On the chiral connection between the ferromagnet,the axisymmetric gravitational problem and the SU(2) vacuum gauge field

A single chiral structure is shown to underly several three-dimensional field equations of physics, e.g., the ferromagnet, the stationary axi-symmetric gravitational problem, and the vacuum SU(2) gauge field in the Coulomb gauge. This connection invites cross-fertilization of exact solutions. As illustrations, exact finite energy solutions are obtained for the ferromagnet via the corresponding Weyl, Kerr, and Tominatsu-Sato solutions of Einstein's gravitational equations. Comments are made on the “local gauge invariance” of the ferromagnet and the gravitational field.     

Non-supersymmetric extremal RN-AdS black holes in $$ \mathcal{N} = 2 $$ gauged supergravity

We investigate extremal Reissner-Nordström-AdS black holes in fourdimensional \( \mathcal{N} = 2 \) abelian gauged supergravity. We find a new attractor equation which is not reduced to the one in the asymptotically flat spacetime. We also argue a formula which is available even in the presence of the scalar potential. We apply them to the T³-model and the STU-model in generic black hole charge distributions. In addition, focusing on the so-called T³-model with a single neutral vector multiplet, we obtain non-supersymmetric extremal Reissner-Nordström-AdS black hole solutions with regular event horizons in the D0-D4 and the D2-D6 black hole charge configurations. The negative cosmological constant emerges even without the Fayet-Iliopoulos parameters.     

Fabrication of micrometer-size solid immersion lens: Composition dependence of wettability of substrate by glass melt

Fine glass particles Na₂O–CaO–B₂O₃–SiO₂ are heated on glassy-carbon substrate to obtain micrometer-size solid immersion lenses (μ-SILs), and the composition dependence of the wetting property between glass melt and glassy-carbon substrate is investigated. The obtained glass particles have the super-spherical shapes with smooth surfaces. The contact angles of the particles are ranging from 125° to 147° depending on the glass composition, and there are the compositions at which the shape of the glass satisfies the optical condition of μ-SIL, showing the correlation between the contact angle and the internal structure of the glass. These results revealed that the super-spherical shape of μ-SIL can be controlled by the glass composition through the wetting property.     

A mild inter- and intramolecular amination of aryl halides with a combination of CuI and CsOAc

A unique combination of CuI and CsOAc was found to catalyze aryl amination under mild conditions. The reaction takes place at room temperature or at 90 °C with broad functional group compatibility. The intramolecular reaction was able to form five-, six-, and seven-membered rings with various protecting groups on the nitrogen atom. The scope of the intermolecular amination, as well as its applications to unsymmetrical N,N′-dialkylated phenylenediamines, was investigated.     

Solvation dynamics of coumarin 153 in alcohols confined in silica nanochannels

Solvation dynamics in alcohols confined in silica nanochannels was examined by time-resolved fluorescence spectroscopy using coumarin 153 (C153) as a fluorescent probe. Surfactant-templated mesoporous silica was fabricated inside the pores of an anodic alumina membrane. The surfactant was removed by calcination to give mesoporous silica (Cal-NAM) containing one-dimensional (1D) silica nanochannels (diameter, 3.1 nm) whose inner surface was covered with silanol groups. By treating Cal-NAM with trimethylchlorosilane, trimethylsilyl (TMS) groups were formed on the inner surface of the silica nanochannels (TMS-NAM). Fluorescence dynamic Stokes shifts of C153 were measured in alcohols (ethanol, butanol, hexanol, and decanol) confined in the silica nanochannels of Cal- and TMS-NAMs, and the time-dependent fluorescence decay profiles could be best fitted by a biexponential function. The estimated solvent relaxation times were much larger than those observed in bulk alcohols for both Cal- and TMS-NAMs when ethanol or butanol was used as a solvent, indicating that the mobility of these alcohol molecules was restricted within the silica nanochannels. However, hexanol or decanol in Cal- and TMS-NAMs did not cause a remarkable increase in the solvent relaxation time in contrast to ethanol or butanol. Therefore, it was concluded that a relatively rigid assembly of alcohols (an alcohol chain) was formed within the silica nanochannels by hydrogen bonding interaction and van der Waals force between the surface functional groups of the silica nanochannels and alcohol molecules and by the successive interaction between alcohol molecules when alcohol with a short alkyl chain (ethanol or butanol) was used as a solvent.     

Redox-assisted ring closing reaction of the photogenerated cyclophanediene form of bis(ferrocenyl)dimethyldihydropyrene with interferrocene electronic communication switching

We synthesized ferrocene-attached dimethyldihydropyrene (DHP) derivatives and investigated their photochemical and redox behaviors. For bis(ferrocenylethynyl)dimethyldihydropyrene (1), reversible photoisomerization between the closed DHP form (1c) and the open CPD form (1o) occurred in high yields upon alternate irradiation of visible (578 nm) light and UV (303 nm) light, whereas no photoisomerization proceeded for bis(pentamethylferrocenylethynyl)dimethyldihydropyrene (2). 1 exhibited reversible switching of electronic communication between the ferrocene (Fc) moieties by photoisomerization of the DHP moiety and demonstrated a novel ring closing reaction induced by oxidation of the Fc moieties. The magnitude of electronic communication, deltaE0' (the difference between the redox potentials of two Fc's), was 63 mV in 1c and 16 mV in 1o, indicating that the electronic communication through the spacer is enhanced in the more developed pi-conjugation of the DHP moiety. The rate constants of the ring closing reaction from 1o+ to 1c+ and from 1o2+ to 1c2+ were estimated at 3.7 and 0.50 s(-1), respectively, by the simulation of cyclic voltammograms.     

Realization of SOMO-HOMO level conversion for a TEMPO-dithiolate ligand by coordination to platinum(II)

We developed a TEMPO-bound dithiolate ligand (= tempodt) and its Pt(diimine)(dithiolate) complex to realize a unique electronic structure with the potential for unprecedented functionalities. The physical properties and electronic structures of tempodt, (tempodt)Pt, and their related compounds were investigated by cyclic voltammetry, UV-visible spectroscopy, electron spin resonance (ESR) spectroscopy, and other techniques. It was revealed that (tempodt)Pt showed an unusual electronic structure in which the HOMO level (= pi-conjugated dithiolate-based orbital) was located above the SOMO level attributed to the TEMPO moiety, and that this situation was achieved via a drastic electronic structure change of SOMO-HOMO level conversion through complex formation. These findings were further supported by an investigation into a one-electron oxidized (tempodt)Pt and related complexes.     

Production of positron emitters and application of their labeled compounds to plant studies

The positron emitters¹¹C,¹³N and¹⁸F and their labeled compounds have been produced for studies on plants using a newly developed positron emitting tracer imaging system. Although this system covers, at present, a limited area in a plant, the distribution of the positron emitter fed into the plant can be visualized dynamically. Further development of positron-emitter-labeled compounds is expected to elucidate the physiological function of plants in vivo.