A new synthetic method for α-ketosilanes employing methoxy(phenylthio)trialkylsilylmethane as an α-silylacyl anion equivalent

Development of a new synthetic method for α-ketosilanes can be achieved by a sequence of alkylation of methoxy(phenylthio)trialkylsilylmethane and oxidation with NaIO₄.     

A facile synthesis of novel chiral phosphonoacetates bearing a stereogenic phosphorus atom

Novel chiral phosphonoacetates bearing a stereogenic phosphorus atom were successfully synthesized by enzyme-catalyzed kinetic resolution of racemic phosphonoacetates.     

Soft x-ray spectroscopy of Ba24Ge100: electronic phase transition and Ba-atom rattling

The electronic states of Ba24Ge100 are studied by soft x-ray photoelectron spectroscopy (XPS) at a high-energy photon factory. A large reduction in the density of states (DOS) at the Fermi level is clearly shown before and after the electronic phase transition at 200 K. The changes in the spectrum widths and the fine structures of the core-level Ba 4d spectra give a very reasonable indication of the Ba-atom rattlings in the clathrate polyhedra. On-resonance experiments using the excitation from Ba 3d to 4f levels display that the wave functions of Ba 5d and 6s orbitals give only a small contribution to make a Fermi surface through the hybridization with the Ge20 cluster orbitals. Importantly, reliable values of the DOS at the Fermi level NEF are successfully deduced, using two data sets of DOS obtained from high-resolution XPS and the total magnetic susceptibilities by a superconducting quantum interference device, to be 0.149 and 0.0427 states eV(-1) (Ge atom)(-1) for a high-temperature and for a low-temperature phase.     

A design of fluorescent probes for superoxide based on a nonredox mechanism

Fluorometric detection of O2-* is performed based on desulfonylation of 3 to the corresponding fluoresceins 4 through nucleophilic substitution, and this fluorescing process is quite specific toward O2-* over H2O2, t-BuOOH, NaOCl, 1O2, HO*, NO*, and ONOO-. Furthermore, effects of glutathione, cytochrome P450 reductase/NADPH, and diaphorase/NADH are relatively small on the fluorescing process of probe 3 with X = Y = F, which is useful to detect O2-* released from neutrophils stimulated by phorbol myristate acetate with satisfactory sensitivity.     

6 j symbols for $U_q (\mathfrak{s}\mathfrak{l}_2 )$U_q (\mathfrak{s}\mathfrak{l}_2 ) and non-Euclidean tetrahedra

We relate the semiclassical asymptotics of the 6j symbols for the quantized enveloping algebra at q a root of unity (resp. q real positive) to the geometry of spherical (resp. hyperbolic) tetrahedra.     

Nickel-catalyzed [2 + 2] cycloaddition reaction using bisallenes

A nickel-catalyzed [2 + 2] cycloaddition of bisallenes has been described. Simple bisallenes are employed for the formation of “head to head” cycloadducts in the presence of Ni(0) with xantphos. The dienyl moiety in a product were applicable for various [4 + 2] cycloaddition reactions. Allene-allenamides under Ni-xantphos system gave the tricyclic compounds through sequential [2 + 2]–[4 + 2] cycloaddition reaction in highly stereoselective manner.     

Formal total synthesis of enigmazole A

A stereoselective formal total synthesis of enigmazole A, a marine macrolide isolated from Cinachyrella enigmatica, is described. Lewis acid mediated intramolecular allylation of an α-acetoxy ether, prepared from alcohol and carboxylic acid fragments was carried out to construct the methylene THP ring with high stereoselectivity. The late-stage macrolactonization of the corresponding seco-acid provided a known synthetic intermediate of enigmazole A.     

A Smart Sensing Method for Object Identification Using Circularly Polarized Luminescence from Coordination‐Driven Self‐Assembly

The potential use of circularly polarized luminescence for object identification in a sensor application is demonstrated. New luminescence probes using pyrene derivatives as sensor luminophores were developed. (R,R)‐Im₂Py and (S,S)‐Im₂Py contain two chiral imidazole moieties at 1,6‐positions through ethynyl spacers (angle between spacers ca. 180°). The probe molecules spontaneously self‐assemble into chiral stacks (P or M helicity) upon coordination to metal ions with tetrahedral coordination (Zn²⁺). The chiral probes display neither circular dichroism (CD) nor circularly polarized luminescence (CPL) without metal ions. However, (R,R)‐Im₂Py and (S,S)‐Im₂Py exhibit intense chiroptical activity (CD and CPL) upon self‐assembly with Zn²⁺ ions. (R,R)‐Im₂Py and (S,S)‐Im₂Py with chemical stimuli‐responsibility allow sensing using the CPL signal as detection output, enabling us to discriminate between a signal from the target analyte and that from non‐target species.     

Photoelectrochemical starch-O<Subscript>2</Subscript> biofuel cell consisting of chlorophyll derivative-sensitized TiO<Subscript>2</Subscript> anode and enzyme-based cathode

A new photoelectrochemical starch-O₂ biofuel cell has been developed, consisting of chlorin-e₆ (Chl-e₆) adsorbed on a TiO₂ layer onto an optical transparent conductive glass electrode as a photoanode, bilirubin oxidase (BOD)-modified electrode as a cathode, and a solution containing starch, glucoamylase, glucose dehydrogenase and NAD⁺ as fuel. The short-circuit photocurrent and the open-circuit photovoltage of this cell are 9.0 μA cm^?2 and 530 mV, respectively. The maximum power, FF and \(\eta\) values are estimated to be 1.7 μW cm^?2, 0.36 and 0.0017 %, respectively. Thus, this new type of the photochemical starch-O₂ biofuel cell has been developed by using the visible light photosensitization of Chl-e₆ on a TiO₂ film photoanode.     

Solar hydrogen production from cellulose biomass with enzymatic and artificial photosynthesis system

Bio-hydrogen gas production from renewable resources of timber waste, including cellulose, lignin, etc., is important in the environmental science and energy source development fields. A solar hydrogen production system by coupling waste paper including cellulose biomass with cellulase and glucose dehydrogenase (GDH), and hydrogen production with platinum nano-particle via the photoreduction of methylviologen (MV²⁺) using the visible light-harvesting function of Mg Chl-a, is developed.