Lewis-Pairing-Induced Electrochemiluminescence Enhancement from Electron Donor-Acceptor Diads Decorated with Tris(pentafluorophenyl)borane as an Electrochemical Protector

This study reports an effective peripheral decoration of organic donor-acceptor diads with B(C₆F₅)₃ for stabilizing electrogenerated radical ions. By employing a common p-type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156-fold increase compared to that of the parent diad. The unprecedented Lewis-pairing-induced ECL enhancement is attributed to the multiple roles of B(C₆F₅)₃: 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C₆F₅)₃ converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π-stacks. This robust, highly ordered columnar nanostructure allowed red-shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal-free ECL systems.     

Finding of Optimal Calcium Ion Probes for Fluorescence Lifetime Measurement

We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement is lower than that by fluorescence intensity measurement.     

Numerical finite-difference time-domain calculation for extreme enhancement of magneto-optical effect at ultraviolet wavelength using Ni-subwavelength grating on SiO2/Ni structure

Optical Review - An extreme enhancement of the polar Kerr magneto-optical (MO) effect was numerically demonstrated using surface plasmon polaritons (SPPs) at the SiO2/Ni interface combined with the...     

Synthesis of hyperolactones A and C

Hyperolactones A ( 1 ) and C ( 3 ) have been synthesized starting from (S)‐malic acid by a straightforward route. The unique spirolactone skeleton was efficiently constructed by one‐pot reaction as a key step. The absolute stereochemistry of hyperolactones was unambiguously established by this synthesis.     

Piezo electric sensor for endocrine-disrupting chemicals using receptor-co-factor interaction.

In vitro screening assays are useful techniques for the determination of receptor-mediated activities in environmental samples. In order to define whether environmental chemicals act as an agonist or antagonist to the human estrogen receptor (hER), we have constructed a biosensor based on ligand-inducible interactions between hER and relative proteins on a quartz crystal microbalance (QCM). The his-tagged proteins, which were expressed in E. coli by recombinant DNA technology, were immobilized on an Au-electrode with Ni(II)-mediated chemisorption using the histidine tag and thiol-modified iminodiacetic acid. The resonance-frequency change of the protein-modified electrode was caused by association or dissociation with the hER relative proteins on the surface in the presence of estrogen. These results suggest that this sensor is applicable as a large-scale screening tool for estrogenic compounds.     

Frequency measurement of pure rotational transitions of OH

Frequencies of pure rotational transitions of OH⁻ ion were measured in the 1-5 THz region with a high-precision tunable far-infrared spectrometer. The measured frequencies were analyzed together with the data of infrared measurements to refine rotational parameters.     

Crosstalk Suppression in Header Recognition Unit Using Time-Space Conversion

We demonstrate a suppression effect of a crosstalk among a target and similar header signals using the header recognition filter designed by a design technique of the multiple-object discriminant filter.     

Micromachining of a thin film by laser ablation using femtosecond laser with masks

A gold thin film was machined by laser ablation using a femtosecond laser with mask patterns in the shape of lines and numbers. The patterns were successfully transferred with proper focusing and laser fluence. The optimal femtosecond laser fluence to keep the line width was about 5.2 mJ/cm² on the mask, and 99 mJ/cm² on the film. The processing resolution was 13 μm, and the narrowest line width was about 4 μm.     

Mössbauer study of the transition metal phosphorus trichalcogenide FePS3 and spin glass Mn0.5Fe0.5PS3

The transition metal phosphorus trichalcogenides MnPS₃ and the FePS₃ are CdCl₂ type layered compounds, where the transition metal ions form a hexagonal lattice. While these compounds order anti-ferromagnetically at low temperature, the magnetic structures are different. We have reported that these mixtures Mn_0.5Fe_0.5PS₃ is a spin glass with a glass transition temperature T _g=33.7 K. Then, in this work, we report that the results of the temperature variation of the ⁵⁷Fe Mössbauer spectra of FePS₃ and Mn_0.5Fe_0.5PS₃, in detail. In the anti-ferromagnetic state of FePS₃, the hyperfine magnetic field H _int increases with decreasing temperature and the Isomer shift I. S. increases slightly with decreasing temperature. However in Mn_0.5Fe_0.5PS₃, the two broadened peaks are observed and the two peaks became a single peak with decreasing temperature at about 50.0 K, which is higher than T _g=33.7 K. In the spin glass Mn_0.5Fe_0.5PS₃, the Mössbauer spectra suggest that the magnetic interactions exist far above T _g.