• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Syntheses and characterization of compounds of niobium and tantalum with phenylimido and phenoxide ligation.

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_9210278_sip1_c.pdf
    Size:
    8.095Mb
    Format:
    PDF
    Download
    Author
    Smith, David Paul.
    Issue Date
    1991
    Keywords
    Dissertations, Academic
    Chemistry, Analytic
    Advisor
    Wigley, David E.
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    The metallacyclopentadiene (DIPp)₂CITa(CCMe₃=CHCH=CCMe₃) (α, α') (DIPP=2,6-diisopropylphenoxide) is isolated from the 2 electron reduction of Ta(DIPP)₂CI₃(OEt₂) in the presence of excess Me₃CC=CH. The α, α' isomer represents the kinetic product of this reaction since it can be thermolyzed to produce (DIPP)₂CITa(CCMe₃=CHCCMe₃=CH) (α, β’). The reactivity of these two isomers toward the addition of ethylene and alkynes has been investigated and found to be driven primarily by steric effects with the less hindered α, β’ isomer showing a more comprehensive chemistry. The rearrangement of α, α' to α, β’ was followed through several kinetic and mechanistic studies. This data support a mechanism involving dissociation of the a,a' isomer to the metallacyclopropene, (DIPP)₂CITa(HC=CCMe₃), and free Me₃CC=CH. These intermediates then recouple to form the thermodynamic product, the α, β’ isomer. The reaction of TA(DIPP)₃Cl₂(OEt₂) with quinoline or 6-methylquinoline (HC) produces the ligand exchange product (η¹-HC)Ta(DIPP)₃CI₂, the 2 electron reduction of either of these products yields [η²-(N,C)-HC]Ta(DIPP)₃ which can be isolated as the phosphine complex [η²-(N,C)-HC]Ta(DIPP)₃(PMe₃) upon reaction with trimethylphosphine. The reaction of either [η²-(N,C)-quinoline]Ta(DIPP)₃ or [η²-(N,C)quinoline] Ta(DIPP)₃(PMe₃) with hydrogen both in the presence and absence of Pd/C produces 1,2,3,4-tetrahydroquinoline and 2,2'-bisquinoline. The production of these compounds implicates the η²-(N,C) bonding mode in selective hydrogenation of heterocycles and ortho functionalization. The reaction of Nb(NEt₂)₂CI₃ with two equivalents of LiNHMes (Mes=2,4,6- C₆H₂Me₃) followed by addition of pyridine produces Nb(NMes)₂CI(py)₂. The reaction of Nb(NEt₂)₂CI₃ with 6 equivalents of LiNHMes produces the first tris imido complex of group 5, [(THF)₂Li][Nb(NMes)₃(NHMes)]. Comparable chemistry is seen with Ta. [(THF)₂Li][Nb(NMes)₃(NHMes)] reacts with lithium alkyls under kinetic conditions to produce [(THF)2Li][Nb(NMes)₃(R)] (R=Me, ⁿSu, ᵗSu, Me₃SiCH₂). Under thermodynamic conditions, however, the reaction of [(THF)₂Li][Nb(NMes)₃(NHMes)] with ᵗBuLi yields the first tetrakis imido complex of group 5, [(THF)₄Li₃][Nb(NMes)₄]
    Type
    text
    Dissertation-Reproduction (electronic)
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Chemistry
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.