-
Selenium-Catalyzed Functionalization of Alkynes Chem. Lett. (IF 1.485) Pub Date : 2021-02-19 Lihao Liao; Xiaodan Zhao
Selenium catalysis has become an exciting area in organic synthesis. In various selenium-catalyzed reactions, different substrates have been utilized. However, alkynes as substrates have received much less attention than other substrates such as alkenes although the triple bond of alkynes possesses versatile reactivities. This review summarizes the progress of selenium-catalyzed alkyne functionalization
-
Dehydrative/Decarboxylative Coupling of Carboxylic Acids with Allylic Alcohols Chem. Lett. (IF 1.485) Pub Date : 2021-02-19 Yusuke Masuda; Misato Ito; Masahiro Murakami
Herein reported is a dehydrative/decarboxylative coupling reaction of carboxylic acids with allylic alcohols, which is co-catalyzed by photoredox and palladium catalysts. α-Hetero- or aryl-substituted carboxylic acids and allylic alcohols, which are both readily available, directly participate in C–C bond formation without any functional group transformation.
-
Transitions among cracking, peeling and homogenization on drying of an aqueous solution containing glucose and starch Chem. Lett. (IF 1.485) Pub Date : 2021-02-19 Hikari Baba; Risa Yoshioka; Satoshi Takatori; Yohei Oe; Kenichi Yoshikawa
A morphological transition was observed in the drying of an aqueous solution containing glucose and starch, which are the monomer and polymer of the same chemical composite. With an increase in the glucose content, the sample exhibits a change from cracking of a 2-dimensional (2D) layer to peeling from the bottom layer. With a further increase in glucose, a 2D homogenous layer is generated. A chemical
-
Ni-Catalyzed Direct Carboxylation of Propargylic Alcohols with Carbon Dioxide Chem. Lett. (IF 1.485) Pub Date : 2021-02-19 Tatsuya Yamahira; Gen Onodera; Tsutomu Fukuda; Masanari Kimura
The carboxylation of propargylic alcohols containing a silyl group at the terminal position was conducted in a CO2 atmosphere at atmospheric pressure in the presence of a nickel catalyst and diethylzinc. Here, CO2 was used as not only the C1 source but also the promoter of the C–OH cleavage processes for the oxidative addition of propargylic alcohols.
-
Single-Crystal-to-Single-Crystal Transformations for the Preparation of Small Molecules, 1D and 2D Polymers Single Crystals Chem. Lett. (IF 1.485) Pub Date : 2021-02-19 Fan Hu; Xinwen Bi; Xinsheng Chen; Qingyan Pan; Yingjie Zhao
The single-crystal-to-single-crystal (SCSC) transformation is a fascinating and valuable outcome of topochemical reactions. Not like the solution-state reactions, the movement and transformation of the molecule in single-crystal state is such a mysterious and attractive research topic. The molecular packing of the monomers prior to the reaction could provide many possibilities for the formation of
-
Advances in Artificial Bilayer Lipid Membranes as a Novel Biosensing Platform: From Drug-screening to Self-assembled Devices Chem. Lett. (IF 1.485) Pub Date : 2021-02-18 Teng Ma; Madoka Sato; Maki Komiya; Xingyao Feng; Daisuke Tadaki; Ayumi Hirano-Iwata
Because of their unique structures and properties, self-assembled bilayer lipid membranes are a subject of intense interest. In this Highlight Review, we summarize recent progress made in research related to bilayer lipid membranes, including the formation of stable free-standing lipid membranes, applications of artificial lipid bilayers as a model cell membrane to study biological processes, and new
-
Nickel-Catalyzed Asymmetric Propargylic Amination of Propargylic Carbonates with Aniline Derivatives Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Hiroaki Tsuji; Yuka Shimizu; Yusuke Miyazaki; Motoi Kawatsura
The study for the development of the nickel-catalyzed highly enantioselective propargylic amination of propargylic carbonates with aniline derivatives is described. The reaction of internal alkyne-substituted propargylic carbonates with a series of aniline derivatives smoothly proceeded in DMSO using a combination of Ni(cod)2 and (R)-SEGPHOS as the catalyst to give the corresponding chiral propargylic
-
Supramolecular nanofibers constructed by hydrogen bonding of chlorophyll dimer Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Shogo Matsubara; Hitoshi Tamiaki
Chlorophyll pigments often assemble in a poor solvent to form less-ordered amorphous aggregates, despite the in vitro self-aggregation observed with chemically modified chlorophyll derivatives biomimicking a chlorosome. Chlorophyll dimer linked with a terephthalamide formed well-defined fiber shaped aggregates in hexane. The nanofiber was constructed by columnar self-aggregation via hydrogen bonding
-
Alkylation of Heteroaryl Chlorides through Homolytic Aromatic Substitution by Alkyl Radicals Derived from Alkyl Formates Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Yuko Ikeda; Tomoya Mandai; Kyohei Yonekura; Eiji Shirakawa
The alkylation of heteroaryl chlorides through a homolytic aromatic substitution (HAS) mechanism was achieved by the use of alkyl formates as alkylating agents in the presence of a tert-butoxy radical precursor, where alkyl radicals are generated from alkyl formates through hydrogen abstraction followed by β-scission with decarboxylation.
-
Tetrafluoroborate anion intercalation into graphite electrode from sulfolane Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Yunju Wang; Yuhao Huang; Hongyu Wang
The electrolyte solution of lithium tetrafluoroborate dissolved in sulfolane is applied in dual-ion batteries. Graphite positive electrode in this solution delivers the reversible anion storage capacity over 80 mAh g−1 at potentials over 4.5 V vs. Li/Li+. The structures of anion-graphite intercalation compounds are investigated in detail by the combination of in situ X-ray diffraction (XRD) and in
-
Regression Modeling and Virtual Screening of Natural Products Exhibiting Antibacterial Activity. An Application of Electronic-Structure Informatics Descriptors Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Toshihiro Ideo; Kazuki Yoshida; Manabu Sugimoto
Machine learning using descriptors suggested for “electronic-structure informatics (ESI)” is carried out to establish a regression model for antibacterial activity of 60 natural products. The obtained model is used for the in-house data containing 175 molecules. The screening result is justified through literature survey in which, at least, 13 compounds listed in the top 20 compounds are shown to have
-
Recent evidence for multifactorial biofilm regulation by heme sensor proteins NosP and H-NOX Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Jiayuan Fu; Steven Hall; Elizabeth M. Boon
Heme is involved in signal transduction by either acting as a cofactor of heme-based gas/redox sensors or binding reversely to heme-responsive proteins. Bacteria respond to low concentrations of nitric oxide (NO) to modulate group behaviors such as biofilms through the well-characterized H-NOX family and the newly discovered heme sensor protein NosP. NosP shares functional similarities with H-NOX as
-
Electron Density-based Estimation of Diradical Character: An Easy Scheme for DFT/Plane-wave Calculations Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Kohei Tada; Yasutaka Kitagawa; Takashi Kawakami; Mitsutaka Okumura; Shingo Tanaka
Density functional theory calculations with plane-wave basis sets are often used for theoretical investigations of solid materials; nevertheless, analysis techniques for open shell structures are insufficient. In this study, we established an electron density-based estimation scheme for the diradical character (y). The values estimated by the proposed and conventional schemes are consistent. Additionally
-
An In-situ Brine Solution in Salt-cavern Supported Redox-flow Battery Using Iron/Organic Materials Chem. Lett. (IF 1.485) Pub Date : 2021-02-13 Hui Wang; Wang Ke; Zhang Wei; Dan Li; Liuping Chen
Salt cavern redox flow batteries with a large salt-cavern storing electrolyte are a promising large-scale energy storage technology. Here a low-cost iron/organic redox material system was proposed to explore salt cavern redox flow batteries. To avoid the formation of ferric hydroxide, ligand threonine was used to enhance the stability of the ferric ion in aqueous solution. Paired with a two electron
-
Concerted Catalysis of Pd and Au on Alloy Nanoparticles for Efficient Heterogeneous Molecular Transformations Chem. Lett. (IF 1.485) Pub Date : 2021-02-11 Hiroki Miura; Tetsuya Shishido
The PdAu random alloy nanoparticle catalyst shows excellent catalytic activity for heterogeneous molecular formations, whereas monometallic Pd or Au catalysts were ineffective. The Pd/Au ratio in the alloy had a significant impact on its catalytic performance, and the catalyst with a low Pd concentration exhibited excellent activity. The concerted catalysis of Pd and Au adjacent on the alloy surface
-
Characteristics of Electrolytic Deoxygenation Devices Using SiC and SWCNT Electrodes Chem. Lett. (IF 1.485) Pub Date : 2021-02-11 Keiichi Kaneto; Sadahito Uto
Electrolytic deoxygenation devices have been fabricated using SiC, SWCNT, graphene, and PEDOT*PSS for the electrodes. Characteristics of devices were studied by measuring currents, O2 and H2 concentrations, and humidity during deoxygenation in a closed container. Performances of the devices being composed of cation or anion exchange membrane are discussed comparing with the standard catalyst of Pt-black
-
Indicator Displacement Assay-based Chemosensor Arrays for Saccharides using Off-the-Shelf Materials toward Simultaneous On-site Detection on Paper Chem. Lett. (IF 1.485) Pub Date : 2021-01-30 Yui Sasaki; Xiaojun Lyu; Qi Zhou; Tsuyoshi Minami
Chemosensor arrays are useful analytical methods in supramolecular analytical chemistry, which discriminate molecular information such as species and their concentrations based on pattern recognition. Molecular self-assembled systems can provide not only the multi-optical response patterns but also easy preparation of chemosensors. In this regard, dynamic covalent-bonds play key roles in competitive
-
Bioinorganic Platforms for Sensing, Biomimicry, and Energy Catalysis Chem. Lett. (IF 1.485) Pub Date : 2021-01-29 Fung Man Ngo; Edmund C. M. Tse
Bioinorganic chemistry is a broad field with multiple branches. In this Highlight Review, the newest excitements in the branch of Bioinorganic Platforms are reviewed. Artificial bioinorganic platforms come in mesmerizing flavors, in particular the following 5 types are the major focus of this Highlight Review. First, single-stranded and double-stranded DNA, RNA, PNA, and their hybrids can be attached
-
Effective Lignin Utilization Strategy: Major Depolymerization Technologies, Purification Process and Production of Valuable Material Chem. Lett. (IF 1.485) Pub Date : 2021-01-28 Pallabi Sinha Roy; Gil Garnier; Florent Allais; Kei Saito
Considering the drawbacks associated with the fossil-based molecules, polymers and materials, lignin has acquired immense popularity owing to its distinct advantages. However, till date it has not been widely commercialized to produce fossil replacements mainly due to its complex structure and purification hassle. Constant research is going on to discover ways to depolymerize lignin to produce various
-
Studies of Ultrafast Molecular Dynamics by Femtosecond Extreme Ultraviolet Absorption Spectroscopy Chem. Lett. (IF 1.485) Pub Date : 2021-01-27 Zhi-Heng Loh
Transient absorption spectroscopy is one of the most widely used experimental techniques for time-resolved studies of ultrafast phenomena. Recent advances in the generation of short-wavelength pulses of ultrashort duration have made transient absorption probing of atomic core level transitions possible. In this Highlight Review, we introduce our recent work on using extreme ultraviolet (XUV) transient
-
Soft X-ray Absorption Spectroscopy to Know Element-Specific Intermolecular Interaction in Solution Chemistry Chem. Lett. (IF 1.485) Pub Date : 2021-01-27 Masanari Nagasaka; Nobuhiro Kosugi
Soft X-ray absorption spectroscopy (XAS) determines element-specific intermolecular interactions of light elements in liquid phase since it is related to a core electron excitation. We have newly developed liquid cells and devices with the precise photoabsorbance control technique. We demonstrate here their applications to XAS in transmission measurement with aqueous acetonitrile solutions and XAS
-
Nanoscale Silver Iodobismuthate Photosensitizer and Its Hybridization with Molecular Dye for Mesoporous TiO2 Film-Based Solid-State Sensitized Solar Cells Chem. Lett. (IF 1.485) Pub Date : 2021-01-26 Seul-Yi Lee; So-Min Yoo; Hyo Joong Lee
Nanoscale Ag2Bi3I11 photosensitizer was prepared on mesoscopic TiO2 film (~1 μm thick) by spin-coating of its low-concentrated precursors. The as-prepared Ag2Bi3I11-sensitizer was tested in the form of solid-state dye sensitized solar cell. When combined with a molecular dye, the hybridized Ag2Bi3I11/dye-sensitized cell showed enhanced characteristics with overall power conversion efficiency of 1.50%
-
Thermally-activated delayed fluorescence for light-emitting devices Chem. Lett. (IF 1.485) Pub Date : 2021-01-26 Hajime Nakanotani; Youichi Tsuchiya; Chihaya Adachi
Harvesting of excited spin-triplet states as light is essential to realize highly efficient electroluminescence (EL) in organic light-emitting devices. In recent years, thermally activated delayed fluorescence (TADF) has attracted much attention as a novel electronic transition process, since it enables harvesting electrically generated triplet energy as EL without the utilization of rare metals such
-
Fluorescence Quenching by Complex of a DNA Aptamer and Porphyrin for Sensitive Detection of Porphyrins by Capillary Electrophoresis Chem. Lett. (IF 1.485) Pub Date : 2021-01-26 Mari Onodera; Kenji Sueyoshi; Mitsuo Umetsu
Here, we used a fluorophore-bound, porphyrin-targeted DNA aptamer to increase the sensitivity of capillary electrophoresis for the detection of a model porphyrin. The complex of the DNA aptamer with the porphyrin induced the transfer of energy from the fluorophore to the porphyrin, resulting in the quenching of fluorescence. Monitoring of the quenching of fluorescence by capillary electrophoresis allowed
-
Non-linear Behavior for Chemical Expansion in Yttrium-doped Barium Zirconate upon Hydration Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Kenta Hoshino; Junji Hyodo; Yoshihiro Yamazaki
The rates of chemical expansion for 20 at% yttrium-doped barium zirconate upon hydration at 100–900°C under water partial pressures of 0.008 and 0.023 atm have been studied using combined thermogravimetry and high-temperature X-ray diffractometry. Non-linear behavior for the rates of expansion as a function of proton concentration under equilibrium conditions was observed, suggesting that defect interactions
-
Solid-State Vibrational Circular Dichroism as Applied for Heterogenous Asymmetric Catalysis: Copper(II) Complexes Immobilized in Montmorillonite Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Hisako Sato; Kazuyoshi Takimoto; Jun Yoshida; Yutaka Watanabe; Akihiko Yamagishi
Solid-state vibrational circular dichroism (SD-VCD) spectra were measured on the ion-exchange adducts of sodium montmorillonite and [Cu(RR- or SS-oxa)]2+ as prepared in the presence of a substrate in Michael additions, (E)-2-butenoyl-2-oxazolidinone. Here RR- or SS-oxa denotes RR- or SS-2,2'-isopropylidene-bis(4-phenyl-2-oxazoline), respectively. By comparing the observed and theoretical VCD spectra
-
Synthesis and Structural Diversification of Artemisinins Towards the Generation of Potent Anti-malarial Agents Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Hiroki Oguri
Artemisinin and its semi-synthetic derivatives have been the corner-stone of malaria chemotherapy. Their life-saving therapeutic effects and characteristic structure bearing a peroxide bridge in a sesquiterpene lactone framework have attracted the attention of both synthetic chemists and synthetic biologists. In this highlighted review, the engineered biosynthesis, chemoenzymatic synthesis, total synthesis
-
Synthesis of Alkaline-soluble Triazine-based Poly(phenylene sulfide)s with Single/Double Pendant Carboxylic Acid Moieties and Their Application to Refractive Index Contrast Materials Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Tomoya Higashihara; Mao-Chun Fu; Kouji Hatakeyama; Shinji Ando; Ryosuke Takahashi; Mitsuru Ueda
The design, synthesis, and optical characterization of refractive-index-contrast (RIC) triazine-based poly(phenylene sulfide)s (PPSs) are investigated. Indeed, novel PPSs with two pendant groups, either tert-butyl (tBu) ester or carboxylic acid groups, at each monomer repeating unit (PPS-2E or PPS-2CA, respectively) were successfully synthesized. PPS-2CA showed high refractive index (n) values of 1
-
Recent progresses in spectroscopies using soft X-ray free-electron laser Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Iwao Matsuda; Yuya Kubota
Novel light sources have been new probes or “eyes” to develop our science and technology. Soft X-ray free-electron laser (SXFEL) is an ultrahigh brilliant soft X-ray source with ultrashort pulse-width, ultrahigh spatial coherence, and tunability of photon energy. Various experimental techniques are designed and examined with SXFEL. In this review, we focus on soft X-ray spectroscopies, such as magnetic
-
New Idea for Narrowing an Energy Gap by Selective Perturbation of One Frontier Molecular Orbital Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Kazuo Tanaka; Yoshiki Chujo
In this manuscript, we will illustrate a new idea for narrowing energy gaps between frontier molecular orbitals (FMOs) by selectively perturbing the levels of highest occupied molecular orbitals (HOMOs) and/or lowest unoccupied molecular orbitals (LUMOs). Initially, the basic concept of the isolated FMOs is explained by employing pentaazaphenalene (5AP) derivatives. It was found that electronic structures
-
Plasma Conversion of Toluene, Naphthalene, and Phenol as Model Tar Compounds in Simulated Synthetic Gas Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Ruiyang Xu; Hao Zhang; Fengsen Zhu; Petric Marc Ruya; Jianhua Yan; Xiaodong Li
A rotating gliding arc (RGA) reactor was investigated for conversion of multiple model tar compounds including toluene, naphthalene, and phenol in simulated synthetic gas, with special focus on the effects of steam concentration (0–20%) and preheating temperature (300–700 °C). The maximum conversions of toluene, naphthalene, and phenol were 89.3%, 84.6% and 95.5%, respectively, at a steam concentration
-
Designing and Exploring a Brand-new Strong Superhydrophobic-Conductive Polyaniline-Polysiloxane Composite Anti-corrosion Coating Chem. Lett. (IF 1.485) Pub Date : 2021-01-23 Haidong Xu; Qinqin Ye; Nali Chen; Huixia Feng; Jianhui Qiu
The superhydrophobic-conductive anti-corrosion mode has attracted much more attention due to the huge economic losses of stainless steel corrosion. Here, a brand-new strong superhydrophobic-conductive polyaniline-polysiloxane (PANIC-RA-POS) anti-corrosion coating was prepared. The internal conductive and dense interpenetrating network polyaniline layer can effectively reduce electrochemical corrosion
-
Preparation of Palladium Metal Intercalated between Graphite Layers with Low Palladium Loading for Cinnamaldehyde Hydrogenation Chem. Lett. (IF 1.485) Pub Date : 2021-01-22 Mika Sodeno; Hidetaka Nanao; Masayuki Shirai
Spherical palladium nanoparticles between graphite layers were prepared by the intercalation of palladium chloride followed by its reduction between graphite layers. The palladium particles intercalated between graphite layers were more active for cinnamaldehyde hydrogenation to hydrocinnamaldehyde and hydrocinnamyl alcohol in n-heptane solvent than those supported on graphite surface.
-
Hairy Particles Synthesized by Living Anionic Polymerization-Induced Self-Assembly and Evaluation of Their Nanostructure Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Toshiki Terao; Hibiki Shiraishi; Mikito Yamazaki; Teruaki Hayakawa; Noboru Ohta; Syuji Fujii; Yoshinobu Nakamura; Tomoyasu Hirai
Hairy particles consisting of polyisoprene-b-polystyrene (PI-b-PS) were synthesized by polymerization-induced self-assembly (PISA) based on living anionic polymerization method. The molecular aggregation state of the hairy particles in wet condition was investigated in detail. The hairy particles in wet state formed core-shell structure with PS core radii of 8.6 nm and PI shell thickness of 4.1 nm
-
—A Method to Prepare Hollow Spherical Hydroxyapatite Granules for Drug Delivery— Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Zhang Dong; Zhu XinWei; Li JinYuan; Zheng ZhaoLi; Liang TongXiang; Yang Hui
A suitable microenvironment provided by artificial granules scaffold plays a critical regulatory role in bone repairing progression. Till now, it is still a challenge to prepare large hydroxyapatite granules (millimetre level) which provide beneficial physical and chemical stimulation for bone reconstruction. Herein, we developed a facile synthetic strategy for synthesizing hydroxyapatite granules
-
Is Oxygen Diffusion Faster in Bulk CeO2 or on (111)-CeO2 Surface? A Theoretical Study Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Aditya Wibawa Sakti; Chien-Pin Chou; Yoshifumi Nishimura; Hiromi Nakai
Ceria (CeO2) is a promising metal-oxide support that is used in three-way catalysis (TWC). The activity of ceria-supported TWC depends on the location and concentration of oxygen vacancies. Oxygen diffusion can occur once the oxygen vacancy was created, and it leads to enhanced catalytic activity. In this study, the density-functional tight-binding method was used to estimate the free-energy barriers
-
Mechanoresponsive Behavior of Rod-Like Liquid Crystalline Luminophores on an Alignment Layer Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Mizuho Kondo; Taku Yamoto; Motoki Tada; Nobuhiro Kawatsuki
Mechanochromic luminescence (MCL) compounds exhibit change of their photoluminescent color in response to mechanical stimuli. The initial molecular alignment of a liquid-crystalline MCL compound was controlled by using an alignment layer. The rubbing method and rubbing direction were successfully determined. Influence of mechanical force on photoluminescent behavior was evaluated.
-
Potassium-Regulated Immobilization of Cortisol Aptamer for Field-Effect Transistor Biosensor to Detect Changes in Charge Distribution with Aptamer Transformation Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Shigeki Kuroiwa; Hiroki Hayashi; Ryo Toyama; Naoto Kaneko; Katsunori Horii; Keishi Ohashi; Toshiyuki Momma; Tetsuya Osaka
Salivary cortisol concentration and its circadian variation were detected by optimizing the ionic concentration of the solution during the immobilization of aptamers on a field-effect transistor biosensor. This was achieved by modifying our previously developed technique of detecting uncharged cortisol using the transformation of negatively charged aptamers by controlling the aptamer spacing. This
-
Hypervalent Organo-λ3-chloranes Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Kazunori Miyamoto; Masanobu Uchiyama
Hypervalent halogen species such as organoiodine(III and V) compounds have long been used as electrophiles/oxidants in organic synthesis, but recent years have seen the emergence of a new class of hypervalent halogen species, organobromine(III) and organochlorine(III) compounds (also termed organo-λ3-bromanes and λ3-chloranes). In this review, we will cover recent developments in the synthesis and
-
Water vapor reduces the effect of Cl-poisoning on CO oxidation over Pt/CeO2 heterogeneous catalysts Chem. Lett. (IF 1.485) Pub Date : 2021-01-21 Yuki Uchiyama; Junji Hyodo; Yoshihiro Yamazaki
The impact of water vapor on the catalytic activities of CO oxidation over Cl-containing Pt/CeO2 was investigated by combining catalytic activity tests, X-ray fluorescence spectroscopy, in-situ Fourier-transform infrared spectroscopy, and low-energy ion scattering. Water vapor reduced the density of chlorine adsorbates near the Pt-CeO2 interface. The utilization of hydroxyl groups near the cleaner
-
An Isolable Bromosilene: Synthesis, Structure, and Substitution Reactions Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Shunya Honda; Yushi Kato; Shintaro Ishida; Takeaki Iwamoto
Due to an intrinsically polar π-bond with a narrow π-π* gap, silenes (silicon-carbon doubly bonded compounds) should receive remarkable attentions as a member of π-conjugation units. We report herein synthesis, structure, and properties of an isolable bromosilene (1). Single-crystal X-ray diffraction analysis revealed the planar geometry around silene moiety with Z-configuration in 1. Substitution
-
Urea-accelerated Iridium-catalyzed 2-Position-selective C–H Borylation of Indole Derivatives Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Jie Wang; Takeru Torigoe; Yoichiro Kuninobu
We developed iridium-catalyzed 2-position-selective C–H borylation of indole derivatives by modifying the structure of a bipyridine-type ligand. The yields ranged from good to excellent, even on a gram scale, and were dramatically improved by the addition of a urea derivative catalyst. The introduced boryl group was converted to chloro, bromo, and phenyl groups without isolation of the borylated intermediate
-
Small Molecule-Based Alkaline-Earth Metal Ion Fluorescent Probes for Imaging Intracellular and Intercellular Multiple Signals Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Yuki Hiruta; Yutaka Shindo; Kotaro Oka; Daniel Citterio
This highlight review overviews recent progress in fluorescence imaging technology for the alkaline-earth metal ions calcium, and magnesium, by small molecule-based fluorescent probes. Fluorescent probes for Ca2+ using 1,2-bis-(o-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid (BAPTA) as a recognition unit are introduced. Focus is set on the fluorescence characteristics and intracellular dynamics of
-
Characterization of organic biomolecules (monosaccharide, fatty acid, and amino acid) by losses on ignition under stepwise increases in temperature Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Yuhi Satoh; Shigeki Wada
The characteristics of loss on ignition (LOI) at 200–500 °C of three types of authentic organic biomolecules (monosaccharides: MSs, fatty acids: FAs, and amino acids: AAs) are evaluated and compared to those of reference organic natural samples. FAs and branched-chain AAs degraded almost completely by 300 °C, whereas MSs and unbranched AAs degraded at a slower rate. The exponential regression coefficients
-
Ambidextrous Solid-State Magnetic Circularly Polarized Luminescence (MCPL) from Red-Green-Blue Color Inorganic Luminophores Without Molecular Chirality Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Takahiro Kimoto; Yuki Mimura; Michiya Fujiki; Yoshitane Imai
Herein, we report the example of red-green-blue full-color magnetic circularly polarized luminescence (MCPL) from three inorganic luminophores in their solid powder form and upon embedding in poly(methyl methacrylate) films; they were examined in the photoexcited state under the Faraday geometry with a 1.6 T permanent magnet in the absence of chiral chemical influences. The MCPL signs associated with
-
Ammonia Combustion Catalysts Chem. Lett. (IF 1.485) Pub Date : 2021-01-20 Satoshi Hinokuma; Kazuhiko Sato
Recent developments for ammonia (NH3) combustion catalysts are covered in this highlight review. NH3 has been proposed as a renewable and carbon-free energy source. However, use of NH3 fuel poses the problems of high ignition temperature and nitrogen oxide (N2O/NOx) production. In order to overcome these issues, a novel catalytic combustion system was probed, and high performance catalysts were developed
-
Photoinduced molecular reorientation of a liquid crystalline polymer with a high birefringence Chem. Lett. (IF 1.485) Pub Date : 2021-01-19 Toshiki Nishizono; Mizuho Kondo; Nobuhiro Kawatsuki
A photoalignable liquid crystalline (LC) polymer comprised of phenyl benzoate with a Schiff-base end moiety is synthesized and its thermally stimulated photoinduced reorientation behavior is investigated using linearly polarized (LP) 365 nm light. A significant in-plane reorientation (D>0.8) is achieved. The reoriented film exhibits a high birefringence (Δn=0.28) and a high thermal stability (~295
-
Ring closure reaction of 19-substituted bilinones to 5-oxaporphyrin metal complexes induced by Zn2+ and Cu2+ –Application to turn-on red fluorogenic probes for zinc ions– Chem. Lett. (IF 1.485) Pub Date : 2021-01-14 Kazuhisa Kakeya; Hiroyuki Fukagawa; Akihiro Teraoka; Tadashi Mizutani
The reaction of 19-phenoxybilinones with Zn2+ caused ring-closure to afford the 5-oxaporphyrin zinc complex under ambient conditions. While bilinones are non-fluorescent, the 5-oxaporphyrin zinc complex fluoresced red light. 19-Phenoxybilinone can be employed as a fluorogenic zinc ion sensor. Among various metal ions, only Zn2+, Cu2+ and Co2+ can induce the ring closure reaction to yield 5-oxaporphyrin
-
Donor-Acceptor Type [5]Helicene Derivative with Strong Circularly Polarized Luminescence Chem. Lett. (IF 1.485) Pub Date : 2021-01-14 Hiromu Kubo; Takashi Hirose; Daiki Shimizu; Kenji Matsuda
Circularly polarized luminescence (CPL) of unsubstituted helicenes is weak due to their low fluorescence quantum yield (Φf) and small dissymmetry factor (gCPL). In this study, we designed and synthesized a donor-acceptor type [5]helicene, 5,10-dicyano-2,13-bis(3,4,5-tris(n-octyloxy)phenyl)[5]helicene. This helicene showed high fluorescence quantum yield (Φf = 0.63) and good |gCPL| (4.2 × 10−3) due
-
Synthesis and Characterization of 5,5'-Bitetracene Chem. Lett. (IF 1.485) Pub Date : 2021-01-14 Masashi Mamada; Kenichi Goushi; Ryota Nakamura; Hironori Kaji; Chihaya Adachi
A tetracene dimer, 5,5'-bitetracene (55BT), has successfully been synthesized for the first time and its structure was confirmed by X-ray single crystal analysis. The electrochemical and optical properties of 55BT were investigated and compared to those of tetracene. Although the photoluminescence quantum yield of 55BT was slightly higher than that of tetracene, the results of the transient absorption
-
Strain-Release Difunctionalization of C–C σ- and π-bonds of an Organoboron Ate-Complex through 1,2-Metallate Rearrangement Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Haruki Mizoguchi; Akira Sakakura
This highlight review describes the recent development of an electrophile-triggered 1,2-metallate rearrangement of organoboronic ester ate-complex, which proceeds through 1,2-difunctionalization of carbon–carbon σ- and π-bonds, using strain energy as a driving force. Coupling reactions of small ring carbocyclic boronic esters, such as cyclopropyl-, bicyclo[1.1.0]butyl-, and cyclopropenyl-boronic ester
-
Tuning of Lewis Acidity of Phebox-Al Complexes by Substituents on the Benzene Backbone and Unexpected Photocatalytic Activity for Hydrodebromination of Aryl Bromide Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Shuichi Nakao; Yoshihiro Nishimoto; Makoto Yasuda
We revealed the effects of the substituents in ligands on properties of Phebox-aluminum complexes. The substituents at the 4-position of Phebox ligands effectively influenced the Lewis acidity via the conjugation between the vacant orbital on the Al atom and π* orbital of the benzene ring, which is supported by DFT calculation. The catalytic activity was also tuned, and series of substituted Phebox-Al(ClO4)2
-
Homogeneous Helical Nanofibers of 12-Hydroxystearic Acid and Long-Chain Amidoamine Derivatives Prepared by Tuning the Gelation Solvent Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Muneharu Minakawa; Makoto Nakagawa; Ke-Hsuan Wang; Yoshiro Imura; Takeshi Kawai
We previously showed that the hybridization of water-insoluble 12-hydroxystearic acid (HSA) with water-soluble long-chain amidoamine derivatives yields hydrogels composed of self-assembled helical nanofibers. In this work, we investigated the effect of introducing an amide group into the alkyl chain of amidoamine derivatives on the helical structure of the nanofibers. We also demonstrated that improving
-
Conductive Boron-Doped Diamond Powder/Nanoparticles for Electrochemical Applications Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Takeshi Kondo
Boron-doped diamond powder (BDDP) and boron-doped nanodiamond (BDND) were developed with the aim of expanding the area of application of conductive diamond electrodes. BDDP and BDND are conductive diamond powders obtained by depositing a boron-doped diamond (BDD) layer on the surface of diamond powder (DP) and nanodiamond (ND) substrates, respectively, by using the chemical vapor deposition method
-
CuCl/AgSbF6 and Rh2(OAc)4 Comparison for the Synthesis of N-O Tethered Three and Five Membered Rings via Diazo Chemistry Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Gokce Merey; H. Nur Kubilay; Olcay Anac
Diazocarbonyl compounds are versatile precursors of carbenes leading to various structures by using several metal catalysts, especially copper and rhodium salts. In this study, eight different diazocarbonyls having N-O moiety were used. The N-O tethered structures were preferred because they may allow some useful transformations of the final products into valuable compounds via N-O cleavage. In the
-
Polariton Chemistry in Cavity Vacuum Fields Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Kenji Hirai; Hiroshi Uji-i
Even without external photon pumping, cavity vacuum fields can be strongly coupled with molecular transitions (electronic excitation and molecular vibration), resulting in the formation of polaritonic states. The energy states of molecular systems are altered under strong coupling, revealing intriguing phenomena, such as improvements in energy/exciton transfer and modulation of chemical reactions.
-
Critical Roles of Surface Oxygen Vacancy in Heterogeneous Catalysis over Ceria-Based Materials: A Selected Review Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Ching-Hsiu Chung; Fang-Yi Tu; Te-An Chiu; Tung-Ta Wu; Wen-Yueh Yu
Surface oxygen vacancy, dynamically created and annihilated under the reaction conditions, may serve as a unique form of active site for heterogeneous catalysis. In this study, the mechanisms of selected reactions (i.e., CO oxidation, water-gas shift, CO2 hydrogenation, alcohol carbonation, and selective catalytic reduction of NO with NH3) proposed by in-situ spectroscopy characterizations were reviewed
-
Chiral Magnetism: Coupling Static and Dynamic Chirality Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Katsuya Inoue
The synthesis, structure, magnetic properties and magnetic structure of two molecular chiral magnets and one inorganic chiral magnet are presented. In magnetic crystals belonging to the Sohncke group, which includes the chiral group, the chiral non-collinear spin structure is achieved through Dzyaloshinsky-Moriya interactions in addition to the usual exchange spin interactions and dipole-dipole spin
-
Influence of reaction temperature on CO2-to-methanol hydrogenation over MZrOx (M = Al, Mn, Cu, Zn, Ga, and In) Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Shohei Tada; Kenta Iyoki
To open up the possibility of synthesizing useful substances from CO2, we have developed new catalysts that hydrogenate CO2 to methanol with high yield at 300 °C and higher. In this study, methanol synthesis via CO2 hydrogenation at 250–350 °C and 10 bar was investigated using Zr-based metal oxide catalysts, MZrOx (M = Al, Mn, Cu, Zn, Ga, and In). The different metals (M) determined the suitable reaction
-
Research Progress on Improvement of Conductivity of MOFs and Its Application in Bionsensors; A Review Chem. Lett. (IF 1.485) Pub Date : 2021-01-13 Bin Shao; Hongshuo Chen; Chuanjin Cui; Jing Li; Ruikun Gonge
Metal organic framework materials (MOFs) have a drawback that limits its wider application: poor electrical conductivity. In this paper, some research advances in improving the conductivity of MOFs in recent years are reviewed. They are divided into two categories: intrinsical improvement of conductivity and extrinsic improvement of conductivity. The application of MOFs with improved electrical conductivity
Contents have been reproduced by permission of the publishers.