The stabilities of organic dyes have been controlled by host-guest complexation and the hybrids have been regarded as novel photofunctional materials. In the present review, the dyes encapsulated in smectites and layered double hydroxides are summarized from the viewpoints of the dye stabilization and possible mechanisms for the stabilization toward decolorization are discussed. In addition, the stabilization of photochemically formed isomer of a photochromic spiropyran, by the interactions with smectite is also presented.
Physical modifications of single-walled carbon nanotubes (SWCNTs) with fullerodendrons, followed by complexation with RuCl3 leads to the formation of CNT-photocatalysts that exhibit high quantum yields (QY = 12.8%) for the production of H2 from water, even under illumination with NIR light (λirr = 1005 nm) in the presence of sacrificial donor. A Z-scheme photocatalytic system, consisting of such a CNT-photocatalyst, BiVO4, and [Co(bpy)3]3+/2+ shows a production of H2 (17 µmol/h) and O2 (5.5 µmol/h) under illumination from a solar simulator (AM-1.5) with a solar-to-hydrogen (STH) efficiency of 0.089%.
Microwave-assisted tertiary carbon radical reaction was developed. The reaction of tertiary xanthates with electron deficient alkenes was prompted by microwave irradiation, and various coupling products possessing quaternary carbon centers were obtained in good yields. The reaction was conducted under simple and common radical condition except for microwave irradiation, and the reaction completed within 5 min.
This study introduces the relationship between physicochemical properties and blending time for two different clays, sepiolite nanofibers (SEP) and halloysite nanotubes (HNT) inside a Nafion matrix of electrolyte membrane used in a proton exchange membrane fuel cell (PEMFC). In the study, short blending time resulted in better homogeneity of Nafion/SEP and Nafion/HNT composite membranes, which displayed improved physicochemical properties compared with those of pristine Nafion membrane.
The solvation process of electrons reflects the solvent structure and its fluctuation sensitively. The solvation process of electrons in room-temperature ionic liquid N,N,N-trimethyl-N-propylammonium bis(trifluoromethylsulfonyl) amide, N1113+ NTf2−, is observed with femtosecond near-IR absorption spectroscopy. A broad absorption band from the solvated electrons shows a continuous blue-shift of 0.09 eV within 1 ns of electron injection. The peak shift kinetics, well represented by a stretched exponential decay function, indicates the presence of two or more different solvation environments in this ionic liquid.
Polydopamine nanoparticles (PDAPs) with an average particle size of about 180 nm were irradiated with a 60Co source. The morphology, thermal stability and free radical signal of γ-irradiated PADPs were characterized. The results suggested that a 200 kGy irradiation dose has little effect on PDAPs. As the γ-irradiation dose increases to 400 kGy, PDAPs degraded significantly, morphology of PDAPs was obviously deformed, thermal stability and EPR intensity was significantly decreased. Furthermore, a degradation mechanism of PDAPs under γ-irradiation was explored.
Three dimensionally ordered macroporous polybenzimidazole was successfully prepared as separator for Li metal deposition and dissolution. The effect of the newly developed separator on the Li metal deposition and dissolution reversibility was investigated. This separator can provide more uniform current distribution in Li|Li symmetrical cells, resulting in more uniform deposition of Li metal due to suppression of Li metal dendrites. The overpotential during Li metal deposition and dissolution was 50 mV at 10 mA cm−2. The deposition and dissolution were stably repeated more than 3000 cycles. It can be said that the three dimensionally macroporous structure is highly useful in forming uniform Li metal.
We report here efficient synthesis of artificial transmembrane molecules (ATMs), via click chemistry of a transmembrane part and membrane-penetrating parts. Synthesized ATMs penetrated the cell membrane by Coulombic force, while they stayed on the cell membrane once they were complexed with streptavidin.
A photoelectric conversion was effectively performed by the photocatalytic decomposition of cellulose film on porous titania electrodes prepared from titania paste containing polyethylene glycol. The cellulose film, deposited from an ionic liquid dispersion, increased the short circuit current density in the titania electrodes because it was oxidized by a photocatalytic reaction at their interface. The polyethylene glycol increased the porosity and surface roughness of the titania film, which enhanced the effective contact area, due to its decomposition during heating.
The methanation performance of a Ni/CeO2 structured catalyst having a spiral shape was investigated using a feed material gas containing 1–11 vol % oxygen. The spiral catalyst exhibited high methane yield for a high oxygen concentration (9–11 vol %) and fast feed flow rate even under an auto-methanation condition, which does not require external heating. Such high methane yield was continuously maintained for 60 hours or longer. Under the auto-methanation over the structured catalyst, the reaction field generated high thermal energy, which did not exceed the Tammann temperature of the nickel component, due to selective hydrogen combustion.
Alternating radical copolymerization of cyclic conjugated diene monomers, i.e., cyclopentadiene and furan, with oxygen were carried out to generate degradable polyperoxides. The cyclopentadiene and furan based-polyperoxides consisted of different regiospecific structures. The regiospecificity of the alternating copolymerization was rationalized by the bond dissociation energies of the carbon-to-oxygen bond of the peroxy radicals based on density functional theory calculations. The thermal degradation behavior of the resulting cyclic conjugated diene-based polyperoxides was also investigated.
Metal-organic framework Ni2(L-asp)2(bipy) (Ni-LAB) crystals with different morphology were prepared by directly mixing metal solution with organic linker solution with assistance of deprotonation agent (DA) and crystallizing at 150 °C for 24 hours. Both metal source and DA played key roles in the formation of crystalline Ni-LAB. Ni-LAB crystals with different morphology were obtained by using various organic/inorganic DA. Single component vapor adsorption experiments indicated that the as-synthesized Ni-LAB crystal S3 exhibits preferential adsorption of methanol (CH3OH) over methyl tert-butyl ether (MTBE).
Bilayer-type layered herringbone (LHB) packing is of great importance because of its remarkably high layered crystallinity and its ability to form extremely smooth ultrathin films which are useful for printed electronics technologies. Here we discuss the origin of the high layered crystallinity in the bilayer-type LHB packing, through the reliable crystal structure analysis of a novel unsymmetrically alkylated benzothienonaphthothiophene (BTNT) derivative.
A series of chrysene-based electron-transporters named BnPyPCs (n = 2, 3, 4) end-capped with two 3,5-di(pyridin-n-yl)phenyl moieties with high thermal and electrical stability were successfully developed. BnPyPCs showed Tm values greater than 390 °C and were used for highly efficient green phosphorescent OLEDs with maximum external quantum efficiency values greater than 20% and long operation lifetime at high brightness of approximately 11000 cd m−2 at a current density of 25 mA cm−2.
The β-arylation and -alkenylation of trifluoromethylacrylic acid with arylboronic acids and alkenes proceed smoothly under rhodium(III) catalysis. The procedures provide useful synthetic routes from readily available building brocks to β-aryl-α-trifluoromethylpropanoic acid and 5,5,5-trifluoro-1,3-butadiene derivatives. Some of the obtained butadienes exhibit strong fluorescence in the solid state.
An alternating glycopolymer was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of a maltose-carrying maleimide and diethylene glycol mono vinyl ether as the monomers. The maleimide derivative was newly synthesized by click chemistry using maltosyl azide and N-propargyl maleimide. This facile methodology for sequence-control of glycopolymers gives the shortest way to the synthesis of the first alternating glycopolymers as mimics of natural glycosaminoglycans.
A facile synthesis of benzo[b]thiophene-3-carboxamides from (ortho-alkynyl)phenyl methoxymethyl sulfides and isocyanates was realized. The method involves a tandem-type, cyclization–addition sequence in the presence of a rhodium catalyst. The reactions proceed under considerably mild conditions (room temperature to 50 °C), providing an efficient and entirely new route to substituted benzo[b]thiophene-3-carboxamide derivatives.
Effect of P/Rh ratio and reduction temperature on catalytic activity and product selectivity of rhodium phosphide (Rh2P) for hydrodeoxygenation (HDO) of phenol was studied to develop production of feedstocks from sustainable resources. The Rh-0.8P (P/Rh = 0.5) catalyst after reduction at 650–700 °C showed the highest HDO conversion and benzene selectivity. High activity and selectivity would be due to formation of Rh2P structure and slightly positive charged Rh site.
This study reports a new approach for the preparation of molybdenum (Mo) with controllable morphology by reducing molybdenum trioxide (MoO3) with ammonia (NH3). It is found that the morphology and particles size of as-prepared Mo are always remained the same as that of used MoO3 except for the high porosity, which resulted from the removal of oxygen/nitrogen. A possible reaction mechanism is proposed. This study may have an important guiding role for the preparation of different characteristics of Mo.
Dinuclear Co–salcy complexes bearing a dibenzofuran linker were explored for the copolymerizations of epoxides with cyclic anhydrides (CAs) or carbon dioxide [salcy = trans-N,N′-bis(salicylidene)-1,2-cyclohexanediamine]. It was found that the absolute configuration of the two Co–salcy moieties and the substituents on the salcy ligand greatly affect their catalyst activity. The optimized heterochiral dinuclear Co–salcy complex demonstrated one of the highest catalyst activities among the previously reported metal catalysts for the epoxide/CA copolymerization.
Hollow TiO2 microspheres are designed from an Ostwald ripening process, then as-synthesized hollow TiO2 spheres are used as a template to synthesize Li4Ti5O12 via a simple hydrothermal synthesis method. Such microspheres display good electrochemical performance, including high capacity, excellent cyclic stability and remarkable rate capability. The hollow Li4Ti5O12 microspheres calcined at 700 °C display extremely good electrochemical performance, including high capacity (174.6 mAh/g at 1 C rate), excellent cyclic stability (97.7% capacity retention after 50 cycles at 1 C rate) and remarkable rate capability (140.3 mAh/g at 15 C-rate).
The interfacial structure of the perfluoro-sulfonic acid ionomer and Pt-loaded carbon in a catalyst ink significantly influences the properties of the catalyst layer in polymer electrolyte fuel cells (PEFCs). This is primarily because some ionomer molecules adsorb onto the catalyst particles. The effect of Pt loading on the adsorption of the ionomer onto the surface of the particles was evaluated using contrast-variation small-angle neutron scattering (CV-SANS). Decreased density and increased thickness of the ionomer-adsorption layer were observed with increasing Pt loading on the carbon. While specific interactions between sulfonic acid groups and Pt catalyst were active, the hydrophobic attraction of the ionomer backbone to the carbon surface was the dominant force in the catalyst inks. The CV-SANS technique was useful for investigating design guidelines for the catalyst ink to improve the structure of catalyst layers.
All-trans polyprenols consisting of one hundred carbons (C100) have been synthesized for the first time via the sulfone coupling of C45 and C55 fragments. The resulting coupling product with four benzenesulfonyl groups were subjected to desulfonylation reaction using Pd(dppp)Cl2/LiBHEt3 followed by removal of the benzyl group at the tail under Benkeser reduction conditions to furnish the title compound.
Newly designed small and hydrophilic click reaction devices, NMs-4,8-diazacyclononynes (NMs-DACNs), have been efficiently synthesized by a one-pot double Nicholas approach. NMs-DACNs react with azides smoothly under copper-free conditions and show higher water solubility than that of previously developed NTs-DACNs.
The type of carrier, polaron and bipolaron, generated in PBTTT-C16 ionic-liquid-gated transistors fabricated with [EMIM][TFSI] or [EMIM][FAP] was identified using Raman spectroscopy. Doping levels were obtained from electrochemical measurements. As the doping level increased, positive polarons were formed; positive bipolarons were then formed and dominant. The critical doping level of the polaron-to-bipolaron transition was 4.5 and 12 mol %/π electron for [EMIM][TFSI] and [EMIM][FAP], respectively. The large anion FAP− impeded the bipolaron formation even at a high doping level.