Local chemical functionalization of single-walled carbon nanotubes (SWCNTs) has been developed as a means of defect doping to enhance the near infrared photoluminescence properties of the materials. Wavelength-tunable and exciton trapping-induced bright emission appears from locally functionalized SWCNTs (lf-SWCNTs). Molecularly designed lf-SWCNTs based on our approach produce new dynamic switching functionalities and greater shifts of the emission wavelength, which gives unique exciton properties to lf-SWCNTs.
Molecular assembly is a widely applied synthetic strategy for the construction of multimolecular architecture at a nanoscale or microscale that can simultaneously target numerous components. Upon the control over size, shape, valency, etc., molecular assembly can fulfill demands to regulate cellular responses even cell fate by approaching different cellular sub-organelles as potential cancer therapy.
In chain-growth polymerization, the polymerization behaviors are governed by the nature of monomer depending on the side-chain structure (e.g. conjugated/non-conjugated, electron-rich/deficient), leading to limitations in (co)polymers we can synthesize. This highlight review summarizes recent development in polymer reactions to overcome such limitations. The key is the design of transformable monomers as well as the utilization of novel organic transformations.
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 bio-hybrid devices based on bilayer lipid membranes.
We present a layer-by-layer functionalization of gold nanorods (GNRs) by polyelectrolytes in order to control precisely the spacer surrounding the metallic nanoparticles but also to modulate its plasmonic properties. Alternate functionalization with negatively and positively charged polyelectrolytes ensures a 2 nm step control of the spacer from 0 nm up to 10 nm, depending on the number of layers. Such process changes the local refractive index and thus induces a red shift of the surface plasmon resonance. Both solution and solid samples were studied.
The ring hydrogenation of 4-propylphenol in aqueous ethanol solution was studied over graphite- and activated carbon-supported palladium catalysts (Pd/G and Pd/C) with 0.1–5 wt % of palladium loadings without using external hydrogen. Decomposition of ethanol produced hydrogen which was responsible for the hydrogenation of 4-propylphenol over palladium metal particles on both the supports in aqueous medium. The different hydrogenation behaviors were discussed based on surface properties of supports.
The relationship between the polymorphism and dynamic properties of acyl chains in triacylglycerols (TAGs) was studied using incoherent quasielastic neutron scattering (IQENS). The influence of cis- and trans-unsaturation was also investigated by comparing the following monoacid TAGs, tristearin, trielaidin, triolein, and trierucin. Glycerol-deuterated TAG samples were employed for the IQENS measurements to reduce the incoherent scattering of the glycerol backbone. Irrespective of the difference of acyl chains, these TAGs showed similar dynamical properties under the same temperature and polymorph. The molecular motion in the β phase with tightly-packed acyl chains showed the characteristics of a harmonic oscillator up to 300 K. In contrast, the α phase with loosely-packed acyl chains started diffusive molecular motions around 190 K.
A molecule-based mixed conductor of proton and electron was synthesized by modifying a nickel(III) dithiolene complex with 1,4-naphthoquinone skeletons. The complex forms a π-stacking column flanked by an infinite hydrogen-bonding chain of water molecules. Room-temperature (RT) proton conductivity was 7.2 × 10−7 S cm−1, which is derived from protons attached to carbonyl oxygens through the chain of water molecules. The compound also shows a relatively high RT electronic conductivity of 4.1 × 10−3 S cm−1 and semiconducting behavior with a small activation energy of 66 meV, which originates from the π-stacking column composed of the neutral radical complexes.
A novel copper(I)-mediated C–N/C–C bond-forming reaction involving tetrafluoroethylene (TFE), imidazolide or benzimidazolide salts, and aryl iodides has been developed. This three-component coupling reaction can provide highly functionalized N-fluoroalkyl heteroaromatic compounds in up to 98% yield via a one-pot procedure. The azacupration of TFE with the copper(I) imidazolide species to afford the fluoroalkylcopper(I) complex is the key process in the transformation.
Vanadium slag usually contains 13.52–19.03 mass % V2O3 and 6.92–14.35 mass % TiO2. The V in vanadium slag is effectively extracted by traditional methods, whereas Ti, a valuable metal, cannot be used. To effectively utilize the Ti, a new method for preparing TiO2 from vanadium slag via AlCl3 chlorination-TiCl4 hydrolysis was proposed in this work. The chlorination of Ti in vanadium slag, thermodynamics of hydrolysis of metal chlorides (TiCl4 and AlCl3), and hydrolysis of chlorides were investigated. Rutile TiO2 containing a small amount of impurities (1.58 mass % Al and 2.03 mass % Cl) was synthesized.
We report that mixed-halogen anti-perovskite-type Li2OHBr1−xXx (X = Cl, I and x = 0–1) materials are prepared by room temperature ball-milling process, and investigate how the halogen mixing affects the total Li+ conductivity. Both solid solution ranges and lattice constants depend on the species of X. Among them, though X = I compounds form solid solution in narrow range of x smaller than 0.15, Li2OHBr0.9I0.1 shows the largest lattice constant and the highest total ionic conductivity at 25 °C (σ25) of 4.9 × 10−6 S cm−1, which is ca. 4 times higher value than that of pristine Li2OHBr. Increasing the lattice constant will be one of the factors to improve total ionic conductivity of the Li2OHBr1−xXx.
Wearable energy storage electronics with high safety and long life have been promising candidates in recent years. Herein, all-solid-state planar micro-supercapacitors (MSCs) were demonstrated by inkjet printing of molybdenum disulfide (MoS2) electrodes. The preprinted PEDOT: PSS film on PI (Polyimide) substrate prepared with a simple and low-cost desktop inkjet printer can greatly improve the electrode conductivity. Additionally, the obtained planar MSCs show good electrochemical performance with high areal capacitance of 323 µF cm−2 and areal energy density of 0.016 µWh cm−2. More importantly, the MSCs exhibit outstanding flexibility with almost no degradation under various bending angles. The capacitance retention can still be maintained at 88.5% even after 8000 cycles, indicating good cycle stability of MSCs. The in-plane flexible MSCs hold great application potential for wearable and integrated energy storage electronics.
The annulative coupling of secondary benzyl alcohols with internal alkynes efficiently proceeds in the presence of a silver catalyst. The reaction gives 1,2,3-substituted indene derivatives selectively as 1:1 coupling products. The procedure provides a straightforward synthetic route to indenes from readily available starting materials upon treatment with a simple reaction system under mild conditions.
Rational molecular design enables the development of stimuli-responsive supramolecular hydrogels. Biocompatible supramolecular hydrogels have great potential for medicinal and pharmaceutical applications. In this review, we focus on supramolecular hydrogels, which show gel-to-sol phase transitions in response to biological-stimuli, and biological-stimuli-induced supramolecular hydrogel formations.
A highly deformable hydrogel, viologen pendant poly-L-lysine-based glutaraldehyde cross-linked hydrogel (PLLV-GA-gel), was characterized using surface-enhanced Raman scattering (SERS) signals under electrochemical control on a roughened Au electrode surface. We found that one-electron reduced forms remain near the electrode surface, preferentially as a dimer, even at the potentials at which all the viologens should be of a further reduced state. Implications of the SERS data were discussed in terms of heterogeneity and dimerization of one-electron reduced form viologens.
An efficient enantioselective acylative desymmetrization of cyclic meso-1,3-diols was developed by using a chiral DMAP derivative 1e having a 1,1′-binaphthyl unit. The reactions required only 0.5 mol % of the catalyst and showed good to excellent enantioselectivity. With this transformation, 5a, a key building block for the synthesis of natural products, was easily obtained in almost enantiomerically pure form after a single recrystallization. Control experiments revealed that tert-alcohol units on the catalyst were responsible for both the catalytic activity and enantioselectivity.
The core technologies of fully automated organic synthesis include the management of large amounts of accumulated reaction examples, machine learning based on these experimental results, and subsequent development of synthesis devices. Digitization of organic synthesis is key in progressing towards full automation. Various attempts at digitization are already enabling the development of a framework, in which the input of a molecular structure is converted into actual molecular synthesis.
Electrochemical conversion of CO2 into fuels or chemical feedstocks is one of the most promising methods for solving the problems of both fossil fuel depletion and global warming. Herein, we report that a CO2 electrolysis cell equipped with a polymer electrolyte membrane and cathode loaded with gold nanoparticles as an electrocatalyst produces carbon monoxide with >90% faradaic efficiency at a current density of 700 mA/cm2 under mild pH conditions. The catalyst layer formed on the electrode had a porous structure that facilitates CO2 diffusion, enabling operation at high current density.
Organolithium reagents are often too unstable to use due to being highly reactive. This limits their application in organic synthesis. This review highlights our approach to various synthetic reactions mediated by organolithium reagents based on flash chemistry conducted in flow reactors, especially utilizing space-integration of the flow reactions.
This paper reports the temperature and relative humidity dependence of self-propelled oil droplets. Self-propelled oil droplets locomote by internal Marangoni convection, which is caused by gradients in the interfacial tension due to surfactant and temperature gradients at the oil/water interface. We discover the external environment dependence of the self-propulsion of a droplet and discuss the mechanism of the property. Our study will serve as an innovative foundation for practical research, such as drug delivery systems.
Furanosteroids are polycyclic natural products isolated from fungus, which consist of wortmannin and viridin containing a [5,6,6,6]-tetracyclic skeleton in addition to a furan ring. They inhibit phosphoinositide 3-kinases, suggesting drug potential. This highlight review describes strategies that have been reported for building the tetracyclic ring skeleton and the all-carbon quaternary center in order to achieve total syntheses of wortmannin and viridin.
Oxidation of graphite is widely recognized as a promising method for large-scale production of graphene-like materials. Chemical oxidation of graphite has been developed for more than 100 years, while electrochemical oxidation has attracted attention over the last 10 years as a simple, safe, and controllable production method for graphene. This review summarizes the electrochemical production of graphene analogs focusing on the electrochemical conditions and form of starting graphite that affect the properties of the products. Electrochemical treatment of graphite by direct current has been applied to various graphite, such as HOPG, graphite rod, graphite foil, and powdered graphite, and generates deeply oxidized graphene materials. On the other hand, treatments with alternative current generate low oxygen content products. Therefore, the electrochemical treatment of graphite provides an option for the controlled production of graphene-like materials.
The Ni-catalyzed C–O/O–H annulation of salicylate esters with alkynes, leading to the production of chromone derivatives is reported. The key step in the reaction is the cleavage of an acyl C–O bond. The presence of a base is essential for the reaction to proceed.
A novel ratiometric assay was developed for the accurate and facile quantification of nucleic acids using a combination of surface-enhanced Raman scattering (SERS) and two kinds of bioorthogonal Raman reporters attached to SERS probes. Normalization of the SERS intensities of a phenylethynylphenyl group by ethynylphenyl group allows the facile and automatic quantification of target DNA down to 86 pM.
Nanosized ZSM-22 with high crystallinity was synthesized rapidly by a high-temperature hydrothermal synthesis method. The effects of synthesis conditions such as crystallization temperature, crystallization time, Si/Al ratios and crystallinity of ZSM-22 were investigated, and the relationship between crystallization temperature and crystallization time was calculated by Arrhenius equation. Meanwhile, the rapid high-temperature synthesis method was effective to synthesize ZSM-22 with Si/Al ratio from 35 to 70. The nanosized ZSM-22 exhibited high light olefin selectivity and a long lifetime in the MTO reaction.
Metal–organic frameworks (MOFs) or coordination polymers (CPs) with metal–sulfur bonds in their secondary building units (SBUs), are promising materials for use in semiconductors, conductivity applications, and photocatalysis. This review describes synthetic approaches to obtain highly crystalline samples, in addition to a discussion of the dimensionalities of the SBUs and the functionalities of sulfur-based CPs/MOFs.
A series of dibenzothiophene/terpyridine conjugated asymmetric electron-transporters named snTPys (n = 2, 3, 4) were developed. A green phosphorescent OLED with snTPy as an electron-transporter exhibited an external quantum efficiency of 24% at 1000 cd m−2 with a long operation lifetime at 50% of the initial luminance of 19,000 hrs at 1000 cd m−2.