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  1. Article: Investigations into Apopinene as a Biorenewable Monomer for Ring-Opening Metathesis Polymerization

    Strick, Benjamin F / Delferro Massimiliano / Geiger Franz M / Thomson Regan J

    ACS sustainable chemistry . 2015 July 06, v. 3, no. 7

    2015  

    Abstract: The ring-opening metathesis polymerization (ROMP) of apopinene is reported. We find that apopinene reacts with Ru-based metathesis catalysts to provide an all trans-polymer with a polydispersity index (PDI) as low as 1.6 and molecular weights in the 1100 ...

    Abstract The ring-opening metathesis polymerization (ROMP) of apopinene is reported. We find that apopinene reacts with Ru-based metathesis catalysts to provide an all trans-polymer with a polydispersity index (PDI) as low as 1.6 and molecular weights in the 1100 to 15 600 g·mol–¹ range (9–127 monomer units). Because apopinene is readily prepared in one-step from myrtenal or two-steps from α-pinene, both of which are commercially available and naturally abundant, these studies indicate that apopinene might find future use as a new biorenewable precursor for the sustainable production of ROMP-based materials.
    Keywords alpha-pinene ; catalysts ; molecular weight ; polymerization
    Language English
    Dates of publication 2015-0706
    Size p. 1278-1281.
    Publishing place American Chemical Society
    Document type Article
    ISSN 2168-0485
    DOI 10.1021/acssuschemeng.5b00255
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: An oxidative [2,3]-sigmatropic rearrangement of allylic hydrazides.

    Strick, Benjamin F / Mundal, Devon A / Thomson, Regan J

    Journal of the American Chemical Society

    2011  Volume 133, Issue 36, Page(s) 14252–14255

    Abstract: The development of an efficient oxidative [2,3]-sigmatropic rearrangement of allylic hydrazides, via singlet N-nitrene intermediates, is reported. The requisite allylic hydrazide precursors are readily prepared and undergo smooth sigmatropic ... ...

    Abstract The development of an efficient oxidative [2,3]-sigmatropic rearrangement of allylic hydrazides, via singlet N-nitrene intermediates, is reported. The requisite allylic hydrazide precursors are readily prepared and undergo smooth sigmatropic rearrangement upon exposure to iodosobenzene. The products of this novel transformation are shown to be useful precursors to a variety of compounds.
    Language English
    Publishing date 2011-09-14
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/ja2066219
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Assessment of DFT for Computing Sum Frequency Generation Spectra of an Epoxydiol and a Deuterated Isotopologue at Fused Silica/Vapor Interfaces.

    Chase, Hilary M / Rudshteyn, Benjamin / Psciuk, Brian T / Upshur, Mary Alice / Strick, Benjamin F / Thomson, Regan J / Batista, Victor S / Geiger, Franz M

    The journal of physical chemistry. B

    2016  Volume 120, Issue 8, Page(s) 1919–1927

    Abstract: We assess the capabilities of eight popular density functional theory (DFT) functionals, in combination with several basis sets, as applied to calculations of vibrational sum frequency generation (SFG) spectra of the atmospherically relevant isoprene ... ...

    Abstract We assess the capabilities of eight popular density functional theory (DFT) functionals, in combination with several basis sets, as applied to calculations of vibrational sum frequency generation (SFG) spectra of the atmospherically relevant isoprene oxidation product trans-β-isoprene epoxydiol (IEPOX) and one of its deuterated isotopologues at the fused silica/vapor interface. We use sum of squared differences (SSD) and total absolute error (TAE) calculations to estimate the performance of each functional/basis set combination in producing SFG spectra that match experimentally obtained spectra from trans-β-IEPOX and one of its isotopologues. Our joined SSD/TAE analysis shows that while the twist angle of the methyl C3v symmetry axis of trans-β-IEPOX relative to the surface is sensitive to the choice of DFT functional, the calculated tilt angle relative to the surface normal is largely independent of the functional and basis set. Moreover, we report that hybrid functionals such as B3LYP, ωB97X-D, PBE0, and B97-1 in combination with a modest basis set, such as 6-311G(d,p), provides good agreement with experimental data and much better performance than pure functionals such as PBE and BP86. However, improving the quality of the basis set only improves agreement with experimental data for calculations based on pure functionals. A conformational analysis, based on comparisons of calculated and experimental SFG spectra, suggests that trans-β-IEPOX points all of its oxygen atoms toward the silica/vapor interface.
    Language English
    Publishing date 2016-03-03
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5207
    ISSN (online) 1520-5207
    DOI 10.1021/acs.jpcb.5b09769
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Vibrational Mode Assignment of α-Pinene by Isotope Editing: One Down, Seventy-One To Go.

    Upshur, Mary Alice / Chase, Hilary M / Strick, Benjamin F / Ebben, Carlena J / Fu, Li / Wang, Hongfei / Thomson, Regan J / Geiger, Franz M

    The journal of physical chemistry. A

    2016  Volume 120, Issue 17, Page(s) 2684–2690

    Abstract: This study aims to reliably assign the vibrational sum frequency generation (SFG) spectrum of α-pinene at the vapor/solid interface using a method involving deuteration of various methyl groups. The synthesis of five deuterated isotopologues of α-pinene ... ...

    Abstract This study aims to reliably assign the vibrational sum frequency generation (SFG) spectrum of α-pinene at the vapor/solid interface using a method involving deuteration of various methyl groups. The synthesis of five deuterated isotopologues of α-pinene is presented to determine the impact that removing contributions from methyl group C-H oscillators has on its SFG response. 0.6 cm(-1) resolution SFG spectra of these isotopologues show varying degrees of differences in the C-H stretching region when compared to the SFG response of unlabeled α-pinene. The largest spectral changes were observed for the isotopologue containing a fully deuterated vinyl methyl group. Noticeable losses in signal intensities allow us to reliably assign the 2860 cm(-1) peak to the vinyl methyl symmetric stretch. Furthermore, upon removing the vinyl methyl group entirely by synthesizing apopinene, the steric influence of the unlabeled C9H14 fragment on the SFG response of α-pinene SFG can be readily observed. The work presented here brings us one step closer to understanding the vibrational spectroscopy of α-pinene.
    Language English
    Publishing date 2016--05
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, Non-U.S. Gov't
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.6b01995
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Assessment of DFT for Computing Sum Frequency Generation Spectra of an Epoxydiol and a Deuterated Isotopologue at Fused Silica/Vapor Interfaces

    Chase, Hilary M / Rudshteyn Benjamin / Psciuk Brian T / Upshur Mary Alice / Strick Benjamin F / Thomson Regan J / Batista Victor S / Geiger Franz M

    Journal of physical chemistry. 2016 Mar. 03, v. 120, no. 8

    2016  

    Abstract: We assess the capabilities of eight popular density functional theory (DFT) functionals, in combination with several basis sets, as applied to calculations of vibrational sum frequency generation (SFG) spectra of the atmospherically relevant isoprene ... ...

    Abstract We assess the capabilities of eight popular density functional theory (DFT) functionals, in combination with several basis sets, as applied to calculations of vibrational sum frequency generation (SFG) spectra of the atmospherically relevant isoprene oxidation product trans-β-isoprene epoxydiol (IEPOX) and one of its deuterated isotopologues at the fused silica/vapor interface. We use sum of squared differences (SSD) and total absolute error (TAE) calculations to estimate the performance of each functional/basis set combination in producing SFG spectra that match experimentally obtained spectra from trans-β-IEPOX and one of its isotopologues. Our joined SSD/TAE analysis shows that while the twist angle of the methyl C₃ᵥ symmetry axis of trans-β-IEPOX relative to the surface is sensitive to the choice of DFT functional, the calculated tilt angle relative to the surface normal is largely independent of the functional and basis set. Moreover, we report that hybrid functionals such as B3LYP, ωB97X-D, PBE0, and B97-1 in combination with a modest basis set, such as 6-311G(d,p), provides good agreement with experimental data and much better performance than pure functionals such as PBE and BP86. However, improving the quality of the basis set only improves agreement with experimental data for calculations based on pure functionals. A conformational analysis, based on comparisons of calculated and experimental SFG spectra, suggests that trans-β-IEPOX points all of its oxygen atoms toward the silica/vapor interface.
    Keywords isoprene ; methodology ; molecular conformation ; oxidation ; oxygen ; silica ; vapors
    Language English
    Dates of publication 2016-0303
    Size p. 1919-1927.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5207
    DOI 10.1021%2Facs.jpcb.5b09769
    Database NAL-Catalogue (AGRICOLA)

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  6. Article ; Online: Uptake of epoxydiol isomers accounts for half of the particle-phase material produced from isoprene photooxidation via the HO2 pathway.

    Liu, Yingjun / Kuwata, Mikinori / Strick, Benjamin F / Geiger, Franz M / Thomson, Regan J / McKinney, Karena A / Martin, Scot T

    Environmental science & technology

    2015  Volume 49, Issue 1, Page(s) 250–258

    Abstract: The oxidation of isoprene is a globally significant source of secondary organic material (SOM) of atmospheric particles. The relative importance of different parallel pathways, however, remains inadequately understood and quantified. SOM production from ... ...

    Abstract The oxidation of isoprene is a globally significant source of secondary organic material (SOM) of atmospheric particles. The relative importance of different parallel pathways, however, remains inadequately understood and quantified. SOM production from isoprene photooxidation was studied under hydroperoxyl-dominant conditions for <5% relative humidity and at 20 °C in the presence of highly acidic to completely neutralized sulfate particles. Isoprene photooxidation was separated from SOM production by using two continuously mixed flow reactors connected in series and operated at steady state. Two online mass spectrometers separately sampled the gas and particle phases in the reactor outflow. The loss of specific gas-phase species as contributors to the production of SOM was thereby quantified. The produced SOM mass concentration was directly proportional to the loss of isoprene epoxydiol (IEPOX) isomers from the gas phase. IEPOX isomers lost from the gas phase accounted for (46 ± 11)% of the produced SOM mass concentration. The IEPOX isomers comprised (59 ± 21)% (molecular count) of the loss of monitored gas-phase species. The implication is that for the investigated reaction conditions the SOM production pathways tied to IEPOX isomers accounted for half of the SOM mass concentration.
    MeSH term(s) Aerosols/chemistry ; Alcohols/chemistry ; Atmosphere ; Butadienes/chemistry ; Hemiterpenes/chemistry ; Humidity ; Isomerism ; Mass Spectrometry/instrumentation ; Mass Spectrometry/methods ; Oxidation-Reduction ; Pentanes/chemistry ; Photochemical Processes ; Sulfates/chemistry
    Chemical Substances Aerosols ; Alcohols ; Butadienes ; Hemiterpenes ; Pentanes ; Sulfates ; isoprene (0A62964IBU)
    Language English
    Publishing date 2015-01-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/es5034298
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Uptake of Epoxydiol Isomers Accounts for Half of the Particle-Phase Material Produced from Isoprene Photooxidation via the HO2 Pathway

    Liu, Yingjun / Geiger Franz M / Kuwata Mikinori / Martin Scot T / McKinney Karena A / Strick Benjamin F / Thomson Regan J

    Environmental Science & Technology. 2015 Jan. 06, v. 49, no. 1

    2015  

    Abstract: The oxidation of isoprene is a globally significant source of secondary organic material (SOM) of atmospheric particles. The relative importance of different parallel pathways, however, remains inadequately understood and quantified. SOM production from ... ...

    Abstract The oxidation of isoprene is a globally significant source of secondary organic material (SOM) of atmospheric particles. The relative importance of different parallel pathways, however, remains inadequately understood and quantified. SOM production from isoprene photooxidation was studied under hydroperoxyl-dominant conditions for <5% relative humidity and at 20 °C in the presence of highly acidic to completely neutralized sulfate particles. Isoprene photooxidation was separated from SOM production by using two continuously mixed flow reactors connected in series and operated at steady state. Two online mass spectrometers separately sampled the gas and particle phases in the reactor outflow. The loss of specific gas-phase species as contributors to the production of SOM was thereby quantified. The produced SOM mass concentration was directly proportional to the loss of isoprene epoxydiol (IEPOX) isomers from the gas phase. IEPOX isomers lost from the gas phase accounted for (46 ± 11)% of the produced SOM mass concentration. The IEPOX isomers comprised (59 ± 21)% (molecular count) of the loss of monitored gas-phase species. The implication is that for the investigated reaction conditions the SOM production pathways tied to IEPOX isomers accounted for half of the SOM mass concentration.
    Keywords gases ; isomers ; isoprene ; neutralization ; photooxidation ; relative humidity ; spectrometers ; sulfates
    Language English
    Dates of publication 2015-0106
    Size p. 250-258.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5851
    DOI 10.1021%2Fes5034298
    Database NAL-Catalogue (AGRICOLA)

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