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

    Browse

    All of KAUSTCommunitiesIssue DateSubmit DateThis CollectionIssue DateSubmit Date

    My Account

    Login

    Quick Links

    Open Access PolicyORCID LibguideTheses and Dissertations LibguideSubmit an Item

    Statistics

    Display statistics

    Towards Supported Nitrogen Containing Fragments on Silica Surface for Catalytic Applications

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Maha PhD dissertation 2019.docx.pdf
    Size:
    5.705Mb
    Format:
    PDF
    Description:
    Maha Aljuhani - Final Dissertation
    Download
    View more filesView fewer files
    Type
    Dissertation
    Authors
    Aljuhani, Maha A. cc
    Advisors
    Basset, Jean-Marie cc
    Committee members
    Huang, Kuo-Wei cc
    Saikaly, Pascal cc
    Astruc, Didier
    Program
    Chemical Science
    KAUST Department
    Physical Science and Engineering (PSE) Division
    Date
    2019-09
    Embargo End Date
    2020-11-17
    Permanent link to this record
    http://hdl.handle.net/10754/660092
    
    Metadata
    Show full item record
    Access Restrictions
    At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2020-11-17.
    Abstract
    This thesis shed lights on metal-nitrogen organometallic fragments supported on silica surface for catalytic applications. It Focuses on group IV and V metal transition as a well-defined single-site catalysts, specifically titanium, hafnium, and tantalum to utilize them in the development of selective heterogeneous catalysis for imine metathesis, hydroamination and hydroaminoalkylation of olefins and alkynes. Developing new metal-nitrogen containing fragments by using easily available and abundant precursors which is silica SiO2 and metal amides complexes. Here, we describe metal fragments starting with hafnium-nitrogen fragment. All the catalysts were prepared by reacting homoleptic metal amido of group IV and V with partially dehydroxylated silica. In most cases the resulting surface amido is monopodal and leads to well defined single site catalysts precursors. In particular with Hf we have isolated hafniaaziridine 2.1 [(≡Si-O-)Hf(η2-MeNCH2)(η1-NMe2)(η1-HNMe2)], imido, and amido fragments 2.3 [(≡Si-O-)Hf(=NMe)(η1-NMe2)], and two intermediates the five-membered ring 2.2 [≡Si-O-Hf(HNMe2)(η2-NMeCH2CH(C6H13)CH2)(NMe2)] and 2.4 [(≡Si-O-)Hf(=NCH2Ar) (η1-NMe2)]. For tantalum 3.1 [(≡Si-O-)Ta=NtBu)(η1-NMeEt)2]; we have isolated two intermediates after treating 3.1 catalyst with aniline substrate lead to isolating 3.3 [(≡Si-O-)Ta(η1σ-NEtMe)2(η1σ-NHtBu)(NHC6H10)], and upon treating with 1-octyne lead to isolating 3.2 [(≡Si-O-)Ta(η1σ-NEtMe)2(η2-NtBuC=CC7H13)]. For titanium-nitrogen fragments, we isolated on silica SiO2-200 4.1 [(≡Si-O2-)Ti(NMe2)2 (η1-HNMe2)] and on SiO2-700 the titaniaaziridine 4.2a [≡Si-O-Ti(NMe2)3] 4.2b, [(≡Si-O-)Ti(η2-MeNCH2)(η1-NMe2)(η1-HNMe2)], the imido, and amido fragments 4.4 [(≡Si-O-)Ti(=NMe)(η1-NMe2)], and the five-membered ring intermediate 4.3 [≡Si-O-Ti(HNMe2)(η2-NMeCH2CH(C6H13)CH2)(NMe2)]. Research in this area has led to isolating several intermediates containing nitrogen fragments, this is the strength of surface organometallic chemistry which allows a deeper understanding of catalytic phenomena which could not be approached either in homogeneous catalysis or in classical heterogeneous catalysis. A molecular level characterization of the surface nitrogen containing fragments have been characterized by SOMC tools such as FTIR and EXAFS spectroscopy, elemental analysis, solid-state single and multiple quantum NMR, advanced DNP-SENS and DFT. A catalytic cycle was proposed based not only on the isolation of intermediates but also based on DFT calculations.
    Citation
    Aljuhani, M. A. (2019). Towards Supported Nitrogen Containing Fragments on Silica Surface for Catalytic Applications. KAUST Research Repository. https://doi.org/10.25781/KAUST-3Z199
    DOI
    10.25781/KAUST-3Z199
    ae974a485f413a2113503eed53cd6c53
    10.25781/KAUST-3Z199
    Scopus Count
    Collections
    PhD Dissertations; Physical Science and Engineering (PSE) Division; Chemical Science Program

    entitlement

     
    DSpace software copyright © 2002-2023  DuraSpace
    Quick Guide | Contact Us | KAUST University Library
    Open Repository is a service hosted 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. For anonymous users the allowed maximum amount is 50 search results.

    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.