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Sample records for benzopyrroles

  1. Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

    Energy Technology Data Exchange (ETDEWEB)

    Sotthewes, K.; Heimbuch, R.; Zandvliet, H. J. W. [Physics of Interfaces and Nanomaterials, MESA" + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands)

    2015-10-07

    Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a “molecular bridge” configuration, where two benzopyrrole groups (lobes) are connected to a Au-induced nanowire, whereas the other two lobes are connected to the adjacent nanowire. Three types of lobe configurations are found: a bright lobe, a dim lobe, and a fuzzy lobe. The dim and fuzzy lobes exhibit a well-defined switching behavior between two discrete levels, while the bright lobe shows a broad oscillation band. The observed dynamic behavior is induced by electrons that are injected into the LUMO+1 orbital of the CuPc molecule. By precisely adjusting the tip-molecule distance, the switching frequency of the lobes can be tuned accurately.

  2. Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

    Science.gov (United States)

    Sotthewes, K.; Heimbuch, R.; Zandvliet, H. J. W.

    2015-10-01

    Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a "molecular bridge" configuration, where two benzopyrrole groups (lobes) are connected to a Au-induced nanowire, whereas the other two lobes are connected to the adjacent nanowire. Three types of lobe configurations are found: a bright lobe, a dim lobe, and a fuzzy lobe. The dim and fuzzy lobes exhibit a well-defined switching behavior between two discrete levels, while the bright lobe shows a broad oscillation band. The observed dynamic behavior is induced by electrons that are injected into the LUMO+1 orbital of the CuPc molecule. By precisely adjusting the tip-molecule distance, the switching frequency of the lobes can be tuned accurately.

  3. Methyl Anthranilate as a Repellent for Western Corn Rootworm Larvae (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Bernklau, E J; Hibbard, B E; Norton, A P; Bjostad, L B

    2016-08-01

    Methyl anthranilate was identified as the active compound in extracts of maize (Zea mays L.) roots that were shown to be repellent to neonate western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae. A bioassay-driven approach was used to isolate the active material from diethyl ether extracts of roots from germinating maize seeds. Separation of the extract on a Florisil column yielded an active fraction of 90:10 hexane:diethyl ether. Analysis with gas chromatography-mass spectrometry identified two compounds in the active fraction: indole (2,3-benzopyrrole) and methyl anthranilate (methyl 2-aminobenzoate). When tested in behavioral bioassays, methyl anthranilate elicited a significant (P repellent response at doses of 1, 10, and 100 µg. In subsequent single-choice bioassays, 1, 10, and 100 µg of methyl anthranilate prevented larvae from approaching 10 mmol/mol concentrations of carbon dioxide, which is normally highly attractive to the larvae. Indole, the other compound identified from the active fraction, did not elicit a behavioral response by the larvae. Methyl anthranilate has potential for development as a management tool for western corn rootworm larvae and may be best suited for use in a push-pull control strategy. PMID:27122493

  4. Separation of nitrogen heterocyclic compounds contained in coal tar absorption oil fraction by solvent extraction; Yobai chushutsuho ni yoru korutaru kyushuyu ryubun ni fukumareru ganchisso fukuso kanshiki kagobutsu no bunri

    Energy Technology Data Exchange (ETDEWEB)

    Egashira, R.; Nagai, M. [Tokyo Inst. of Tech., Tokyo (Japan). Graduate School of Science and Engineering

    2000-09-01

    The liquid-liquid equilibrium properties (distribution coefficient and separation selectivity) between the feed of coal tar absorption oil fraction and the solvent (aqueous solution of methanol or that of tetrahydrothiophene-1,1-dioxide (sulfolane)) were experimentally measured with changing various conditions (water content in the solvent, etc.) in order to study the performance of operation and of separation. Nitrogen heterocyclic compounds (2,3-benzopyridine (quinoline), 3,4-benzopyridine (isoquinoline), and 2,3-benzopyrrole (benzo[b]pyrrole, indole)) were extracted preferentially to aromatic hydrocarbon (2-methylnaphthalene) in all case. The distribution coefficients of heterocyclic compounds and aromatic hydrocarbon decreased, and the separation selectivities of the heterocyclic compounds relative to the aromatic hydrocarbon increased with the water content in the extract. The aqueous solution of methanol was superior as a solvent to that of sulfolane in terms of both operation and separation performances. The above distribution coefficients were used to carry out the simple process simulation of extraction operation where the solvent was the aqueous solution of methanol. The multi-stage structure of equilibrium stage and counter-current contact between the feed and solvent improved the concentrations and yield of the heterocyclic compounds in the product that indicated process feasibility of the separation technique. (author)

  5. Solvent extraction of nitrogen heterocyclic compounds contained in coal tar absorption oil fraction - Improvement of separation performance by addition of aluminum chloride to solvent

    Energy Technology Data Exchange (ETDEWEB)

    Egashira, R.; Salim, C. [Tokyo Institute of Technology, Tokyo (Japan). Dept. of International Development Engineering, Graduate School of Science and Engineering

    2001-05-01

    The liquid-liquid equilibrium properties between the coal tar absorption oil fraction feed and the solvent (aqueous solution of methanol and aluminum chloride) were experimentally measured for nitrogen heterocyclic compounds (2,3-benzopyridine (quinoline), 3,4-benzopyridine (isoquinoline), and 2,3-benzopyrrole (indole)), homocyclic compounds (aromatics), and oxygen heterocyclic compounds. Nitrogen compounds were, extracted preferentially to the other compounds, and no oxygen compound was detected in the extract under all conditions. The distribution ratios of nitrogen compounds and aromatics increased with a larger mass fraction of AlCl{sub 3} in the extract. This increase in the distribution ratio was especially large for quinoline and isoquinoline, and the maximum ratios of quinoline and isoquinoline were 26 and 85 times larger, respectively, than in the cases without AlCl{sub 3} in the solvent. The separation selectivities for quinoline and isoquinoline relative to aromatics increased considerably with the mass fraction of AlCl{sub 3} in the extract, and the maximum ratios were 5 and 17 times higher than in the cases without AlCl{sub 3}. The separation selectivity for indole was apparently not affected by the addition of AlCl{sub 3}.

  6. Assessment of changes in the aroma and sensory profile of dawadawa due to modification in fermentation conditions

    International Nuclear Information System (INIS)

    charateristic odour of faeces. The levels of all but eight (2-Methlpropyl acetate; 2- Pentylfuran; 1-Pentanol; 2,6-dimenthlpyrazine; 2,3,5- Trimethlpyrazine; Phenylethanal; Methyl phenylacetate and Benzyl alcohol) of the aroma compounds were either not identified in the control sample or significantly different ( P≤0.05) in the control compared to the treated samples. Aroma compounds known to have low odour thresholds such as 2-methylfuran; 2-metylfuran, dimethl trisulfide, 2,6-dimethlpyrazine, 2,3,5-trimethlpyrazine and 2,3-benzopyrrole were all at significantly different levels in al the samples they occurred. Generally the odour compunds with pungent and objectionable odours were present at higher levels in the control than in the treated samples. This work has shown that the objectionable/undesirable odour in dawadawa can be reducesd by applying the methods investigated. The most practical effective methods which can be applied by SMEs to reduce the atypical odour of dawadawa is to carry out the fementation in an enclosed chamber with a predetermined oxygen concentration or at a low temperature of 15°C which can be obtained by strong air-conditioning. (au)