Nd-isotopic composition of Phanerozoic sediments in the Inner Zone of Southwest Japan Arc: implications on provenance characteristics and contribution to formation of mature island arc system

The Nd-isotopic data on sedimentary and metamorphic rocks of SW Japan Arc allow their discrimination into five different depleted mantle (Tdm) model age clusters, 2.6-2.45 Ga, 2.3-2.05 Ga, 1.9-1.55 Ga, 1.45-1.25 Ga, 1.2-0.85 Ga. The 2.6-2.45 Ga and 1.9-1.55 Ga model ages are also coincident with U-Pb inherited zircon ages of the above two epochs as well as the major magmatic activity in the Sino-Korean Craton (SKC). The 2.3-2.05 Ga model ages can be considered as the initial formation ages for the precursors of sedimentary rocks. The Nd-isotopic data suggest that the Hida Belt was most likely formed as a part of the SKC. The mantle underlying the Ryoke Belt had continental lithospheric signature during Triassic-Jurassic period. The 1.9-1.55 Ga model ages, especially 1.8 Ga~, can be associated with the formation of this belt. The source material for the sedimentary rocks occurring in the accretionary terrane of northeastern areas in the SW Japan Arc was probably in and around the SKC of the Ryoke Belt itself. The sedimentary rocks occurring in southwestern areas of the Arc were mainly composed of materials derived from a relatively younger source (1.45-0.85 Ga).     

Bovine serum albumin-mediated enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylate

Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxyalate (AC) was performed at 25 degrees C in aqueous buffer solution (pH 7) in the presence of bovine-serum albumin (BSA) to afford four [4 + 4] cyclodimers, i.e., anti- and syn-head-to-tail (HT) (1 and 2) and anti- and syn-head-to-head (HH) dimers (3 and 4), of which only 2 and 3 are chiral. We found that (1) BSA possesses four sets of binding sites for AC of different affinities, stoichiometries, and chiral environment for photoreaction, which bind 1, 3, 2, and 3 AC molecules with binding constants of 5.3 x 107, 1.3 x 105, 1.4 x 104, and 3.0 x 103 M-1, respectively, (2) the regioselectivity of photodimerization is switched from HT to HH by adding BSA (the HH/HT ratio varies from 0.28 to 4.3), (3) BSA-mediated photodimerization of AC affords optically active products 2 and 3 of up to 29% and 41% ee, respectively. It is emphasized that the selective excitation of bound substrate, utilizing the spectral shift upon complexation with BSA, is not a prerequisite for efficient photochirogenesis using biomolecules.     

Synthesis, structure, and reactivity of a eta(3)-1-hydroxyallyl complex: protonation of an alpha,beta-unsaturated carbonyl compound bound to palladium(0) and platinum(0)

The direct addition of a proton to a carbonyl oxygen in an eta2-enone complex of palladium and platinum led to the quantitative formation of eta3-1-hydroxyallyl complexes of palladium and platinum, of which X-ray diffraction analysis showed typical eta3-allyl structure.     

Diastereoselective photocycloaddition of axially chiral monothiosuccinimides to 1,1-diphenylethylene

Photolysis of axially chiral monothiosuccinimides in the presence of diphenylethylene gave spirothietanes effectively, where the cycloaddition took place diastereoselectively by way of the steric effect of the ortho-substituent on the phenyl ring.     

Mono-Gold(I)-Catalyzed Enantioselective Intermolecular Reaction of Ynones with Styrenes: Tandem Diels–Alder and Ene Sequence

Gold-catalyzed intermolecular reaction leading to dihydronaphthalene derivatives in one pot from two equivalents of ynones with respect to styrene is uncovered. The [4+2] Diels–Alder cycloaddition of ynones and styrenes is catalyzed by a mono-gold(I) complex and the conjugated acid to provide an unstable 3,8a-dihydronaphthalene to subsequently undergo an intermolecular ene-type reaction with the π-activated ynone to afford multi-component coupling dihydronaphthalene products. Linear relationships between chiral ligand-gold complexes and chiral dihydronaphthalene products proves mono-gold catalysis that triggers an asymmetric tandem Diels–Alder and ene reaction sequence.     

In Situ Transmission Electron Microscopy Observation of Melted Germanium Encapsulated in Multilayer Graphene

Germanene is a two-dimensional germanium (Ge) analogous of graphene, and its unique topological properties are expected to make it a material for next-generation electronics. However, no germanene electronic devices have yet been reported. One of the reasons for this is that germanene is easily oxidized in air due to its lack of chemical stability. Therefore, growing germanene at solid interfaces where it is not oxidized is one of the key steps for realizing electronic devices based on germanene. In this study, the behavior of Ge at the solid interface at high temperatures is observed by transmission electron microscopy (TEM). To achieve such in situ heating TEM observation, this work fabricates a graphene/Ge/graphene encapsulated structure. In situ heating TEM experiments reveal that Ge like droplets move and coalesce with other Ge droplets, indicating that Ge remains as a liquid phase between graphene layers at temperatures higher than the Ge melting point. It is also observed that Ge droplets incorporate the surrounding amorphous Ge as Ge nuclei, thereby increasing its size (domain growth). These results indicate that Ge crystals can be grown at the interface of van der Waals materials, which will be important for future germanene growth at solid interfaces.     

Formation of multiple aerial LED signs in multiple lanes formed with AIRR by use of two beam splitters

Optical Review - We propose multiple aerial imaging system by use of two beam splitters in the optical system of aerial imaging by retro-reflection (AIRR). The AIRR optical system consists of a...     

Self‐Healing,Expansion–Contraction,and Shape‐Memory Properties of a Preorganized Supramolecular Hydrogel through Host–Guest Interactions

Supramolecular materials cross‐linked between polymer chains by noncovalent bonds have the potential to provide dynamic functions that are not produced by covalently cross‐linked polymeric materials. We focused on the formation of supramolecular polymeric materials through host–guest interactions: a powerful method for the creation of nonconventional materials. We employed two different kinds of host–guest inclusion complexes of β‐cyclodextrin (βCD) with adamantane (Ad) and ferrocene (Fc) to bind polymers together to form a supramolecular hydrogel (βCD‐Ad‐Fc gel). The βCD‐Ad‐Fc gel showed self‐healing ability when damaged and responded to redox stimuli by expansion or contraction. Moreover, the βCD‐Ad‐Fc gel showed a redox‐responsive shape‐morphing effect. We thus succeeded in deriving three functions from the introduction of two kinds of functional units into a supramolecular material.