Chiral porphyrin dimer with a macrocyclic cavity for intercalation of aromatic guests

Chiral diporphyrin receptor 1, which has a macrocyclic cavity to sandwich aromatic guest molecules via double π-π stacking interactions, enabled the naked-eye detection of an aromatic explosive as well as chiral discrimination in NMR.     

Stimulation on the addition reactivity of fluorinated vinyl monomers—Facile carbon-carbon bond formation by the aid of fluorine substituents

The high addition reactivity of fluorinated vinyl compounds toward radical and anionic species was demonstrated to afford facile methods for the carbon-carbon bond formation by the aid of fluorinated substituents of vinyl groups. Some of the reactions are proved to be applicable to the preparation of polymers by radical or anionic polyaddition reaction mechanism. The investigation on the anionic reactivity order of fluorinated acrylates and methacrylates may contribute to the development in the field of the estimation by the computer chemistry to determine which effect of the fluorine-substitution would control the reactions.     

Autocatalytic membrane-amplification on a pre-existing vesicular surface

In water, phosphoric membrane molecule (V(-)) self-assembled to form an anionic giant vesicle, the surface of which served as a catalyst for the autocatalytic formation of V(-) from its membrane precursor (V*), and the amplified V(-) produced a new vesicle using the original vesicle as a scaffold.     

Corrosion behavior of Mg,AZ31, and AZ91 alloys in dilute NaCl solutions

Corrosion behavior of extruded Mg, extruded AZ31 alloy, and cast AZ91 alloy was investigated by electrochemical measurements in dilute NaCl solutions. Corrosion products and passivation films were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. All specimens exhibit the corrosion and passivation zones in dilute NaCl solutions. The aluminum content and alloy microstructure influence the corrosion and passivation processes. AZ91 alloy shows the broadest passivation zone followed by AZ31 alloy and Mg. AZ91 alloy reveals a highest corrosion resistance, and preferential attack is located at the primary Mg phase. Its relatively fine β-phase (Mg₁₇Al₁₂) network and Al₂O₃/Al(OH)₃ compounds produced on the passivation film are the main factors which limit the corrosion progress as compared with AZ31 alloy and Mg. The thick passivation product on AZ31 alloy is the key factor which restricts the corrosion attack in dilute solutions.     

Ion diffusion and electrochemical capacitance in aligned and packed single-walled carbon nanotubes

Direct measurement of ion diffusion in aligned, densified single-walled carbon nanotube electrodes showed that the diffusion coefficient for transport of ions (KSCN in acetonitrile) parallel to the alignment direction of the nanotubes was close to the theoretical limit of perfectly straight pores, achieving a value 20 times larger than that of activated carbon electrodes (1 × 10(-5) vs 5 × 10(-7) cm(2)/s). In contrast, the diffusion coefficient for ion transport perpendicular to the alignment direction was an order of magnitude smaller (8 × 10(-7) cm(2)/s). As an example of the ramifications of this anisotropic diffusion phenomenon, the difference in performance of the aligned carbon nanotubes as electrochemical-capacitor electrodes was evaluated. At low discharge rates, the performances of the two orientations were identical, but as the discharge rate was increased, a more rapid decline in capacitance was observed for the perpendicular orientation (66 vs 14% decline in capacitance when the discharge current was increased from 0.01 to 1 A/g). Furthermore, the maximum power rating of the perpendicular electrode was lower than that of the parallel electrode (1.85 vs 3 kW/kg during operation at 1 V).     

Modification of orientation birefringence of cellulose ester by addition of poly(lactic acid)

Effect of the addition of poly(lactic acid) (PLA) to cellulose acetate propionate (CAP) on the optical anisotropy is studied considering the morphology and molecular orientation. It is found that PLA is miscible with CAP when the amount of PLA is less than 3 wt.%. The dissolution of PLA chains having large intrinsic birefringence into CAP phase enhances the orientation birefringence of a stretched film, although the viscosity and thus the relaxation time of PLA is significantly shorter than those of CAP. The high level of orientation of PLA chains without relaxation is attained by the cooperative alignment with CAP chains. As a result, a retardation film having appropriate birefringence can be designed by polymer blends composed of biomass-based materials. When the amount of PLA is more than 3 wt.%, however, phase separation occurs. In the case of the blends with phase-separated morphology, the orientation birefringence is not greatly enhanced by blending PLA, because the molecular orientation of PLA in PLA phase relaxes immediately as compared with that of CAP.     

Preparation of Different Poly 3-Alkylthiophene Ultrathin Films at the Surface of Chemically Adsorbed Monolayer Having Thienyl Group

Polymerization processes of two types ultrathin films containing polythienyl groups anchored to the substrate surface through siloxane bonds were investigated. When the oxidative polymerization on the Chemically Adsorbed (CA) monolayer prepared with 11-(3-thienylundecyl)trichlorosilane (TTS) was performed in the acetonitrile solution containing 3-octylthiophene monomer and FeCl₃, the thienyl groups in the CA monolayer and the outer 3-octylthiophene monomers were polymerized each other along the directions of both in-plane and out-of-plane of the CA monolayer. On the other hand, when the oxidative polymerization was performed without the additive 3-octylthiophene monomer, the long conjugated linkage of the thienyl groups was not formed in the CA monolayer. The highest conductivity of the film prepared with the additive 3-octylthiophene of about 10 nm thickness was 10^?2 S/cm.     

Preparation of 2-Methoxy-3,4-methylenedioxybenzaldehyde (Croweacin Aldehyde) from Pyrogallol

2-Methoxy-3,4-methylenedioxybenzaldehyde (croweacin aldehyde) of high purity was prepared in 55% overall yield from pyrogallol.     

Scrambling time from local perturbations of the eternal BTZ black hole

Journal of High Energy Physics - The Goldstone equivalence theorem allows one to relate scattering amplitudes of massive gauge fields to those of scalar fields in the limit of large scattering...