The electrochemical redox reactions of organic polymers bearing robust unpaired electrons were investigated to determine the applicability of these polymers to rechargeable batteries. Such an “organic radical battery” would be environmentally friendly and have high-power characteristics. This highlight review describes the performance of a battery using a nitroxyl radical polymer as the cathode active material. The electron-transfer mechanism and recent developments that should lead to the practical application of the organic radical battery are also described.
Alkaline-earth carbonates (M = Ca, Sr, and Ba) with delicate hierarchical structures were prepared via self-assembly of nanocrystals in solution without using any surfactant at room temperature. The CO2 generated during the coprecipitation is believed to play an important role in the formation of these structures.
Fluorinated TiO2 (F-TiO2) particles with good dispersion stability were synthesized at a temperature lower than 100 °C using fluorine gas. The average particle sizes and ζ potentials of F-TiO2 particles were around seven times smaller and 1.4 times larger, respectively, than those (2200 nm and −19.35 mV) of untreated TiO2 particles in water. However, the existence of TiOF2 prepared at a temperature higher than 100 °C might negatively affect the dispersion stability of TiO2. To prepare the fluorinated TiO2 without TiOF2, it is essential for optimizing the beneficial effects of surface fluorination against the dispersion stability of TiO2.
Acyloins are efficiently synthesized in three steps from alkynes via hydrosilylation followed by an addition-type ozone oxidation and hydrogenation. The key intermediate α-silylperoxy ketone is convertible to not only acyloin but also O-silylated acyloin and diketone.
Sodium-vanadate-doped ordered mesoporous carbon foams (V-MCFs) were prepared through an evaporation-induced self-assembly strategy. The resultant V-MCFs exhibit highly ordered mesostructure with specific surface areas of 714 m2 g−1 and uniform pore sizes of 4.1 nm. The surface wettability and graphitization degree of V-MCFs were increased due to the incorporation of sodium vanadate into the carbon matrix. Besides, sodium vanadate brings a pseudo-capacitive effect in V-MCFs. V-MCFs thus exhibit higher capacitance and fast charge–discharge properties compared with pure mesoporous carbon foams.
We now describe the finding that a copolymer of 9,9-dioctylfluorenyl-2,7-diyl and bipyridine (BPy) can extract in “one-pot” ≈96–97%-enriched (6,5)-SWNTs in m-xylene and p-xylene not containing metallic SWNTs, which was revealed by vis–near IR absorption, photoluminescence, and Raman spectroscopies.
A facile approach for the synthesis of multiarmed selenium/carbon (Se/C) coaxial nanorods by using chitosan as morphology-directing agents and selenious acid as the Se source has been demonstrated in the present study. Multiarmed Se/C nanorods, consisting of I-, Y-, T-, and cross-shaped configurations, were prepared by controlling the temperature and the ratio of amount of chitosan and Se in the reaction systems.
A series of double B mixed perovskite oxides La0.75K0.25Mn1−xFexO3 (x = 0.2–0.5) were synthesized under mild hydrothermal conditions and characterized by powder X-ray diffraction, SEM, ICP, XPS, iodometric titration, and SQUID. All the compounds corresponded to orthorhombic structure of space group Pnma and presented a cuboid morphology. The oxidation state of Fe is +3 whereas Mn is a mixed valence of Mn3+/Mn4+. The curves M vs. T for all the compositions indicated the coexistence of ferro- and antiferromagnetic contribution.
A formal synthesis of antimalarial diterpenoid 7,20-diisocyanoadociane, isolated from marine sponge Adocia sp., was achieved. The authors synthesized Corey’s synthetic intermediate 2 for 7,20-diisocyanoadociane. This synthesis involves the synthesis of a perhydropyrene derivative using a sequential isomerization–intramolecular Diels–Alder reaction as the key step.
Cyclopropyl imines reacted with nickel(0) in the presence of IPr to give the expected six-membered aza-nickelacycles confirmed by X-ray crystallography. The molecular structure of aza-nickelacyles shows monomeric η1-aza-nickelenolate structures. The reaction of aza-nickelacycle with an enone occurred to generate an η3-oxa-allylnickel complex.
A flow-stretching assay was employed to elucidate polycation/DNA interactions at the single-molecule level. Bacteriophage λ-DNA (48.5 kbp) was attached at one end to a PEG-modified glass surface and stretched by buffer flow. The stretched DNA had an approximate length of 12 µm. Upon injection of polylysine homopolymer, the DNA folded into a globule structure within a few seconds. Injection of a polylysine graft copolymer having hydrophilic dextran side chains also induced collapse of the stretched DNA. In comparison to these polymers, a copolymer with higher graft content did not cause DNA collapse but rather caused 25% shrinkage of the extended DNA. These results were compared with those observed with unstretched DNA.
The Ta2O5-modified Pt electrode, which was prepared by electrodeposition of Ta on a Pt electrode from 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) ionic liquid and subsequent calcination, possesses excellent electrocatalytic activity toward the oxidation of formaldehyde to CO2 in 0.5 M H2SO4 solution compared with the bare Pt electrode. This significant improvement in catalytic performance may be attributed to the strong metal–oxide interaction as well as hydroxide spillover effect of the modified electrode. A possible reaction mechanism is proposed.
Graphene oxide, a chemically modified graphene, has been attracting wide attention because of promising adaptability to a wide variety of applications. However, the properties of graphene oxide itself are not known well. Using a conductive cantilever, we observed a current image of graphene oxide nanosheets of various thicknesses. Current–voltage characteristics were found to reflect the local conductivity normal to the nanosheets. Under high electric fields, the conduction was well described in terms of Poole–Frenkel emission mechanism. The fitting of I–V curves to the Poole–Frenkel model provides information on dielectric properties, and the relative permittivity of graphene oxide was found to be 4.8 ± 0.8.
Highly luminescent CdSe/ZnS nanocrystals were prepared in an aqueous solution. CdSe cores capped with thiolglycolic acid (TGA) were coated with a ZnS shell through photochemical decomposition of TGA in a Zn-dispersed solution. The molar ratios of Cd2+:TGA:Se2− upon core synthesis were crucial to obtain CdSe/ZnS showing high photoluminescence (PL) efficiency. High PL efficiency (50%) with narrow spectral width (50 nm) was obtained after photochemically coating the core with a thick ZnS shell after optimizing the solution composition during ultraviolet irradiation.
Highly stable microbubble dispersions with mean bubble radii of less than 100 µm stabilized solely with nonionic surfactant of glyceryl monostearate are reported, and the stability was sustained for more than 10 months which is attributed to the presence of lamellar liquid-crystal gels. The elastic response of the interface provides a physical barrier to collapse of dispersed microbubbles. Our study identifies a route to fabricate extremely stable dispersions of microbubbles.
We synthesized a new oligothiophene derivative with pyridine end groups and investigated their optical properties. Upon adding an aqueous polystyrene sulfonic acid solution, it forms homogeneous polymer complex films with protonated structure. Furthermore, reversible color change in photoluminescence in response to a base due to reversible protonation of pyridyl end groups in oligothiophene was demonstrated, which can be applied to acid sensors.
In this paper, the use of molecularly imprinted membrane (MIM) for chromatographic separation is described. Poly(vinylidene fluoride) hollow-fiber membranes were grafted on an imprinted polymer layer by using 4-vinylpyridine and trimethylolpropane triacrylate as monomer and crosslinker and were applied as the chromatographic media. During separation, naproxen enantiomers were separated efficiently, and the separation factor was 2.36. Molecularly imprinted membrane chromatography (MIMC) showed an apparently opposite transport behavior compared to molecularly imprinted polymer (MIP)-packed chromatography.
Oxidation of guanosine (G) with electrochemically generated superoxide (O2•−) leads to the imidazolone (Iz) derivative as a single-electron oxidation product of G. A crucial step in the mechanism of the oxidation is the proton-coupled electron transfer (PCET) from G to the hydroperoxy radical (HO2•) that is derived from O2•−.
New polymer materials, including thin films, soft gels, and hollow capsules, consisting of composite polymer nanofilms were prepared by the Cu(I)-catalyzed Huisgen click reaction between lipophilic polymers or between lipophilic and hydrophilic polymers. Because the lipophilic polymer, or hydrophilic polymer and copper catalyst were present in the oil or aqueous phase, respectively, the crosslinking reaction proceeded only at the phase interface. The combination of lipophilic and hydrophilic polymers produced “Janus” nanofilms with both hydrophilic and lipophilic surfaces.
Various eutectic mixtures and organic alloys have been prepared by changing combination of four-component mixtures of 1-naphthylmethylammonium n-alkanoates, which implies high-fidelity control of molecular recognition in the solid state.
We succeeded in the first direct intercalation of an organic compound into carbonate layered double hydroxide (LDH) by using alcohol as the solvent at 50 °C. Furthermore, carbonate ion in carbonate LDH was easily exchanged with chloride or nitrate ion in methanol.
The selectivity and sensitivity of N,N′-bis(4-diethylaminosalicylidene)hydrazine (sensor 1) toward Cu2+ ion have been established both by distinct “naked-eye” color change as well as UV–vis spectrophotometry. Sensor 1 formed 1:1 complex with Cu2+ ion where the most stable s-trans form of the sensor is trapped in the high energy conformer. Single-crystal X-ray structure of sensor 1 supports its s-trans conformation. Theoretical calculations support well the experimental result.
π-Conjugated poly(9,10-dioctyl-9,10-dihydrophenanthrene-2,7-diyl) and a related polymer were prepared by dehalogenative organometallic polycondensation using the corresponding dibromo compound. The polymers are photoluminescent and show a tendency to self-assemble.
The (ΛLLL)2 isomer of a CoIII3 trinuclear complex anion, [Co3(L-cys)6]3−, selected exclusively the (Λ)2 isomer of a CoIII2AgI3 pentanuclear complex cation, [Ag3Co2(aet)6]3+, from its racemic (Δ)2/(Λ)2 isomer, giving only the (Λ)2(ΛLLL)2 isomer of a 1:1 complex salt, [Ag3Co2(aet)6][Co3(L-cys)6]. Notably, the (Λ)2 isomer of [Ag3Co2(aet)6]3+ was also selected, but preferentially, by the (ΔLLL)2 isomer of [Co3(L-cys)6]3− in the course of the formation of [Ag3Co2(aet)6][Co3(L-cys)6].
A single phase of Ca4Bi6O13 crystal was obtained at lower calcination temperature in a citric acid complex method than in a solid-state reaction. From the diffuse reflection spectra, it was found that Ca4Bi6O13 is direct-gap material and that the optical band gap is 2.92 eV. After heating at 600 °C or above, the specific surface area of Ca4Bi6O13 powder was ca. three times larger when prepared by a citric acid complex method than by solid-state reaction. Further, it was confirmed that the photocatalytic activity of Ca4Bi6O13 for the degradation of Methylene Blue (MB) was higher in a citric acid complex method than in a solid-state reaction under visible-light irradiation (λ ≥ 420 nm).
Proline-substituted coumarin compounds were prepared and used as environment-sensitive fluorescence probes. Phosphorylation and dephosphorylation of tyrosine derivatives labeled with the coumarin–proline conjugate induced marked changes in fluorescence intensity allowing phosphatase activity to be monitored.
The spin dynamics of photoconductive tetrathiafulvalene (TTF) derivatives containing 2,5-diphenyl-1,3,4-oxadiazole (PPD) was examined using time-resolved electron spin resonance (TR-ESR) spectroscopy. TR-ESR signals of a frozen solution sample under visible excitation were attributed to the excited triplet state T1, which was populated via intersystem crossing from the excited singlet state S1 as confirmed by TR-ESR spectral simulations. From DFT calculations, the spin-density distribution of the T1 state was found to be concentrated around the linker between the TTF and PPD molecules.
Aggregates of single-walled carbon nanotubes (SWCNTs) were deposited unidirectionally on highly oriented PTFE film made by friction transfer. The friction-transferred PTFE film possesses many straight channels of various sizes running along the transfer direction. SWCNT aggregates were preferentially deposited parallel to the channels when SWCNTs in a form of dry powder were sprinkled, as confirmed by Raman microscopy and anisotropic electrical resistivity. Furthermore, the SWCNT film can be transferred to another substrate surface by simply stamping the SWCNT/PTFE film on it.
Transfection using ultrasound exposure in the presence of nanobubbles can overcome an important barrier for nonviral gene delivery, that is entering the nucleus without cell division. The monitoring of the relationship between fluorescent protein expression and cell division reveals that ultrasound-mediated transfection with liposomal bubbles is independent on the disappearance of nuclear membrane at mitosis.
A new convenient method for the synthesis of dibenzo[a,h]anthracenes and picenes using ruthenium-catalyzed regioselective C–H arylation of aromatic ketones has been developed. Acetophenone derivatives and 1,4-benzenediboronates were coupled in 2:1 ratios to form p-terphenyl derivatives. Conversion of the acetyl group to an ethynyl group, followed by cycloaromatization provided the desired fused aromatic compounds. An organic field-effect transistor fabricated from one of these products gave moderate hole mobility.
At the interface of the toluene/water system, H4TPyP4+ and CuTPPS4− formed heteroaggregates, which could recognize the chirality of D- and L-phenylalanines (Phe) and other amino acids, though neither H4TPyP4+ nor CuTPPS4− could indicate the chirality of the amino acids. The composition of H4TPyP4+:CuTPPS4− in the aggregate was estimated as 1:1 as reported in an aqueous solution. But, CD spectra of the interfacial heteroaggregates were different from that in the aqueous solution, suggesting different chiral interaction. The present results suggest a new mode of the interfacial chiral reaction exhibited by the synergistic effect of the heteroaggregation of the inversely charged porphyrins.
An α-carboline derivative, 9,9′-m-phenylenedi-α-carboline (mCaP) was designed and synthesized as a host material for phosphorescent OLEDs. By using a combination with phosphorescent emitters such as FIrpic and Ir(ppy)3, we have successfully developed high-performance OLEDs with a power efficiency (ηp,100) at 100 cd m−2 of 37 lm W−1 for blue, and 94 lm W−1 for green, respectively.
Polycyanurate networks were densely built by crosslinking of bisphenols and triazine. A molecular dynamics study of the networks from bisphenol A, bisphenol E, and fluorene bisphenol qualitatively reproduced the glass-transition temperatures in correct orders.
The title compounds having two 9-triptycyl rotors, two acetylene shafts, and an acene base were synthesized by coupling reactions as molecular spur gears. Their molecular structures were compared to evaluate the meshing of rotor moieties and the orientation of the two gear shafts. The mechanism of rotation of three-toothed rotors was explored by NMR spectroscopy and DFT calculations in terms of gear rotation and slippage.
In this study, we investigated the possibility of employing an insulin amyloid without the cell binding motif sequence as a novel cell adhesion material. Immobilized insulin amyloid on cell culture plates shows higher cell adhesion properties compared with untreated plates. Interestingly, cells adhered to the insulin amyloid displayed marked cell proliferation. It was also demonstrated that the insulin amyloid interacted with fibronectin present within the serum.
A metal-ion-mediated duplex of triazole-linked DNA (TLDNA) was synthesized via thymine–mercury(II)–thymine (T–Hg–T) base pairing. The electron-transport properties of the mercury-mediated duplex deposited on a solid substrate were determined by time-resolved microwave conductivity (TRMC) measurements.
Enantioselective synthesis has been achieved using chiral compounds arising from mono- and dideuterated methyl groups as chiral inducers in conjunction with asymmetric autocatalysis. The absolute configuration of the product was controlled by the small degree of chirality generated by the difference between the partially deuterated methyl groups (CDH2 and CD2H) and the non-deuterated methyl group (CH3) in N-benzoyl-α-methylalanine.
The first total synthesis of kaempferol-3-O-β-L-arabinopyranosyl-(1→4)-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside (1), a 3,7-triglycosylflavone, which was isolated from the aerial parts of Fagonia taeckholmiana, was accomplished in 13 steps and 9.2% overall yield from commercially available kaempferol. We efficiently employed phase-transfer-catalyzed (PTC) glycosylation for the construction of phenol glycosides. Applying this approach will allow the preparation of derivatives for further study of structure–activity relationships (SAR).
Despite the potential synthetic utility of N-Boc α-ketimino esters as prochiral ketimines to give chiral α-tertiary amines, there has been no general method to access these molecules in a practical fashion. We report herein a procedure for the one-step synthesis of N-Boc α-ketimino esters starting from the corresponding α-keto esters.