Au nanoclusters (Au NCs) supported on SiO2 effectively adsorbed 1, 3-dimethyltrisulfane (DMTS), which is responsible for the aged odor of Japanese sake. Smaller-size Au NCs exhibited higher adsorption amount of DMTS than those of larger Au NCs. In order to investigate theoretically the selective adsorption of DMTS, density functional theory calculations were carried out for different sizes of Au NCs. These calculations showed that Au NCs decompose and adsorb DMTS selectively on the Au NC surface.
We synthesized hinokitiol-modified SN-38 prodrugs and fabricated their nano-prodrugs which are nanoparticles composed of only prodrug molecules by the reprecipitation method. These nano-prodrugs possessed high dispersion stability, and further research revealed that the tropone skeleton of hinokitiol is the key structure for the dispersion stability in our prodrug design. In addition, the nanoparticles of hinokitiol-modified SN-38 showed much higher cytotoxicity against cancer cells than irinotecan, the pharmaceutically available prodrug of SN-38.
Fine structure of intrinsic fluorescent emission from nonconjugated amine-containing compounds is firstly investigated, which is found to rely on concentration and kind of solvent. Manifest differences in fluorescent intensity and curve shape between samples in water and chloroform are observed and explained.
Although spirobiacridine (SBA) derivatives show a promising potential not only for thermally activated delayed fluorescent (TADF) emitters but also as host material for blue phosphorescent emitters, only limited research has been reported in the literature. Here, we developed an SBA-based host material, mCN-SBA, which realized a blue phosphorescent OLED with an external quantum efficiency of 19.8%, and Commission Internationale de l'Éclairage (CIEx,y) of (0.16, 0.23).
Live-cell protein labeling using a protein tag and a fluorescent probe is a powerful approach for studying protein localization and dynamics. Herein, we engineered a protein tag, PYP-tag, to image membrane proteins with high contrast. Mutations of charged amino acids on the surface of PYP-tag led to the enhancement of labeling kinetics and brightness. Furthermore, the modification of the surface charge did not affect its expression on the cell surface, and we succeeded in applying this labeling technique to high-contrast imaging of translocation of glucose transporter 4.
This study discovered that Pd/SiO2 simultaneously catalyzes two different types of dehydrogenation reactions: (1) thermal decomposition of CH4 and (2) non-oxidative CH4 coupling. We demonstrated that useful C2 hydrocarbons can be synthesized as by-products during H2 and nanocarbon production via the thermal catalytic decomposition of CH4.
Synthesis of anisotropic Ag nanoprisms (AgPRs) contributes to the development of high performance plasmonic devices. The localized surface plasmon resonance wavelength of AgPRs was successfully tuned within 500–600 nm by sequential irradiation of 470-nm and 525-nm light to the Ag nanospheres for predetermined periods of time. We have clarified the mechanism in which the AgPRs are synthesized by the first irradiation, which act as the seeds for the growth in the second irradiation with remaining Ag nanospheres being consumed.
We have studied the rotational dynamics and orientation of a single water molecule trapped inside carbon nanocavities based on fullerene C60 possessing a hydrophobic potential surface. By modifying the hydrophobicity of the concave surface, the local electrostatic potential changed from positive to negative. The 1H NMR analyses unveiled the anisotropic rotational behavior of the water molecule. Additionally, the fluctuation in the angular momentum of the water molecule was found to occur on a subpico-second time scale, indicating the vapor-like feature.
This paper reports an aqueous solar-charging redox battery (SCRB) with optimal redox couple combination, a single device that integrates a bromine-ferricyanide redox flow battery and solar cell through a linkage of KBr3/KBr positive electrolyte for simultaneous conversion and storage of solar energy. The battery can be directly charged upon 1 sun illumination (100·mW·cm−2), and discharge at an output voltage of 0.58 V delivering discharge capacity of 33.63 mAh/L and the solar energy conversion efficiency is 0.06%.
Mononuclear Cu(II) complexes bearing a bidentate bisamidine ligand were newly synthesized and characterized. The catalytic activity was evaluated in the hydrogenation of carbon dioxide to formate salts. A substantial enhancement of the catalyst turnover number was achieved by the imidazoline-based complex, indicating that amidines serve as effective ancillary ligands for homogeneous copper catalysis.
p-Nitroanisole (pNA) confined in submicron- and micron-sized pores in polyimide films shows enhanced dipolar polarization and polar switching characteristics in the liquid state, as revealed by hysteresis in the polarization (P)-electric field (E) curves. They reflect interface-induced orientational polarization of confined pNA molecules, i.e. inversion of molecular orientation depending on the direction of the external electric field. Such an enhanced orientational polarization is not observed for the bulk pNA nor pristine polyimide films, and interactions between the confined pNA molecules and the surface of the pores are indispensable for the polar switching phenomena.
The stopped-flow-optical absorption and -ESR spectra of a quercetin (QueH2) derived semiquinone anion radical (Que−•, half-life time ∼31 ms) were detected by mixing the O2−• radical and QueH2 in dimethylsulfoxide (DMSO). Based on the time-dependent optical absorption and ESR measurements, the second-order decay rate of the Que−• radical yielding charge-transfer dimer complex (Que2) was determined to be 2 × 106 M−1·s−1.
The [4 + 2] cycloaddition of styrenes with arynes was achieved via 1:1 cross-coupling by a nickel catalyst. This protocol applies to a variety of styrenes and arynes generated in situ from o-(trimethylsilyl)aryl triflates to afford 9,10-dihydrophenanthrenes involving substituted aromatic rings. By using this method, a naturally occurring stilbenoid is easily synthesized.
A lipophilic l-glutamate-derived gelator having multiple amide linkages is dissolved in liquid 1-methoxy-4-nitrobenzene (MNB) by heating. Upon cooling this solution below ca. 337 K, a sol-to-gel transition occurs and the liquid MNB molecules are confined in the self-assembled gel networks. This organogel shows significant enhancement of dipolar polarization and hysteresis is observed in the polarization (P)-electric field (E) curves. The cooling of the gel to ambient temperature affords a solid dispersion phase, which does not show such enhanced dipolar polarization nor the P-E hysteresis. The electric field-induced macroscopic polarization of MNB molecules thus occurs only when they are in the liquid phase and confined in the interstitial domains of the MNB gel.
We designed and synthesized two donor-π-acceptor-type dithieno[3,4-b:3′,4′-d]phosphole derivatives. The position of substituents on the dithienophosphole moiety was found to play an important role in the frontier molecular orbitals and the hybrid character of electron-withdrawing phosphole and electron-donating thiophene. Thus, the modulation of frontier molecular orbitals would be an effective strategy to develop organic functional materials based on dithieno[3,4-b:3′,4′-d]phospholes.
In the present method, detection power of flame atomic absorption spectrophotometry (FAAS) was increased by utilizing a T-cut-slotted quartz tube (T-SQT) and combining with atom trap and hydrogen supported revolatilization (T-SQT-AT-FAAS) in order to determine indium at trace levels. Hydrogen gas instead of toxic organic solvents was provided to the system as reducing medium in order to release the atoms trapped on the inner walls of SQT. The method indicated a linear range between 10.0–150 µg L−1, and limit of detection and quantification (LOD/LOQ) values were calculated under the optimal conditions as 2.4 and 7.8 µg L−1, respectively. A 1333 fold enhancement was achieved in the detection power of the conventional FAAS by 7.2 mL min−1 sample/standard solution for 6.0 min period of trapping. Validity and applicability of the proposed determination system was checked in lettuce samples with spiking experiments. The results were satisfactory within the range of 91.0–106.7%. Recovery results represent the high accuracy of the method for the lettuce matrix, and %RSD was found to be 2.9% indicating the high precision.
The effect of a magnetic field on the water contact angle for magnetic elastomers with various plasticizer contents was investigated. At a plasticizer content below 60 wt %, there was no change in contact angle when a magnetic field of 370 mT was applied. For magnetic elastomers with a plasticizer content above 65 wt %, a change in contact angle of approximately 8.0° was observed (e.g. 38° at 0 mT and 46° at 370 mT for 65 wt % plasticizer content). Dynamic viscoelastic measurements showed that magnetic elastomers with a plasticizer content below 60 wt % demonstrate the magnetorheological (MR) effect with changes in storage modulus higher than ∼1 MPa. Atomic force microscopy for magnetic elastomer with a plasticizer content of 50 wt % revealed that the averaged Young’s modulus was 233 ± 52.1 kPa at 370 mT and 83 ± 5.4 kPa at 0 mT, indicating that the MR effect is caused not only on a bulk but also on a mesoscopic scale. Magnetic elastomers specialized for cell culture were obtained by optimizing the plasticizer content, that exhibit the MR effect with changes in storage modulus from 1.3 × 104 Pa to 9.4 × 105 without changing the surface properties.
This paper describes the performance of organic droplet mixing using a digital microfluidic (DMF) device. DMF devices have been applied to the dispensation and transportation of aqueous droplets using electrostatic forces and are suitable for quantitative analysis that requires rapid mixing and reactions. However, DMF devices have not been applied to organic materials. We revealed the behavior of a manipulated organic droplet exposed to different voltages. We expect this device to be a powerful tool for high throughput screening of organic materials.
Nickel methyl 3-devinyl-pyropheophorbide-a was unexpectedly synthesized by chemical modification of naturally occurring chlorophyll-a. The removal of the 3-substituents proceeded by heating in an acidic solution at 80 °C. 1-Hydroxyethyl, vinyl, acetyl, and ethynyl groups at the 3-position were eliminated under mild conditions, but the 3-ethyl, hydroxymethyl, and formyl groups could not be done. This 3-unsubstituted compound, obtained in up to 31% yield, was similar to sedimentary porphyrins. Therefore, this work would advance understanding of the biomarker identities in geological samples.
A highly fluorescent 2,2′-bianthryl derivative bearing urea groups (2) was prepared as an anion receptor. The UV-vis and fluorescence titrations of 2 in various organic solvents revealed that the association constants (K11) were correlated with acceptor number and Swain acity of the solvents used, and tetrahydrofuran was found to strongly enhance the K11 for Cl− and AcO− due to enthalpy driven complexation, in which naked eye detection of AcO− was achieved.
Dual hydrogen bonding intramolecular bridge pivoted by fluoro group for 1,2-bis(2-fluorophenyl)-3,8-dimethoxy-acenaphthenediol in solution is ascertained as simultaneous contribution of mutual fluoro group demonstrated by tangible through-space-couplings in 1H and 19F NMR. The shared fluorine atom inside non-coplanarly accumulated aromatic rings molecule adopts quite adequate position free from interfering solvation to interact with two intramolecular hydrogen atoms prior to stronger hydrogen-accepting oxygen atoms nearby so that essentially weak fluorine-concerning non-classical and classical hydrogen bonds fix reinforcingly intramolecular spatial organization.
Cyclotetrasiloxane-containing polymers are a special kind of macromolecule, but currently there is a lack of efficient ways to prepare suitable monomers. Herein, we would like to report the synthesis of a series of cyclotetrasiloxanes with two SiH groups, which are then used for preparation of various ring-containing polymers. The resulting polymers can be cured with simple organic bases to obtain transparent elastomers which leave no metal leftover and are highly thermally stable.
CO2 methanation was conducted at low temperatures with an electric field. Results show that 5 wt %Ru/CeO2 catalyst exhibited high and stable catalytic activity for CO2 methanation with the electric field. The kinetic investigations and in-situ DRIFTS measurements revealed that Ru/CeO2 catalyst promoted CO2 methanation and Ru at the Ru–CeO2 interface (low-coordinated Ru sites) contributes to the reverse water gas shift reaction at low temperatures in the electric field.
We theoretically estimated pKa of N-containing heterocycles in DMSO by a quantum chemistry method with a polarizable continuum model, which was previously developed for estimating pKa of molecules in water. We numerically show the present scheme also works for DMSO solvent as accurately as for water. According to the obtained result, we confirmed transferability of obtained parameters in calculating pKa using Gibbs energy in different solvent conditions.
The reactions of a W≡Si triple-bonded complex, i.e. a silylyne complex, with alkynes gave [2+2] cycloaddition products, which are formally regarded as conjugated metallasilacyclobutadienes. X-ray crystallography and DFT calculations however revealed that the products have a non-planar W–Si–C–C four-membered metallacyclic linkage with a diagonal Si•••C interaction.
A homogeneous rhenium(I) electrocatalyst possessing hydroxy and ammonio groups in the second coordination sphere is reported for the reduction of carbon dioxide (CO2) to carbon monoxide, wherein the former and latter groups induce a high local concentration of protons and local coulombic interactions with a metallocarboxylate reaction intermediate, respectively. In a comparison with precedent catalysts possessing single functional groups in the spheres, we found that the catalyst exhibits a concerted improvement over these single functional groups in the efficiencies of catalysis, based on experimental standard electrode potentials for the reduction in aqueous N,N-dimethylformamide or acetonitrile solutions and the equilibrium potentials depending on the catalytic systems.
In this letter, Bi nanoparticles/reduced graphene oxide (Bi NPs/rGO) composites catalysts were prepared by a simple solvothermal method. The obtained Bi NPs/rGO composites can be used as high-efficiency and bifunctional catalysts for photocatalytic dye degradation and hydrogenation. Especially, the Bi NPs/rGO showed a very high catalytic activity for aromatic nitro-compound reduction, which revealed a potential application in industrial hydrogenation.
Herein we report self-assembled metallo-cage complexes, M11(L1)6 (M = ZnII, CdII), formed from 4-fold-symmetric ZnII-porphyrin-centered tetrakis-meso-(5′-methyl-2,2′-bipyridyl) ligands. The structures of these two D3-symmetric cages have been characterized by 1D and 2D NMR, ESI-MS, and XRD analyses. A common structural feature of these complexes is their inner molecular binding site at the axial position of each square-pyramidal ZnII-porphyrin in the crystal structure, which would provide a method to place molecular coordination sites inside or outside the cage complex with the minimum chemical modification.
A new class of inorganic–organic hybrid photomechanical material has been created by mono-substitution of polyhedral oligomeric silsesquioxane (POSS) with an azobenzene group via amide bond formation. This compound formed needle-like molecular crystals showing reversible photoinduced bending motions. This finding provides a new design concept of photomechanical materials for various applications.
The one-step synthesis of 2-hydroxy-2-(trifluoromethyl)malonates is described. The nucleophilic trifluoromethylation of commercially available 2-oxo-malonates was possible by use of the Ruppert-Prakash reagent (Me3SiCF3) in the presence of a catalytic amount of bases such as tetramethylammonium fluoride (TMAF) or LiOAc in THF or DMF at room temperature. The method can be applied to the synthesis of unsymmetrical 2-hydroxy-2-(trifluoromethyl)malonates with a sterically demanding ester group. Gram-scale synthesis of 2-hydroxy-2-(trifluoromethyl)malonates and their derivatization to a trifluoromethyl barbituric acid derivative were demonstrated.
We describe the sublimation property of a flavin molecule as a solution to the surfactant residue problem of single-walled carbon nanotubes. Thermogravimetric analysis, UV-vis spectroscopy, and NMR indicate our flavin has sublimability. The saturated vapor pressure of the flavin was calculated to be 0.08 Pa at 250 °C. Careful vacuum and temperature control or further modification of the molecular structure is necessary to avoid competing thermal reactions.
In this work, lithium titanate (Li4Ti5O12)/N-doped carbon/stainless steel mesh (LTO/N-C/SSM) flexible electrodes for Li-ion capacitors were successfully prepared without binder via a facile method of electrostatic spray deposition (ESD) using hexadecyl trimethyl ammonium bromide (CTAB) as carbon source. The performances of LTO/N-C/SSM electrodes were investigated using half-cells with Li foil as counter electrode. The LTO/N-C/SSM flexible electrode exhibits an excellent rate capability and cycling stability. At a current rate of 50 C, the specific capacity of the LTO/N-C/SSM electrode reaches 94 mA h g−1. After 1000 cycles at 3 C, the discharge specific capacity of the LTO/N-C/SSM electrode remains 83%. The energy density and power density of the LICs full-cell based on the LTO/N-C/SSM electrode as anode and commercial activated carbon (AC) as cathode are 125 Wh kg−1 and 3.5 kW kg−1, respectively.