Minute displacement and strain analysis using lensless Fourier transformed holographic interferometry

An optical system for lensless Fourier transformed holographic interferometry is constructed to enable the measurement of minute displacements from nanometers to micrometers scale and to obtain corresponding strain distributions using a CCD camera with poor spatial resolution. Since a Fourier spectrum of an object beam is recorded on a hologram in this technique, the image reconstruction is easily performed with a single pass of 2-D fast Fourier transformation. Then, the map of the phase difference over the whole field is obtained by comparing two images before and after deformation. A suitable and effective unwrapping process is, however, inevitably required since the phase difference distribution is wrapped from −π to π in this technique. For phase unwrapping, the maximum spanning tree method is adopted here, which seeks a spanning tree that maximizes overall edge weights given by the cross amplitude. In-plane and out-of-plane displacements are obtained separately from the phase difference distributions at one's request. Moreover, in-plain strain is easily calculated from the in-plane displacement distribution.     

A simplest isolable monocyclic thiepin. Synthesis,structure, and thermal stability of 2,7-di-tert-butylthiepin

As an example of a simplest isolable monocyclic thiepin, 2,7-di-tert-butylthiepin (2) has been synthesized from 2,6-di-tert-butylthiopyrylium salt, and the thermal properties together with the X-ray crystal structure of (2) have been examined.     

Construction of azacycles based on endo-mode cyclization of allenes

A new procedure for constructing monocyclic five- and six-membered azacycles by the endo-mode ring-closing reaction of allenylazido derivatives under neutral conditions has been developed. The azabicyclo[m.n.0] compounds were prepared by applying this newly developed procedure. The seven-membered azacycle was prepared when the allene possessing an unsubstituted carboxyl amido functionality was submitted to the basic conditions. In addition, indole and quinoline skeletons were synthesized using this procedure.     

Confined organization of Au nanocrystals in glycolipid nanotube hollow cylinders

Mild fabrication of anisotropic metal-lipid nanotube (LNT) nanocomposites, in which Au nanoparticles of 3-10 nm wide are organized in a glycolipid nanotube hollow cylinder, has been achieved by filling the internal channel of the LNT with HAuCl(4) aqueous solution by capillary force and subsequent photochemical reduction of [AuCl(4)](-).     

Oxygenative cleavage of catechols including protocatechuic acid with molecular oxygen in water catalysed by water-soluble non-heme iron(III) complexes in relevance to catechol dioxygenases

Catechol dioxygenase model oxygenations have been performed for the first time in water by using water-soluble nonheme iron(III) complexes, enabling the oxygenation of protocatechuic acid and other catechols.     

Use of glass capillaries to suppress thermal convection in NMR tubes in diffusion measurements

Diffusion ordered spectroscopy (DOSY) is used to determine the translational diffusion coefficients of molecules in solution. However, DOSY is highly susceptible to spurious spectral peaks resulting from thermal convection occurring in the NMR tube. Thermal convection therefore must be suppressed for accurate estimation of translational diffusion coefficients. In this study, we developed a new method to effectively suppress thermal convection using glass capillaries. A total of 6 to 18 capillaries (0.8‐mm outer diameter) were inserted into a regular 5‐mm NMR tube. The capillaries had minimal effect on magnetic field homogeneity and enabled us to obtain clean DOSY spectra of a mixture of small organic compounds. Moreover, the capillaries did not affect chemical shifts or signal intensities in two‐dimensional heteronuclear single quantum coherence spectra. Capillaries are a simple and inexpensive means of suppressing thermal convection and thus can be used in a wide variety of DOSY experiments. Copyright © 2016 John Wiley & Sons, Ltd.     

Selective Metallation of 3-Halothiophenes: Practical Methods for the Synthesis of 2-Bromo-3-formylthiophene

Selective lithiation of 3-bromothiophene was accomplished under controlled conditions without formation of undesired thienyllithium compounds. A thienyl Grignard reagent derived from 2-bromo-3-iodothiophene was transformed into 2-bromo-3-formylthiophene in high selectivity by formylation with dimethylformamide (DMF) at optimal reaction temperature.     

Salt effect on polyaddition of bifunctional cyclic carbonate and diamine

The effect of various additives was examined for polyaddition of bifunctional cyclic carbonate and diamine giving poly(hydroxyurethane). Lithium chloride and lithium fluoride especially proved to be effective for the acceleration that resulted in giving polymers with higher molecular weights without coloration. The IR spectroscopic analysis of the mixtures of the additives and the carbonate monomer suggested that the acceleration with the lithium salts depends on the activation of the carbonyl group to enhance its electrophilicity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6282–6286, 2005     

Efficient synthesis of methylenetetrahydrofurans and methylenepyrrolidines by formal [3+2] cycloadditions of propargyl substrates

Recent developments concerning the synthesis of methylenetetrahydrofurans and methylenepyrrolidines by one-pot formal [3+2] cycloadditions involving propargylic (and allylic) alcohols and amines with electrophilic alkenes are described. The synthetic methods provide powerful tools to prepare highly functionalized oxygen- and nitrogen-containing five-membered ring systems. The reactions can be effectively promoted by base, base/transition metals, and Lewis acids, depending on the substrates.