KUKU

KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Kinetic and Spectroscopic Investigation of Structural Influences on Hydrogen-atom Transfer Reactivity of N5-Ligated Oxomanganese(IV) Complexes

    Thumbnail
    View/Open
    Available after: 2020-05-31 (5.735Mb)
    Issue Date
    2018-05-31
    Author
    Massie, Allyssa A
    Publisher
    University of Kansas
    Format
    201 pages
    Type
    Dissertation
    Degree Level
    Ph.D.
    Discipline
    Chemistry
    Rights
    Copyright held by the author.
    Metadata
    Show full item record
    Abstract
    High valent iron- and manganese-oxo intermediates perform important hydrogenatom transfer (HAT) reactions in both biological and synthetic systems. There has been extensive characterization of HAT reactivity of enzymatic and synthetic oxoiron(IV) species, and these complexes have been shown to cleave a wide range of C-H bonds. Although there is no evidence for this type of reactivity by manganese enzymes in nature, several synthetic oxomanganese(IV) species are also capable of activating C-H bonds. However, whereas oxoiron(IV) species have been extensively characterized, the factors that influence HAT reactivity of oxomanganese(IV) species is poorly understood. In an effort to further understand the structure-reactivity relationship of oxomanganese(IV) species, a series of novel oxomanganese(IV) species with subtle perturbations to the equatorial ligand field of the neutral, pentadentate supporting ligand were prepared. Extensive spectroscopic studies, including structural characterization by X-ray absorption spectroscopy (XAS), revealed very minor geometric and electronic structure changes. Kinetic studies of C-H bond containing substrates offered insight into the effects of the ligand perturbations on the reactivity of these oxomanganese(IV) species. Electron donation from the supporting ligand decreases the rate of C-H activation. Conversely, weakening the ligand field through the use of a bulkier ligand dramatically speeds up HAT reactivity, allowing for the reaction with the strong C-H bonds of cyclohexane at rates exceeding that of oxoiron(IV) species with similar ligands. Further, it was discovered that the reaction with cyclohexane could be carried out catalytically in the presence of excess oxidant. The products of catalytic cyclohexane oxidation, cyclohexanol and cyclohexanone, provided evidence of the ability of this oxomanganese(IV) species to perform substrate hydroxylation. Lastly, peroxomanganese(III) species are proposed to be important intermediates in many biological systems. However, in both biological and synthetic systems, the factors that determine the cleavage of the O-O versus Mn-O bonds are not well understood. A novel peroxomanganese(III) species was prepared using electrochemically generated superoxide. The electrochemical reduction of this species was probed to further understand the effects of supporting ligand, which has an amide group trans to the peroxo.
    URI
    http://hdl.handle.net/1808/29307
    Collections
    • Chemistry Dissertations and Theses [336]
    • Dissertations [4475]

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    The University of Kansas
      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps