Novel configurational structures of sodium tetrakis(3-heptafluorobutylryl-(+)-camphorato) Ln(III) complexes with a trapped Na+ by Na+...FC interactions in the solid state and in solution

For newly prepared sodium tetrakis(3-heptafluorobutylryl-(+)-camphorato) Ln(III) complexes, the X-ray crystal analysis revealed an unprecedented pseudo-achiral dodecahedron (DD-8 (D(2d))), whereas in CHCl3 solution, the exciton CD and 19F NMR spectra showed a novel chiral Delta-SAPR-8 (C4) configuration which is stereospecifically formed by a trapped Na+ ion with Na+...FC (fluorocarbon) interactions.     

Two Polymorphs of (Anilinium)(18-Crown-6)[Ni(dmit)2]: Structure and Magnetic Properties

Two polymorphs of monovalent [Ni(dmit)₂]⁻ (dmit²⁻=2-thioxo-1,3-dithiole-4,5-dithiolate) crystals A and B, (anilinium)(18-crown-6)[Ni(dmit)₂], were prepared, and the structure and magnetic properties were investigated. In these crystals, the [Ni(dmit)₂]⁻ molecules form dimers, which arranged into chains between the supramolecular cation structure (anilinium)(18-crown-6). In crystal A, supramolecular cation formed a regular stack, inducing ladder structure of [Ni(dmit)₂], whose magnetism had been well fitted by spin ladder equation with the spin gap of Δ=190 K. Crystal B is ca. 3% more densely packed compared to crystal A. Due to the dense packing, supramolecular cation stack is distorted, which prevented the intermolecular interaction between [Ni(dmit)₂]⁻ dimers in direction corresponds to the ladder-leg direction in crystal A. Reflecting the [Ni(dmit)₂]⁻ arrangement, crystal B showed a temperature dependence of magnetic susceptibility well reproduced by the singlet-triplet thermal activation model, whose antiferromagnetic exchange interaction (2J) was 140 K.     

CYP119 plus a Sulfolobus tokodaii strain 7 ferredoxin and 2-oxoacid:ferredoxin oxidoreductase constitute a high-temperature cytochrome P450 catalytic system

The cytochrome P450 superfamily of enzymes catalyzes a broad range of oxidative processes involved in the metabolism of fatty acids, biosynthesis of sterols, and elimination of drugs and xenobiotics. Application of the unique properties of P450 enzymes as fine biocatalysts in biotechnology is limited due to their thermal instability and the requirement for auxiliary electron-donor proteins and cofactors. CYP119, a thermophilic P450 enzyme from Sulfolobus solfataricus, was characterized some time ago, but no high-temperature redox partners have been available for it. Here we report reconstitution of CYP119 with a novel high-temperature electron-donor system consisting of a ferredoxin and 2-oxoacid:ferredoxin oxidoreductase from Sulfolobus tokodaii strain 7 that, unlike all other known P450 electron-donor partners, utilizes coenzyme-A and pyruvic acid rather than NADH or NADPH as the source of electrons. The oxidation of lauric acid by the reconstituted system increased 16-fold as the temperature increased from 25 to 70 degrees C and was functional for more than 30 min at the higher temperature. This first in vitro high-temperature P450 catalytic system is a key step in the development of practical high-temperature monooxygenase systems.     

Layer-by-layer assembled multilayer films of titanate nanotubes, Ag- or Au-loaded nanotubes, and nanotubes/nanosheets with polycations

Aqueous suspensions of hydrothermally synthesized titanate nanotubes and poly(diallyldimethylammonium chloride) (PDDA) have been employed to fabricate multilayer films on various substrates in a layer-by-layer fashion. Atomic force microscopy displays the dense coverage of the substrate surface by the nanotubes. UV-vis absorption spectroscopy confirms the consecutive growth of PDDA/nanotube layer pairs. Single crystalline Ag and Au nanoparticles with narrow size distribution spatially correlating with the nanotubes have been obtained by treating the nanotubes with AgNO(3) or HAuCl(4) aqueous solution followed by chemical reduction. The noble metal nanoparticles show a strong surface plasmon absorption band. A multilayer film construction of the noble-metal-loaded nanotubes has also been achieved. This process has been further extended to the heteroassembly of nanotubes/nanosheets in different layer sequences.     

Tetrahedral Co(II) coordination in alpha-type cobalt hydroxide: Rietveld refinement and X-ray absorption spectroscopy

We report a Rietveld refinement analysis and X-ray absorption study on a green-color Cl(-)-intercalated alpha-type cobalt hydroxide phase. The refinement clearly demonstrated that one-fifth to one-sixth of the Co(II) at octahedral sites was replaced by pairs of tetrahedrally coordinated Co(II) on each side of the hydroxide plane, represented by a structural formula of [Co(octa)(0.828)Co(tetra)(0.348)(OH)2](0.348+)Cl(0.348).0.456H2O. X-ray absorption spectroscopy also indicated that the divalent cobalt were in local neighboring environments of both octahedral and tetrahedral coordination. Furthermore, UV-vis spectroscopic measurements elucidate the typical green/blue color of an alpha-type cobalt hydroxide.     

Gas-phase generation of highly reactive hexatriyne-bridged [6n]paracyclophynes

[6n]Paracyclophenediynes 2a-d (n = 3-6) having [4.3.2]propellatriene units were prepared as precursors of the corresponding [6n]paracyclophynes. Laser irradiation of 2a-d produced the negative ions of [6n]paracyclophynes 1a-d (n = 3-6) by extrusion of the indan fragments, which were detected by time-of-flight mass spectrometry.     

10-Oxo-10H-5λ,10λ-thianthren-5-ylideneamine as a probe for stereochemistry in the formation and amination of fluoro-λ-sulfanenitriles

The fluorination of 10-oxo-10H-5λ⁴,10λ⁴-thianthren-5-ylideneamine (2) with Selectfluor™ affords 5-fluoro-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (4). The amination of 4 with morpholine gives 5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (5). The stereochemical course of both reactions has been studied, while the configurations of their products, cis-isomer 4 and trans-5-morpholino-10-oxo-5,10-dihydro-5λ⁶,10λ⁴-thianthren-5-nitrile (trans-5) are elucidated by the use of X-ray crystallographic analyses.