There are two main focuses to this thesis. The first is to explore interactions of weakly coordinating anions, specifically observing how they affect the cation they are
paired with. Choosing the right anion for a reaction could be crucial to get high yields or
good selectivity, so having an anion that could be tuned to different coordination strengths
is useful. The previously synthesized imidazolyl phenyl (IMP) anions can be made with
various functionalities that vary the coordination strength.
The IMP anions, which have only been paired and studied with metal cations, were
paired with triethylammonium to be able to investigate the interactions in an organic ion
pair. IR and NMR spectroscopy as well as computational methods were used to explore
the steric and electronic interactions between the ions. IR spectroscopy was used to attempt
to see the triethylammonium N-H stretching frequency shift depending on which anion was
paired with it. Similarly, 1H NMR spectroscopy saw a shift in the triethylammonium CH2
resonances when changing the coordinating anion. A scale was made using this data to see
which anions are weakly coordinating anions and which are strongly coordinating anions.
Computational approaches were used to supplement the experimental results we
obtained. DFT calculations were done to calculate the energy of interaction between the
anion and cation and compared to the experimental scale obtained using NMR
spectroscopy. Using the web program SambVca 2.1, % buried volume calculations were
performed to gain an understanding of the steric volume each anion had around the position
it coordinated to the cation. Lastly, NBO calculations were performed to determine the
charge on each atom of the ions before and after coordination to investigate how
coordination affected the individual charges at each atom.
The second focus is to find new catalysts for the Z-selective isomerization of
terminal alkenes. Previous members in the Dobereiner lab have done extensive research on
molybdenum catalyzed isomerization of terminal alkenes. It was proposed that the PCy3
ligand plays a large role in inducing Z-selectivity because of its large size. To test this, a
smaller ligand, specifically 1,3-dimethyl-N-heterocyclic carbene, was used in place of
PCy3. DFT experiments showed the energy barrier for the E mechanism is lower than the
Z mechanism.
Using the molybdenum catalyst as inspiration, DFT was used to test the same
complex, but replacing Mo with W. The computational results suggest that the tungsten
catalyst would also be Z-selective and would have better conversion because it has lower
energy barriers compared to the Mo complex. These results are promising, but synthesizing
the complex to test it experimentally would help be certain that the tungsten catalyst will
perform better. / Chemistry
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/8900 |
| Date | 08 1900 |
| Creators | Steets, Justin, 0009-0004-9823-2164 |
| Contributors | Dobereiner, Graham, Zdilla, Michael J., 1978-, Wengryniuk, Sarah E., Dorfner, Walter |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Text |
| Format | 285 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/8864, Theses and Dissertations |
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