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The electronic structure of eight zinc-centered porphyrin macrocyclic molecules are investigated using density functional theory for ground-state properties, time-dependent density functional theory (TDDFT) for excited states, and Franck-Condon (FC) analysis for further characterization of the UV-vis spectrum. Symmetry breaking was utilized to find the lowest energy of the excited states

The electronic structure of eight zinc-centered porphyrin macrocyclic molecules are investigated using density functional theory for ground-state properties, time-dependent density functional theory (TDDFT) for excited states, and Franck-Condon (FC) analysis for further characterization of the UV-vis spectrum. Symmetry breaking was utilized to find the lowest energy of the excited states for many states in the spectra. To confirm the theoretical modeling, the spectroscopic result from zinc phthalocyanine (ZnPc) is used to compare to the TDDFT and FC result. After confirmation of the modeling, five more planar molecules are investigated: zinc tetrabenzoporphyrin (ZnTBP), zinc tetrabenzomonoazaporphyrin (ZnTBMAP), zinc tetrabenzocisdiazaporphyrin (ZnTBcisDAP), zinc tetrabenzotransdiazaporphyrin (ZnTBtransDAP), and zinc tetrabenzotriazaporphyrin (ZnTBTrAP). The two latter molecules are then compared to their phenylated sister molecules: zinc monophenyltetrabenzotriazaporphyrin (ZnMPTBTrAP) and zinc diphenyltetrabenzotransdiazaporphyrin (ZnDPTBtransDAP). The spectroscopic results from the synthesis of ZnMPTBTrAP and ZnDPTBtransDAP are then compared to their theoretical models and non-phenylated pairs. While the Franck-Condon results were not as illuminating for every B-band, the Q-band results were successful in all eight molecules, with a considerable amount of spectral analysis in the range of interest between 300 and 750 nm. The π-π* transitions are evident in the results for all of the Q bands, while satellite vibrations are also visible in the spectra. In particular, this investigation finds that, while ZnPc has a D4h symmetry at ground state, a C4v symmetry is predicted in the excited-state Q band region. The theoretical results for ZnPc found an excitation energy at the Q-band 0-0 transition of 1.88 eV in vacuum, which is in remarkable agreement with published gas-phase spectroscopy, as well as our own results of ZnPc in solution with Tetrahydrofuran that are provided in this paper.

ContributorsTheisen, Rebekah (Author) / Huang, Liang (Author) / Fleetham, Tyler (Author) / Adams, James (Author) / Li, Jian (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2015-03-07
Description
In an industrialized world that relies heavily on low cost production and packaging produced without a viable end-of-life strategy, the accumulation of non-biodegradable plastics in the environment and particularly the oceans today is an urgent problem of global proportions. Plastics pose a significant threat to marine mammals due to mistaken

In an industrialized world that relies heavily on low cost production and packaging produced without a viable end-of-life strategy, the accumulation of non-biodegradable plastics in the environment and particularly the oceans today is an urgent problem of global proportions. Plastics pose a significant threat to marine mammals due to mistaken ingestion as well as potential release of plasticizers and other chemicals. However, the interactions and consequences of ingestion of oceanic plastics by marine mammals have not been thoroughly studied. In this literature review, information regarding plastic ingestion by marine mammals was compiled to estimate the magnitude of adverse impacts and identify major knowledge gaps. Using comprehensive Boolean search terms in Web of Science of literature published between 1960 and 2020, it was determined that there were large discrepancies in the amount of research conducted among 10 different categories of marine mammals, with cetaceans being the primary focus group of most studies (70.3). In addition, different areas of the world, such as southern Africa, were found to have a disproportionately small number of studies on plastic impacts on marine mammalian life in their surrounding marine waters. Differences were found in the amount of plastics ingested by marine animals and a hypothesis of explaining these observations was formulated, attributing potential ingestion of plastic to the debris resembling different food sources in the mammals’ diets as well as different feeding mechanisms.
ContributorsFredette-Roman, Cassidy (Author) / Polidoro, Beth (Thesis director) / Rolsky, Charles (Committee member) / Halden, Rolf (Committee member) / School of Life Sciences (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12