Chemoselective borylation at an Ar–Br bond of bromoaryl triflates over an Ar–OTf bond was reported. A variety of borylaryl triflates having B(neop), B(pin) or B(dan) group were directly accessible in high yield by a copper-catalyzed reaction with diborons.
In this work, microwave irradiation was introduced into a hydrothermal process to solidify heavy metals in MSWI fly ash. The reagent, Na2HPO4, showed a significant effect on the synthesis of zeolite-like materials, reducing the leaching concentration of heavy metals. The heavy metals morphologically transformed from acid-soluble form to a more stable form after treatment. Furthermore, the leaching concentration of all heavy metals reached the standard limit with 30 min curing.
The layered metal dichalcogenides, especially molybdenum disulfide nanosheets, as novel two-dimensional materials have attracted the attention of many researchers. The catalytic applicability of MoS2 is however, limited by its low electrical conductivity. We report the preparation of MoS2 nanosheets on nitrogen-doped graphene (MoS2/NG) by a single step hydrothermal route, which can enhance their physicochemical properties and electrical conductivity. According to spectroscopic and microscopic characterizations, nitrogen doped graphene with 3D crumpled network structure was successfully decorated with MoS2 nanosheets to obtain the desired hybrid material. Due to their high activity for catalytic reduction reactions, we immobilized gold nanoparticles on the as synthesized support. The catalytic reduction of several nitroarenes was evaluated in the presence of NaBH4 and the results proved high activity of the presented catalyst. The turnover frequency of AuNPs@MoS2/NG was found to be 1976 h−1 for 4-nitrophenol reduction which was higher than most of previously reported values even at relatively low concentration of catalyst and NaBH4.
In a novel disconnection of isoquinoline ring synthesis at the C7–C8/C4a–C8a bonds, these bonds can be formed by a [4+2] cycloaddition between thiophene S,S-dioxide and alkynes. With a subsequent C–H arylation of the resulting hexaarylisoquinoline at the C3 position, the synthesis of a fully substituted isoquinoline has been achieved.
Ni-Sn alloy catalysts were prepared and applied to the hydrogenation of 4-nitrostyrene at 383–423 K using H2 gas as the hydrogen donor. Ni3Sn2 alloy showed a significantly high conversion and selectivity towards 4-aminostyrene (Conv. 100%, Sel. 99%). Various unsaturated nitro compounds were also successfully converted into their corresponding unsaturated amines.
Pt nanosheets were prepared by impregnating graphene oxide powder using a drop of an aqueous H2PtCl6 solution in cyclohexane, followed by heating at 453 K in an autoclave. The H2PtCl6 captured in the interlayers between stacked graphene oxide sheets was reduced to Pt metal during heating to form Pt nanosheets.
A vitamin B12 derivative with a trifluoromethyl group as an axial ligand, heptamethyl trifluoromethylaquacobyrinate perchlorate, [[(CF3)(H2O)Cob(III)7C1ester]ClO4], is prepared and characterized by elemental analysis, 1H NMR, 19F NMR, ESI-MS, UV-vis absorption, and cyclic voltammetry. The Co–CF3 complex shows homolysis of the Co(III)–CF3 bond under visible light irradiation, which releases a CF3 radical that can be detected by a radical trapping experiment.
An ethylenedioxy derivative of a bis-fused donor composed of tetrathiafulvalene and tetraselenafulvalene (EO-ST-STP) was successfully synthesized. X-ray structure analysis revealed that (EO-ST-STP)2X (X = PF6 and ClO4) adopted the so-called β-type molecular packing. A tight-binding band calculation suggested these salts had a closed Fermi surface. Both salts exhibited high conductivity of σrt = 990–1200 S cm−1 and metallic temperature dependence down to TMI = 50–70 K.
Addition of sodium salts in hydrothermal synthesis was revealed to significantly influence the morphology and particle size of WO3 particles due to oriented growth. The plate-like shaped WO3 particles prepared with appropriate amounts of alkaline salts such as NaHCO3 and NaOH exhibited much higher activity for O2 evolution in the presence of Fe3+ electron acceptor, compared to that prepared without any additives and a highly-active commercial one.
A chiral spiro compound (1a) having 1,3-dithiol units has been synthesized as a stereogenic tetrathiafulvalene analogue. Spiro 1a was resolved into two enantiomers by chiral HPLC, and they exhibited remarkable chiroptical properties featuring dehydroindene-dithiol chromophore in C2 symmetry. In addition, electrochemical properties were also investigated by using cyclic voltammetry and electronic spectra of cationic species.
Gold nanoparticle were modified with goat-IgG and used as a mass-probe for dot blotting. On the spots of a blotting membrane, where anti-IgG antibody was cast, the IgG-modified gold nanoparticles were deposited through immunochemical interaction. Laser desorption/ionization mass spectrometry desorbed the gold nanoparticles as Au+ ions, and indicated the presence of 20 pg of anti-IgG antibody. The detection limit of the mass spectrometry was 1,000 times better than that of naked-eye observation of the color of gold nanoparticles.
(Yb1−xPrx)2O3+δ catalysts with C-type cubic structure were synthesized by a co-precipitation method. By introducing the Pr ion into Yb2O3, the enhancement in the catalytic N2O decomposition activity was recognized through the improvement of the redox behavior due to the synergistic effects of Yb2+/3+ and Pr3+/4+ ions without any noble metal contribution. Among the samples prepared, (Yb0.85Pr0.15)2O3+δ exhibited the highest N2O decomposition activity, and can completely decompose N2O at 600 °C.
Hydrophobic SBA-15 has been found to improve catalytic activity of supported Pt nanoparticles for ethylene oxidation at 0 °C. Pt nanoparticles stabilized inside the hydrophobic mesopores enabled smooth ethylene conversion and CO2 formation at a steady state due to constant removal of physisorbed water formed during ethylene oxidation.
We report here a synthetic route to unsymmetric cyano-substituted oligo(p-phenylene-vinylene)s (COPVs), which have not been reported so far. These molecules were synthesised in high yield through a simple pathway of step-wise Knoevenagel condensation. The proposed study improves the molecular design strategies of COPVs towards solid fluorescent materials. This synthetic pathway gives various novel COPVs. The properties of the obtained COPVs are also discussed.
A simple, one-pot synthesis of 1,4,5,8,9,12-hexaazatriphenylene (HAT) derivatives with different symmetries and multiple, distinct functional groups was developed. HAT derivatives containing amine and amidine groups with C3 symmetry and HAT derivatives containing amine, amidine, and nitrile functionalities with C2 symmetry were obtained by reacting 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT(CN)6) with propyl amine and aniline, respectively. Crystal structure analysis, infrared spectra, and density functional theory calculations demonstrated that the amidine structures were stabilized by intramolecular hydrogen bonds.
Composites were prepared using [Au(CN)2]− complexes and steroidal alkaloid glycosides (SAGs) from tomato, including hydrophilic sugar and hydrophobic aglycone groups. Supramolecular sheet, tubular and unique structures were obtained, depending on the molecular structure of the SAG. Polymeric [Au(CN)2]−n units in these supramolecular structures resulted in aurophilic interactions that produced luminescent aggregates, depending on the SAG.
A sub-nanosecond visible laser coupled with a liquid chromatograph is utilized for atmospheric pressure laser ionization (APLI). We reveal that the range of applicable substances for nonresonant three-photon ionization is determined by the proton affinity and the ionization potential, the latter of which is lowered by solvation with eluents. APLI with a visible laser can be used for fragmentation- and background-free detection of analytes as well as to investigate the ionization threshold of solvated molecules.
A new type of silica–organic hybrid nanoparticle (HNPs) ∼30 nm in size, consisting of vinylsilylated silica nanoparticles (SNPs) of size ∼2 nm and 1,6-hexanedithiol as the organic linker, were prepared by their interconnection via the thiol–ene reaction. The particle size of the HNPs varied depending on the concentration of the linker. Additionally, they could be dispersed in organic solvents and further successful chemical modification of the internal surfaces of HNPs indicated the accessibility of guest species into the internal nanospaces.
We developed the synthesis of one-dimensional polythiophenes inside single-wall carbon nanotubes (SWCNTs). Direct vapor-phase reaction with dibromobithiophenes provided long-conjugated polythiophenes through dehalogenative polymerization in the cavities of SWCNTs. Tethering of the large number of thiophene units was confirmed by optical absorption measurement and high-resolution transmission electron microscopic (HR-TEM) observation. Raman spectroscopy indicated that restricted one-dimensional inner space of SWCNTs enables s-trans coplanar conformation of thiophene moieties. We also revealed a weak p-doping of metallic SWCNTs selectively occurred by bromine molecules, which were generated during the synthesis of polythiophenes.
By combining three kinds of DNA hairpins (one involving both aptamer sequence and trigger sequence, and the other two to amplify the signal by hybridization chain reaction), a food toxin ochratoxin A (OTA) was selectively detected with a remarkably high sensitivity. The signal was visualized with the use of the peroxidase-like function of G-quadruplexes that were formed from the terminal sequences of two adjacent fragments in the DNA nanowire. Even 0.08 ppb of OTA was successfully detected.
The first successful ionothermal synthesis of silicoaluminophosphate (SAPO) with the LTA framework is presented. SAPO-LTA was synthesized in 1-butyl-3-methylimidazolium bromide ([C4mim]Br) in the presence of tetramethylammonium fluoride ([Me4N]F). [C4mim]Br is solvent as well as structure-directing agent (SDA) whereas [Me4N]F functions as both mineralizer and co-SDA. The presented ionothermal synthesis offers an efficient method compared to the conventional hydrothermal synthesis.
The thermodynamic activity of Li2O in Li0.23La0.61TiO3 (LLT) was measured by an electrochemical galvanic cell using YSZ as the reference electrode to determine the phase boundary of reaction of different CO2 contents with Li2O in LLT to form Li2CO3. The Li2O activity in LLT was evaluated from the electromotive force (EMF) vs. log(PCO2) plot. The lithium ion conductivity in LLT was investigated by AC impedance measurements and the bulk and grain-boundary conductivities were isolated by identifying the frequency-independent plateau regions on the capacitance bode-plot which showed two temperature-independent distinct plateaus associated with bulk and grain boundary response. The grain boundary conductivity was >1 order of magnitude lower than that of the bulk and the activation energies for bulk and grain boundary lithium ion conduction were 0.47 ± 0.01 and 0.77 ± 0.02 eV. The Kohlrausch stretching parameter (β) was calculated from the normalized plot of complex modulus (M′′) vs. frequency.
Studies were carried out to explore catalytic NO–CO reactions promoted by La-loaded and unloaded Al2O3 supported Pd in both powder and cordierite monolithic honeycomb forms. La introduction significantly enhanced catalytic activity toward the NO–CO reaction. The results of in situ FT-IR studies suggest that the promotion effect of La is a consequence of efficient formation of surface nitrite species and their reactivity upon introduction of CO as a reactant.
Palladium cataCXium A catalyst was more effective than t-Bu3PPd catalyst for unstoichiometric Suzuki-Miyaura coupling polymerization of excess dibromofluorene with pinacol fluorenediboronate or pinacol benzothiadiazoleboronate, affording high-molecular-weight conjugated polymers with pinacol boronate ends. Furthermore, polymerization of excess dibromocyclopentadithiophene and pinacol benzothiadiazolediboronate with this Pd catalyst yielded high-molecular-weight donor-acceptor conjugated alternating copolymer with boronate ends.
Cu/Fe-cocatalyzed cross-coupling reactions between 3-bromobenzo[b]thiophene and hydroxyaryls are described herein. The combination of Cu and Fe catalysts is important for the progress of the reactions, and the use of triphenylphosphine oxide as a ligand suppresses the dehalogenation of 3-bromobenzo[b]thiophene, and promptly facilitates the reaction. The obtained aryl benzo[b]thienyl ethers can be converted to π-extended thienobenzofuran derivatives via Pd-catalyzed dehydrogenative cyclizations.
We report that simple aryl(trialkyl)silanes undergo cross-coupling reaction with alkyl (pseudo)halides in the presence of copper iodide/phenanthroline catalyst and cesium fluoride. Various aryl(trialkyl)silanes and alkyl electrophiles having iodine, bromine, chlorine, and tosyloxy group are applicable to the present reaction. Because such silanes are stable and readily accessible by catalytic C–H silylation, this protocol allows us to synthesize alkylarenes rapidly.
Thermoresponsive poly(N-isopropylacrylamide) with triazole copolymer brushes, poly(NIPAAm-co-TZ), grafted on porous silica (P-SiO2) was synthesized, and the temperature swing-based mutual separation of trivalent lanthanide ions (Ln3+) was demonstrated. The results indicated that the polymer brushes enabled adsorption/desorption of Ln3+ depending on differences in the interactions between the individual Ln3+ and TZ moieties, and the hydration state.
It is well recognized that the thickness of TiO2 film serving as hole blocking layer (bl-TiO2) in planar n-i-p structured perovskite solar cells is required to be thin for the purpose of reducing charge transporting resistance. However, the TiO2 film thickness should be multi-dimensional considering that a too thin bl-TiO2 film might not achieve full coverage on the rough surface of substrate. Moreover, the TiO2/perovskite heterojunction properties could also be strongly affected by the bl-TiO2 thickness, which has rarely been investigated as far as we know. Herein, we deposited the different thickness of bl-TiO2 layer through a multi-spin-coating process with a mildly acidic solution of titanium isopropoxide in ethanol. The thickness of bl-TiO2 layer, roughness of FTO/bl-TiO2 surface, coverage of bl-TiO2 on FTO and the transmission variation of FTO/bl-TiO2 were systematically reported. Additionally, the depleted degree of TiO2/perovskite heterojunction was found to be strongly affected by n-side bl-TiO2 thickness, which was analytically discussed by the photoluminescence (PL) measurement. The PL emission spectra incident from different sides of FTO/bl-TiO2/perovskite structure, excitation power dependent PL spectra and PL excitation spectra at different detected wavelength were comprehensively conducted to reveal the band bending effect and depletion thickness across the heterojunction.
Light-harvesting efficiency can be prominently increased by using ternary blend polymer solar cells, in which a wide-bandgap crystalline polymer is incorporated into a binary blend of a low-bandgap polymer and a fullerene derivative. This is partly due to the complementary absorption bands over a wide wavelength range, and partly ascribed to the thick photoactive layer. As a result, the best power conversion efficiency of 9.40% was obtained for the ternary blend device with a thickness of ≈300 nm.
DBU-catalyzed fixation of gaseous carbon dioxide to organic and polymeric compounds is completed in a few minutes at an atmospheric pressure and temperature. The CO2-fixation to propargylamines and their polymers that have a pyridine group in dimethyl sulfoxide proceeded to give the corresponding oxazolidinone and polyoxazolidinone in 100% conversion. The fixation was very efficient and was completed in 48 h, even under air. The present CO2-fixation is characterized by a high speed and efficient reaction, without metal catalysis.
A facile method to recycle wasted expandable polystyrene (WEPS) into graphite polystyrene bead (GPS) is described in this paper. The recycled beads were characterizied by FTIR, SEM, TGA, GPC and XRD, and the results showed that the molecular weight (Mn) was equal to 99.25% of the standard polystyrene and there was no decline in thermal stability. This method provided several advantages such as easy operation, low energy consumption, low contamination, high purity and high yield of product.
Chlorophyll (Chl) d, which is a major pigment in an oxygenic photosynthetic organism Acaryochloris marina, was almost fully inserted into the circularly arranged binding sites of B800 bacteriochlorophyll (BChl) a in a bacterial light-harvesting protein, LH2. The 3-formyl group in Chl d was hydrogen-bonded with the polypeptides in essentially the same manner as the 3-acetyl group in BChl a in native LH2.
CuY zeolite is a promising catalyst for oxidative carbonylation of methanol to dimethyl carbonate (DMC). In this work, auto-reduction at high temperature and vapor-induced reduction were comparatively investigated to activate the CuY precursors. XPS, XRD as well as CO adsorption demonstrated that methanol as reduction agent can achieve a high proportion of Cu(I) and avoid the formation of Cu(0) as far as possible, which is responsible for the enhanced DMC yield.