Hiroki Miura

Supported Pd–Au alloy catalysts were developed for the highly efficient and selective hydrosilylation of α,β-unsaturated ketones and alkynes. The Pd/Au atomic ratio of the Pd–Au alloy and the supporting material affected the catalytic activity, and supported Pd–Au alloy nanoparticles with a low Pd/Au atomic ratio functioned as highly active heterogeneous catalysts under mild reaction conditions. Structural characterization of supported Pd–Au alloy catalysts by X-ray diffraction, X-ray absorption

Controlled nucleation in a micromixer and further crystal growth were used to synthesize Ni₂(2,6-ndc)₂dabco (2,6-ndc - 2,6-naphthalenedicarboxylate, dabco - 1,4-diazabicyclo[2.2.2]octane), also termed DUT-8(Ni) (DUT = Dresden University of Technology), with narrow particle size distribution in a range of a few nm to several μm. The crystal size was found to significantly affect the switching characteristics, in particular the gate opening pressure in nitrogen adsorption iso

As a consequence of the urgent demand for an electro-optic (EO) polymer modulator with an elevated temperature stability, we have prepared a selection of EO polymers having glass transition temperatures of up to 194°C. The measured half-wave voltage characteristics of the fabricated Mach-Zehnder interference modulators revealed an excellent thermal resistance at 105°C for approximately 2,000 hours. By utilizing traveling-wave electrodes on the modulator, the high-frequency response at 10-40 GHz

Environmentally benign catalyst: A PPh3-modified Ru/CeO2 catalyst showed excellent catalytic activity toward direct CH arylation by using various aryl chlorides in the reaction (see scheme). The catalyst was found to act heterogeneously and could be recycled without significant loss of activity. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by th

We report that ruthenium complexes effectively catalyzed the carboxylate-directed addition of aromatic C–H bonds to aldehydes. The reactions of aromatic acids with a variety of aromatic aldehydes including unactivated ones proceeded efficiently to give the corresponding isobenzofuranone derivatives in high yields. The combination of ruthenium(II) complexes with tricyclohexylphosphine led to highly nucleophilic aryl–metal species, which enabled versatile [3 + 2] cycloaddition in the absence of a

Since C(sp³)-O bonds are a ubiquitous chemical motif in both natural and artificial organic molecules, the universal transformation of C(sp³)-O bonds will be a key technology for achieving carbon neutrality. We report herein that gold nanoparticles supported on amphoteric metal oxides, namely, ZrO₂, efficiently generated alkyl radicals via homolysis of unactivated C(sp³)-O bonds, which consequently promoted C(sp³)-Si bond formation to give d

A Pd-Au alloy efficiently catalyzed the [2+2+2] cycloaddition of substituted alkynes. Whereas monometallic Pd and Au catalysts were totally ineffective, Pd-Au alloy nanoparticle catalysts with a low Pd/Au molar ratio showed high activity to give the corresponding polysubstituted arenes in high yields. A variety of substituted alkynes participated in various modes of cycloaddition under Pd-Au alloy catalysis. The Pd-Au alloy catalysts exhibited high air tolerance and reusability.

Intermolecular [2+2+1] carbonylative cycloaddition of aldehydes with alkynes and subsequent oxidation to γ-hydroxybutenolides is achieved using a supported ruthenium catalyst. A ceria-supported ruthenium catalyst promotes the reaction efficiently, even with an ambient pressure of CO or without external CO, thus giving the corresponding γ-hydroxybutenolide derivatives in good to high yields. Moreover this catalyst can be reused with no loss of activity.

The sequence of cobalt silicide phase formation in cobalt/amorphous-silicon multilayer thin films has been investigated using differential scanning calorimetry, cross-sectional transmission electron microscopy, thin film x-ray diffraction, and energy dispersive x-ray analysis in a scanning transmission electron microscope. Multilayer thin films with various overall atomic concentration ratios (2Co:1Si, 1Co:1Si, 1Co:2Si) and various bilayer thicknesses were used in this study. It was found that a

A simple heterogeneous Ru/CeO2 catalyst was found to be effective for transfer-allylation from homoallyl alcohols to aldehydes, followed by isomerization to give the saturated ketones in high yields.

Versatile and practical: Intermolecular hydroacylation of internal alkynes takes place in the presence of Ru catalysts together with HCO(2)Na and Xantphos to give the corresponding conjugated enones. Aromatic aldehydes with or without coordinating groups could be used in the present catalytic system. The solid Ru/CeO(2) catalysts can be recycled for several times without significant decreases in yield (see scheme).

A selective and atom-economical synthesis of isoindolinones is described. This novel synthetic strategy involves two catalytic reactions: the ruthenium-catalyzed regioselective alkenylation of aromatic C-H bond of aromatic amides with internal alkynes, and subsequent intramolecular cyclization of the resulting alkene with amide functionalities. The addition of only a catalytic amount of bases is required for efficient construction of the desired isoindolinones, and no byproducts are formed in th

Supported ruthenium catalysts promote coupling of various kinds of aromatic carboxylic acids with internal alkynes, giving the corresponding multi-substituted phthalide derivatives in high yields. The supported Ru catalyst can be recycled at least five times with no loss of activity.

Efficient borylation of sp3 C–O bonds by supported Au catalysts is described. Au nanoparticles supported on TiO2 showed high activity under mild conditions employing low catalyst loading conditions without the aid of any additives, such as phosphine and bases. A variety of allyl, propargyl, and benzyl substrates participated in the heterogeneously catalyzed reactions to furnish the corresponding allyl, allenyl, and benzyl boronates in high yields. Besides, Au/TiO2 was also effective for the dire

Dehydrogenative synthesis of esters from primary alcohols proceeded efficiently over a ZrO₂-supported copper catalyst. A variety of esters were obtained from primary alcohols as well as diols in good to high yields. The key to the dehydrogenative synthesis of esters is the concerted effect of the acid-base pairs on ZrO₂ and metallic copper.