Isolation of four new flavonoids from Melicope triphylla

Four new flavonoids, 3,5-dihydroxy-7,8-dimethoxy-3',4'-methylenedioxyflavone (1), 3,5-dihydroxy-7-methoxy-3',4'-methylenedioxyflavone (2), 3,5-dihydroxy-7-isopentenyloxy-8-methoxy-3',4'-methylenedioxyflavone (3) and 5-hydroxy-3-isopentenyloxy-7-methoxy-3',4'-methylenedioxyflavone (4), were isolated from the leaves of Melicope triphylla. In addition, two known flavonoids were detected including 5-hydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (5) and 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3',4'-methylenedioxyflavone (6). The structures of the new compounds were established by spectroscopic methods.     

Crystallographic interface control of the plasmonic photocatalyst consisting of gold nanoparticles and titanium(iv) oxide

A big question in the field of plasmonic photocatalysis is why a typical photocatalyst consisting of gold nanoparticles and rutile titanium(iv) oxide (Au/R-TiO₂) usually exhibits activity much higher than that of Au/anatase TiO₂ (Au/A-TiO₂) under visible-light irradiation. Shedding light on the origin should present important guidelines for the material design of plasmonic photocatalysts. Au nanoparticles (NPs) were loaded on ordinary irregular-shaped TiO₂ particles by the conventional deposition precipitation method. Transmission electron microscopy analyses for the Au/TiO₂ particles ascertain that faceting of Au NPs is induced on R-TiO₂ by using a domain-matching epitaxial junction with the orientation of (111)_Au//(110)_R-TiO2, whereas non-faceted hemispherical Au NPs are exclusively formed on A-TiO₂. The faceting probability of Au NPs (P_f) on R-TiO₂ increases with decreasing Au particle size (d_Au) to reach 14% at d_Au = 3.6 nm. A clear positive correlation between the photocatalytic activity and P_f in several test reactions indicates that the heteroepitaxial junction-induced faceting of Au NPs is the principal factor for governing the plasmonic photocatalytic activity of Au/TiO₂. In light of this finding, R-TiO₂ nanorods with a high percentage (95%) of {110} facets were hydrothermally synthesized and used for the support of Au NPs. Consequently, the P_f value increases to as much as 94% to enhance the photocatalytic activity with respect to that of Au/R-TiO₂ with P_f = 14% by factors of 2.2–4.4 depending on the type of reaction.

In the represented plasmonic photocatalyst consisting of Au nanoparticles (NPs) and TiO₂, the combination of crystal facet engineering of TiO₂ and atom-level-interface control between Au NP and TiO₂ gives rise to a drastic activity enhancement.     

Visualization of flow and vortex structure around a swimming loach by dynamic stereoscopic PIV

Loach has a unique swimming style of bending the whole body and staying at the bottom of water. We studied the three-dimensional flow field around and behind the loach using stereoscopic-PIV. We captured flow fields in horizontal and vertical plane, and it seems loach leaves vortex tube arches. From the analysis of body motion and flow field, we propose flow structure with vortex tube arches connected along the loach body. After being released, they are separated and flow away and dissipate. This research article was submitted for the special issue on Animal locomotion: The hydrodynamics of swimming (Vol. 43, No. 5).     

Gold‐Nanoparticle‐Loaded Carbonate‐Modified Titanium(IV) Oxide Surface: Visible‐Light‐Driven Formation of Hydrogen Peroxide from Oxygen

Gold nanoparticle‐loaded rutile TiO₂ with a bimodal size distribution around 10.6 nm and 2.3 nm (BM‐Au/TiO₂) was prepared by the deposition precipitation and chemical reduction (DP‐CR) technique. Visible‐light irradiation (λ>430 nm) of the BM‐Au/TiO₂ plasmonic photocatalyst yields 35 μm H₂O₂ in aerated pure water at irradiation time (t_p)=1 h, and the H₂O₂ concentration increases to 640±60 μm by the addition of 4 % HCOOH as a sacrificing electron donor. Further, a carbonate‐modified surface BM‐Au/TiO₂ (BM‐Au/TiO₂‐CO₃^2?) generates a millimolar level of H₂O₂ at t_p=1 h with a quantum efficiency (Φ) of 5.4 % at λ=530 nm under the same conditions. The recycle experiments confirmed the stable performance of BM‐Au/TiO₂.     

The Solid-State and Solution Conformations of (+)-Chelidonine

The solid-state and solution conformations of (+)-chelidonine ( 1 ), a biologically active alkaloid, were determined by X-ray diffraction and ¹H-NMR spectroscopy, X-Ray diffraction analysis revealed a conformer with B/C ‘anti-type’ cis conjunction, a half-chair of ring B , and a twist half-chair of ring C. One H₂O molecule per one alkaloid molecule was cocrystallized and stabilized by H-bonding with OH? C(11). Analysis of the thermal behavior of the crystal showed more thermal stability in the monohydrate than the anhydrate. The NMR measurement of concentration and temperature dependences in CDCl₃ and in (CD₃)₂SO suggested that the OH group of 1 was intramolecularly H -bonded to N(5) in (CD₃)₂SO and intermolecularly H-bonded to the solvent in CDCl₃. Conformational-energy calculations by the MNDO method showed that the intramolecular H -bond was little affected by the conformational stabilization of 1 .     

Solvent-free asymmetric conjugate addition of malonates to enones using a diaminomethylenemalononitrile organocatalyst

Diaminomethylenemalononitrile organocatalyst 1 efficiently promotes the asymmetric conjugate addition of malonates to α,β-unsaturated ketones to afford the corresponding addition products in high to excellent yields with up to 98% ee.     

8-METHOXYPSORALEN PLUS UVA INDUCES THE 72 kDa HEAT SHOCK PROTEIN IN ORGAN-CULTURED NORMAL HUMAN SKIN

Abstract The proteins induced by heat and other stressors, called heat shock proteins (HSP) or stress proteins, are considered to play a general role in protection from cellular injury. Exposure to UVA (320400 nm) following application of 8-methoxypsoralen (8-MOP), termed PUVA is commonly used in the field of dermatology. In order to understand the induction of HSP in PUVA-treated human skin, indirect immunofluorescence using a monoclonal antibody specific for the 72 kDa HSP (HSP 72) was carried out in organ-cultured normal human skin that was treated with PUVA. When the organ-cultured skin was treated at 37°C for 1 h with 8-MOP at a final concentration of 10 or 100 μg/mL and exposed to UVA (51.3 kJ/m²), nuclear immunofluorcscence of HSP 72 was detected in the epidermal cells 12 h after UVA irradiation. In contrast, the induction of HSP 72 was not detected either by UVA irradiation or 8-MOP treatment. These results suggest that PUVA treatment is one of the stressors for human skin, and DNA damage caused by PUVA induces HSP 72.     

Chiral induction controlled by aggregation of organometallics: trifluoromethylated aminoalcohols for chiral ligands in Et2Zn alkylation of benzaldehyde

Chiral induction in the reaction of Et2Zn with PhCHO by fluorinated chiral amino alcohols was correlated to the extent of aggregation of Et2Zn species, which was estimated by manometric study.     

Adsorption properties and behavior of the platinum group metals onto a silica-based (Crea + TOA)/SiO2–P adsorbent from simulated high level liquid waste of PUREX reprocessing

To separate platinum group metals (PGMs) from high level liquid waste (HLLW), a novel silica-based (Crea + TOA)/SiO₂–P adsorbent was synthesized by impregnating Crea (N′,N′-di-n-hexyl-thiodiglycolamide) and TOA (trioctylamine) two extractants into the macroporous SiO₂–P support with a mean diameter of 60 μm. Adsorption properties and behavior of PGMs from simulated HLLW onto the novel silica-based (Crea + TOA)/SiO₂–P adsorbent were investigated by batch method. It was found that (Crea + TOA)/SiO₂–P adsorbent exhibited good adsorption selectivity for PGMs over the other tested fission product element in a wide HNO₃ concentration. This adsorbent showed strong affinity to Pd(II) but almost no adsorption for rare earth elements. Adsorption process of PGMs could be expressed by Langmuir monomolecular layer adsorption mode and be governed by the chemisorption process. In addition, the adsorption isotherms and thermodynamic parameters of tested elements were calculated by Langmuir equation, Freundlich equation and van’t Hoff equation, respectively.     

Applications of Pillar[n]arene‐Based Supramolecular Assemblies

Macrocycles are an important player in supramolecular chemistry. In 2008, a new class of macrocycles, “pillar[n]arenes”, were first discovered. Research efforts in the area of pillar[n]arenes have elucidated key properties, such as their shape, reaction mechanism, host–guest properties, and their versatile functionality, which has contributed to the development of pillar[n]arene chemistry and their applications to various fields. This Minireview describes how pillar[n]arene‐based supramolecular assemblies can be applied to supramolecular gel formation, reactions, light‐harvesting systems, drug‐delivery systems, biochemical applications, separation and storage materials, and surface chemistry.