The impact of N-heterocyclic carbenes (NHC) as ligands for transition metal catalysis has been rigorously investigated since their isolation by Arduengo in 1991. NHCs have become abundant in late-transition metal chemistry. This is attributed to NHCs being stronger sigma-donors than even the strongest phosphine analogues, thus constructing a transition metal-NHC complex with improved stability, catalytic reactivity, and selectivity. Additionally, pincer ligands have become recognized as an important class of ligands for transition metal complexes. The unique steric and electronic tunability of pincer ligands has resulted in pincer-transition metal complexes being exploited as catalysts for a multitude of transformations. Both ligand classes, NHC and pincer, have been reported as stable organometallic catalysts that demonstrate high catalytic activity. The combination of these two ligand systems by incorporation of NHCs into pincer ligands has attracted considerable attention. NHC pincer systems have been reported as stable organometallic catalysts that demonstrate high catalytic activity. The expansion of -NHC ligand precursor methodologies and application of the newly reported methodologies in order to diversify -NHC ligand architectures is reported. Extension of the amine elimination methodology yielded unsymmetrical NHC Ta pincer complexes. Studies on the manipulation of the previously reported symmetrical -NHC pincer Ta complex’s coordination sphere to synthesize a rare Ta diimido complex with unique reactivity towards advantageous proton sources and oxidative amination of aminoalkenes are also expanded upon. These next generation catalysts developed from these architectures may prove useful in catalyzing a broad array of transformations not previously accessible through the four standard NHC containing pincer ligand architectures.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-5314 |
| Date | 14 August 2015 |
| Creators | Box, Hannah Killian |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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