Displacement-type ferroelectricity with off-center magnetic ions in perovskite Sr(1-x)Ba(x)MnO3

We report a ferroelectric transition driven by the off-centering of magnetic Mn(4+) ions in antiferromagnetic Mott insulators Sr(1-x)Ba(x)MnO(3) with a perovskite structure. As x increases, the perovskite lattice shows the typical soft-mode dynamics, as revealed by the momentum-resolved inelastic x-ray scattering and far-infrared spectroscopy, and the ferroelectricity shows up for x ≥ 0.45. The observed polarization is comparable to that for a prototypical ferroelectric BaTiO(3). We further demonstrate that the magnetic order suppresses the ferroelectric lattice dilation by ～70% and increases the soft-phonon energy by ～50%, indicating the largest magnetoelectric effects yet attained.     

A Highly Modular One‐Pot Multicomponent Approach to Functionalized Benzo[b]phosphole Derivatives

Benzo[b]phosphole derivatives have attracted significant attention for their unique optoelectronic properties with potential for application in materials science. Herein we report a modular approach to a benzo[b]phosphole derivative based on a one‐pot sequential coupling of an arylzinc reagent, an alkyne, dichlorophenylphosphine (or phosphorus trichloride and a Grignard reagent), and an oxidant (for example H₂O₂, S, or Se). The approach allows for the construction of a library of previously inaccessible, structurally diverse benzo[b]phosphole derivatives with unprecedented ease.     

Dramatic Mechanistic Change in Acid‐Catalyzed Arylation of Azafulleroids Depending on their Ambident N/C Basicity: Formation of Cyclopentene Centered Pentakisadduct

Azafulleroid, amino‐bridged [5,6]‐open fullerene, has the ambident N/C basicity of the incorporated enamine moiety. Acid‐catalyzed arylation of N‐substituted azafulleroids proceeded via two types of initial N/C protonation to perform monoarylation or 1,4‐bisarylation for the N‐alkyl substituents and shuttlecock‐type pentakisarylation for the N‐phenyl substituent. The dramatic product change was explained by considering the possible mechanism as well as the DFT computational results.     

Synthesis of novel 1,3-dithiolan-2-one derivatives

Novel 1,3-dithiolan-2-one derivatives were prepared starting from α, β- or β, γ-dichlorinated carboxylic esters and potassium O-ethyl dithiocarbonate. The scope and the mechanism of this reaction were investigated. The biological uses of the compounds obtained here were examined.     

A test of boson mappings of fermion systems

The Otsuka-Arima-Iachello Method, the Belyaev-Zelevinsky-Marshalek boson expansion method, and the boson expansion theory are each used to map a solvable fermion hamiltonian onto a boson space. Comparison of the spectra and transition rates obtained by these three boson mapping methods are compared to the exact values.     

Effects of t-butyl substituents on valence tautomerism of 7-t-butyl-7-cyano-1,3,5-cycloheptatrienes to the norcaradiene form

Introduction of t-butyl groups to the 2-, 3-, 2,4-, or 2,5-positions of 7-t-butyl-7-cyano-1,3,5-cycloheptatriene dramatically shifts the cycloheptatriene - norcaradiene equilibrium to the norcaradiene form. The nonbonded interaction is an important factor.     

N−H Imine as a Powerful Directing Group for Cobalt‐Catalyzed Olefin Hydroarylation

N‐alkyl and N‐aryl imines have been frequently used as directing groups in rhodium‐ and cobalt‐catalyzed hydroarylation reactions of olefins and alkynes. However, the scope of such hydroarylation reactions has been limited by the difficulty of preparation of sterically hindered imines by condensation, and also by the steric bulkiness of the imine group itself. Reported herein is that an N?H imine serves as an alternative and highly effective directing group for cobalt‐catalyzed hydroarylation of olefins, and unlocks many of the limitations associated with the previously employed N‐aryl imine directing group. The power of this minimal nitrogen directing group is manifested in a fourfold ortho alkylation of benzophenone imine, and it occurs rapidly at ambient temperature.     

Monatomic gas as a singular limit of polyatomic gas in molecular extended thermodynamics with many moments

The difference in the theoretical structure between monatomic and polyatomic gases in highly nonequilibrium states is discussed from the viewpoint of molecular extended thermodynamics (MET) of rarefied gases, which is free from the local equilibrium assumption. The MET theories of these two types of gases are based on the moment balance equations with different hierarchy structures due to whether the internal degrees of freedom of a molecule are incorporated in their distribution functions or not. In particular, the number of balance equations in the MET theory of polyatomic gases is greater than the number in the corresponding theory of monatomic gases. The closure procedure for the system of balance equations of polyatomic gases obtained in a recent paper (Arima et al., 2014) is adopted. We prove that the solutions for polyatomic gases converge, in the limit where the degrees of freedom of a molecule D$D$ tend to 3, to the ones for monatomic gases provided that we impose appropriate initial conditions compatible with monatomic gases. Thus a MET theory of rarefied monatomic gases can be identified as a singular limit of the corresponding MET theory of rarefied polyatomic gases. As illustrative examples, the asymptotic behaviors when D→3$D\to 3$ in the dispersion relation of ultrasonic waves and in the shock wave structure are shown.     

Effect of molecular weight on the morphology of polystyrene/poly(methyl methacrylate) composite particles prepared by the solvent evaporation method

The effect of molecular weight on the morphology of polystyrene (PS)/poly(methyl methacrylate) (PMMA) composite particles was investigated. PS/PMMA composite particles with different molecular weights (M*=MwPS+MwPMMA)/2 approximately 2x10(4)-1x10(6) g.mol(-1)) were prepared by the release of toluene (T) from PS/PMMA/T (1/1/24, w/w/w) droplets dispersed in an aqueous solution of polyoxyethylene nonylphenyl ether nonionic surfactant (Emulgen 911). As T evaporated, the spherical droplets phase separated, resulting in snowmanlike composite particles with Janus morphology. The nonspherical shape was closely related to the morphology, which depended on M*. The interfacial tension between the phase-separated PS and PMMA phases increased with an increase in M*, and this would allow the formation of the snowmanlike shape to decrease the interfacial area between the PS and the PMMA phases.     

Self-motion of a phenanthroline disk on divalent metal ion aqueous solutions coupled with complex formation

The self-motion of a 1,10-phenanthroline disk on divalent metal ion aqueous solutions was investigated as a simple autonomous motor coupled with complex formation. The characteristic features of motion (continuous and oscillatory motion) and their concentration regions differed among metal ions, and the frequency of oscillatory motion depended on the temperature of the aqueous solution. The nature of the characteristic motion is discussed in relation to the stability constant of complex formation between phenanthroline and a metal ion, and the difference in surface tension between phenanthroline and its metal complex as the driving force.