Theses and Dissertations
Issuing Body
Mississippi State University
Advisor
Mead, Keith T.
Committee Member
Foster, Stephen C.
Committee Member
Emerson, Joseph
Committee Member
Lewis, Edwin
Committee Member
Sygula, Andrzej
Date of Degree
12-11-2015
Document Type
Dissertation - Open Access
Major
Chemistry
Degree Name
Doctor of Philosophy
College
College of Arts and Sciences
Department
Department of Chemistry
Abstract
The synthesis and characterization of the first series of tetra-NHC-Ag(I)-X cubane clusters are reported. The clusters were characterized with 1H and 13C NMR spectroscopy, ESI-TOF MS, and single crystal X-ray diffraction. Crossover experimental data were consistent with intramolecular exchange, which can be visualized by a molecular rotating type mechanism. Additionally, -NHC Zr(IV) pincer type complexes were synthesized and characterized with 1H and 13C NMR spectroscopy, CHN combustion analysis, and X-ray crystallography. A large rate effect was observed based on the halogen and metal center for the hydroamination/cyclization of unactivated aminoalkenes. Zirconium based pincers provided faster reaction rates than their hafnium counterparts (Zr>Hf). Precatalysts with iodide ligands provided faster reaction rates than their bromide and chloride counterparts (I>Br>Cl). The mechanism of hydroamination for Zr(IV) -NHC complexes was also investigated for bis(iodide) and bis(amido) ligand classes. A full kinetic analysis of substrate and precatalyst have been identified along with the formation of small amounts of an oxidized product. The proposed mechanism contains an imido-type intermediate whose formation depends greatly on which set of ligand class is used.
URI
https://hdl.handle.net/11668/19611
Recommended Citation
Clark, Wesley D., "N-heterocyclic Carbene Complexes of Ag(I) and Zr(IV): Ag(I)-Halide Cubane Type Clusters and the Mechanism of Hydroamination with -NHC Pincer Complexes" (2015). Theses and Dissertations. 3288.
https://scholarsjunction.msstate.edu/td/3288
Comments
catalysis||organometallic