Synthesis and structural analysis of a novel iodinated cyclopentadienone via ring-contraction iodination and its application in synthesis of alkyne-functionalized cyclopentadienones.

The first iodinated cyclopentadienone was isolated and its structure was confirmed by single crystal X-ray analysis. Based on this intermediate, the first direct C-C bond formation on cyclopentadienone ring was achieved. The photo induced intramolecular charge transfer of alkynylated cyclopentadienones was evaluated by solvent polarity effect on their electronic absorption spectra.

Polythiophene containing thermally removable solubilizing groups enhances the interface and the performance of polymer-titania hybrid solar cells.

A polythiophene derivative containing thermally removable branched ester solubilizing groups has been prepared and tested as a processable organic semiconductor polymer with tunable electronic and chemical properties for hybrid polymer-inorganic solar cells. Thermal removal of the protecting group enhances the interface between the organic and inorganic components while also contributing to better light absorption, energy transfer, and overall cell performance.

Effects of the environment on microperoxidase-11 and on its catalytic activity in oxidation of organic sulfides to sulfoxides.

Microperoxidase-11 (MP-11, also known as heme undecapeptide of cytochrome c) was immobilized by encapsulation into sol-gel silica glass and by physisorption, chemisorption, and covalent attachment to silica gel. We then compared these species with one another and with dissolved microperoxidase-11 as catalysts for the sulfoxidation of methyl phenyl sulfide by hydrogen peroxide. MP-11 is prone to oligomerization in solution, both via axial ligation and via intermolecular interactions. When the ligation oligomerization is suppressed upon immobilization, heme becomes more accessible, and the sulfoxide yield increases 4-6 times, from 15% up to 95%. When the ligation oligomerization of dissolved MP-11 is suppressed by protonation and acetylation of amino groups and by addition of methanol, sodium dodecyl sulfate (SDS), or trifluoroethanol, the sulfoxide yield increases 3-5 times (up to 76%). The oligomerization via intermolecular interactions is important for preserving enantioselectivity in immobilized and dissolved MP-11. For MP-11 in amine-rich and especially alcohol-rich environments, the enantioselectivity is vanishingly low, presumably because amino and hydroxyl groups cause a conformation change in the catalyst. In other environments, the MP-11 species are aggregated via intermolecular interactions in micellar (SDS) solution and on the surface of the silica gel, or via axial ligation in aqueous buffer at pH 6.0. Under these conditions, the enantioselectivity is enhanced; the enantiomeric excess (ee) becomes as high as 46%. An understanding of the effects of the aggregation state and consequent properties on the catalytic activity of MP-11 allowed us to control the yield and enantioselectivity of sulfoxidation reaction.