Synthesis of through‐space conjugated polymers containing [2.2]paracyclophane and thieno[3,4‐b]pyrazine in the main chain

We synthesized through‐space conjugated polymers with [2.2]paracyclophane and thieno[3,4‐b]pyrazine units in the main chain by the Sonogashira–Hagihara coupling reaction. The obtained polymers were soluble in common organic solvents, and homogeneous thin films were readily obtained from the polymer solutions by spin‐coating techniques. The polymers exhibited the extension of the conjugation length via the through‐space interaction. The polymers showed orangish‐red emission with peak maxima of around 610 nm in diluted solutions and their thin films, which were derived from the thieno[3,4‐b]pyrazine moieties. The optical and electrochemical behaviors of the polymers containing pseudo‐para‐ and pseudo‐ortho‐linked [2.2]paracyclophane were identical. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009     

Homogeneous anionic PPE hybrids with silica gel

Anionic poly(p‐phenylene‐ethynylene) (PPE) incorporated polymer hybrids were synthesized from the PPE and tetramethoxysilane together with the organic polymers such as poly(vinylpyrrolidone) via a sol–gel method. Up to 10 wt % of the anionic PPE could be dispersed homogeneously in the resulting polymer hybrid matrix. The obtained polymer hybrids exhibited controllable photoluminescence properties by the modification of the internal environment of organic–inorganic polymer hybrids by changing the organic/inorganic ratios. The photoluminescence of the anionic PPE surrounded by the polymer hybrid matrix was reinforced against the thermal irradiation. Moreover, the photoluminescence of the obtained organic–inorganic polymer hybrids was also tuned by utilizing ionic interactions between the anionic PPE and the inorganic matrix. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3749–3755, 2008     

Bis(tetrahydrofuran-κO)(meso-5,10,15,20-tetraisopropylporphy­rinato-κ4N)iron(III) perchlorate

The title complex, [Fe(C₃₂H₃₆N₄)(C₄H₈O)₂]ClO₄, shows an S₄-ruffled porphyrin ring, where the maximum deviation of the meso-carbon from the least-squares plane of the [Fe(C₂₀N₄)] core is as high as 0.675 (9) Å. This is the highest class of deviation among S₄-ruffled iron(III) porphyrin complexes. The average Fe—N_p bond distance is 1.967 (12) Å (N_p denotes an N atom of the equatorial ligand).     

Crystal structures and phase stability in pseudobinary CaAl2−xZnx

Samples in the pseudobinary system CaAl_2−xZn_x (0?x?2) were synthesised from the elements. Three different structure types, the C15 and C36 Laves phase structures and the KHg₂ (CeCu₂) structure, were observed. The structures and homogeneity ranges of the underlying phases were investigated by electron microscopy and thermal analysis as well as X-ray powder diffraction. The stability ranges for the different structure types were found to be 0?x?0.18, 0.28?x?0.68 and 0.93?x?2 for the C15, C36 and KHg₂ structure types, respectively.     

Element geochemistry of Holocene sediment and paleoenvironmental change in the Changjiang Estuary

Analyses of 41 elements reveal that Holocene sediments In the Changjiang Estuary bear regular elemental compositions in different sedimentary environments, and Holocene sediments came mainly from the Changjiang River based on compositions of REEs and most trace elements. Some heavy metals are more enriched in the surface sediment than in the deltaic sediments, reflecting human impact. Elemental compositions of the river channel sediment are related to the influence of proximal sediments. Sedimentary environments exert some influences on elemental compositions. Some chemical indices can be used to record chemical weathering undergone by the Changjiang sediment and environmental change.     

Synthesis and characterization of biocompatible magnetic glyconanoparticles

Magnetic glyconanoparticles were synthesized via the co-precipitation method. Iron (II) and iron (III) chloride were co-precipitated out of solution by the addition of ammonium hydroxide in an aqueous solution containing carbohydrate stabilizers such as d-gluconic acid, lactobionic acid and Ficoll^® at 75-80 °C. Stable magnetic glyconanoparticles were formed in a simple and direct process. Dynamic light scattering and transmission electron microscopy were used to characterize the surface-coated magnetic nanoparticles. In vitro cell viability studies of the glyconanoparticles were conducted with the mouse fibroblast cell lines. The magnetic glyconanoparticles revealed to be non-toxic at a concentration as high as 0.1 mg/mL.     

Ribitol in Solution Is an Equilibrium of Asymmetric Conformations

Ribitol (C₅H₁₂O₅), an acyclic sugar alcohol, is present on mammalian α-dystroglycan as a component of O-mannose glycan. In this study, we examine the conformation and dynamics of ribitol by database analysis, experiments, and computational methods. Database analysis reveals that the anti-conformation (180°) is populated at the C3–C4 dihedral angle, while the gauche conformation (±60°) is seen at the C2–C3 dihedral angle. Such conformational asymmetry was born out in a solid-state ¹³C-NMR spectrum of crystalline ribitol, where C1 and C5 signals are unequal. On the other hand, solution ¹³C-NMR has identical chemical shifts for C1 and C5. NMR ³J coupling constants and OH exchange rates suggest that ribitol is an equilibrium of conformations, under the influence of hydrogen bonds and/or steric hinderance. Molecular dynamics (MD) simulations allowed us to discuss such a chemically symmetric molecule, pinpointing the presence of asymmetric conformations evidenced by the presence of correlations between C2–C3 and C3–C4 dihedral angles. These findings provide a basis for understanding the dynamic structure of ribitol and the function of ribitol-binding enzymes.