Electrophoretic deposition of phthalocyanine in organic solutions containing trifluoroacetic acid

The absorption spectra of copper phthalocyanine (CuPc) 1,2-dichloroethane (DCE) solutions containing trifluoroacetic acid (TFAA) shows that the number of protons coordinating to the CuPc molecule was 1 and 2 for the first and second proton adducts, respectively, which indicates the formations of CuPcH(+) and CuPcH(2)(2+). This CuPc molecule may act as a catalyst to dissociate TFAA into trifluoroacetate anion (A(-)) and H(+) and form the proton adducts. The electrical conductivity dependence of the solution on CuPc concentration also supports this mechanism. A dense film of CuPc was deposited on an indium tin oxide cathode plate by electrophoresis of the solution. Similar dense films of a wide variety of phthalocyanines (MPc; M = Cu, H(2), Fe, Ni, Zn, Pb, VO) were also deposited using this method. Similar films of CuPc were also formed using dichloromethane (DCM) and 1,1,1-trichloroethane (TCE) in place of DCE. Depositions are ascribed to the migration of positively charged monomers (i.e., protonated MPc). Scanning electron microscopy revealed that these films are composed of fibrous crystallites, size of which was found to increase with the electrophoresis time, the strength of the applied electrical field and the concentration of CuPc in the bath. The influence of the dielectric constant of the organic solvent on the film growth is discussed.     

Structural change of a cofactor binding site of flavoprotein detected by single-protein fluorescence spectroscopy at 1.5 k

The visible fluorescence spectrum of single flavoprotein at a temperature of 1.5 K has been measured by one-photon excitation. The flavoprotein studied was a photoswitchable enzyme, photoactivated adenylyl cyclase. The time course of the spectrum revealed a structural change occurring at a rate of 10(-3) s(-1) around hydrogen bonds at the flavin cofactor binding site.     

Synthesis and electropolymerization of fullerene-terthiophene dyads

Fullerene derivatives having a terthiophene unit connected by a triple bond were newly synthesized and the electroactive polymers were obtained by electrolytic oxidation of the terthiophene moiety.     

Convenient Preparation of 2-Deoxy-3,5-di-O-p-toluoyl-α-D-erythro-pentofuranosyl Chloride

By using acetyl chloride as HCl generator, the procedure for the Hoffer preparation of the α-chloro sugar 4a was significantly improved. The α-configuration of the chloro atom was confirmed by using NOE measurement. Sequential transformation of 4a to the β-anomer and to the furfuryl derivative 6 was studied.     

High-resolution angle-resolved photoemission study of Ni(1 1 1) surface state

High-resolution angle-resolved photoemission spectroscopy (ARPES) has been conducted to study the Shockley state (SS) in ferromagnetic Ni(1 1 1) located at the point of the surface Brillouin zone. We have determined the Fermi wave vector and Fermi energy of the state with excitation photon energies of hν = 6.9-27.5 eV. On the basis of ARPES spectral shape analyses, we have found significant electron-electron interaction in the SS.     

Bis(μ‐cyst­amine‐κ4N,S:S′,N′)­bis­[(2‐amino­ethane­thiol­ato‐κ2N,S)­iridium(III)] tetrabromide dihydrate

In the complex cation of the title compound, [Ir₂(C₂H₆NS)₂(C₄H₁₂N₂S₂)₂]Br₄·2H₂O, which was obtained by rearrangement of [Re{Ir(aet)₃}₂]³⁺ (aet is 2‐amino­ethane­thiol­ate) in an aqueous solution, two approximately octahedral fac(S)‐[Ir(NH₂CH₂CH₂S)₃] units are linked by two coordinated di­sulfide bonds. The complex cation has a twofold axis, and the two non‐bridging thiol­ate S atoms in the complex are located on opposite sides of the two di­sulfide bonds. Considering the absolute configurations of the two octahedral units (Δ and Λ) and the four asymmetric di­sulfide S atoms (R and S), the complex consists of the Δ_RRΔ_RR and Λ_SSΛ_SS isomers, which combine to form the racemic compound.     

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.