Synthesis and isolation of a monoamine having a thermodynamically stabilized pseudo-chirotopic nitrogen

We have synthesized a tricyclic monoamine, (1S,4R)-(E)-7,3′-heptenylene-2,3:5,6-dibenzo-7-azabicyclo[2.2.1]heptane (1), by applying a ring-closing metathesis reaction in the key step of the synthetic route and by using preparative chiral HPLC for the separation. The X-ray crystallographic analysis of its salt with (1R)-camphor-10-sulfonic acid showed that the geometry and absolute configuration are (E) and (1S,4R), respectively. The theoretical calculations revealed that the inversion of the nitrogen atom at the 7-position of (1S,4R)-(E)-1 thus isolated takes place through a very slow process and that the configuration of the N(7) is highly biased to (R), indicating that (1S,4R)-(E)-1 is a thermodynamically controlled N-pseudo-chirotopic compound ((1S,4R,7R): (1S,4R,7S) = 99.68:0.32 at 120 °C).     

On the Lp–Lq maximal regularity for the linear thermoelastic plate equation in a bounded domain

This paper is concerned with the thermoelastic plate equations in a domain Ω: subject to the boundary condition: u|=D_νu|=θ|=0 and initial condition: (u, u_t, θ)|_t=0=(u₀, v₀, θ₀). Here, Ω is a bounded domain in ?ⁿ(n≧2). We assume that the boundary ?Ω of Ω is a C⁴ hypersurface. We obtain an L_p–L_q maximal regularity theorem. Copyright © 2008 John Wiley & Sons, Ltd.     

Two significantly different conformations in crystal: formation of a molecular dimer governed by cation-π interactions

Two significantly different conformations were observed in crystal of 1, which form an unsymmetrical molecular dimer governed by cation-π interactions between a pyridinium cation and a phenyl ring, whereas compound 2 forms a head-to-tail type of dimer.     

Properties of hadron and quark matter studied with molecular dynamics

We study the hadron-quark phase transition in a molecular dynamics (MD) of quark degrees of freedom. The hadron state at low density and temperature, and the deconfined quark state at high density and temperature are observed in our model. We investigate the equations of state and draw the phase diagram at wide baryon density and temperature range. We also discuss the transport property, e.g. viscosity, of $q\bar q$ matter. It is found that the ratio of the shear viscosity to the entropy density is less than one for quark matter.     

Fractality and degree correlations in scale-free networks

Fractal scale-free networks are empirically known to exhibit disassortative degree mixing. It is, however, not obvious whether a negative degree correlation between nearest neighbor nodes makes a scale-free network fractal. Here we examine the possibility that disassortativity in complex networks is the origin of fractality. To this end, maximally disassortative (MD) networks are prepared by rewiring edges while keeping the degree sequence of an initial uncorrelated scale-free network. We show that there are many MD networks with different topologies if the degree sequence is the same with that of the (u,v)-flower but most of them are not fractal. These results demonstrate that disassortativity does not cause the fractal property of networks. In addition, we suggest that fractality of scale-free networks requires a long-range repulsive correlation, in the sense of the shortest path distance, in similar degrees.     

Facile synthesis of biphenyl-fused BODIPY and its property

A biphenyl-fused BODIPY was synthesized through a facile oxidative cyclization of peripheral aryl-substituents at the β-position of the BODIPY unit. The extended π-system of the fused BODIPY induces near-infrared (NIR) absorption and strong π-π interactions in the solid state. These features are beneficial for the application of the dye as a functional material. The biphenyl-fused BODIPY dye was demonstrated to exhibit photocurrent conversion ability on the basis of its n-type semiconducting property.     

Cascade reactions in crystals through cation-π-controlled reorientation on exposure to HCl gas

Exposure of 4-azachalcones to HCl gas produced the corresponding HCl salts with a head-to-tail stacked alignment, irradiation of which produced the corresponding syn-HT dimers with high regio- and stereoselectivities, thus showing the effectiveness of the cascade process in crystals.     

Sodium methoxide: a simple but highly efficient catalyst for the direct amidation of esters

A simple NaOMe catalyst provides superior accessibility to a wide variety of functionalized amides including peptides through direct amination of esters in an atom-economical and environmentally benign way.     

Xanthene dyes induce membrane permeabilization of bacteria and erythrocytes by photoinactivation

We analyzed the photoinactivation of the membrane functions of bacteria and erythrocytes induced by xanthene dyes. The dyes tested were rose bengal, phloxine B, erythrosine B and eosin B. These dyes induced the leakage of K(+) from Staphylococcus aureus cells within minutes of photoirradiation, in the order of rose bengal > phloxine B > erythrosine B > eosin B. The ability of dyes to inhibit respiration was weak, except for rose bengal, and the dyes dissipated the membrane potential in similar time traces with changes in K(+) permeability. The xanthene dyes also induced the leakage of K(+) from bovine erythrocytes upon photoirradiation in the same order as that observed with bacteria. Furthermore, we found that the ability to cause the leakage of K(+) from erythrocytes was associated with dye-induced morphological changes, forming a crenated form from the normal discoid. These results are discussed in connection with the ability of xanthene dyes to generate singlet oxygen and bind to bacterial cells, and further compared with the actions of cationic porphyrins, which induced photoinactivation of bacteria through respiratory inhibition.