Palladium-catalyzed carbon-carbon and carbon-heteroatom bond construction are among the most significant and powerful methods in organic synthesis. Numerous investigations are focusing on the application and development of the ground-state reactivity of palladium catalyst. Recently, visible light-induced palladium catalysis has been reported to enable some unprecedented transformations via the photoexcited-state of the palladium complex, which could not be achieved under traditional thermal conditions. This highlight review discusses the recent progress in this sort of novel synthetic methods.
An epitaxial Li2MnO3(001) thin film electrode with layered rock-salt structure was tested in an all-solid-state battery configuration for the first time. Using amorphous Li3PO4 solid electrolyte, good discharge capacity after the 5th cycle, excellent reversibility for 100 cycles, and high rate capability at room temperature were observed. The same electrode showed significant capacity fading when cycled in liquid electrolyte. The all-solid configuration could prevent electrolyte decomposition, Mn dissolution, and oxygen extraction from Li2MnO3 electrode.
CO2 methanation over a Ni/CeO2 catalyst was investigated under the feeding of a raw material gas containing oxygen of 1–10 vol % concentration. The presence of oxygen greatly improved the methanation activity and provided high methane yield, even with cutting external heating, near room temperature. This positive phenomenon was caused by the fact that hydrogen-combustion by oxygen selectively occurred on the Ni/CeO2 catalyst, and a large amount of thermal energy was generated. We found a novel route of CO2 methanation that can be driven without external heating, even near room temperature, which we named auto-methanation.
Photocatalytic overall water splitting into hydrogen and oxygen on RuO2-loaded Sm3+-doped CeO2 was examined. Pure CeO2 showed a negligible small activity, however Sm3+ doped CeO2 with heterogeneous doping structure synthesized by solid state reaction exhibited an efficient activity, whereas Sm3+-doped CeO2 with homogeneous doping structure showed little activity when prepared by co-precipitation method. In this study, the relation between photocatalytic activity and surface doping structure was investigated.
To clarify the effect of multi-anchoring groups on diphenylpyranylidene (DP) sensitized solar cells for improving charge-transfer rate, di-anchored DP dyes were synthesized for the first time for comparison with a novel mono-anchored DP dye. A solar cell based on di-anchored dye showed enhanced photocurrent and open circuit voltage compared to mono-anchored dye, leading to 32% higher power conversion efficiency of 5.18%, which resulted from the higher molar extinction coefficient and larger charge transfer resistance in the interface of TiO2 and di-anchored dye.
Monomers of 4-vinylaniline, and 4-vinylpyridine were studied to investigate the influence of charges of the initiator on the dispersion stability of the new polymer particles created using soap-free emulsion polymerization. The surface of the polymer particles included some functional groups originated from the monomers and some from the initiators, based on measurement of their zeta potentials. Therefore, during the polymerization, the dispersion stability was maintained when using cationic initiators. On the other hand, aggregation of particles occurred when anionic initiators were used due to the electrostatic attraction between the hydrophilic and hydrophobic groups on the polymer surfaces.
The nanostructure control of strong coupling has been less thoroughly investigated in organic semiconductor structures than in resonator structures. We achieved strong coupling by introducing a layered silicate between a silver nanodisk resonator and a porphyrin organic semiconductor, where the porphyrin nanostructure is monomeric and parallel to the silicate surface.
An electrochemiluminescence (ECL) sensor was constructed with graphitic carbon nitride nanosheets (g-C3N4 NSs) as the luminophor and multi-walled carbon nanotubes (MWCNT) as signal amplifier. It was interesting to find that the ECL signal could be quenched by epinephrine (EP) and the variation of ECL signal was linearly related to the concentration of EP. Based on this finding, a simple and sensitive method for the determination of EP was established. The quenching mechanism of EP on the ECL system is discussed.
A novel series of hole-transporters for organic light-emitting devices (OLEDs) was developed with the aim of high thermal and electrical stability. This was achieved by introducing benzothieno[3,2-b]benzothiophene (BTBT) moieties as end-cap groups. These BTBT-end-capped hole-transporters exhibited superior thermal stability with a glass transition temperature (Tg) of over 150 °C and high electrical stability in green phosphorescent OLEDs at a high brightness of over 8000 cd m−2 (current density: 15 mA cm−2).
Antifreezing proteins (AFPs) have been found in many organisms ranging from bacteria to vertebrates that inhabit subzero environments. AFPs are believed to adsorb the surface of nascent ice crystals and prevent water molecules from accessing the ice surface at the bound location. We here focused on AFP from Rhagium inquisitor (RiAFP) as a target and performed molecular dynamics (MD) simulations of RiAFP on ice surface in water below melting temperature to investigate how RiAFP affects the ice growth. It was found that the ice growth from the prismatic face is suppressed and that from the basal face is accelerated, respectively due to the RiAFP binding. Furthermore, mutations to RiAFP, where all Thr are replaced by Gly, resulted in loss of antifreezing nature due to reduced binding to the ice surface.
A modified one-bilayer polyelectrolyte reverse osmosis membrane was fabricated using poly(allylamine hydrochloride) and poly(sodium-4-styrene sulfonate) as polycation and polyanion, glutaraldehyde as a crosslinker and polyethylene glycol (PEG-600) as a surface modifier by the spraying assisted layer-by-layer assembly method. The results show that the PEG modified membrane possesses higher permeate flux (ca. 21 L/m2h) than the unmodified one (ca. 3 L/m2h) with a similar salt rejection. Furthermore, the PEG modifier dramatically enhances the membrane anti-microbial property (ca. 98.6%).
A reaction between an N-phosphine oxide-substituted imidazolylidene (PoxIm) and MOTf (M = Li or Na) in THF afforded the complexes [(PoxIm)x(MOTf)y(THF)z] through the coordination of the N-phosphoryl group to Na+ or Li+, which was unambiguously confirmed by 13C and 31P NMR spectroscopy and single-crystal X-ray diffraction analyses. These measurements confirmed that the carbene moieties in these complexes remain intact. In solution, PoxIm and MOTf might form the complexes in a 3:2 ratio (i.e., x = 3, y = 2), while ratios of 1:1 (M = Li; x = 1, y = 1) and 2:1 (M = Na; x = 2, y = 1) were observed in the solid state.
Using an advanced physical deposition method, a supported ionic liquid, Et3NHCl·CuCl2 immobilized on cyclodextrin modified zeolite, was developed as an efficient desulfurizer. Quantum chemical calculations were employed for the determination of the size of Et3NHCl·CuCl2, Et3NH+, and CuCl3−. Et3NH+ can be included into the cavity of β-cyclodextrin, suggesting that Et3NHCl·CuCl2 can be well dispersed on the surface of zeolite. Two deposition modes were proposed due to an excessive molar ratio 7:1 of Et3NHCl·CuCl2 to β-cyclodextrin in favor of H2S removal.
The first iron-catalyzed cross-coupling reaction of alkyl halides with alkylaluminum reagents (alkyl–alkyl Negishi coupling) is developed using an iron/bisphosphine catalyst system. The reaction shows high functional group tolerance: various primary alkyl halides possessing a non-protected indole, carboxyl, or hydroxy group are coupled with primary alkylaluminum reagents in good yields. Potassium fluoride plays a key role to promote the reaction by generating an aluminate species, which facilitates the transmetalation between the organoaluminum and the iron catalyst.
We investigated the introduction of basic strong pyridine compounds into the hole-transporting layer in solid-state dye-sensitized solar cells to obtain a good power output under low-intensity illumination. It was found that the ionization potential of the hole-transporting layer was shifted by the basicity of pyridine compounds, an especially large shift of the ionization potential was obtained by strongly basic pyridine compounds.
Three crosslinked films with different ratios of hydrophilic and hydrophobic monomers were prepared using trimethylene carbonate backbone with ester free structure. Oligo(ethylene glycol) (OEG) was selected as hydrophilic moieties due to the high mobility, hydrophilicity and biocompatibility. The obtained crosslinked films were evaluated by thermal properties, mechanical properties, surface properties, and protein adsorption. The results showed soft properties with high biocompatibility, depending on the introduction rate of OEG.
During the last years, lead perovskites have achieved high power conversion efficiency of 23%. However, their long-term stability and toxicity are still crucial issues that required attention. In this study, we are the first to report on the synthesis and characterizations of a new lead-free mixed halide-chalcogenide perovskite MABiI2S (MBIS), and have determined its physical and optical properties by various testing methods. The MBIS has a low bandgap of 1.52 eV, with an extended absorption onset up to over 1000 nm. Solar cells fabricated with the MBIS were inspected and device improvements were applied.
The adsorption process at a liquid/graphite interface was investigated by scanning tunneling microscopy for a series of ester and amide derivatives which have a different number of phenyl rings in the core structure. We found that ester derivatives showed high cooperativity despite the lack of hydrogen bonding and that the Gibbs free energy for adsorption during the elongation process negatively increased with increasing number of phenyl groups in the core structure.
We synthesized phosphole-bridged porphyrin dimers and evaluated their optical and electrochemical properties. The porphyrin dimers exhibited broadened and red-shifted absorption relative to thienylene- and p-phenylene-bridged reference dimers, suggesting effective π-conjugation between the porphyrins through the phosphole linker. The more positive reduction potentials of phosphole-bridged porphyrin dimers compared to reference dimers are attributed to the electron-accepting ability of the phosphole linker.
A chiral bis-phosphoric acid derived from a BINOL (1,1′-bi-2-naphthol) dimer as a chiral backbone was developed. The catalytic efficiency of this bis-phosphoric acid was compared with that of a reported bis-phosphoric acid having a single BINOL backbone in the Diels-Alder reaction of acrolein with 1,3-dien-1-ylcarbamate. The detailed structural analysis of these bis-phosphoric acid catalysts, coupled with the stereochemical outcome of the Diels-Alder reaction, led to the identification of the specific properties of the bis-phosphoric acid catalysts responsible for the high enantioselectivity.
Quinhydrone is regarded as a donor-acceptor complex composed of hydroquinone and quinone. Here we show that 1,5-dibromo-2,6-naphthoquinhydrone shows electron transport in the transistors. The donor and acceptor frontier orbitals are approximately the same, but in addition to the strong acceptor ability of the quinone, enhancing and canceling contributions of the second bridge orbital result in monopolar transport.
Conjugate addition of 2-tributylstannyl-1,3-dithiane to α,β-unsaturated ketones has been achieved by the combined use of Cu(OTf)2 and Et3SiOTf in CH2Cl2 at room temperature. Thus, the corresponding β-(1,3-dithian-2-yl)-substituted ketones were obtained in moderate to high yields under mild conditions.
Organic long-persistent luminescence can be observed in any film fabrication method, such as spin coated, thermally evaporated and melt casted. Although photophysical properties are independent on fabrication methods, OLPL intensity is strongly influenced by film thickness. In addition, m-MTDATA:PPT pair shows longer duration than that of TMB:PPT pair because of higher ΦPL of m-MTDATA:PPT pair.
Metallic silver with a nanofilament morphology was directly formed on electrodes with a combination of electrochemical processes and a silver halide photography development reaction. Metallic silver was first electrodeposited on a substrate electrode, and then converted to silver iodide through a combined electrochemical/chemical process. The silver iodide on the electrode was then treated with a photographic developer solution, giving metallic silver with the nanofilament morphology. The use of carbon paper as the substrate electrode gave superior adhesive stability of the nanofilaments for future functionalization.
Soft templates, which are composed of CTAB and Pluronics, are demonstrated to guide the growth of water-dispersable Pd@Au core-shell nanorods. Moiré fringes, which occur through the plane-matching epitaxial growth without the rotation of planes, are widely observed with their alignment perpendicular to 〈110〉 directions. Optical absorbance measurements indicate the dominant effect of Pd cores, and the resonance peaks reside in the visible region.
A copper-catalyzed chloroamination of alkenes with chlorotrimethylsilane and N-fluorobenzenesulfonimide has been developed. The reactions were complete within 1 h at 120 °C by means of microwave heating. The present chloroamination proceeds with a perfect regioselectivity and is compatible with various functional groups. The preliminary mechanistic investigation revealed that the reaction involves a radical process. The utility of the present method was demonstrated by scalable, operationally simple and safe system.
An octahedral metal-organic framework (MOF), UiO-68, with two hydroxymethyl groups (UiO68-hyd) was synthesized for the first time and the hydroxy groups were post-synthetically modified with iso(thio)cyanates to form (thio)urethanes. Several organotins and tertiary amines were used as catalysts for the modification of UiO68-hyd with butyl isocyanate (BuNCO), and 70% of hydroxy groups reacted after 7 days. Moreover, various isocyanate and isothiocyanate compounds were successfully modified on UiO68-hyd.
Amorphous transition metal polysulfides are promising high capacity electrode active materials for sodium secondary batteries. Here we report the superior electrode performance of amorphous Na2TiS3. Crystalline (c-) and amorphous (a-) Na2TiS3 were prepared by solid phase reaction with heat treatment and mechanochemical reaction, respectively. a-Na2TiS3 showed 10 fold higher ionic conductivity (1.5 × 10−6 S cm−1) than that of c-Na2TiS3. The all-solid-state cells using c-Na2TiS3 and a-Na2TiS3 showed reversible capacities of 110 mAh g−1 and 250 mAh g−1, respectively. Amorphization of Na2TiS3 is a powerful way to improve electrode performance in all-solid-state sodium secondary batteries.
Recently, nanoparticles have emerged as promising contrast agents for various imaging applications. In this paper, we present the synthesis and characterization of a novel hybrid nano-structure, consisting of an iron oxide@gold nanoparticle, labeled with technetium-99m, for trimodal SPECT/CT/MRI imaging. The particles showed efficient capabilities as CT/MRI imaging agent and high radiochemical yield, indicating a potential single hybrid material for multimodal SPECT/CT/MRI.
Cellular uptake of rigid and flexible supramolecular hemoprotein assemblies formed by cytochrome b562 was investigated. Multivalent cell-penetrating tags on the protein surfaces of the assemblies improve the efficiency of cellular uptake into HeLa cells in a manner which depends on the number of arginine residues in the tags and the main-chain rigidity of the assemblies. A rigid protein assembly with an arginine tetramer tag shows 10-fold higher cellular uptake efficiency than a corresponding assembly without an arginine tag.