rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Mechanisms of transition metal catalyzed additions to olefins
  name:
    name part: Nowlan, Daniel Thomas, 1976-
    role:
      role term: creator
  name:
    name part: Singleton, Daniel A.
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2005
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: electronic
    form: remote
  abstract: Transition metal catalyzed reactions have an important place in synthetic chemistry, but the mechanistic details for many of these reactions remain undetermined. Through a combination of experimentally determined ¹³C kinetic isotope effects (KIEs) and density functional theory (DFT)calculations, some of these reactions have been investigated. The cyclopropanation of an olefin catalyzed by rhodium (II) tetrabridged complexes has been shown to proceed through an asynchronous, but concerted mechanism. DFT does not provide an accurate transition structure for the reaction of an unstabilized carbenoid with an olefin, but it does predict an early, enthalpically barrierless transition state which is consistent with the reactivity of unstabilized carbenoids. For the case of stabilized carbenoids, the theoretical structures predict the KIEs accurately and a new model is proposed to explain the selectivity observed in Rh₂(S-DOSP)₄-catalyzed cyclopropanations.The chain-elongation step of atom transfer radical polymerization (ATRP) has been shown to be indistinguishable from that of free radical polymerization (FRP) for the CuBr/2,2̕-bipyridine system. While DFT calculations predict an earlier transition state than observed, the calculations suggest that with increasing levels of theory the predicted KIEs come closer to the observed KIEs. A recently proposed [2 + 2] mechanism for the cyclopropenation of alkynes catalyzed byRh₂(OAc)(DPTI)₃ has been shown not to be a viable pathway. Rather, the experimental KIEs are predicted well by canonical variational transition state theory employing the conventional mechanism for cyclopropenation via a tetrabridged rhodium carbenoid. DFT calculations also suggest an alternativeexplanation for the observed enantioselectivity. The ¹³C KIEs for metal-catalyzed aziridination have been measured for three separate catalytic systems. While the KIEs do not completely define the mechanism, all of the reactions exhibit similar KIEs, implying similar …
  note: by Daniel Thomas Nowlan.
  note: "Major Subject: Chemistry"
  note: Title from author supplied metadata (automated record created on Sep. 21, 2005.)
  note: Vita.
  note: Abstract.
  note: Electronic resource.
  note: Mode of access: World Wide Web.
  note: System requirements: World Wide Web access and Adobe Acrobat Reader.
  note: Ph. D. Texas A&M University 2005.
  note: Includes bibliographical references.
  note: Text (Dissertation).
  subject:
    topic: Major chemistry
  subject:
    topic: cyclopropenation
  subject:
    topic: kinetic isotope effects
  subject:
    topic: cyclopropanation
  subject:
    topic: Mechanism
  subject:
    topic: catalysis
  identifier: http://hdl.handle.net/1969.1/2308
  record info:
    record content source: TXA
    record creation date: 051018
    record change date: 20151102140354.0
    record identifier: in00002078637