The present review summarizes the prominent properties, in particular, the unique optical properties, generated by 9,9-diarylfluorene moiety introduced into polymer main chains in addition to the synthesis of polymers containing diarylfluorene moieties on the basis of results of the studies reported mainly in this decade. Polymers usually show both high refractive index and low birefringence besides many other physical and chemical properties. This review focuses not only on the polymers but also the composite materials, and discloses excellent polymer materials. In addition, synthesis and properties of novel related monomers and their corresponding polymers are also described.
Pseudomacrocyclic compounds with 2,2′-bipyridine subunits and multimetal-assisting functional molecules with salamo and dipyrrin moieties as the N2O2 ligation moieties are described. The unique and suitable arrangement of these ligation units results in highly synergistic functions in the metallo-supramolecular systems.
Carbonate ions in the aqueous electrolyte solution improved both the photocurrent and the stability of a porous BiVO4 semiconductor electrode used for water splitting under visible light up to 520 nm. The photocurrents in AHCO3 (A = Na and K) solutions at 1.23 V were approximately six times higher than that in Na2SO4 aqueous solution. The maximum incident photon-to-current efficiency (IPCE) was 45% at 420 nm without any surface modifications.
Superhydrophobic cellulosic materials with remarkable self-cleaning ability and satisfactory long-term chemical stability were fabricated by depositing self-assembled silane monolayer onto ultrathin titania film precoated nanofibers of natural cellulosic substances without altering the initial material structures and morphologies.
A vitamin B12 derivative was immobilized on a core–shell hyperbranched polymer, and the hybrid polymer was characterized by GPC, UV–vis, IR as well as TEM analyses. The hybrid polymer exhibits catalysis for the dehalogenation of phenethyl bromide to form ethylbenzene and 2,3-diphenylbutane by irradiation with UV light at room temperature.
The tether-assisted synthesis of rotaxane by olefin metathesis is described. The bis(crown ether)s, in which two crown ethers are connected by a linker, were converted to tethered rotaxanes, followed by removal of the linkers to produce rotaxane. The biscrown structures promoted the formation of the tethered rotaxane, resulting in a notable improvement in the yield of the rotaxane.
High surface area Co3O4–CeO2 catalysts were prepared by the simple calcination of carbonate–precursor mixtures at 300 °C. The Co3O4–CeO2 catalyst with a Co/Ce molar ratio of 1 showed high activity for toluene decomposition, comparable to that of Pt(0.08 wt %)/zeolite catalyst. The total decomposition of toluene was achieved at degradation temperatures as low as 200 °C. The Co3O4–CeO2 catalyst was highly stable, even after two weeks of reaction.
A novel coordination polymer of zinc(II) biphenyldicarboxylate bearing a sulfone group, [Zn(sbdc)(H2O)3]·(H2sbdc)·H2O (H2sbdc: sulfone biphenyldicarboxylic acid), has been synthesized. It is composed of a one-dimensional chain structure of alternating Zn(II) cations and sbdc anions. This coordination polymer possesses noncoordinating uncharged acid H2sbdc existing between the chains with hydrogen-bonding networks. The proton conductivity of [Zn(sbdc)(H2O)3]·(H2sbdc)·H2O strongly depended on the relative humidity (RH), being 2.5 × 10−7 S cm−1 at 95% RH. The activation energy for proton conductivity was estimated to be 0.32 eV at 95% RH.
Fluorescein is exclusively popular owing to bright fluorescence of its R2− dianion. While the structure of the latter and tautomerism of the H2R form are well established, only the species with COO− and OH groups has been supposed for HR− up to now. Using absorption, emission, and excitation at different pH in non-HBD solvents, DMSO, acetonitrile, and acetone, we reveal that 10–12% of HR− ions nevertheless exist as “phenolate” monoanion with nonionized COOH group.
To study microstructure of Na2O–B2O3–SiO2–Al2O3 glass, which is a starting material for preparing porous glass, 11B one-dimensional (1D) magic-angle spinning (MAS) spectra and results of two-dimensional (2D) 11B–11B homonuclear correlation experiment under MAS are examined at 21.8 T. We conclude that two of the four peaks observed for 11B are assigned to borate rings, which we assign as the main components in the boron-rich phase to be removed by acid leaching.
Hexagonal needles of BaSiF6 microcrystals have been prepared by using a hydrothermal method with Ba(NO3)2, SiO2, and HF in the presence of NH4Cl or ethylenediamine dihydrochloride as the metal chelating agent. The metal chelating agent plays an important role in controlling the aspect ratios of the BaSiF6 microcrystals. X-ray diffraction was used to confirm that the axes of the hexagonal needles of BaSiF6 are aligned along the c axis.
Resonance Raman spectroscopy has been applied to two distinct temporal species of indoleamine 2,3-dioxygenase during catalytic turnover. We have identified two oxygen-isotope-sensitive Raman modes at 569 and 798 cm−1 for the two respective species. The 16O18O analysis of the 798 cm−1 band indicates the existence of a ferryl-oxo heme, which is inconsistent with the previously proposed reaction mechanism. The present study thus provides a physical basis for the structures of the possible reaction intermediates.
Trehalose at 10–30% (w/w) greatly stabilized bovine serum albumin (BSA) against thermal denaturation. The highest stabilization was reached in 30% trehalose at 65 °C, when the protein’s half life was increased from 72 to 335 min. A kinetic analysis based on the Lumry–Eyring mechanism of inactivation showed that BSA denaturation can be described by a first-order rate expression with an apparent activation energy ranging from 238.1 to 246.4 kJ mol−1.
A new kind of front contact counter electrode with multi-wall carbon nanotube array on a nonconductive substrate and a thin metal layer was designed for dye-sensitized solar cells. Under standard AM 1.5 irradiation (100 mW cm−2), a device with such counter electrode yielded an overall conversion efficiency of 2.53%.
Biocompatible sensor particles with high nitric oxide (NO) sensitivity were fabricated by a combination of layer-by-layer assembly and acid-free chitosan dissolving techniques. The sensor particles encapsulating 4,5-diaminofluorescein (DAF-2), an NO fluorescent probe, can detect 5–500 nM NO and had higher cytocompatibility as compared to DAF-2 molecules. These sensor particles will be useful for quantitative and spatial analyses of extracellular NO molecules from living cells.
In this paper, a new-type composite photocatalyst of titania/carbon (TiO2/C) with three-dimensional ordered macroporous (3DOM) structure was successfully prepared by combining the macroporous structure of 3DOM carbon and the catalytic properties of TiO2. Under ultraviolet light, the obtained 3DOM TiO2/C materials were used to degrade Methyl Orange solution as simulated organic waste–water and had a high catalytic activity. Furthermore, compared with commercial Degussa p25 catalyst, obtained 3DOM TiO2/C materials displayed an excellent regenerative ability.
Gold nanoclusters stabilized by the poly(N-vinyl-2-pyrrolidone) hydrophilic polymer (Au:PVP) catalyzed the intramolecular cycloaddition of primary amines to unactivated alkenes in the presence of formic acid derivatives. The reaction proceeded under neutral to slightly acidic conditions in air.
Complete hydrodechlorination of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) and its derivatives 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD) was achieved using a hydroxyapatite-supported Pd nanoparticle catalyst (Pd0HAP) in the presence of molecular hydrogen under mild reaction conditions. The catalytic activity of Pd0HAP was significantly higher than those of previously reported Pd catalysts.
Novel gold nanoparticles (GNPs) as a SERS probe were prepared using two types of functional PEG/oligoamine polymers possessing biotin as biotag molecules at the PEG end or a coumarin moiety as a Raman probe molecule between the PEG and oligoamine segments. Eventually, the GNPs showed excellent dispersion stability under physiological conditions, as well as remarkable SERS signal resulting from molecular recognition between streptavidin and the biotin tag, even in the presence of bovine serum albumin (BSA).
Pyranine, a multivalent anionic fluorescent dye, triggered the budding and production of small vesicles from giant vesicles that consisted of zwitterionic and cationic lipids. Calorimetric analysis and microscopic observations revealed that the binding of pyranine induced domain formations of the lipid bilayer followed by membrane fission.
Dicationic species, naphthalene-1,8-diylbis(diphenylmethylium), successfully promoted oxidative arylation of the sulfur atom in (4-N,N-dialkylaminophenyl) phenyl sulfides with (4-N,N-dialkylaminopheny)silanes, affording triarylsulfonium salts in good yield.
Amphiphilic diblock copolymers comprising poly(methyl methacrylate-co-spirobenzopyran methacrylate) and poly(ethylene glycol) were synthesized using atom transfer radical polymerization to develop a new photoresponsive drug carrier. The diblock copolymers formed core–shell polymeric micelles with photoresponsive inner cores. Spirobenzopyran in the core was isomerized to the merocyanine form by UV irradiation, which resulted in reduction of the micellar size without decrease in the association number. This inferred that the strongly intermolecular interactions between merocyanine residues caused the conformational change of the core segments, following reduction of the micellar size.
Introduction of branched alkyl chains at the terminal positions of sexithiophene drastically improves the solubility of the compound, while still maintaining satisfactory charge carrier mobility. Field-effect transistors based on spin-coated films of the sexithiophene derivative exhibited p-type characteristics. Post thermal treatment enhanced crystallinity of the films and afforded a field-effect mobility of 0.11–0.18 cm2 V−1 s−1 and an on/off ratio of 104.
Hydrogenation activity of aromatic hydrocarbons was remarkably increased when the residual chlorine on Ru/Al2O3 and Ru/SiO2 was removed by washing. On the basis of FT-IR spectra in the CO region, a site active for hydrogenation reactions was created by removal of the residual chlorine.
Ordered Ni/Al2O3 core–shell nanowire arrays were prepared in porous alumina membrane via alternating current electrodeposition and chemical etching methods. The shape of the inner Ni core is columnar with a diameter of 50 nm. The shape of the outer Al2O3 shell is a regular hexagon and the well thickness is about 40 nm. This novel structured material can be used as a media for magnetic storage and high-temperature nanoelectronic devices.
The degradation effects of benzoylferrocene (BF) on poly(ethylene glycol) (PEG) and poly(methyl methacrylate) (PMMA) were investigated using MALDI-MS. It is supposed that the release of free radicals in solution by BF plays a key role in the decomposition of PEG and PMMA. MALDI-MS combined with examination of the degradation by BF could be applied to the analysis of synthetic polymer structures containing the PEG and PMMA chain.
Readily available cinnamic acids possessing a hydroxy group including ferulic acid efficiently undergo direct decarboxylative arylation under palladium catalysis to form hydroxylated stilbenes. The reaction of related acids is also described.
Tighter packing of aromatic group-substituted N-acylamino acids in micelles at lower basicity significantly enhances intermolecular steric hindrance between adjacent amphiphiles and helps the formation of chiral mesoporous silica with higher enantiopurtiy.
Silica nanoparticles, the surface of which was modified by a 3-aminopropylsilyl group, compacted gene-size DNA in aqueous solutions in the presence of Na+ or K+. The DNA-compaction efficiency of histone-size (10 nm diameter) nanoparticles is greater than that of large (100 nm) nanoparticles under similar experimental conditions.
This paper describes surfactant-free and template-free synthesis of gold nanorods/nanobelts (Au-NRBs) using ciprofloxacin (CF) as a reducing/stabilizing agent (a fluoroquinolone antibiotic). Synthesized Au-NRBs were stable and easily soluble in water. Scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and UV–visible spectroscopy are used for characterization of synthesized Au-NRBs. Indeed, synthesized Au-NRB-modified electrodes show high electrocatalytic properties toward oxidation of ethanol in alkaline solution (0.1 M NaOH).