The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform

Scott A. Reid - One of the best experts on this subject based on the ideXlab platform.

  • Probing Radical Pathways in Electrophilic Addition of Halogens: Classical vs. Bridged Intermediates
    Chemical Physics Letters, 2012
    Co-Authors: Lisa George, Aimable Kalume, Scott A. Reid
    Abstract:

    Abstract We examine radical mediated pathways in electrophilic addition to the Simplest Alkene, ethylene, where the structure of the radical intermediate has been extensively debated. Starting from the π-complex with a dihalogen, C 2 H 4 ⋯I 2 , isolated in an inert matrix, we initiate reaction by photolytically cleaving the I 2 bond. We succeed in trapping and spectroscopically interrogating the symmetrically bridged radical complex, which calculations confirm is the global minimum on the C 2 H 5 I Potential Energy Surface (PES). Consistent with the participation of a bridged intermediate, radical addition preferentially but not exclusively yields the anti -stereoisomer of the 1,2-diiodoethane product.

Lisa George - One of the best experts on this subject based on the ideXlab platform.

  • Probing Radical Pathways in Electrophilic Addition of Halogens: Classical vs. Bridged Intermediates
    Chemical Physics Letters, 2012
    Co-Authors: Lisa George, Aimable Kalume, Scott A. Reid
    Abstract:

    Abstract We examine radical mediated pathways in electrophilic addition to the Simplest Alkene, ethylene, where the structure of the radical intermediate has been extensively debated. Starting from the π-complex with a dihalogen, C 2 H 4 ⋯I 2 , isolated in an inert matrix, we initiate reaction by photolytically cleaving the I 2 bond. We succeed in trapping and spectroscopically interrogating the symmetrically bridged radical complex, which calculations confirm is the global minimum on the C 2 H 5 I Potential Energy Surface (PES). Consistent with the participation of a bridged intermediate, radical addition preferentially but not exclusively yields the anti -stereoisomer of the 1,2-diiodoethane product.

Aimable Kalume - One of the best experts on this subject based on the ideXlab platform.

  • Probing Radical Pathways in Electrophilic Addition of Halogens: Classical vs. Bridged Intermediates
    Chemical Physics Letters, 2012
    Co-Authors: Lisa George, Aimable Kalume, Scott A. Reid
    Abstract:

    Abstract We examine radical mediated pathways in electrophilic addition to the Simplest Alkene, ethylene, where the structure of the radical intermediate has been extensively debated. Starting from the π-complex with a dihalogen, C 2 H 4 ⋯I 2 , isolated in an inert matrix, we initiate reaction by photolytically cleaving the I 2 bond. We succeed in trapping and spectroscopically interrogating the symmetrically bridged radical complex, which calculations confirm is the global minimum on the C 2 H 5 I Potential Energy Surface (PES). Consistent with the participation of a bridged intermediate, radical addition preferentially but not exclusively yields the anti -stereoisomer of the 1,2-diiodoethane product.

A Koss - One of the best experts on this subject based on the ideXlab platform.

  • ethene propene butene and isoprene emissions from a ponderosa pine forest measured by relaxed eddy accumulation
    Atmospheric Chemistry and Physics, 2017
    Co-Authors: Robert C Rhew, Malte Julian Deventer, Andrew A Turnipseed, C Warneke, John Ortega, Steve Shen, Luis Martinez, A Koss
    Abstract:

    Abstract. Alkenes are reactive hydrocarbons that influence local and regional atmospheric chemistry by playing important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. The Simplest Alkene, ethene (ethylene), is a major plant hormone and ripening agent for agricultural commodities. The group of light Alkenes (C2-C4) originates from both biogenic and anthropogenic sources, but their biogenic sources are poorly characterized, with limited field-based flux observations. Here we report net ecosystem fluxes of light Alkenes and isoprene from a semiarid ponderosa pine forest in the Rocky Mountains of Colorado, USA using the relaxed eddy accumulation (REA) technique during the summer of 2014. Ethene, propene, butene and isoprene emissions have strong diurnal cycles, with median daytime fluxes of 123, 95, 39 and 17 µg m−2 h−1, respectively. The fluxes were correlated with each other, followed general ecosystem trends of CO2 and water vapor, and showed similar sunlight and temperature response curves as other biogenic VOCs. The May through October flux, based on measurements and modeling, averaged 62, 52, 24 and 18 µg m−2 h−1 for ethene, propene, butene and isoprene, respectively. The light Alkenes contribute significantly to the overall biogenic source of reactive hydrocarbons: roughly 18 % of the dominant biogenic VOC, 2-methyl-3-buten-2-ol. The measured ecosystem scale fluxes are 40–80 % larger than estimates used for global emissions models for this type of ecosystem.

Chen Yuzhong - One of the best experts on this subject based on the ideXlab platform.

  • Ruthenium-Catalyzed Cross Coupling Reactions of Alkynes and Alkenes
    e-Publications@Marquette, 1998
    Co-Authors: Chen Yuzhong
    Abstract:

    Transition-metal-mediated cross coupling reaction of alkynes and Alkenes has recently gained increasing significance in organic chemistry because it represents an efficient method for the formation of new carbon-carbon bond. In recent years, two types of the coupling reactions have been developed: intramolecular couplings of enynes and intermolecular couplings of alkynes and Alkenes. These results were classified into two mechanistic pathways, one not involving carbon-carbon bond cleavage, insertion mechanism, and the other involving carbon-carbon bond cleavage, metathesis mechanism. While the coupling reactions of alkynes with substituted Alkenes have been well developed, there are very few reports on the coupling of alkynes with the Simplest Alkene, ethylene documented in the literature. Our research goal is to develop a new rutheniumbased system to study the coupling reactions of alkynes with ethylene, and extend its scope to enyne and substituted Alkenes