Near-infrared absorbing boron-dibenzopyrromethenes that serve as light-harvesting sensitizers for polymeric solar cells

Hexylthiophene-conjugated boron-dibenzopyrromethenes with benzo[1,3,2]oxazaborinine rings, 1, that absorb near-infrared light with relatively high molecular extinction coefficients have been synthesized. The incorporation of 3-hexylthiophene-conjugated dye 1a at a blend ratio of 5 wt % into a polymeric solar cell based on a P3HT/indene-C(70) bisadduct (IC(70)BA) bulk heterojunction structure improved power conversion efficiency from 3.7 to 4.3%. The present work suggests that well-defined near-infrared absorbing BODIPY analogues can potentially be used as photosensitizers in polymeric solar cells.     

Structure and magnetism of the quasi-1-d K4Cu(MoO4)3 and the structure of K4Zn(MoO4)3

Single crystals of K(4)Cu(MoO(4))(3) and nonmagnetic K(4)Zn(MoO(4))(3) have been grown by the flux-growth method. K(4)Cu(MoO(4))(3) can be described as a quantum quasi-1-d antiferromagnet with correlations between neighboring Cu(2+) ions but no magnetic long-range ordering down to 0.4 K. Comparison of the structure and magnetic properties of isostructural A(4)Cu(MoO(4))(3) (A = K, Rb) allows the isolation of the effects of low dimensionality from structural distortion along the Cu-O-Mo chains. The characteristic one-dimensional behavior is hence suppressed to lower the temperature in K(4)Cu(MoO(4))(3) in comparison with that of the Rb analogue. For example, a broad peak in the specific heat is observed ~2.3 K at 0 T, which is consistent with the onset of the quantum spin liquid state.     

The adsorption of SO2 on iron surfaces studied by x-ray photoelectron spectroscopy

The interaction of SO₂ with evaporated iron surfaces in the temperature range 80–450 K was investigated by using X-ray photoelectron spectroscopy. At 300 K, SO₂ decomposed at the initial stage of the interaction and gave adsorbed S with the S2p peak at 161.9 eV and adsorbed O with the O1s at 530.0 eV. Further exposure of SO₂ gave adsorbed SO₄ with S2p at 166.8 eV O1s at 531.3 eV, being different in binding energies from ionic SO₄^2?. This indicates the two stage reaction Of SO₂ with iron surface; SO₂(gas) → S(ads) + 20(ads), SO₂(gas) + 2O(ads) → SO₄(ads). The first reaction did not occur at low temperature or in the presence of adsorbed O. The adsorbed SO₄ formed at 80 K showed a quantitative decomposition reaction into S(ads) and O(ads) in the temperature range 200–350 K.     

The kinetics and thermochemistry of the gas phase reaction of cyclopentadiene and iodine. Relevance to the heat of formation of cyclopentadienyl iodide and cyclopentadienyl radical

The rate of the reaction of cyclopentadiene with iodine has been followed spectrophotometrically over the temperature range 171.7° to 276.5°C. The reaction first proceeds almost to the point of equilibrium with cyclopentadienyl iodide and HI, although the final products are fulvalene and HI. Equilibrium constants obtained are those predicted by bond additivity. A third-law value of δH⁰_{f 298} (c-C₅H₅I,g) = 49 kcal/mole is obtained. Rate studies of the reaction up to the iodide equilibrium, yield values for the rate constant . Uncertainty in the Arrhenius parameters, as well as doubts as to the applicability of the usual assumption that E₃ = 1 ± 1 kcal/mole, make difficult an evaluation of total cyclopentadienyl stabilization energy (TSE) from these data. However, the value is probably 15 < TSE < 20.     

Kinetics of the pyrolysis of 1,2-diiodoethylene

The spectrophotometric determination of the rate of pyrolysis of 1,2-diiodoethylene from 305.8 to 435.0° (with additional data on the addition of iodine to acetylene from 198.1 to 331.6°) has resulted in the observation of both a (in part heterogeneous) unimolecular process (A), and an iodine atom catalyzed process (B). For the homogeneous unimolecular process, log (k_A/sec^?1) ≈ 12.5–46/θ would appear to be reasonable, while log (k_B/M^?1 sec^?1) = 11.8–23.9/θ, where θ = 2.303RT in kcal/mole. It is suggested that a donor–acceptor complex intermediate may explain the observed rate constant of process B and analogous reactions in other systems.     

The improved synthesis of OPC-29030, a platelet adhesion inhibitor via diastereoselective oxidation of chiral non-racemic sulfide

An improved synthetic route of OPC-29030, the platelet adhesion inhibitor, was established via the diastereoselective oxidation of a chiral non-racemic sulfide (R)-5 to (S(S))-6 by the catalytic oxidation using VO(acac)(2) and cumene hydroperoxide (CHP) in the presence of MS4A. Under the current condition, the diastereoselectivity was not influenced by the presence of moisture, and moderate to high selectivity (72% de) was obtained at -30 degrees C. The obtained sulfoxide, which diastereomeric excess was easily raised by the recrystallization, could successfully lead to OPC-29030.     

Ligand-controlled highly stereoselective syntheses of e- and z-allylsilanes from dienes and aldehydes using nickel complex

Synthetic methods of highly stereocontrolled E- and Z-allylsilanes were developed. When a toluene solution of diene having a silicon moiety and aldehyde was refluxed in the presence of silane using a catalytic amount of Ni(cod)(2) bearing PPh(3), E-allylsilane was obtained in high yield. On the other hand, when the reaction was carried out in THF upon heating in the presence of Ni(cod)(2), imidazolium salt, Cs(2)CO(3), and PPh(3), Z-allylsilane was formed as a sole product.     

FI catalysts: new olefin polymerization catalysts for the creation of value-added polymers

This contribution reports the discovery and application of phenoxy-imine-based catalysts for olefin polymerization. Ligand-oriented catalyst design research has led to the discovery of remarkably active ethylene polymerization catalysts (FI Catalysts), which are based on electronically flexible phenoxy-imine chelate ligands combined with early transition metals. Upon activation with appropriate cocatalysts, FI Catalysts can exhibit unique polymerization catalysis (e.g., precise control of product molecular weights, highly isospecific and syndiospecific propylene polymerization, regio-irregular polymerization of higher alpha-olefins, highly controlled living polymerization of both ethylene and propylene at elevated temperatures, and precise control over polymer morphology) and thus provide extraordinary opportunities for the syntheses of value-added polymers with distinctive architectural characteristics. Many of the polymers that are available via the use of FI Catalysts were previously inaccessible through other means of polymerization. For example, FI Catalysts can form vinyl-terminated low molecular weight polyethylenes, ultra-high molecular weight amorphous ethylene-propylene copolymers and atactic polypropylenes, highly isotactic and syndiotactic polypropylenes with exceptionally high peak melting temperatures, well-defined and controlled multimodal polyethylenes, and high molecular weight regio-irregular poly(higher alpha-olefin)s. In addition, FI Catalysts combined with MgCl(2)-based compounds can produce polymers that exhibit desirable morphological features (e.g., very high bulk density polyethylenes and highly controlled particle-size polyethylenes) that are difficult to obtain with conventionally supported catalysts. In addition, FI Catalysts are capable of creating a large variety of living-polymerization-based polymers, including terminally functionalized polymers and block copolymers from ethylene, propylene, and higher alpha-olefins. Furthermore, some of the FI Catalysts can furnish living-polymerization-based polymers catalytically by combination with appropriate chain transfer agents. Therefore, the development of FI Catalysts has enabled some crucial advances in the fields of polymerization catalysis and polymer syntheses.     

A simple proline-based organocatalyst for the enantioselective reduction of imines using trichlorosilane as a reductant

A simple and inexpensive proline-based organocatalyst was developed for the reduction of imines using trichlorosilane as a reductant. The reduction of N-aryl imines in the presence of 10 mol % of N-pivaloyl-l-proline anilide was carried out to give the corresponding amines in excellent yields (up to 99%) with high enantioselectivities (up to 93% ee).     

Enhancing effect of water vapor on the reduction of lean NOx by ethanol over an Ag/Al2O3 catalyst supported on cordierite honeycomb

The Ag/Al₂O₃ catalyst supported on cordierite honeycomb (Ag/Al₂O₃/ cordierite) is highly active forthe reduction of lean NOx by ethanol. Addition of H₂O enhances the NOx reduction to CO₂ and N₂, and suppresses the formation of by-products such as CO, CH₃CHO and C₂H₄.