An atropisomeric ML cage mixture displaying guest-induced convergence and strong guest emission in water.

Introduction of atropisomeric axes into a bent bispyridine ligand leads to the quantitative formation of a complex mixture of atropisomeric ML cages upon treatment with metal ions. Whereas the isomer ratio of the obtained cage mixture, consisting of up to 42 isomers, is insensitive to temperature and solvent, the quantitative convergence from the mixture to a single isomer is accomplished upon encapsulation of a large spherical guest, namely fullerene C. The observed isomerization with other guests depends largely on their size and shape (, <10 and 82% convergence with planar triphenylene and bowl-shaped corannulene guests, respectively).

Effects of ruthenium hydride species on primary amine synthesis by direct amination of alcohols over a heterogeneous Ru catalyst.

Heterogeneously catalysed synthesis of primary amines by direct amination of alcohols with ammonia has long been an elusive goal. In contrast to reported Ru-based catalytic systems, we report that Ru-MgO/TiO acts as an effective heterogeneous catalyst for the direct amination of a variety of alcohols to primary amines at low temperatures of 100 °C without the introduction of H gas. The present system could be applied to a variety of alcohols and provides an efficient synthetic route for 2,5-bis(aminomethyl)furan (BAMF), an attention-getting biomonomer.

Intrinsic asymmetric ferroelectricity induced giant electroresistance in ZnO/BaTiO superlattice.

Here, we combine the piezoelectric wurtzite ZnO and the ferroelectric (111) BaTiO as a hexagonal closed-packed structure and report a systematic theoretical study on the ferroelectric behavior induced by the interface of ZnO/BaTiO films and the transport properties between the SrRuO electrodes. The parallel and antiparallel polarizations of ZnO and BaTiO can lead to intrinsic asymmetric ferroelectricity in the ZnO/BaTiO superlattice. Using first-principles calculations we demonstrate four different configurations for the ZnO/BaTiO/ZnO superlattice with respective terminations and find one most favorable for the stable existence of asymmetric ferroelectricity in thin films with thickness less than 4 nm.

IR super-resolution imaging of avian feather keratins detected by using vibrational sum-frequency generation.

IR super-resolution imaging of the cross section of the rachis of an avian feather was carried out by using a vibrational sum-frequency generation (VSFG) detected IR microscope with a sub-micrometer spatial resolution. In the YYX polarization combination, we clearly observed strong signals in the entire region of the rachis at the amide I vibration of β-keratin. On the other hand, the signal disappears from most of the cross section in the XXY polarization combination.

Organic-inorganic nanocrystal reductase to promote green asymmetric synthesis.

An acetophenone reductase from (APRD) was immobilized by the organic-inorganic nanocrystal method. The APRD nanocrystal presented improved stability and recyclability compared with those of the free APRD. Moreover, the APRD nanocrystal reduced broad kinds of ketones with excellent enantioselectivities to produce beneficial chiral alcohols such as ()-1-(3',4'-dichlorophenyl)ethanol with >99% yield and >99% ee.

Thermo-driven self-assembly of a PEG-containing amphiphile in a bilayer membrane.

Self-assembly of lipid molecules in a plasma membrane, namely lipid raft formation, is involved in various dynamic functions of cells. Inspired by the raft formation observed in the cells, here we studied thermally induced self-assembly of a synthetic amphiphile, bola-AkDPA, in a bilayer membrane. The synthetic amphiphile consists of a hydrophobic unit including fluorescent aromatic and aliphatic components and hydrophilic tetraethylene glycol chains attached at both ends of the hydrophobic unit.

Aromatic Fluorination of Multiblock Amphiphile Enhances Its Incorporation into Lipid Bilayer Membranes.

We designed multiblock amphiphiles and , which consist of perfluorinated and non-fluorinated hydrophobic units, respectively. Absorption spectroscopy revealed that both amphiphiles are molecularly dispersed in organic solvent, while they form aggregates under aqueous conditions. Furthermore, we investigated whether and can be incorporated into DOPC lipid bilayer membranes, and found that the maximum concentration of that can be incorporated into DOPC lipid bilayer membranes is 43 times higher than that of .

Real-time and observation of structural evolution of giant block copolymer thin film under solvent vapor annealing by atomic force microscopy.

An instrumentation technique for real-time, and real space observation of microphase separation was proposed for ultra-high molecular weight block copolymer thin films (1010 kg mol, domain spacing of 180 nm) under high solvent vapor swelling conditions. This is made possible by a combination of a homebuilt chamber which is capable of supplying sufficient amount of vapor, and force-distance curve measurements which gives real-time swollen film thickness and allow active feedback for controlling the degree of swelling. We succeeded in monitoring the domain coarsening of perpendicular lamellar structures in polystyrene--poly(methyl methacrylate) thin films for eight hours tapping mode imaging.

Bipolar Electrochemistry: A Powerful Tool for Electrifying Functional Material Synthesis.

Electrosynthesis is a powerful method for the synthesis of organic, inorganic, and polymeric materials based on electron-transfer-driven reactions at the substrate/electrode interface. The use of electricity for synthetic reactions without the need for hazardous chemical oxidants and reductants is recognized as a green and sustainable method. Other advantages include control of the reaction selectivity by tuning the electrode potentials.

Towards a Scalable Synthesis of 2-Oxabicyclo[2.2.0]hex-5-en-3-one Using Flow Photochemistry.

Cyclobutene lactones hold great potential as synthetic building blocks, yet their preparation by photochemical rearrangement in batch can often be a bottleneck in synthetic studies. We report the use of flow photochemistry as a tool to enable a higher-throughput approach to the synthesis of 2-oxabicyclo[2.2.

Raman cell imaging with boron cluster molecules conjugated with biomolecules.

Raman spectroscopic measurements and theoretical calculation revealed that the Raman bands corresponding to the B-H stretching vibrations of two types of simple icosahedral boron clusters, -carborane 3 and -dodecaborate 4 appeared at approximately 2450-2700 cm, and did not overlap with those of cellular components. Although -carborane 3 possesses a possible property as a Raman probe, it was difficult to measure Raman imaging in the cell due to its poor water solubility. In fact, -carborane derivative 6, which internally has an alkyne moiety, exhibited very weak Raman signals of the C[triple bond, length as m-dash]C stretching and the B-H stretching vibrations were barely detected at a 400 ppm boron concentration in HeLa cells.

Crystal structure of a DNA duplex cross-linked by 6-thioguanine-6-thioguanine disulfides: reversible formation and cleavage catalyzed by Cu(ii) ions and glutathione.

Herein, we determined the crystal structure of a DNA duplex containing consecutive 6-thioguanine-6-thioguanine disulfides. The disulfide bonds were reversibly formed and cleaved in the presence of Cu(ii) ions and glutathione. To our knowledge, this is the first reaction in which metal ions efficiently accelerated disulfide bond formation between thio-bases in duplexes.

Donor-acceptor polymers containing thiazole-fused benzothiadiazole acceptor units for organic solar cells.

Two p-type semiconducting donor-acceptor polymers were designed and synthesized for use in organic solar cells. The polymers combine a benzodithiophene (BDT) donor and a thiazole-fused benzothiadiazole (TzBT) acceptor. Two TzBT acceptor units are compared, one with an alkylthio group (P1) and the other with a more strongly electron-withdrawing alkylsulfonyl group (P2) at the fused thiazole ring.

Nephelauxetic effect of the hydride ligand in SrLiSiOH as a host material for rare-earth-activated phosphors.

Strontium lithium orthosilicate hydride SrLiSiOH was synthesized by the reaction of SrSiO with LiH at 700 °C in a H rich atmosphere. Rietveld refinement of the neutron powder diffraction pattern revealed that SrLiSiOH is isostructural to SrLiSiOF (space group 2/) and its channel-like structure preferentially accommodates H ions over F ions. In addition, SrLiSiOH is stable in air and its Eu-doped analog exhibits yellow photoluminescence with an emission band at 544 nm and a broad excitation band ranging from 250 to 450 nm.

Metal-to-Semiconductor Transition and Electronic Dimensionality Reduction of CaN Electride under Pressure.

The discovery of electrides, in particular, inorganic electrides where electrons substitute anions, has inspired striking interests in the systems that exhibit unusual electronic and catalytic properties. So far, however, the experimental studies of such systems are largely restricted to ambient conditions, unable to understand their interactions between electron localizations and geometrical modifications under external stimuli, e.g.

Buoyant force-induced continuous floating and sinking of Janus micromotors.

A novel bubble-induced ultrafast floating and sinking of micromotors based on the difference between buoyant force and gravity is proposed. Asymmetric micromotors were prepared by modification with Au and Pt layers for the two faces of glassy carbon beads (GCBs) by the bipolar electrodeposition technique. After the accumulation of enough oxygen bubbles by the decomposition of HO at the Pt layer, the upward net force acting on the micromotor drove its movement to the air/solution interface.

Development of a Split SNAP-CLIP Double Labeling System for Tracking Proteins Following Dissociation from Protein-Protein Complexes in Living Cells.

The split SNAP-tag protein-fragment complementation assay (PCA) is a useful tool for imaging protein-protein interactions (PPIs) in living cells. In contrast to conventional methods employed for imaging PPIs, the split SNAP-tag PCA enables tracking of proteins following dissociation from protein-protein complexes. A limitation of this system, however, is that it only allows for labeling and tracking of one of the proteins forming the protein-protein complex.

High-Pressure Polymorph of NaBiO3.

A new high-pressure polymorph of NaBiO3 (hereafter β-NaBiO3) was synthesized under the conditions of 6 GPa and 600 °C. The powder X-ray diffraction pattern of this new phase was indexed with a hexagonal cell of a = 9.968(1) Å and c = 3.

Financial Knudsen number: Breakdown of continuous price dynamics and asymmetric buy-and-sell structures confirmed by high-precision order-book information.

We generalize the description of the dynamics of the order book of financial markets in terms of a Brownian particle embedded in a fluid of incoming, exiting, and annihilating particles by presenting a model of the velocity on each side (buy and sell) independently. The improved model builds on the time-averaged number of particles in the inner layer and its change per unit time, where the inner layer is revealed by the correlations between price velocity and change in the number of particles (limit orders). This allows us to introduce the Knudsen number of the financial Brownian particle motion and its asymmetric version (on the buy and sell sides).

Financial Brownian particle in the layered order-book fluid and fluctuation-dissipation relations.

We introduce a novel description of the dynamics of the order book of financial markets as that of an effective colloidal Brownian particle embedded in fluid particles. The analysis of comprehensive market data enables us to identify all motions of the fluid particles. Correlations between the motions of the Brownian particle and its surrounding fluid particles reflect specific layering interactions; in the inner layer the correlation is strong and with short memory, while in the outer layer it is weaker and with long memory.

Optical control of two-photon excitation efficiency of alpha-perylene crystal by pulse shaping.

Optimized pulse shaping experiments were carried out on the control of two-photon excitation efficiency of an alpha-perylene crystal in the temperature region from 30 to 290 K. It was found that a pulse train with a pulse interval of 90 fs and an alternately reversing phase relation increased the excitation efficiency by a factor of 2 for the whole temperature region. The pulse shape characteristic for effective efficiency increase was reduced by double pulse experiments in which the dependence of the emission intensity on the pulse interval and relative phase between pulses were measured.

Characteristics of a newly isolated fungus Geotrichum candidum Dec 1 with broad degradation spectrum of xenobiotic compounds.

A newly isolated fungus, Geotrichum candidum Dec 1 (abbreviated as Dec 1), was found to have the ability to degrade many xenobiotic compounds such as synthetic dyes, food coloring agents, molasses, organic halogens, lignin and kraft pulp effluents. The broad spectrum of the degradation of these compounds are associated mainly with peroxidases produced by the fungus.