Doctoral Dissertations

Date of Award

12-2019

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

David M. Jenkins

Committee Members

Michael D. Best, Brian K. Long, Howard L. Hall

Abstract

N-Heterocyclic carbenes (NHCs) have been an incredibly important ligand in the field of organometallic chemistry for the last 25 years. The ability of this ligand platform to stabilize higher oxidation states on transition metals and to form highly stable metal carbon bonds has revolutionized organometallic chemistry by replacing ligands such as phosphines. While NHCs are highly effective for organometallic chemistry on transition metals, there are still several areas in which NHCs have had limited applications. This dissertation covers research conducted towards remedying such shortcomings of NHCs in three specific fields: (1) modification of noble metal surfaces, (2) development of asymmetric variants of NHCs, and (3) the use of NHCs as ligands in actinide chemistry. First, two novel methods were developed to place NHCs on gold surfaces. Functionalized NHC precursors protected with carbon dioxide (CO2) were applied to gold film over nanosphere (AuFON) surfaces. Alternatively, gold(I) NHC complexes, were synthesized and applied to gold nanoparticles (AuNPs). Both AuFONs and AuNPs were analyzed with surface-enhanced Raman spectroscopy (SERS) through a collaborative study. Second, the first examples of chiral macrocyclic tetra-NHCs were synthesized and characterized. These polydentate class of NHC ligands could be important for asymmetric catalysis. The oxidation chemistry of one ligand system ligated to iron(II) was studied extensively. Third, the first examples of uranium octa-NHC complexes were prepared. These uranium complexes have the most uranium-carbon bonds of any reported molecule.

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