Bulletin of the Chemical Society of Japan

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ISSN / EISSN : 0009-2673 / 1348-0634
Published by: The Chemical Society of Japan (10.1246)
Total articles ≅ 37,500
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Teruyuki Nakato, Thipwipa Sirinakorn, Wataru Ishitobi, Emiko Mouri, Makoto Ogawa
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210314

Binary colloids of morphologically different two particle species cause phase separation containing liquid crystalline phases. Although electric alignment of colloidal nanosheets has been investigated for the colloidal systems consisting of single nanosheet species, that of binary nanosheet colloids has scarcely been examined. We report herein the electric alignment of aqueous binary colloids composed of niobate (NB) nanosheets from K4Nb6O17 and commercially available graphene oxide (GO) platelets. The NB–GO binary colloids show multiphase coexistence involving liquid crystalline phases induced by the NB nanosheets, whereas the employed GO particles do not contribute to the liquid crystallinity. The NB nanosheets in the binary colloids are electrically aligned in parallel to an AC voltage (1 kV cm−1 peak to peak, 50 kHz) applied to the sample. When the concentration of GO in the binary colloids is low enough, the GO particles are also electrically aligned although they hardly respond to electric field in the absence of NB nanosheets. Combined optical microscopy of bright-field, polarized, and fluorescence observations demonstrates that isolated GO particles are dragged by the aligning motion of the NB nanosheets forming liquid crystalline domains. The results indicate that collective motions of colloidal nanosheets can make participation of isolated particles.
Hideto Matsuoka, Yuki Shibano, Ikuko Akimoto, Yuki Kanzaki
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210307

Naphthalene diimides (NDIs) are a promising material for n-type polymer acceptors in thin-film devices such as organic light-emitting diodes. The intersystem crossing (ISC) pathway of NDIs has been extensively studied, relying heavily on the accuracy of quantum chemical calculations. However, the theoretical results are inconsistent with the experimental findings. In this work, time-resolved electron paramagnetic resonance (tr-EPR) was applied to NDIs for the first time in order to elucidate the ISC pathway and assign their electronic structures. With the help of quantum chemical calculations, tr-EPR clearly demonstrated that ISC occurs via an upper excited triplet state (T4) after photoexcitation. The zero-field splitting (ZFS) constants of the NDIs, which strongly correlate with their spin density distributions, were experimentally determined by tr-EPR. We demonstrate that an ab initio complete active space self-consistent field is required to interpret the ZFS constants of the NDIs. From the theoretical analyses of the constants and phosphorescence measurements, the spin state observed in the tr-EPR spectra was identified as the lowest excited triplet state, illustrating that quick internal conversion occurs after the ISC process.
Tokuhisa Kawawaki, Nobuyuki Shimizu, Yusuke Mitomi, Daichi Yazaki, Sakiat Hossain, Yuichi Negishi
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210311

We have been aiming to reduce the amount of platinum (Pt) needed in catalysts for automobile exhaust-gas purification and fuel cell electrodes. To achieve this, we have attempted to: 1) establish simple methods for synthesizing ligand-protected ~1-nm-sized Pt clusters with a narrow distribution in the number of constituent atoms; 2) load these clusters onto supports, while retaining their number of constituent atoms, to prepare supported ~1-nm-sized Pt clusters; and 3) elucidate the catalytic activity of each type of supported ~1-nm-sized Pt cluster. These studies have revealed that: 1) ligand-protected ~1-nm-sized Pt clusters stable in the atmosphere can be isolated with high purity by a combination of polyol reduction and ligand-exchange reaction; 2) ~1-nm-sized Pt clusters can be loaded onto the support without aggregation when the clusters are adsorbed on the support and then calcined at an appropriate temperature; and 3) Pt17 clusters loaded onto γ-alumina exhibit high activity and durability for exhaust-gas purification, whereas Ptn clusters (n = ~35, ~51, or ~66) loaded onto carbon black exhibit high activity and durability for the oxygen reduction reaction (which occurs at fuel cell electrodes). This account describes our previous studies and explores future prospects for supported ~1-nm-sized Pt clusters.
Masahito Murai, Ryuji Taniguchi, Kazuhiko Takai
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210305

Regiodivergent carbene/alkyne metathesis for the selective synthesis of 2-alkylidenebicyclo[4.1.0]heptanes and 1-alkenylbicyclo[3.1.0]hexanes from common 1,6-enynes precursors was demonstrated. The cyclization mode could be switched by simple addition of diamine ligands to control the relative orientation of the approaching chromium Schrock carbene equivalents generated in situ from gem-dichromiomethanes toward triple bonds.
Yasuo Kameda, Kana Tsutsui, Yuko Amo, Takeshi Usuki, Kazutaka Ikeda, Toshiya Otomo
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210315

Scattering angle dependence has been experimentally examined for inelasticity effect on the intramolecular interference term observed from the time-of-flight neutron diffraction method. Internuclear distance and its root-mean-square displacement for liquid pure D2O, C6D6 and CCl4, have been determined from the least squares fitting analysis of the observed total interference term in the high-Q region. Although “apparent shrinkage” in the intramolecular distance has obviously been observed for the light nuclei pair at large scattering angle data (2θ > ca. 70°), it has been revealed that the apparent shrinkage in the D…D distance for D2O and C6D6, in which the inelasticity effect is expected to be most significant, is found to be suppressed well within ca. 1% for the data observed for the scattering angle below ca. 2θ < ca. 50°. Structural parameters determined have been compared with those determined from the gas-phase electron diffraction method in order to obtain insight of the effect of intermolecular interaction to molecular geometry in the liquid phase.
Kuan-Hua Lin, Yu-Chi Lin, Chiung-Yao Huang, Yen-Ju Tseng, Shu-Rong Chen, Yuan-Bin Cheng, Tsong-Long Hwang, Sheng-Yang Wang, Hsing-Yin Chen, Chang-Feng Dai, et al.
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210261

Further chemical investigation of the ethyl acetate extract of the soft coral Sarcophyton tortuosum has led to the isolation of ten terpenoidal metabolites, including six new compounds, secoditerpenes secotortuosenes A and B (1 and 2), diterpenes tortuosenes C and D (3 and 4) and tortuosumol (5), and a biscembranoid bisotrtuolide cyclobutane A (6), along with four known compounds, ketoemblide (7), sartrolide G (8), emblide (9), and sarcrassin E (10). Compounds 5 and 6 are metabolites of the intra- and intermolecular [2+2] cyclizations, respectively. Notably, 1 and 2 are 12-membered carbocyclic compounds possessing a 2-methyl-3-oxopentanyl side chain and represented an unprecedented molecular skeleton, while compound 6 possessing a unique cyclobutanyl biscembranoid skeleton, and the absolute configuration of 1 and 5 was determined by TDDFT ECD calculations. Tortuosene A was found to display significant inhibitory effects on the generation of the superoxide anion inNformyl-methThe bioassays showed that compound 5 exhibited selective cytotoxicity against the growth of Molt-4 cell line, while 6 exhibited inhibitory activity against P388, K562, and HT-29 cancer cell lines. Compounds 3, 5-7 showed effects for inhibition toward the generation of superoxide anion, while 3, 6, and 7 displayed inhibition activity against elastase release in fMLF/CB-induced neutrophils. In addition, compounds 6, 7, and 10 exhibited anti-inflammatory activity by inhibiting nitric oxide generation in the LPS-induced RAW 264.7 cell assay.
Kejia Zhao, Yuelin Huang, Mohamed E. El-Khouly, Jiaxuan Liu, Bin Zhang, Yingping Zou, Yu Chen
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210318

By using poly {[9,9-dioctyl-9H-fluorene] -alt- (1,1,2,2- tetra- phenylethene)} (POFTPE) as an electron donor, and Y6 (or C60) as electron acceptor, solution-processed bulk heterojunction optoelectronic switching devices with a configuration of ITO/POFTPE:Y6(C60)/ITO, which can respond to both the optical and electrical stimuli, have been successfully fabricated. Both the electron transfer and energy transfer from POFTPE to Y6 will occur simultaneously in the blends system under light illumination, while no energy transfer between POFTPE and C60 occurs, expect for electron transfer. Both the ITO/POFTPE:Y6/ITO and ITO/POFTPE: C60/ITO show typical nonvolatile rewritable memory effect in the dark or under light illumination. Upon illumination with different wavelength lights, the switching bias window (Δ|VON-VOFF|), switching-on voltage and the ON/OFF current ratio of the ITO/POFTPE: Y6(5:1) /ITO device decrease with decreasing the incident light wavelength due to the increased free charge carrier concentration caused by light illumination. In contrast to the POFTPE: Y6 blends, the POFTPE:C60 blends-based device measured in the dark shows smaller switch-on voltage, ON/OFF current ratio and switching bias window under the same experimental conditions. This work shows one of the very promising strategies for exploring the nonvolatile multilevel storage by tailoring optoelectronic switching and memory performance of the materials via illumination with different wavelength lights.
Mohammad Moniruzzaman, Yoshio Yano, Toshikazu Ono, Yoshio Hisaeda, Hisashi Shimakoshi
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210316

Electrochemical transformations of DDT into oxygen-incorporated products, amides and esters, catalyzed by the B12 derivative, heptamethyl cobyrinate perchlorate, have been developed under aerobic conditions. The dechlorinative oxygenation of DDT formed the acyl chloride as an intermediate for the synthesis of the amide and ester in the reaction with the amine and alcohol, respectively. This electrochemical method demonstrated with 20 oxygen-incorporated dechlorinated products up to 88% yields with 15 new compounds and was also successfully applied to the conversion of methoxychlor to an amide and ester.
Nieves López-Salas, Markus Antonietti
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210264

The current mandates of a sustainable society and circular economy lead to the request that materials chemistry, but also chemistry as such, has to become significantly redesigned. Changes include commonplaces as the glassware we use, the minimization of wastes and side products or replacement strategies in the materials choice, among others. In this context, “carbons” are very versatile and already have found their place in a myriad of applications for a “carbon-neutral” society. They already take key enabling positions for sensors and biomaterials preparation, as energy conversion and storage electrode, or as effluent remediation sorbents. Herein, we describe how carbon chemistry can be again re-designed to outperform benchmark materials in a number of fields, especially in energy storage, (electro)catalysis, as sorbent, but also in a new chemistry of the confined state.
Akihiko Yamagishi, Kazuyoshi Takimoto, Kenji Tamura, Fumi Sato, Hisako Sato
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210291

Baseline separation was achieved when dansylated alanine methyl ester (denoted by dan-ala-me) was eluted with methanol on a HPLC (high performance liquid chromatography) column (5 cm × 4 mm (i.d.)) packed with an ion-exchange adduct of synthetic hectorite and Δ-[Ru(phen)3]2+ (phen = 1, 10-phenanthroline). In order to unravel the separation mechanisms, the adsorption state of R- or S-dan-ala-me on a modified clay surface was investigated by means of the solid-state vibrational circular dichroism spectroscopy. It was deduced that a dan-ala-me molecule changed its conformation, depending on the chirality relation to a co-adsorbed Ru(II) complex. The theoretical simulation of an associate between a Ru(II) complex and a dan-ala-me molecule supported the conclusion.
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