Amphoteric diblock copolymers (S10Vn, n = 5, 10, and 20) composed of anionic poly(sodium p-styrenesulfonate) and cationic poly(vinylbenzyl trimethylammonium chloride) blocks were prepared via a controlled radical polymerization method. S10V10 was insoluble in pure water owing to its electrostatic interactions, but S10V5 and S10V20 were soluble in pure water. S10V5 and S10V10 exhibited upper critical solution temperature behaviors, and the transition temperature decreased with increasing sodium chloride concentration.
We develop a new ZnO nanowire (NWs) array knock sensor based on a piezoelectric nanogenerator. The ZnO NWs arrays generated by the hydrothermal method are deadlocked so that the tops of the two arrays are in contact with each other to form a closed circuit, thereby generating a new type of piezoelectric nanogenerator. On this basis, the ZnO NWs array knock sensor was developed for the first time with this piezoelectric nanogenerator as the crux element and installed on an engine to measure the voltage characteristics. By comparing the low-speed and high-speed output voltage characteristics of simulated knocking, high-intensity knocking can output a larger voltage, while knocking can generate a higher voltage within 0.02 s.
Considering the drawbacks associated with fossil-based molecules, polymers and materials, lignin has acquired immense popularity owing to its distinct advantages. However, to 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 aromatic chemicals. This highlight review summarizes the key investigations carried out in the field of lignin valorization, purification and the valuable products generated from lignin.
This review covers a brief discussion about the advantages and challenges associated with the current lignin depolymerization technologies, their separation techniques and the promising end-use applications of the lignin-derived compounds.
Circularly polarized luminescence (CPL) has attracted significant attention in the fields of chiral photonics and optoelectronic materials science. In a CPL-emitting system, a chiral luminophore derived from chiral molecules is usually essential, and a pair of enantiomeric luminophores is indispensable for the typical selective-emission of right- and left-handed CPL. This review focuses on non-classical CPL systems that do not use pairs of enantiomers and introduces symmetry-breaking CPL systems that do not use optically active molecules, and covers photoexcited chiral-switching, spontaneous-resolution, cryptochirality, and magnetic CPL.
Non-classical circularly polarized luminescence (NC-CPL) system is a method that uses no pair of enantiomeric molecules and symmetrybreaking CPL (SB-CPL) system is a method that uses no optically active molecules. These NC-CPL and SB-CPL systems produce photoexcited chiral-switching, spontaneous-resolution, cryptochiral, and magnetic CPL.
The synthesis of biocompatible nanomaterials from synthetic organic molecules, as well as the spin state switching of spin crossover complexes, are presently of interest. However, in the case of labile Fe2+ complexes, it is challenging to induce dynamic transitions using supramolecular strategies. In the present work, highly organized structures made of glycyrrhetinic acid polyglycosides induced equilibrium between low and high spin states in an [Fe(TACN)2]2+ complex. Hybrids composed of these polyglycosides with this complex exhibited nanostructures such as nanosheets in addition to spin crossover phenomena and changes in oxidation state. Glycyrrhetinic acid polyglycoside derivatives also demonstrated an extremely low degree of change in spin crossover and resistance to oxidation state changes. The present technique of combining naturally occurring molecules with discrete coordination complexes is expected to allow the design of flexible, stimuli-responsive supramolecular coordination systems.
Nowadays, exploring the chemistry of curved π-conjugated molecules is one of the big trends in organic chemistry. Recently, research interests have been shifted to heteroatom containing analogs. Among these, bowl-shaped π-conjugated molecules with heteroatoms included within their skeletons have gained interest due to their synthetic difficulty and have been developed dramatically as a motif for heteroatom-doped carbon materials. Here, this review highlights analogs based on polycyclic aromatic hydrocarbons, represented by triangulenes, sumanenes and corannulenes, with heteroatoms. These studies have disclosed the effect of heteroatoms in curved π-surfaces.
Nowadays, chemistry of curved π-conjugated molecules is one of the big trends in organic chemistry. Among these, bowl-shaped π-conjugated molecules containing heteroatoms have gained interest due to their synthetic difficulty and as a motif for heteroatom-doped carbon materials. This review highlights the analogs based on polycyclic aromatic hydrocarbons with heteroatoms. These researches have disclosed the effect of heteroatoms in curved π-surface.
Non-graphitized carbons attract interest as anode materials for high performance batteries. Therefore, a 3D soft and hard carbon composite material with controlled pores via dual-salt assisted strategy was fabricated and applied to potassium ion batteries (PIBs). The eutectic salt plays an important role as template while inhibiting the graphitization of carbon. The obtained porous composite material has a connected pore structure and a large interlayer spacing, which is beneficial to the diffusion and insertion of potassium ions. The material exhibits considerable potassium storage performance in terms of high reversible capacity, excellent rate capability and long cycling stability. The storage mechanism of potassium has been also explored. The present study provides a new insight for the development of anode materials for potassium ion batteries.
We describe a modification of the lactate biofuel cell to increase its capacity. A new multi-step enzyme reaction system without NAD was prepared using a bioanode modified with lactate oxidase, pyruvate decarboxylase, and pyrroloquinoline quinone-dependent aldehyde dehydrogenase. Its operating time was 6 times longer than that of the biofuel cell using the lactate oxidase-modified bioanode at constant current measurement of 1 mA cm−2 because of suppression of the diffusion overpotential due to the decrease in the fuel concentration.
Derivatives of a new tris-fused donor composed of two vinyl-extended TTF (EBDT) units and one extended TTF with an anthraquinoid spacer (TTFAQ) (3a–c and 4a) were successfully synthesized. X-ray structure analysis of the tetrakis(methylsulfanyl) derivative 3b revealed that the TTFAQ unit adopts the so-called saddle conformation similar to most the neutral TTFAQs, and that half of the 3b molecules are stacked with each other. Cyclic voltammetry suggested that two positive charges in 3b2+ and 4a2+ were mainly distributed on the EBDT units, while two positive charges of 3c2+ were mainly located on the TTFAQ unit.
The electrochemical behavior of uranium (IV) tetrachloride in ionic liquid–DMF mixture was studied for the first time in order to build a redox flow battery (RFB) using U as an electrode active material. A quasi-reversible UIII/UIV couple was observed in an [EtMeIm][Tf2N]–DMF mixture (1:1 v/v) at 298 K and the reversibility improved by the addition of Cl−. The repeatability of UIII/UIV couple was high. These results indicated that the UIII/UIV couple is suitable for the anode reaction of the RFB.
Water at interfaces plays essential roles in many natural phenomena and engineering applications. However, the molecular behavior of interfacial water is still a matter of intense debate. Thus far, many experimental and theoretical methods have been employed to elucidate the real picture (structure, dynamics, hydrogen bonding states, etc.) of interfacial water and its relevance to interfacial phenomena and material functions. The author reviews these works and discusses the principles and limitations of the analytical methods. The significant representative findings on water-mediated interfacial phenomena are also introduced.
In this review, the author introduces experimental and theoretical approaches to investigate water at interfaces. The principles and their limitations, and essential findings in this field are also discussed.
Herein, we report palladium-catalyzed decarboxylative α-polyfluoroarylation of ketones. As a result of reaction condition screening, XPhos and Ruphos were selected as ancillary ligands for Pd(0) catalysts. The reaction was applied to a variety of substrates. A cross-over experiment was conducted to gain insight into the reaction mechanism.
The title electron acceptors are planar molecules undergoing reversible two-stage one-electron reduction processes. In the crystal of selenadiazole derivative (1), tetrameric structure is formed by two kinds of chalcogen bond (ChB), which is further connected by ChB and weak hydrogen bond (WHB). Although sulfur analogue (2) has only weaker ChB, it crystallizes isomorphously to 1 forming ChB-tetramer, thus contribution from ChB is more dominant than WHB in determining the crystal packing, which is different from the corresponding tetracyanoquinodimethane analogues.
This paper demonstrates structural analysis for single detonation nanodiamond (DND) particles, with a size below 6 nm, by tip-enhanced Raman spectroscopy (TERS). Single DND particles show Raman spectra different from that of the aggregates obtained by conventional micro-Raman spectroscopy. Our results suggest that single-particle TERS measurement is a promising technique for revealing structural distribution of individual DND particles and its dependence on synthesis conditions.
Antisense oligonucleotides (AS-ODNs) attach to mRNA in a sequence specific manner and eventually inhibit protein expression. The target mRNA locates in cytoplasm; therefore AS-ODNs must be delivered there. We have shown that a β-1,3-glucan schizophyllan (SPG) forms a macromolecular complex with AS-ODNs and the complex is up-taken by a cell expressing a β-1,3-glucan receptor. The number of the AS-ODNs in this complex had a distribution, in a range of 2–10. Recently we successfully isolated a complex containing only one AS-ODN molecule. The aim of this letter is to evaluate the delivering efficacy of this new monodisperse low molecular weight complex, comparing with the previous one.
Brønsted acidic deep eutectic solvent (DES) formed from 1:2 mole ratio of imidazole (Im) and p-toluenesulfonic acid (PTSA) [Im:2PTSA] was applied for the first time to synthesize 4-phenyl-1,3-dioxane (PDO) through Prins condensation of styrene with formaldehyde. The DES [Im:2PTSA] intensified the Prins condensation by breaking up the balance limitation of phase interface between organic styrene and aqueous formaldehyde, increasing the compatibility of both phases, and promoting PDO formation.
Bicontinuous cubic liquid-crystalline assemblies were obtained by mixing a polymerizable ionic liquid with a glycolipid. Polymerization of the ionic liquid in the molecular assemblies was achieved by UV irradiation in the presence of a photoinitiator, which provided a quasi-polymer film preserving the bicontinuous cubic assemblies with a gyroid nanostructure.
Coordination-driven self-assembly of metal ions and organic ligands has been extensively applied over the past few decades, towards construction of various functional two-dimensional (2D) and three-dimensional (3D) architectures. The majority of these structures are homoleptic in nature, consisting of one type of ligand. However, the functionality of self-assembled complexes can be potentially increased by increasing their complexity. To address this, recent efforts have been concentrated on synthesis of heteroleptic complexes composed of more than one type of ligand. This review article highlights the recent developments of 2,2′:6′,2′′-terpyridine (tpy)-based self-assembled heteroleptic coordination complexes. The first part of this review collects examples of heteroleptic tpy complexes constructed in a stepwise manner with metalloligands as primary components, and the one-pot strategies are described in the second part.
Coordination-driven self-assembly has been widely used in construction of various functional two- and three-dimensional architectures. The functionality of self-assembled complexes can be potentially increased by increasing their complexity. Hence, the substantial efforts have been devoted to preparing heteroleptic complexes composed of more than one type of ligand. This review article highlights the recent developments of 2,2':6',2''-terpyridine (tpy)-based heteroleptic complexes.
We investigated the effect of succinic anhydride (SA) addition on electrochemical behavior of magnesium (Mg) metal electrodes. A sufficient amount of SA addition suppressed the decomposition of the anion and the formation of the carbonated layer. This made it possible to suppress the passivation of Mg metal, and revealed that the cross-section surface with high electrochemical activity had a significant effect on the electrochemical behavior of Mg metal electrodes.
To prevent dendrite formation by metallic lithium (Li) on the negative electrode in Li-S batteries, the use of a Li-intercalated carbon electrode and Li-pre-doped Li-S cell is proposed. These two cell systems achieved adequate charge-discharge performance for next-generation cell systems, even under severe input-output demands, owing to the use of a graphite negative electrode. Combination of enhanced cell safety and ease of cell production was successfully achieved.
Periodate ion (IO4−), as a high-value-added chemical reagent, could be produced photoelectrochemically on a WO3 photoanode in NaIO3 aqueous solution under simulated solar light irradiation. The faradaic efficiency to IO4− (FE(IO4−)) reached 82% in 0.1 M NaIO3 aqueous solution. The FE (IO4−) was greatly affected by the concentration of alkaline cation as well as IO3− ion.
In solvent freezing, polyurethane gels cross-linked with tetraarylsuccinonitrile (TASN) moieties which can be cleaved to afford pink-colored and yellow-fluorescent radicals by mechanical stress, show mechano-activated fluorescence based on dissociated TASN radicals and provide a consistent reaction field with vinyl monomers. We herein propose a toughening of a polymer network via freezing-induced mechanochemistry. Through the consistent reaction field, the toughness of resulting polymer networks can be changed by the number of repeated freeze-thaw cycles and the concentration of dissociated TASN radicals.
Hydrogel microspheres (microgels) are water-swollen, soft colloidal particles composed of cross-linked hydrophilic or amphiphilic polymer chains. Due to their fascinating properties such as biocompatibility, colloidal stability, and rapid stimulus responsivity, microgels are expected to find numerous applications in a wide variety of fields. The understanding and development of microgels with colloidal-sized dimensions has been propelled in particular by visualization techniques. Their history and recent progress in microgel evaluation using such visualization techniques are summarized in this review.
Hydrogel microspheres (microgels) are water-swollen, soft colloidal particles composed of cross-linked hydrophilic or amphiphilic polymer chains. The understanding and development of microgels with colloidal-sized dimensions has been propelled in particular by visualization techniques. Their history and recent progress in microgel evaluation using such visualization techniques are summarized in this review.
A hollow-shaped caged triarylphosphine with three bulky triarylmethyl substituents at the positions meta to the P atom was synthesized. Its gold(I) complex was synthesized and characterized by NMR spectroscopy and X-ray diffraction analysis. A cationic gold(I) complex with this ligand was applied to 1,8-enyne cycloisomerization.
Chlorination of triptycene tribenzoquinone 1H using sulfuryl chloride gives new perchlorinated derivative 1Cl, which exhibits a significantly enhanced electron-accepting property compared to 1H. Unlike 1H, due to complementary nested packing and π-stacking of the chlorinated benzoquinone blades in the crystal, 1Cl forms two-dimensional (2D) arrays, which stack up into a multi-layered structure. Considering the particular structure-forming ability, together with its strong electron-accepting property, 1Cl would provide an interesting building block for the design of 2D electronic organic materials.
Methods that can rapidly and accurately extract or isolate nucleic acids would facilitate the capability for scientists to access key information regarding nucleic acid molecular signatures. Knowing these molecular signatures could contribute to development of strategies for detecting, treating, and diagnosing diseases based on nucleic acids. However, major impediments to accessing nucleic acids are their natural characteristics, including concentration and size. Here we review the development of nanomaterial-based devices to isolate circulating nucleic acids from biological samples, including blood, urine, cell, and virus; these devices enable enhancement of isolation and extraction efficiency compared to conventional methods.
In this review, we summarize the recent development of nanomaterial-based devices to isolate circulating nucleic acids from biological samples, including blood, urine, cell, and virus as powerful alternatives to conventional tools, which would facilitate the capability for scientists to access key information regarding the nucleic acid molecular signatures used in molecular diagnostic.
This paper proposes a technical approach for seamlessly setting the conditions of continuous flow synthesis from batch data. We directly detected the acid chloride formation from Fmoc-l-Phe-OH in batch using the in-line monitoring technology ReactIR and logically calculated the residence time under continuous flow conditions based on kinetic study. Assisted by this simulation method, the sequential flow operations, which consist of acid chloride formation from Fmoc-l-Phe-OH, cooling and coupling with Fmoc-l-Phe-Cl and H2N-l-Phe-OMe, were completed in approximately 1 min.
Spin crossover iron(III) compounds containing the tridentate Schiff base ligand and its cocrystal, [Fe(acpa)2]I (1) and [Fe(acpa)2][1,3,5-TITFB(I−)] (2) (Hacpa = N-(1-acetyl-2-propylidene)(2-pyridylmethyl) amine, 1,3,5-TITFB = 1,3,5-triiodotrifluorobenzene), were synthesized and their crystal structures and magnetic properties characterized in detail. 1 exhibits abrupt spin crossover (SCO) behavior (T1/2 = 182 K) with thermal hysteresis loop being 23 K while showing gradual SCO behavior for 2 without thermal hysteresis loop.
This review discusses methods for increasing the efficiency of photoelectric conversion systems using photosystem I (PSI) and photosystem II (PSII) isolated from thermophilic cyanobacteria. The structure and electron transfer pathways for PSI and PSII are described, followed by a description of a new type of photoelectric conversion system and its application in light-sensing devices using PSI or PSII. Photoelectron transfer is demonstrated by spectroscopic and electrochemical measurements. A strategy to enhance photocurrent intensity is described, involving wiring photosynthetic reaction centers onto a self-assembled monolayer on an electrode. We review the fundamental concept behind these semi-artificial photosynthetic systems, as well as representative examples from published papers, including those from our laboratory.
This review discusses methods for increasing the efficiency of photoelectric conversion systems using photosystem I (PSI) and photosystem II (PSII) isolated from thermophilic cyanobacteria. Fabrication of photoelectric conversion systems and their applications in light-sensing devices using PSI or PSII are described. A strategy to enhance photocurrent intensity is also described, involving wiring photosynthetic reaction centers onto a self-assembled monolayer on an electrode.
Electric switches are one of the most fundamental electric circuitries. Recent developments in single-molecule techniques allow us to study various electric-switching phenomena on the single-molecule scale. In this study, the switch of the current through a single molecule of a biphenothiazine derivative was investigated using the break junction technique. The biphenothiazine derivative undergoes acid-base reaction-induced electronic modulation due to the reversible structural transformation between a closed shell and an open shell, resulting in a change in the electronic gap and effective tunneling barrier height. We succeeded in controlling the single-molecule electric conductivity of the biphenothiazine derivative wired to two Au electrodes by allowing the reaction to proceed reversibly on the electrode.
Liquid marble (LM) can be prepared by the adsorption of hydrophobic powder on the gas–liquid interface of a water droplet. Generally, LM is prepared using hydrophobic powder with a size of >100 nm. LM is opaque and the inside of LMs cannot be observed because the surface powder adsorbs and scatters the visible light. In this study, a pH-responsive clear LM (CLM) is prepared using tertiary amino groups containing hydrophobic silica particles with a diameter of ∼20 nm. The shape of CLM changed under acidic conditions, because the tertiary amino groups on the silica particles became hydrophilic under these conditions.
Pheophorbide a (Phed-a), a naturally occurring chlorophyll catabolite, has been receiving much attention as a biologically-derived photosensitizer in photodynamic therapy (PDT) because of its high phototoxicity even in anoxic environments. Interaction of phed-a with G-quadruplex DNAs possessing a variety of folding topologies has been investigated to elucidate the molecular recognition of G-quadruplex DNA by phed-a, which is crucial to determine its PDT efficacy in tumor hypoxia. We found that phed-a binds selectively to the 3′-terminal G-quartet of parallel G-quadruplex DNAs.
This highlight review overviews our recent advances on enantioselective propargylic substitution reactions catalyzed by transition metal complexes including cooperative and hybrid catalysts for the last 15 years.
This highlight review overviews our advances on enantioselective propargylic substitution reactions catalyzed by transition metal complexes including cooperative and hybrid catalysts for the last 15 years.
In this study, a rapid prototyping method for droplet generators using pipette tips and glass capillaries (pipette-tip-shelled capillary microfluidic device (PiT-CMD)) is described. The proposed device can be fabricated without precise concentric alignment. The reproducibility of the device and controllability of the droplet size are examined by simulations and experiments. The variation in droplet size among different devices was less than 5%, reflecting the high reproducibility of the device. Moreover, bead encapsulation using a PiT-CMD is demonstrated.
We report a facile method for preparation of amphiphilic Janus silica nanospheres using layered double hydroxide as a protective support. The unprotected part of silica nanospheres is modified with a hydrophobic reagent. This type of Janus silica nanospheres can be used as a novel colloidal surfactant for stabilization of the Pickering emulsion for at least 2 months.
Vanadium nanoparticles were produced by laser ablation of a vanadium metal plate in a reductive aqueous solution. Transmission electron microscopy and electron energy-loss spectroscopy revealed that the nanoparticles had an average diameter of 13.2 nm, and consisted of a metallic vanadium core with a slightly oxidised surface. Although vanadium nanoparticles produced in pure water dissolved quickly, mainly as V(V) ions, those produced in a reductive aqueous solution with trisodium citrate and sodium dodecyl sulphate were dispersed for a few hours.
An organic viologens/TEMPO-SO3K aqueous flow battery with neutral NaCl solution as supporting electrolyte was proposed, and the battery cycling process was further explored. During the charging/discharing process, the side reactions, such as hydrogen evolution reaction (HER), chlorine evolution reaction (CER) and oxygen evolution reaction (OER), inevitably occurred and changed the pH value of electrolyte, further influencing the redox reaction activity of active material. To balance the pH change, addition of alkaline solution to the anolyte was proposed. A significant enhancement of the cycling stability was observed, and only 5.4% capacity decay was presented after 1200 cycles.
Advancement in synthetic materials chemistry has brought about a new family of two-dimensional nanostructures (nanosheets) which have a variety of promising applications. In particular, synthesis of platinum group metal (PGM) oxide nanosheets such as RuO2 and IrO2 and PGM nanosheets (Pt, Ru, Rh, Pd, etc) have attracted researchers owing to the advantages of nanosheets versus nanoparticles, and the wide range of applications that PGM materials may realize. This highlight review will provide a summary of state-of-the-art PGM nanosheets and a critical assessment on the possible applications of the innovative nanomaterials.
Nanosheets represent a new family of two-dimensional nanostructures with a variety of promising applications. Platinum group metal and metal oxide nanosheets have attracted particular interest owing to the advantageous contrasted with nanoparticles. Here, we will provide a summary of nanosheets based on platinum group metal and some conceivable applications of the innovative nanomaterials.
Natural sphingosine analogues containing a β, β′-dihydroxy α-amino acid framework demonstrate potent antifungal or immunosuppressive activity and are potential candidates for the development of chemical tools or pharmaceuticals. This Highlight Review presents the total syntheses of sphingosine analogues, myriocin, mycestericins and sphingofungin E, focusing on the strategies used for stereoselective construction of the quaternary α-amino acid motif embedded in these sphingosine analogues. Various methods have been developed, including C–C/C–N bond formation and desymmetrization strategies, leading to the development of efficient and divergent synthetic routes.
This Highlight Review sheds light on the total syntheses of myriocin, mycestericins and sphingofungin E, focusing on the strategies for stereoselective construction of the quaternary α-amino acid motifs embedded in these sphingosine analogues. Various methodologies have been developed, including the C-C/C-N bond formation and desymmetrization strategies. These efforts have led to the development of efficient and divergent synthetic routes to these sphingosine analogues.