Measuring Light Field of Light Source with High Directional Resolution Using Mirrored Ball and Pinhole Camera

This paper presents a method of measuring a light field of a light source with high directional resolution using a mirrored ball and a pinhole camera. The light field describes a spatial and directional distribution of radiances from the light source. The directional distribution is expanded by a reflection on the mirrored ball, and the radiances are measured by a charge-coupled device (CCD) camera with a pinhole lens. The light source is laterally moved by a robot arm to measure the directionally expanded light field, and each pixel on a CCD can obtain the radiances from the light source through the pinhole lens with high directional resolution. The light field is estimated from the pixel value and the position of each pixel using a ray tracing technique. The light field of a krypton lamp was experimentally measured by the proposed method, and the accuracy of the measurement was evaluated against the irradiances measured by a spectro-radiometer at sample points.     

Synthesis, structure, and physical properties of 1,11-o-benzeno[2]orthocyclo[2](1,2)tropyliophane

The title compound (2) has been synthesized, the structure and the physical properties of which are investigated by X-ray, spectroscopic analyses, and MO calculations. There exists charge transfer (CT) interaction between the tropylium ion and the facing phenyl ring. From the pK_R⁺ value of 2, it can be clear that the cation 2 is stabilized by the CT interaction. In spite of the presence of bond weakening σ-π orbital mixing, the cation 2 withstands retro[4+4]type bond cleavage, which is quite interesting when compared to a facile cleavage for the congener with anthracene photodimer type structure.     

Selective chemical vapor deposition synthesis of double-wall carbon nanotubes on mesoporous silica

Double-wall carbon nanotubes (DWNTs) have been selectively synthesized over Fe/Co loaded mesoporous silica by catalytic chemical vapor deposition of alcohol. Several silica materials with desired pore diameter and morphology have been investigated for the DWNT growth. The diameter distribution and selectivity of the DWNT are found to depend on the reaction temperature, pore size, and thermal stability of the support material. A high-yield synthesis of DWNTs has been achieved at 900 degrees C over high-temperature stable mesoporous silica. The outer diameter of DWNTs is found to be in the range of 1.5-5.4 nm with a "d" spacing of 0.38 +/- 0.02 nm between inner and outer layers, which is much larger than those of multiwall carbon nanotubes.     

A practical procedure for the synthesis of esonarimod, (R,S)-2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid,an antirheumatic agent (part 1)

An efficient and practical procedure for the synthesis of esonarimod, (R,S)-2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (1), a new antirheumatic drug, has been developed. The intermediate, 2-methylene-4-(4-methylphenyl)-4-oxobutanoic acid (2), was prepared by Friedel-Crafts acylation of toluene with itaconic anhydride (3) in the presence of aluminum trichloride and nitrobenzene in 63% yield without silica gel column purification. Compound 1 was prepared by Michael addition of 2 with thioacetic acid (4) in 74% yield. Overall, 1 was obtained in 47% yield from 3. The structures and synthetic mechanisms of by-products (five compounds) of 2 were also clarified.     

Aminyl radical cyclization by means of anodic oxidation. Stereoselective synthesis of cis-1-methyl-2,5-disubstituted pyrrolidines

Neutral aminyl radicals generated by anodic oxidation of lithium alkenylamides 2 undergo a stereoselective cyclization to give $\text{cis}$-1-methyl-2,5-disubstituted pyrrolidines 4. Their $\text{cis}$ stereochemistry was confirmed by a comparison with $\text{trans}$-1,2-dimethyl-5-phenylpyrrolidine, the structure of which was established by X-ray crystallographic analysis of its quarternary ammonium bromide 6.     

Theoretical study of benzonitrile clusters in the gas phase and their adsorption onto a Au(111) surface

We made theoretical calculations for a benzonitrile molecule and its clusters in the gas phase and as adsorbed on the Au(111) surface, to explain the observation by scanning tunneling microscope, that is, the trimer formation of cyanophenyl porphyrins adsorbed onto the Au(111) surface. With regard to the gas-phase species, ab initio calculations showed that (1) the benzonitrile dimer has a single stable structure that is planar and antiparallel; (2) the trimer has two isoenergetic stable structures, that is, a planar and cyclic structure and an antiparallel and nonplanar one; (3) the clusters are more stable, at low temperatures, than the monomer. For the adsorbed species, we made quantum mechanical/molecular mechanical calculations in which the interaction between the adsorbates and the surface is evaluated in a molecular-mechanical way by using analytical potential functions and an image charge model. Because the stable structures were found to be similar to those in the gas phase, the cluster formation of adsorbed cyanophenyl porphyrins was attributed to the interaction between cyanophenyl groups, which is barely affected by adsorbate-surface interaction. It was also found that the adsorbed cyclic benzonitrile trimer is more stable than the monomer and the dimer because the relative stability is dependent on enthalpy alone. We therefore concluded that the preferential formation of trimers by the adsorbed cyanophenyl porphyrins is due to the negligible contribution of entropy to the relative stability of the adsorbed species and that the adsorption hardly changes the situation found in the gas phase.     

Manipulating the Through‐Space Spin–Spin Interaction of Organic Radicals in the Confined Cavity of a Self‐Assembled Cage

We show a new approach to manipulating the through‐space spin–spin interaction by utilizing the confined cavity of a self‐assembled M₆L₄ coordination cage. The coordination cage readily encapsulates stable organic radicals in solution, which brings the spin centers of the radicals closer to each other. In sharp contrast to the fact that the radical in solution in the absence of the cage is in a doublet state, in the presence of the cage through‐space spin–spin interaction is induced through cage‐encapsulation effects in solution as well as in the solid state, resulting in the triplet state of the complex. These results were confirmed by ESR spectroscopy and X‐ray crystallography. The quantity of triplet species generated by encapsulation in the cage increases with increasing affinity of the radicals to the cage. We estimated the affinity between several types of guests and the cage in solution by cyclic voltammetry. We also demonstrate that the through‐space interaction of organic radicals within the self‐assembled coordination cage can be controlled by external stimuli such as heat or pH.     

Palladium-catalyzed allylation of imines with allyl alcohols

A catalytic system, Pd(OAc)2 (10 mol %)-P(n-Bu)3 (20 mol %)-Et3B (360 mol %), promotes allylic alcohols to undergo the allylation of anisidine-imines of aromatic and aliphatic aldehydes and furnishes homoallylamines in good to moderate yields. The reaction shows unique stereoselectivity, giving anti-isomers selectively. [reaction: see text]     

Generation of ynolates via reductive lithiation using flow microreactors

A new method has been developed for the generation and subsequent reaction of ynolates in a micro flow reactor system. This new procedure allowed for ynolates to be prepared at 0 °C or ambient temperature within 1 min via a reductive lithiation reaction, whereas the corresponding batch processes generally require low temperature control and extended reaction times of up to 1 h. The resulting ynolates were applied to the olefination of carbonyl compounds, with the reactions reaching completion in a much shorter reaction time in the continuous flow reactor than the batch reactor. These results highlight the practical utility of the ynolate reaction, and represent the first reported example of the use of lithium naphthalenide in a flow microreactor, which would contribute to progress of the flash chemistry.     

Neutron Diffraction Study on the Structure of Aqueous LiNO3 Solutions

Neutron diffraction measurements were carried out at 25 °C for aqueous LiNO₃ heavy water solutions, (*LiNO₃) _x (D₂O)_1?x where x = 0.1, 0.05 and 0.01, in which the ⁶Li/⁷Li isotopic ratios were varied. Structural information on intermolecular nearest neighbor Li⁺···D₂O interactions in the extensive concentration range was derived from the first-order difference function, ?_Li(Q), obtained from the difference in scattering cross sections between ⁶Li- and ⁷Li-enriched sample solutions. The nearest neighbor Li⁺···O distance and coordination number for sample solution with x = 0.1 were determined to be r _LiO = 1.969 (8) Å and n _LiO = 4.12 (6), respectively, corresponding to the four-coordinated Li⁺ ion in the solution. On the other hand, those obtained for the solution with x = 0.01 are r _LiO = 2.00 (2) Å and n _LiO = 6.0 (2), respectively, indicating that hexaaqua Li⁺ is dominant in the dilute solution. These results clearly indicate that a concentration dependence of the hydration number of Li⁺ occurs in the aqueous solutions.