Refine Search

New Search

Results: 94,316

(searched for: publisher_group_id:5407)
Save to Scifeed
Page of 1,887
Articles per Page
by
Show export options
  Select all
Masahito Murai, Ryuji Taniguchi, Kazuhiko Takai
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210305

Abstract:
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

Abstract:
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.
Teruyuki Nakato, Thipwipa Sirinakorn, Wataru Ishitobi, Emiko Mouri, Makoto Ogawa
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210314

Abstract:
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.
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

Abstract:
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.
Hideto Matsuoka, Yuki Shibano, Ikuko Akimoto, Yuki Kanzaki
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210307

Abstract:
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.
Ryota Sugimoto, Masahiro Morimoto, Shigeki Naka
Published: 14 October 2021
Abstract:
We investigated the patterning of organic light-emitting diodes using a blue laser irradiation after making uniform device. Laser patterning was carried out in the atmosphere after the organic layer was deposited. The laser irradiation part was quenched, and it was shown that optional patterning was possible. This technique is expected as a fabrication technique for on-demand pattern emission.
Joshua Kyle Stanfield, Osami Shoji
Published: 14 October 2021
Abstract:
Cytochrome P450BM3 is a haemoenzyme that catalyses the monooxygenation of unactivated C—H bonds. In the absence of an appropriate substrate, however, P450BM3 remains in an inactive state and catalysis does not proceed. Traditionally, mutagenesis has been the mainstay technique employed to overcome this limitation, opening P450BM3 up for non-native substrate hydroxylation. This highlight review will discuss a different approach, wherein native substrate mimics (decoy molecules) are employed to trick P450BM3 into mistakenly hydroxylating non-native substrates. This decoy molecule system has the advantage that the wild-type enzyme can be utilised, and laborious mutagenesis can be avoided. Major developments from the first discovery of decoy molecules to the present day will be briefly covered herein.
Koji Yamamoto, Itsuki Yamada, Masaru Kameyama, Yosuke Nakamura
Published: 14 October 2021
Abstract:
Carbazole-containing 1,2-azaborine derivatives bearing various substituents were synthesized by using bora-Friedel–Crafts reactions of 1,8-diphenylcarbazole derivatives, and the substituent effects on their photophysical properties were investigated. Furthermore, three carbazole-containing azaborine dimers with different annulation manners between the azaborine and benzene moieties were also successfully synthesized, and the effects of dimerization and differences in the annulation manners on their photophysical properties were disclosed.
Hiroyuki Takeda, Makoto Shimo, Gai Yasuhara, Ken Kobori, Motoko S. Asano, Yutaka Amao
Published: 14 October 2021
Abstract:
Three kinds of heteroleptic Cu(I) complexes having a phenanthroline-based ligand acting as a chromophore and bearing benzoxazole, benzothiazole, and thiazole moieties were synthesized. Introduction in the phenanthroline ligands of electron-withdrawing five-membered aryl groups caused large red-shifts in the metal-to-ligand charge transfer bands, showing visible light absorption up to 500 nm. The obtained Cu(I) complexes exhibited emissions with quantum yields of 0.01–0.04 and long lifetimes of 0.4–3 μs.
Que D. Nguyen, Kosuke Kikuchi, Mariko Kojima, Takafumi Ueno
Published: 14 October 2021
Abstract:
We investigated the effect of linkers on the dynamics of cargo proteins by using a protein needle (PN) scaffold linked to superfolder green fluorescent proteins (sfGFPs) via various linkers. High-speed atomic force microscopy (HS-AFM) revealed clear images of the sfGFP motions on the PN. The results showed that the mobility of cargo proteins is affected by the flexibility and length of linker as well as the intermolecular interactions between the cargo protein and the scaffold protein.
Tsukasa Aoyagi, Ryunosuke Yoshino, Yuki Mitsuta, Rikuri Morita, Ryuhei Harada, Yasuteru Shigeta
Published: 14 October 2021
Abstract:
The C-terminal binding protein 2 (CtBP2) plays a role in apoptosis and embryogenesis. Genetic knockout studies have been demonstrated to cause severe developmental defects and embryonic lethality. CtBP2 has three key domains and dimerizes for a significant role by binding with nicotinamide adenine dinucleotide (NADH). However, the molecular mechanism of CtBP2 dimerization and the effect of NADH binding are unknown. In this study, we performed molecular dynamics (MD) and docking simulation to reveal the mechanism of C-terminal binding protein 2 (CtBP2) dimerization and the effect of NADH binding to the dimer formation. Our MD simulation results detected seven salt bridges that are important for CtBP2 dimerization. And docking simulation demonstrated that the holo-monomer gave a higher probability of correct docking pose than the apo-monomer. Moreover, in docking simulation using a PXDLS model peptide, that holo form gave more docking poses than that apo form. These results suggested that the holo form has a structure that facilitates the formation of dimers and the binding of PXDLS peptides.
Itaru Suzuki, Yuya Takenaka, Yoshitaka Morishita, Ikuya Shibata
Published: 14 October 2021
Abstract:
The nucleophilic addition of ketene silyl acetals 2 into 2H-azirines 1 proceeded in the presence of Lewis acids such as InX3 or Sc(OTf)3 to give N-unprotected aziridines 3. The mild Lewis acidity of the catalyst is important for the achievement of this coupling. The generated aziridine 3 could then be transformed into either oxazolines or γ–amino carbonyls.
Baodian Fan, Ping Li, Linqin Jiang, Aijun Yang, Jiansheng Li, Haiyan Luo, Hao Xiong, Lingyan Lin, Yu Qiu
Published: 14 October 2021
Abstract:
Synergetic effects were observed in oriented-NaNbO3/g-C3N4 heterostructure system synthesized from in situ pyrolysis of urea with hydrothermally prepared NaNbO3 microcuboids. Chemically wrapping NaNbO3 with appropriate amount of g-C3N4 forms an efficient heterojunction which separates photoexcited charges and the internal electric field produced by oriented NaNbO3 grains facilitates their transfer. The mechanism developed here is applicable to enhancing photoelectrical utilization in other perovskite systems.
Kota Kurokawa, Hisashi Sugime, Shin-Ichi Naya, Hiroaki Tada
Published: 14 October 2021
Abstract:
Gold truncated nanopyramids smaller than 10 nm with clean surfaces were formed on SrTiO3 naocubes (Au TNPy//SrTiO3 NCs, // denotes heteroepitaxial junction) by the deposition precipitation method without surface modifier, while the shape of Au nanoparticles (NPs) on irregular shaped SrTiO3 NPs was hemisphere-like (Au HS/SrTiO3 NPs). As a probe reaction, the oxidation of o-phenylenediamine (OPD) to 2,3-diaminophenazine (DAP) by H2O2 was carried out with the catalysts in the dark at 25°C. Au TNPy//SrTiO3 NCs exhibit significantly higher catalytic activity for the oxidation reaction than Au HS/SrTiO3 NPs. Kinetic analyses indicated that H2O2 can be more effectively activated to be utilized for the OPD oxidation in the former system than the latter system.
Bozhen Li, Zejun Wang, Yiming Li, Yaping Zhang, Yufeng He, Pengfei Song, Rongmin Wang
Published: 14 October 2021
Abstract:
The hydroxyapatite nanowire (HAnW), a novel synthesized biocompatible material without any transition metals, was applied to catalytic degradation of antibiotics. Importantly, tetracycline (TC), a common drug, could be rapid adsorbed and catalytic degraded by HAnW, and the removal got to 85% within 5 min at room temperature.
Takayuki Yamamoto, Ayumi Takeuchi, Junji Ohnishi, Satoshi Yasuno, Munekazu Motoyama, Yasutoshi Iriyama
Published: 7 October 2021
Abstract:
Effects of target-substrate (TS) distance during pulsed laser deposition process on the chemical structure and lithium-ion conductivity of amorphous lithium phosphate (LPO) thin films are investigated. The shorter TS distance results in lower Li concentration, longer phosphate chain, and higher ionic conductivity. The ionic conductivity of 2.7 × 10−7 S/cm is obtained at 25 °C in the LPO thin film with short TS distance.
Sobi Asako, Ikko Takahashi, Takashi Kurogi, Yoshiaki Murakami, Laurean Ilies, Kazuhiko Takai
Published: 7 October 2021
Abstract:
An easy-to-handle sodium dispersion in paraffin oil (SD), in combination with inexpensive and environmentally benign 1,3-dimethyl-2-imidazolidinone (DMI) as an additive enables the Birch-type reduction of a variety of arenes with high yields, selectivity, and tolerance of functionality such as ether, alcohol, amine, amide, and carboxylic acid.
Hyun-Ju Jang, Seong-Hee Lee, Eui-Jeong Park, Hae-In Kim, Jong-Tae Son
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1747-1750; https://doi.org/10.1246/cl.210287

Abstract:
An ultra-high capacity Li[Ni1/3Co1/3Mn1/3]O2 (T-LNCM) cathode material was synthesized using a novel MnO2 template comprising nanorods of 114 nm diameter, which increased the surface area of the material to 3.19 m2 g−1. Owing to its large surface area and high lithium diffusion coefficient (4.72 × 10−14 cm2 s−1), T-LNCM exhibits an ultra-high capacity of 220.2 mAh g−1 at 0.1 C. The capacity of T-LNCM is significantly higher than that of the conventional LNCM cathode material.
Takashi Hibino, Kazuyo Kobayashi, Takuma Hitomi
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1729-1732; https://doi.org/10.1246/cl.210321

Abstract:
Direct utilization of combustible waste as an energy resource is very attractive for improving waste-to-energy conversion efficiency. Herein, we report a high-performance solid oxide fuel cell (SOFC) that can be supplied continuously with plastic waste as a fuel. Iron(III) oxide powder functioned as a pseudofuel in the ion transfer process and as a catalyst for gasification of the plastic. The resultant SOFC provided peak power densities of 0.71, 0.68, and 0.57 W cm−2 for nylon 66, polyethylene, and polystyrene, respectively.
Tomohiro Yasukawa, Sanshiro Kume, Yasuhiro Yamashita, Shū Kobayashi
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1733-1735; https://doi.org/10.1246/cl.210355

Abstract:
Nitrogen-doped carbon-supported Co/Cu bimetallic catalysts were found to catalyze olefination of aldehydes with ethyl diazoacetate. In the presence of triaryl phosphine with electron-withdrawing groups, various aromatic aldehydes could be converted into unsaturated esters in good to high yields. The system is heterogeneous, allowing for recovery and reuse of the catalyst for several runs without significant loss of activity.
Wuxiao Ding, Naohiro Kameta, Ayako Oyane
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1743-1746; https://doi.org/10.1246/cl.210413

Abstract:
Facilely synthesized thioether amphiphile can self-assemble into nanotubes in water. The nanotubes exhibit quick reactive oxygen species (ROS)-responsivity in H2O2 or against the ultraviolet-triggered ROS from the encapsulated corannulene. Oxidation of the thioether amphiphile disassembles the long nanotubes into short ones and eventually into solubilized amphiphile.
Masashi Kaneko, Yuji Sasaki, Eriko Wada, Masahiko Nakase, Kenji Takeshita
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1765-1769; https://doi.org/10.1246/cl.210402

Abstract:
Density functional theory calculation is applied to predict the stability constants for Eu3+ and Am3+ complexes in aqueous solution for molecular modelling of novel separation agents for minor actinides over lanthanides. Logarithm of experimental stability constants correlates with calculated complex formation enthalpies with high reproducibility (R2 > 0.98). Prediction of stability constants of novel chelates is demonstrated and indicates a potential availability of the derivatives of diethylenetriaminepentaacetic acid type chelate in acidic condition and enhancement of Am3+ selectivity over Eu3+.
Naoki Hamao, Yuki Yamaguchi, Ken-Ichi Mimura, Koichi Hamamoto
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1784-1786; https://doi.org/10.1246/cl.210374

Abstract:
A garnet-type electrolyte sheet for all-solid-state batteries was fabricated by modified cold sintering method. The pores in the electrolyte sheet were closed during the cold sintering process, and the grain-boundary resistance was reduced. The impurity phase formed after cold sintering was removed by annealing treatment at higher temperatures.
Arnoldus Lambertus Dipu, Ichiro Yamanaka
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1762-1764; https://doi.org/10.1246/cl.210356

Abstract:
Unsupported Ni2P catalysts synthesized by the hydrothermal method were studied for the direct dehydrogenative conversion of methane to hydrocarbons. The unsupported Ni2P catalyst showed smaller crystallite size and porous surface structure due to the absence of calcination and reduction at higher temperatures and performed better catalytic activity at 1173 K. It has been found that the simple hydrothermal method was effective for the synthesis of active unsupported Ni2P catalyst.
Takashi Nakamura
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1822-1830; https://doi.org/10.1246/cl.210418

Abstract:
This highlight review summarizes our recent studies of macrocyclic receptors with precise molecular recognition properties based on two concepts, assembly of metal complex units, and desymmetrization of molecular components. The metallomacrocycles realized a unique molecular binding by utilizing multipoint coordination and rigidity of the metal complex units. The desymmetrized homooligomeric macrocycles achieved a precise multipoint recognition by employing the unsymmetrically arranged interaction moieties.
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

Abstract:
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

Abstract:
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.
Rikuo Kajiwara, Koji Hirano, Masahiro Miura
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1814-1817; https://doi.org/10.1246/cl.210439

Abstract:
A Cu-mediated ortho-selective C–H cyanation of phenols with ethyl cyanoformate as the cyano source has been developed. The key to success is the introduction of 4,4’-di-tert-butyl-2,2’-bipyridine (dtbpy) bidentate auxiliary on the phenol oxygen, which is easily attachable, detachable, and recyclable. The newly developed protocol is tolerated to several carbonyl functional groups, which are incompatible with previous Lewis-acid-promoted cyanation of phenols.
Yuhi Satoh, Shigeki Wada
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1758-1761; https://doi.org/10.1246/cl.210350

Abstract:
The loss on ignition (LOI) of fatty acids (FAs; including carbon numbers of C8–C24) in vegetal and animal organic reference samples at 200–500°C was examined. The total FAs in the samples preferentially disappeared through LOI operation compared to the other compounds. The average carbon numbers in total FAs did not change substantially from their original values due to LOI, regardless of the temperature. However, the unsaturation ratios in each FA species fluctuated throughout the operation.
Naoto Sato, Yoshiyuki Kuroda, Hiroaki Wada, Atsushi Shimojima, Kazuyuki Kuroda
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1770-1772; https://doi.org/10.1246/cl.210387

Abstract:
Cage siloxanes modified with diisopropylsilanol groups were synthesized and crystallized into a layered structure containing 1,3,5-trimethylbenzene molecules in the interlayer voids, which indicates that the organic groups attached to the silanol groups have an important role in the assembling behavior of cage siloxanes.
Ryukichi Takagi, Yuhei Yamasaki
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1781-1783; https://doi.org/10.1246/cl.210403

Abstract:
Alkaline earth metal salts of chiral bis-sulfonimide were prepared in this study. Asymmetric Diels-Alder reactions catalyzed by these metal salts were examined to evaluate the performance of bis-sulfonimide as a chiral ligand. The Diels-Alder reaction between 2-propenoyl pyrazole and cyclopentadiene catalyzed by the calcium salt afforded the cycloaddition product with moderate stereoselectivity.
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

Abstract:
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.
Kazuyuki Nishio, Yuta Udagawa
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1794-1796; https://doi.org/10.1246/cl.210351

Abstract:
A nanoporous gold (NPG) film was formed on a Ti sheet or sputter-deposited thin Ti film by the anodization of a thin gold film on the Ti substrates in oxalic acid. A remarkably low anodic current of the Ti sheet compared with that of the Al sheet indicates that Ti is a stable substrate for the NPG film formed by the anodization. It is also confirmed that the preanodization of the Ti sheet significantly improves the adhesion of the NPG film to Ti. By increasing the anodic potential, NPG film was formed on sputter-deposited thin Ti film with a thickness of 130 nm.
Thuy Thi Thu Pham, Youhei Chitose, Tran Thi Thanh Tam, Wei-Lun Tseng, Tzu-Chau Lin, Manabu Abe
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1810-1813; https://doi.org/10.1246/cl.210420

Abstract:
A series of dipolar-type terphenyl derivatives 1–3 featuring an electron donor (p-NMe2C6H4 group) and acceptor (p-NO2C6H4 group) unit was synthesized and their photophysical properties were investigated. By using aromatic heterocycles (thiophene, furan, pyrrole) as the π-linkers between the donor and acceptor units, significant effects on the bathochromic shift and enhancement of the two-photon absorption wavelength and the two-photon absorption cross-sections were observed, respectively.
Han Vinh Huynh
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1831-1841; https://doi.org/10.1246/cl.210435

Abstract:
The Huynh electronic parameter (HEP) is a modern alternative method to determine ligand donor strengths by 13C NMR spectroscopy of metal NHC complexes containing the ligand of interest. Using the HEP, the electronic properties of numerous classical Werner-type and organometallic ligands have been evaluated thus far. Moreover, it has been extended to the HEP2, which provides a means to measure bidentate chelators. This Highlight Review covers recent applications of the HEP and its variants from 2016 onwards.
Ganesh T. Kamble, Mohamed S. H. Salem, Tsukasa Abe, HanSeok Park, Makoto Sako, Shinobu Takizawa, Hiroaki Sasai
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1755-1757; https://doi.org/10.1246/cl.210367

Abstract:
Enantioselective oxidative couplings of 4-hydroxycarbazoles using a chiral dinuclear vanadium(v) complex have been achieved for the first time. Under the mild reaction conditions, the corresponding dimeric 4-hydroxycarbazoles were obtained in up to 90% ee.
Atsushi Uno, Kenji Arima, Maki Ushida, Yuka Katayama, Masako Shimazaki, Kanako Amano, Reiko Namikawa, Kazuo Sakurai
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1778-1780; https://doi.org/10.1246/cl.210334

Abstract:
SiRNA was complexed with a β-1,3-glucan schizophyllan and intravenously administrated into mouse. The complexed siRNA was escaped from renal excretion and remained in blood. The monocytes in spleen were found to capture the complex and cause the longer residence time of the complexed siRNA as well as increased size of the complex.
Syun Gohda, Hironobu Ono, Yasuhiro Yamada
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1773-1777; https://doi.org/10.1246/cl.210382

Abstract:
A metal-free covalent triazine framework was synthesized from 2,4,6-tricyano-1,3,5-triazine (TCT-CTF) through open-system and liquid-phase synthesis using trifluoromethanesulfonic acid as both a catalyst and a solvent. In conventional closed-system methods, metal ions used as catalysts remained even after purification, and large quantities could not be synthesized. The proposed method solved these problems and synthesized higher-quality TCT-CTF with a layered structure and a composition with a C/N ratio of 1, which is close to the ideal value.
Afang Zhao, Qiang Li, Na Zhang, Huining Deng, Li Zhao, Shicai Xu, Junye Zhang, Hussein Baqiah
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1751-1754; https://doi.org/10.1246/cl.210338

Abstract:
A polyamide-based nanocomposite reverse osmosis membrane was fabricated by introducing tannic acid coated carbon nanotubes (CNTs) into the oil-phase solution of trimesoyl chloride using an interfacial polymerization approach. The obtained membrane exhibits high permeate flux (67.6 L/m2h), salt rejection (99.4%), fouling resistance, antibacterial and anti-adhesion properties. After silver nanoparticles was embedded into the CNT pore channels, the permeate flux (73.1 L/m2h) and antibacterial property were further improved.
Kaito Matsuda, Yuto Kobayashi, Sayaka Inoue, Yusuke Morita, Tomoya Ishikawa, Takeshi Uyama, Akinori Shimono, Takeru Ito, Makoto Misono, Yuichi Kamiya, et al.
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1736-1739; https://doi.org/10.1246/cl.210246

Abstract:
Pore structure of (NH4)4SiW12O40 sponge crystal was successfully elucidated by means of Ar adsorption isotherm analysis combined with molecular probe method and molecular modeling. The pores consist of spherical voids or “cages” with diameter of ca. 12 Å and these are connected by smaller “windows”. These “cages” and “windows” are clearly resolved in the pore size distribution analysis for the first time. Molecular probe method elucidated the diameter of the “windows” is larger than 8.5 Å and smaller than 10.2 Å, being consistent with molecular modeling.
Satoru Iwata, Mamoru Ohtuji, Shintaro Kobayashi, Misa Aoyama, Kiyoshi Tanaka
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1791-1793; https://doi.org/10.1246/cl.210396

Abstract:
Novel photosensitized trifluoromethylthiazole-5-carboxylic acid dyes having different numbers of thiophene π-conjugation spacers (MCL15, MCL17, and MCL19) and a benzodithiophene spacer with long alkyl side chains (MCL40) are synthesized. The resulting extension of the π-conjugation system leads to redshift in the absorption wavelength. The long alkyl side chains of benzodithiophene cause a dispersed aggregation effect; therefore, the co-adsorbent becomes unnecessary for dye-sensitized solar cell (DSSC) fabrication. The DSSCs fabricated using these dyes exhibit increased conversion efficiency compared with those without a thiophene unit (MCL05).
Kinuka Tano, Eriko Sato
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1787-1790; https://doi.org/10.1246/cl.210332

Abstract:
Photodimer of 9-anthracene carboxylic acid was used as crosslinker for bisepoxides and a degradable network polymer was synthesized at 100–110 °C in the presence of a base catalyst. The resulting network polymer was thermally decrosslinked at 150 °C within 30 min and completely solubilized in an organic solvent. Detailed investigation of the thermal dissociation behavior revealed that dissociation of more than 80% of 9-AC dimer unit was required for complete solubilization of the network polymer.
Junke Ou, Hao Wang, Jiayi Wang, Shugen Wu
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1797-1800; https://doi.org/10.1246/cl.210314

Abstract:
Pistachio shell derived porous carbon with large amount of micropores is fabricated via a straightforward chemical activation and used as a selenium host material for lithium-selenium batteries. The as-obtained Se/carbon cathode displays a first discharge capacity of 713.1 mAh g−1 and displays a superior reversible capacity of 422.3 mAh g−1 after 100th cycle at 0.2 C (1C = 675 mA g−1). Furthermore, at a large rate of 10 C (6.75 A g−1), it still displays a reversible capacity of 221.2 mAh g−1. Such unique porous carbon as a selenium host material with superior electrochemical performances suggests great potential for the practical application of the Li-Se batteries.
Haidong Xu, Congcong Miao, Luyao Wang, Liang Zhang, Huixia Feng, Jianhui Qiu
Published: 5 October 2021
Chemistry Letters, Volume 50, pp 1818-1821; https://doi.org/10.1246/cl.210343

Abstract:
A robust superhydrophobic perfluoropolysiloxane and self-doped polyaniline/epoxy resin composite coating (EPAN-RA-POS) was prepared. The structure is composed of the internal self-doped polyaniline/epoxy resin layer and the outer superhydrophobic perfluoropolysiloxane layer. The contact angle (CA) and sliding angle (SA) of EPAN-RA-POS are 165.0° ± 1.5 and 1.2° ± 0.7, respectively, the protection efficiency and immersion durability of EPAN-RA-POS reach 99.99% and 408 h, the superhydrophobicity is only lost after 330 peeling experiments.
Akihiko Yamagishi, Kazuyoshi Takimoto, Kenji Tamura, Fumi Sato, Hisako Sato
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210291

Abstract:
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.
Kouki Oka, Miho Kataoka, Yusuke Kaiwa, Kenichi Oyaizu
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210283

Abstract:
Hydrogen has a high energy density and produces only water during combustion; consequently, it has attracted considerable attention as a next-generation sustainable energy source. To be used on a daily basis, hydrogen-storage materials need to stockpile hydrogen safely and to release it using only small amounts of energy. Chemically bonded hydrogen stored in a polymer is highly safe, enabling hydrogen to be stored under ambient conditions in a non-volatile, non-toxic, and non-flammable manner. Herein, we report the dehydrogenation reactions of alcohol-substituted vinyl polymers at mild temperatures. Poly(allyl alcohol) was dehydrogenated at 65–95 °C in the presence of an iridium complex catalyst to produce poly(acrylic acid) due to the extremely low activation energy (10 kJ/mol) associated with the catalyst-specific cycle. Poly(allyl alcohol) exhibits a hydrogen-storage density of 6.8 wt% by releasing two equivalents of hydrogen gas, which demonstrates that alcohol-substituted vinyl polymers can be used to stockpile hydrogen and release it under mild conditions.
Hui Cui, Yi Xie, Yingxiang Ye, Yanshu Shi, Bin Liang, Banglin Chen
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210237

Abstract:
Removing of CO2 to purify CO2/C2H2 mixture through porous material is a more energy saving method compared with the traditional cryogenic distillation. Those CO2-selective adsorption porous materials are ideal for directly producing high-purity C2H2, especially allowing sieving separation with infinite selectivity but without sacrificing any uptake capacity. Here, we report an ultramicroporous metal–organic framework (MOF) [Cu(hfipbb)(H2hfipbb0.5)] (1), [H2hfipbb is 4,4’-(hexafluoroisopropylidene) bis(benzoic acid)] has been studied for inverse separation of CO2 from C2H2 under ambient conditions. This Cu-based MOF material was comprehensively demonstrated as an efficient CO2-selective adsorbent used for C2H2 purification by single-component adsorption isotherms, providing its promising for the industrial acetylene purification.
Nieves López-Salas, Markus Antonietti
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210264

Abstract:
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.
Fumika Wakayama, Ryo Ito, Kwihwan Park, Moeka Ishida, Yutaro Yamada, Shuta Ichihara, Hitoshi Takada, Shinji Nakamura, Ayumu Kato, Tsuyoshi Yamada, et al.
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210266

Abstract:
We have developed a method for the esterification of carboxylic acids with alcohols using amphipathic, monolithic-resin bearing sulfonic acid moieties as cation exchange functions (monolith-SO3H). Monolith-SO3H efficiently catalyzed the esterification of aromatic and aliphatic carboxylic acids with various primary and secondary alcohols (1.5–5.0 equiv) in toluene at 60–80 °C without the need to remove water generated during the reaction. The amphipathic property of monolith-SO3H facilitates dehydration due to its capacity for water absorption. This reaction was also applicable to thioesterification, wherein the corresponding thioesters were obtained in excellent yield using only 2.0 equiv of thiol in toluene, although heating at 120 °C was required. Moreover, monolith-SO3H was separable from the reaction mixtures by simple filtration and reused for at least five runs without decreasing the catalytic activity.
Masauki Morie, Ryo Sekiya, Takeharu Haino
Bulletin of the Chemical Society of Japan; https://doi.org/10.1246/bcsj.20210287

Abstract:
Lower- and/or upper-rim functionalization of calix[4]arene realized a variety of calix[4]arene systems. Compared to these monomeric calix[4]arenes, covalently linked calix[4]arene oligomers have not been studied well. Calix[4]arene oligomers can be utilized as building blocks of supramolecular complexes as well as for the synthesis of calix[4]arene polymers. This background motivated us to develop synthetic procedures for calix[4]arene oligomers and to conduct conformational analysis of these oligomers. We produce oligomers ranging from the monomer to the pentamer. The coupling of the pentamer with 2,3-dibenzyloxy-1,4-benzenedicarboxylic acid can access a decamer and oligomers. NMR measurements, X-ray crystal structure analysis, and computational studies demonstrate that calix[4]arene oligomers can regulate their length by changing the conformations of the calix[4]arene cores.
Page of 1,887
Articles per Page
by
Show export options
  Select all
Back to Top Top