Synthesis and Chiroptical Properties of Quinoxaline-Fused Polyaza[5]–[7]helicenes with Orange-Color CPL Emissions

We achieved a two-type synthesis of quinoxaline-fused polyaza[5]- and [7]helicenes through consecutive N−H/C−H coupling with a hypervalent iodine reagent as a key reaction. By fusing electron-deficient quinoxaline, these polyazahelicenes constitute an efficient donor-acceptor type of molecule with absorption edges that reach up to approximately 650 nm. Evaluating the chiroptical properties reveals that the polyazahelicene exhibits a rare orange circularly polarized glow with a luminescence dissymmetry factor (g_lum value) of 0.003.     

Comparison of CP-PC-SAFT and SAFT-VR-Mie in Predicting Phase Equilibria of Binary Systems Comprising Gases and 1-Alkyl-3-methylimidazolium Ionic Liquids

This study compares performances of the Critical Point-based revision of Perturbed-Chain SAFT (CP-PC-SAFT) and the SAFT of Variable Range and Mie Potential (SAFT-VR-Mie) in predicting the available data on VLE, LLVE, critical loci and saturated phase densities of systems comprising CO, O₂, CH₄, H₂S, SO₂, propane, the refrigerants R22, R23, R114, R124, R125, R125, R134a, and R1234ze(E) and ionic liquids (ILs) with 1-alkyl-3-methylimidazolium ([C_nmim]⁺) cations and bis(trifluoromethanesulfonyl)imide ([NTf₂]⁻), tetrafluoroborate ([BF₄]⁻) and hexafluorophosphate ([PF₆]⁻) anions. Both models were implemented in the entirely predictive manner with k₁₂ = 0. The fundamental Global Phase Diagram considerations of the IL systems are discussed. It is demonstrated that despite a number of quantitative inaccuracies, both models are capable of reproducing the regularities characteristic for the considered systems, which makes them suitable for preliminary estimation of selectivity of the ILs in separating various gases.     

Fluorescence Response and Self-Assembly of a Tweezer-Type Synthetic Receptor Triggered by Complexation with Heme and Its Catabolites

There is increasing interest in the development and applications of synthetic receptors that recognize target biomolecules in aqueous media. We have developed a new tweezer-type synthetic receptor that gives a significant fluorescence response upon complexation with heme in aqueous solution at pH 7.4. The synthetic receptor consists of a tweezer-type heme recognition site and sulfo-Cy5 as a hydrophilic fluorophore. The receptor–heme complex exhibits a supramolecular amphiphilic character that facilitates the formation of self-assembled aggregates, and both the tweezer moiety and the sulfo-Cy5 moiety are important for this property. The synthetic receptor also exhibits significant fluorescence responses to biliverdin and bilirubin, but shows very weak fluorescence responses to flavin mononucleotide, folic acid, and nicotinamide adenine dinucleotide, which contain smaller π-scaffolds.     

Analysis of detected signal performance in multi-tracks of optical disk memory using convex-shaped recording mark

The possibility of multi-valued optical disk memory by using a convex-shaped recording mark fabricated by two-photon absorption is investigated. We fabricate a numerical model for convex-shaped recording marks and evaluate the signal characteristics in terms of the signal-to-noise ratio (SNR). The numerical results show that 6 bit data can be realized when the acceptable average SNR is 2 and a length of the mark is 4T.     

Optical Coherence Tomographic Features of Macular Diseases

Optical coherence tomography (OCT) is a new diagnostic technology which allows visualization of a cross-sectional image of the anterior eye and the retina in vivo with a high resolution similar to a histological section by light microscopy. Although the fundus can be examined at the semihistologic level by a biomicroscope, histopathologic study has been difficult because of the rare opportunity for retinal biopsy or enucleation. OCT reveals the intraretinal structure of macular diseases on the histopathologic level. In this article, we review the research on various macular diseases using OCT at Gunma University School of Medicine.     

Water-stable helical structure of tertiary amides of bicyclic β-amino acid bearing 7-azabicyclo[2.2.1]heptane. Full control of amide cis-trans equilibrium by bridgehead substitution

Helical structures of oligomers of non-natural β-amino acids are significantly stabilized by intramolecular hydrogen bonding between main-chain amide moieties in many cases, but the structures are generally susceptible to the environment; that is, helices may unfold in protic solvents such as water. For the generation of non-hydrogen-bonded ordered structures of amides (tertiary amides in most cases), control of cis-trans isomerization is crucial, even though there is only a small sterical difference with respect to cis and trans orientations. We have established methods for synthesis of conformationally constrained β-proline mimics, that is, bridgehead-substituted 7-azabicyclo[2.2.1]heptane-2-endo-carboxylic acids. Our crystallographic, 1D- and 2D-NMR, and CD spectroscopic studies in solution revealed that a bridgehead methoxymethyl substituent completely biased the cis-trans equilibrium to the cis-amide structure along the main chain, and helical structures based on the cis-amide linkage were generated independently of the number of residues, from the minimalist dimer through the tetramer, hexamer, and up to the octamer, and irrespective of the solvent (e.g., water, alcohol, halogenated solvents, and cyclohexane). Generality of the control of the amide equilibrium by bridgehead substitution was also examined.     

Evaporation of VC and TiC in floating zone melting

The evaporation of vanadium carbide during floating zone systems was examined. The evaporation composition and rate were measured as a function of the melt composition. At a composition of C/V = 0.72, the dependence of evaporation rate on ambient gas pressure (P) was measured at the range of 3.5–40 atm of helium and argon. The evaporation rate was proportional to P^-0.70 in helium and P^-0.31 in argon. The same results were obtained with TiC. These pressure dependences are shown to be expected for laminar and turbulent free convective mass transport.     

Coupling of Alkynes on a Pd-Pd Bond to Generate an Electrophilic µ-Butenediylidene Moiety

The first dipalladium μ-PPh(3) complex (1) was obtained by the facile loss of two CH(3)CN ligands from [Pd(2)(PPh(3))(2)(CH(3)CN)(4)](PF(6))(2) in CH(2)Cl(2). Coupling of p-tolylacetylene (p-TolC identical withCH) with 1 or its precusor afforded the μ-butenediylidene complex 2, treatment of which with CH(3)CN resulted in PPh(3) migration to give 3.     

Room-temperature reversible spin Hall effect

Reversible spin Hall effect comprising the direct and inverse spin Hall effects was electrically detected at room temperature. A platinum wire with a strong spin-orbit interaction is used not only as a spin current absorber but also as a spin-current source in the specially designed lateral structure. The obtained spin Hall conductivities are 2.4 x 10(4) (Omega m)(-1) at room temperature, 10(4) times larger than the previously reported values of semiconductor systems. Spin Hall conductivities obtained from both the direct and inverse spin Hall effects are experimentally confirmed to be the same, demonstrating the Onsager reciprocal relations between spin and charge currents.