.19pmid: N/A

A conductometric study was carried out concerning the selective ion transport of alkali and alkaline earth metal ions, mainly in acetonitrile (AN), across a membrane of polyacrylamide (PAA) coupled to such ionophores as tetraethylene glycol monododecyl ether, hexaethylene glycol monododecyl ether, dibenzo-18-crown-6, and cryptand222B. A sintered glass filter membrane was impregnated with PAA-ionophores and the conductivity of the solution of one side of the membrane was measured in order to monitor the ion transport across the membrane from the opposite side. Alkali and alkaline earth metal ions could pass across the ionophore-free PAA membrane, but the ions were entrapped in the PAA-ionophore membranes. Tetraethylammonium and perchlorate ions, however, could pass across both the PAA and the PAA-ionophore membranes. The entrapped ions could pass across the PAA-ionophore membranes if a complexing reagent was added to the solution on one side of the membrane by forming complexes with the reagent. The limiting equivalent conductivities and the ion association constants of (Li-12C4)+ClO4−, (Li-Cryp22)+ClO4−, (K-DB18C6)+ClO4−, (K-Cryp222)+ClO4−, (Mg-12C4)2+2ClO4−, (Ba-DB18C6)2+2ClO4−, (Ba-Cryp22)2+2ClO4−, and (Ba-Cryp222)2+2ClO4− were determined. The limiting equivalent conductivities were used to compare the relative conductivity values among different species obtained the conductometric measurements of ion transport across the membrane.

Kijima, Masashi; Akimoto, Kei; Sakawaki, Akira; Sato, Takeo

doi: 10.1246/bcsj.65.23pmid: N/A

The redox behaviors of high-spin (10,20-diaryletioporphyrinato II) iron(III) complexes were investigated by cyclic voltammetry in both anodic and cathodic regions in dichloromethane. Whether the redox waves are due to a porphyrin-ring-centered reaction or a metal-centered reaction was examined in terms of the spectroelectrochemical results and Hammett reaction constants.

Minagawa, Yukinori; Yajima, Fumikazu

doi: 10.1246/bcsj.65.29pmid: N/A

An advanced new method for the separation of yttrium ions from other rare earth ions using nonequilibrium extraction in the DTPA–B2EHPA system has been demonstrated. The extraction stages for obtaining yttrium oxide of 99.9% purity from yttrium oxide of 60% purity as a starting material were estimated to be about fifteen, which was the smallest value ever obtained, compared with the usual method (50–100 stages). The mechanism of the extraction reaction is discussed.

Kato, Kazumi

doi: 10.1246/bcsj.65.34pmid: N/A

In order to consider the factors affecting the photocatalytic properties of TiO2, TiO2 powders with controlled characteristics such as the crystalline phase, the crystallite size, and the specific surface area were prepared by hydrolyzing Ti(Oi-C3H7)4. The photocatalytic property of the photo-oxidation of ethanol on the powder depended on the crystallite size and the microstructure. Ethanol was oxidized completely in the suspensions of the powders after illumination for 2 h while being bubbling with oxygen. The crystallite sizes of the powders were in the range of 20–30 nm. The microstructure of the powders consisted of the aggregation of fine and individual particles.

Matsushima, Ryoka; Suzuki, Masakazu

doi: 10.1246/bcsj.65.39pmid: N/A

A series of substituted 2-hydroxychalcones (HC) were prepared, most of which underwent efficient and clean photochemical conversion into flavylium cations (FV) in acidic solution and polymer film, although strongly dependent on the pH and medium conditions as well as the HC structures. 4′-Methoxy and 4′-dimethylamino derivatives showed relatively high thermal stabilities of the colored mixtures, well-separated absorption bands of the HC and FV forms, almost quantitative conversion from HC to FV in the photostationary-state mixtures, and good photochromic performances in solution and polymer film, without suffering from the dissolved oxygen or moisture. A few of them showed relatively high reversibilities in the HC–FV interconversions under special pH and medium conditions.

Fujio, Mizue; Goto, Mutsuo; Funatsu, Kimito; Yoshino, Takanori; Saeki, Yoshihiro; Yatsugi, Ken-ichi; Tsuno, Yuho

doi: 10.1246/bcsj.65.46pmid: N/A

Solvolysis rates of 2-phenyl-2-methylpropyl and 2-(p-methoxyphenyl)-2-methylpropyl p-toluenesulfonates were determined in a wide variety of solvents and the solvent effects were analyzed based on the Winstein–Grunwald equation. The solvent effect on neophyl solvolyses failed to give a single linear correlation with the 2-adamantyl YOTs parameter. There was dispersion behavior for the respective binary solvent series between neophyl kΔ substrates and 2-adamantyl tosylate. The pattern of dispersion could not be interpreted in terms of nucleophilic solvent assistance. The response to the solvent polarity (m value for each binary solvent series) was significantly lower for both the methoxy and the unsubstituted derivatives than the m = 1.0 for the limiting kc solvolysis, and appreciably lower for the methoxy derivative than for the unsubstituted one. Linearity of the solvent effects between both neophyl systems and also between other kΔ substrates implied the existence of a unique kinetic solvent polarity scale YΔ characteristic of the β-aryl-assisted (kΔ) solvolysis. The dispersion behavior and reduced m value for the kΔ solvolysis were compatible with the entire π-delocalization of cationic charge between the assisting aryl-ring and the reaction center in the transition state.

Tamagaki, Seizo; Ueno, Masanori; Tagaki, Waichiro

doi: 10.1246/bcsj.65.55pmid: N/A

The reaction of 10-methylacridinium perchlorate with a variety of N,N-disubstituted alkylamines or aralkylamines was investigated in the presence or absence of air. In all cases studied, 10-methyl-9,10-dihydroacridine was produced in approximately 50% yield or more. In addition, either 10-methyl-9(10H)-acridinone or 9-(dialkylamino)-10-methylacridinium perchlorate or both were isolated, each yield being greatly dependent on the bulkiness of alkyl groups on the amines. In the blanket of air, significant amounts of aldehyde was detected. The mechanism was discussed.