{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/86671"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/86671","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"The Synthesis and Characterization of Organometallic and Inorganic Manganese and Iron Complexes; Probing Structural and Electronic Effects on Reactivity","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Cannella, Anthony; 0000-0001-6519-2443"],"institution":"State University of New York at Buffalo","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Lacy, David","Chemistry"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-02-21T21:36:17Z","date_published":"2025-02-21T21:36:17Z","updated_at":"2026-07-27T19:05:34Z","subjects":["chemistry"],"languages":["eng"],"rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10477/86671","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lacy, David","Chemistry"]},{"key":"dc:creator","label":"Author","values":["Cannella, Anthony; 0000-0001-6519-2443"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-02-21T21:36:17Z","2020"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Text","Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/10477/86671"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","Traditionally nature has used complex enzymes with ionic and paramagnetic centers to accomplish tasks like the activation of molecular oxygen and water splitting. Replicating these processes with biomimetic organometallic and inorganic metal complexes has been of interest to the scientific community for at least a century. This dissertation details the work towards this goal using manganese and iron complexes with varying structural and electronic properties to investigate the effect these perturbations have on reactivity. Early work by the author sought to synthesize a fully organometallic manganese-oxo heterocubane using cyclopentadienide as an ancillary ligand. While no cubane was ever synthesized, these experiments lead to a fundamental understanding of the nature between the manganese(II) center and the Cp ring slip in bis(cyclopentadienide) manganese(II). This work serves as the focus of Chapter 2. In Chapter 3, the focus of this work shifted to the synthesis of the biomimetic 2,2',2''-nitrilotris(N-arylacetamide) manganese(II) complexes with various R groups (R = NO2, Cl, Br, H, and OMe) on the para position of the aryl ring. These complexes were synthesized as bis(tetramethyl ammonium) salts and had axial acetate ligands. The NTANO2 variant of the ligand afforded the best crystals for diffraction and the structural details of the newly synthesized manganese and cobalt variants were compared to those of the previously synthesized iron and zinc variants. This led to the conclusion that the structural differences between these complexes is most likely due to the ionic crystal radii of the metal center and not the electronic effect of the ligand. The electrochemical studies also confirmed the lability of the acetate ligand, which was consistent with a previous work by the lab. These complexes demonstrated a liner free energy relationship via the construction of a Hammett plot between the electrochemical reduction potential and the electronic effect of the para substituent on the aryl ring. This relationship was also demonstrated for the previously synthesized iron(II) 2,2',2''-nitrilotris(N-arylacetamide) complexes with R = NO2, F, Et, and OMe. Finally, we sought to determine the nature of the mechanism by which iron NTAR reduces molecular oxygen. The two possible mechanisms for O2 reduction are inner sphere electron transfer and outer sphere electron transfer. The inner sphere mechanism is biologically relevant while the outer sphere mechanism is not. We proposed that our complexes follow the outer sphere mechanism which can be modeled by the Marcus cross relation. The focus of Chapter 4 was to determine the self-exchange rate constant of the iron complexes. In order for self-exchange occur the free energy of the system must be zero. Practically, this means that the two species are redox partners. It was determined that the dimeric species that forms as the product of the reaction between the iron NTAR complex and O2 was not a redox partner to the iron(II) monomer. Due to the lability of the acetate ligand in solution we attempted the synthesis of iron NTAR complexes with different axial ligands (X = NCS , CN , OH , Br , and Cl ) and only the NCS compounds were isolable. We also synthesized the potassium salts of the iron NTAR complexes which have an axial DMA ligand, which was confirmed via NMR spectroscopy. All of these iron NTAR compounds were unstable when oxidized and free ligand was formed instead of an iron(III) redox partner. Therefore, we synthesized a known iron(II/III) redox pair with a similar trisurea ligand. The self-exchange rate constant was determined via NMR spectroscopy to be 6.26 x 103 ± 1.39 x 102 M-1 s-1. This led to the calculation of the rate constant for the reduction of O2 via the MCR to be 1.49 M-1 s-1. This value is close to the experimentally determined value of 0.4 M-1 s-1 and we can conclude that the iron NTAR system reduces O2 via an outer sphere mechanism.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The Synthesis and Characterization of Organometallic and Inorganic Manganese and Iron Complexes; Probing Structural and Electronic Effects on Reactivity"]}]}],"canonical_facts":{"dc:contributor":["Lacy, David","Chemistry"],"dc:creator":["Cannella, Anthony; 0000-0001-6519-2443"],"dc:date":["2025-02-21T21:36:17Z","2020"],"dc:description":["Ph.D.","Traditionally nature has used complex enzymes with ionic and paramagnetic centers to accomplish tasks like the activation of molecular oxygen and water splitting. Replicating these processes with biomimetic organometallic and inorganic metal complexes has been of interest to the scientific community for at least a century. This dissertation details the work towards this goal using manganese and iron complexes with varying structural and electronic properties to investigate the effect these perturbations have on reactivity. Early work by the author sought to synthesize a fully organometallic manganese-oxo heterocubane using cyclopentadienide as an ancillary ligand. While no cubane was ever synthesized, these experiments lead to a fundamental understanding of the nature between the manganese(II) center and the Cp ring slip in bis(cyclopentadienide) manganese(II). This work serves as the focus of Chapter 2. In Chapter 3, the focus of this work shifted to the synthesis of the biomimetic 2,2',2''-nitrilotris(N-arylacetamide) manganese(II) complexes with various R groups (R = NO2, Cl, Br, H, and OMe) on the para position of the aryl ring. These complexes were synthesized as bis(tetramethyl ammonium) salts and had axial acetate ligands. The NTANO2 variant of the ligand afforded the best crystals for diffraction and the structural details of the newly synthesized manganese and cobalt variants were compared to those of the previously synthesized iron and zinc variants. This led to the conclusion that the structural differences between these complexes is most likely due to the ionic crystal radii of the metal center and not the electronic effect of the ligand. The electrochemical studies also confirmed the lability of the acetate ligand, which was consistent with a previous work by the lab. These complexes demonstrated a liner free energy relationship via the construction of a Hammett plot between the electrochemical reduction potential and the electronic effect of the para substituent on the aryl ring. This relationship was also demonstrated for the previously synthesized iron(II) 2,2',2''-nitrilotris(N-arylacetamide) complexes with R = NO2, F, Et, and OMe. Finally, we sought to determine the nature of the mechanism by which iron NTAR reduces molecular oxygen. The two possible mechanisms for O2 reduction are inner sphere electron transfer and outer sphere electron transfer. The inner sphere mechanism is biologically relevant while the outer sphere mechanism is not. We proposed that our complexes follow the outer sphere mechanism which can be modeled by the Marcus cross relation. The focus of Chapter 4 was to determine the self-exchange rate constant of the iron complexes. In order for self-exchange occur the free energy of the system must be zero. Practically, this means that the two species are redox partners. It was determined that the dimeric species that forms as the product of the reaction between the iron NTAR complex and O2 was not a redox partner to the iron(II) monomer. Due to the lability of the acetate ligand in solution we attempted the synthesis of iron NTAR complexes with different axial ligands (X = NCS , CN , OH , Br , and Cl ) and only the NCS compounds were isolable. We also synthesized the potassium salts of the iron NTAR complexes which have an axial DMA ligand, which was confirmed via NMR spectroscopy. All of these iron NTAR compounds were unstable when oxidized and free ligand was formed instead of an iron(III) redox partner. Therefore, we synthesized a known iron(II/III) redox pair with a similar trisurea ligand. The self-exchange rate constant was determined via NMR spectroscopy to be 6.26 x 103 ± 1.39 x 102 M-1 s-1. This led to the calculation of the rate constant for the reduction of O2 via the MCR to be 1.49 M-1 s-1. This value is close to the experimentally determined value of 0.4 M-1 s-1 and we can conclude that the iron NTAR system reduces O2 via an outer sphere mechanism.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/86671"],"dc:language":["eng"],"dc:publisher":["State University of New York at Buffalo"],"dc:rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"dc:subject":["chemistry"],"dc:title":["The Synthesis and Characterization of Organometallic and Inorganic Manganese and Iron Complexes; Probing Structural and Electronic Effects on Reactivity"],"dc:type":["Text","Dissertation"]},"updated_at":"2026-07-27T19:05:34Z"}