Master of Science, University of Akron, 2023, Chemistry

The realm of porphyrin chemistry is thriving and continues to grow as it yields more applications. These macrocycles are highly conjugated dyes, catalysts, active sites, and photosensitizers that possess unique properties. Following the groundwork laid by Latos-Grazynski and Furuta, N-confused tetraphenylporphyrin (NCTPP) and its silver(III) analogue were synthesized. These complexes were characterized via UV-visible spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and magnetic circular dichroism (MCD) spectroscopy. Ag(III)NCTPP exhibits a Soret band around 449 nm and Q bands near 648 nm, 602 nm, 556 nm, and 521 nm. Its MCD spectrum has a positive-to-negative amplitude pattern between 600 nm and 700 nm that inverts upon protonation. The electronic structure was then analyzed and compared to Ziegler and Nemykin's previously synthesized nickel N-confused tetraphenylporphyrin. That complex was deprotonated, and thus exhibited the opposite behavior.

Committee: Christopher Ziegler (Advisor); Aliaksei Boika (Committee Member); Chrys Wesdemiotis (Committee Member) Subjects: Chemistry

Doctor of Philosophy, University of Akron, 2013, Chemistry

Organic photoactive molecules and polymers are gaining much attention due to their potential applications in organic photovoltaic devices and organic electronics. Organic photovoltaic devices suffer from low efficiencies that result from low charge carrier mobilities and short exciton diffusion lengths. To increase the efficiency of organic photovoltaic devices, much of the focus of current research in this field is on panchromic organic molecules, suitable donor-acceptor molecules and self-organized organic semiconductors. Controllable nano-morphologies of donor and acceptor molecules via self-assembly, together with structured interfaces which are important for efficient charge separation and transport, may reduce the problems and yield photovoltaics with much higher efficiencies. Porphyrins are stable, largely planar, aromatic macrocycles, which makes them excellent at forming aggregates by way of pp-interactions. Their aromatic structures and resulting favorable redox and excited state properties, in turn, make them excellent model compounds for the study of photo-induced processes. N-Confused porphyrins are structural isomers of porphyrins which show physical and chemical properties different than that of regular porphyrins. N-Confused porphyrins are interesting molecules due to their structure, reactivity, solvent dependent tautomerization and metal binding properties. This dissertation presents synthetic methods to design new derivatives of porphyrins and N-confused porphyrins to obtain new photophysical properties as well as incorporate these molecules into self-assembled nano-morphologies. Several forms of intermolecular interactions are used in non-covalent syntheses and self assembly, most prominently hydrogen bonding and p-stacking interactions. Porphyrins substituted with peripheral polyalkyl chains have been shown to have liquid crystal properties and usually form columnar mesophases within certain temperature ranges. In the first project o (open full item for complete abstract)

Committee: David Modarelli Dr. (Advisor); Michael Taschner Dr. (Committee Member); Chrys Wesdemiotis Dr. (Committee Member); Matthew Espe Dr. (Committee Member); Kevin Cavicchi Dr. (Committee Member) Subjects: Chemistry; Organic Chemistry

Master of Science (M.S.), University of Dayton, 2012, Chemistry

Coordination of two [Ru(bipy)2Cl]+ moieties (where bipy = 2,2′-bipyridine) to the pyridyl nitrogens in the 5,10-positions of meso-5,10,15-(4-pyridyl)-20-(pentafluorophenyl)porphyrin gives the diruthenium porphyrin complex II. Insertion of copper(II) into the porphyrin center allows for the third pyridyl nitrogen to be coordinated to Pt(dmso)Cl2. Electronic transitions associated with the ruthenium porphyrin include an intense Soret band and four less intense Q-bands in the visible region of the spectrum. An intense π-π* transition in the UV region associated with the bipyridyl groups and a metal to ligand charge transfer (MLCT) band appearing as a shoulder to the Soret band are also observed. A slight blue shift of the Soret band and collapse of the Q-bands into one band is observed upon insertion of Cu(II) into the porphyrin center. No change in the electronic spectrum is observed upon coordination of the Pt(dmso)Cl2 moiety. Electrochemical properties associated with the complexes include a redox couple in the cathodic region attributed to the porphyrin and a redox couple in the anodic region due to the RuIII/II couple. DNA titrations of the complex III and IV indicate that both complexes interact strongly with DNA potentially through a partial intercalation mechanism. Gel electrophoresis studies indicate that complex IV has a greater effect on DNA migration through the gel than the well-known DNA binding agent cis-platin. Irradiation of aqueous solutions of complex III and supercoiled DNA at a 5:1 base pair to complex ratio (in the absence of oxygen) with visible light above 400 nm shows a nicking of the DNA. Repeat experiments in the presence of oxygen show that the complex III photocleaves the DNA, giving the linear form, as evidenced by gel electrophoresis. The cell studies show that the diruthenium porphyrin, complex II, is very toxic to the melanoma cells but appears to be overly toxic to normal cells when irradiated to be a feasible photosensitizer for PDT. (open full item for complete abstract)

Committee: Shawn Swavey (Advisor); Gerald Keil (Committee Member); Kevin Church (Committee Member) Subjects: Chemistry

Doctor of Philosophy, University of Akron, 2010, Polymer Science

Organic materials are part of the 3rd generation photovoltaics which focus on providing cost-effective energy production and ease of use. Moreover, organic materials are easy to process, are chemically flexible, and are easy to handle. One method to overcome an intrinsic disadvantage in organics, small exciton diffusion lengths, is to utilize π-π stacking in aromatic materials. One example is discotic liquid crystals which can self-assemble to form continuous charge conduction pathways. A new series of porphyrin based discotic liquid crystals had been previously synthesized and had shown photovoltaic efficiencies of 0.7%. This was very high for a potentially unaligned discotic phase. To understand the reason for this, the structure and morphology of these materials was characterized using DSC, WAXD, SAED and PLM amongst other techniques. The alignment of discotic liquid crystals has been problematic in the past due to their high viscosities. Only thermal gradient alignment and magnetic field alignment proved successful in large scale orientation of these materials. This series showed a stable liquid crystalline phase at room temperature and also a metastable solvent induced crystal phase. The peripheral n-alkyl chain length was varied from C8 to C12. The liquid crystalline phase for all samples showed a ribbon-like morphology. WAXD showed a hexagonally packed columnar structure with significant helical ordering within the columns. A coiled coil structure has been proposed as the only possible structure. This stable Col*hh phase was seen in all the samples. This work is the first observed evidence of a coiled coil structure for an achiral discotic liquid crystal. This would indicate that discotic columnar systems mimic biological systems where coiled coils are found commonly. Sample QE12C also showed a unique undulating morphology. To understand the morphology the n-C14 alkyl chain length molecule was investigated. Characterization showed that the undulating phase (open full item for complete abstract)

Committee: Stephen Cheng Dr. (Advisor); Mark Foster PhD (Committee Chair); Dhinojwala Ali PhD (Committee Member); Carri Gustavo PhD (Committee Member); Pang Yi PhD (Committee Member) Subjects: Materials Science; Physics; Polymers

Doctor of Philosophy, University of Akron, 2006, Chemistry

In order to understand and mimic the processes that occur in photosynthesis, the photophysical properties of a series of porphyrinic molecules have been investigated. N-Confused tetraphenylporphyrin (NCTPP) differs from tetraphenylporphyrin (H2TPP) by having one of the pyrrolic nitrogens inverted and facing outside the macrocycle, with a C-H group inside. The inverted pyrrole ring in NCTPP results in a change in the pi-system of the macrocycle, leading to photophysical properties that are different than those of H2TPP. The first project was intended to investigate the photophysical properties of the two NCTPP tautomers, as well as several substituted (di- and tetra-) NCTPP derivatives using several spectroscopic techniques, including steadystate absorption and emission spectroscopy, time correlated single photon counting, femtosecond transient absorption and nanosecond transient absorption spectroscopy. The second project consisted of the studies the photophysical characterization of pentameric N-confused porphyrin-zinc tetraphenylporphyrin artificial light-harvesting array (NCP-ZnP4), the photophysical properties of an N-confused-pyromellitimide array (NCP-Pym4), and the photophysical characterization of an N-confused porphyrin-pyrene donor acceptor dyad (NCP-Pyr). The supramolecular systems NCP-ZnP4, NCP-Pym4 and NCP-Pyr represent the first structures where an N-confused porphyrin has been covalently incorporated into an array designed to involve highly efficient photoinduced energy and electron transfer processes. Free base corroles differ from free base porphyrin by having one of meso methine carbons replaced by a direct pyrrolepyrrole linkage. The fourth project in this dissertation involved the photophysical characterization of four free base triphenylcorroles using steady state absorption and emission spectroscopy, and time correlated single photon counting experiments. The photophysical results indicate that similar to NCTPP, there is noticeable solvent depe (open full item for complete abstract)

Committee: David Modarelli (Advisor) Subjects: Chemistry, Physical

Doctor of Philosophy, University of Akron, 2006, Chemistry

Two high resolution single X-ray crystal structures of meso-substituted free-base corroles are presented: 5,10,15-triphenylcorrole and 5,10,15-tris(pentafluorophenyl)corrole. The internal NH protons are clearly assignable to different nitrogens, which represents the two tautomer limits of corrole. Four free-base corroles with electron-donating or electron withdrawing groups on the para or 2 through 6-positions of the meso phenyl rings were prepared via either Paolesse or Gross conditions and investigated for their absorption and emission properties. Absorption, steady-state, and time resolved fluorescence measurements were performed on all compounds in both nonpolar (dichloromethane) and polar (dimethylacetamide) solvents. The experimental evidence points to hydrogen bonding with an internal N-H group as the most likely factor in the solvent dependent photophysical behavior of these corroles, that is also highly dependent upon substitution. An improved methodology for the N-alkylation of the porphyrin isomer N-confused porphyrin is presented. The combination of polar solvent conditions and the use of the base Cs2CO3 afford externally modified products in high yield without separation difficulties and without the use of large excesses of alkylating reagent. The further transformation and metalation of these products provides opportunities for the construction of metalloenzyme model complexes, peptide adducts, and chromophore assemblies. Using the same strategy, a pyrene can be covalently attached via the external nitrogen of N-confused porphyrin. Absorption, calculation and steady-state measurement were performed on the compound. Calculation indicate a open fashion comformation favored, and the fluorescence of pyrene was turned off, probably due to an energy transfer to N-confused moiety. However, further experiments need to be done to fully understand the interaction between the two moieties. By growing crystals in the presence of an excess of a carboxylate modified (open full item for complete abstract)

Committee: Christopher Ziegler (Advisor) Subjects: Chemistry, Inorganic

Master of Science, University of Akron, 2005, Chemistry

The photophysical properties of both the interior and exterior protonated tautomers of N-confused tetraphenylporphyrin (NCTPP) in coordinating and non-coordinating solvents were investigated using UV-visible absorption spectroscopy and fluorescence spectroscopy. In addition, a series of zinc N-confused tetraphenylporphyrins (Zn(NCTPP)) with a ligand coordinated at the axial site were synthesized from the methods of Girolami, Rauchfuss, and Angelici, and crystallized via slow solvent diffusion. The series includes Zn4 (NCTPP)2 (O2CCH3)3(OH), Zn(NCTPP)(DMSO), and Zn(NCTPP)(Pyridine). The objectives of this research were to probe the reasons normal tetrapyrroles are the macrocycle of choice in biological systems, metallate NCTPP with biologically relevant transition metals, coordinate derivatives of biological ligands to the metal center, and characterize the resultant compounds. We found that Zn4(NCTPP)2(O2CCH3)3(OH) is a model compound for the zinc-dependent aminopeptidase in Aeromonas proteolytica.

Committee: Christopher Ziegler (Advisor) Subjects: Chemistry, Inorganic

PhD, University of Cincinnati, 2022, Engineering and Applied Science: Materials Science

Over the years, it has become apparent that renewable radiation has the highest potential as a form of energy. Since incident photons may produce energy, one of the best renewable power collecting applications is photovoltaic. However, there are still obstacles such as efficiency reduction caused by the heat generated. Another energy saving concern is the severe energy loss of the residential and commercial buildings through window. The SHIELD initiative, which is supported by a department of energy agency in the US, advocates substituting multiple pane windows with single-pane windows for cost- and energy-effectiveness. By depositing PT substances on one side of the glass, we are able to raise the temperature of the panel itself and achieve energy balance on both sides of the glass, a performance innovative solution by our innovation strategy of visible transparent thermal isolation. Photothermal material (PT) should be wavelength tunable with high visible transparency and highly absorptive to ultraviolet and infrared spectrum bands. Iron oxide nanoparticles and iron oxide coated by copper sulfide nanoparticles will be studied in both solid and liquid systems. We will employ single wavelength light and AM 1.5 to investigate the PT characteristics of Fe3O4 with polymer coatings and Fe3O4@Cu2-xS with polymer coatings on the glass substrates. The PT mechanisms will be identified based on the thin coating's localized surface plasmon resonance (LSPR) effect and Mie theory. Wavelength tunable materials as thin coatings will be designed, synthesized, and deposited on various transparent substrates. Without the use of any extra thermal isolations, such PT coatings will raise the surface temperature of the glass and significantly lower the U of single pane windowpanes. In this way, a wavelength-tunable, transparent PT coating offers a possible option for the Department of Energy's SHIELD program. In our study, PT materials as thin film coatings will be irradiated by (open full item for complete abstract)

Committee: Donglu Shi Ph.D. (Committee Member); Jing Shi Ph.D. (Committee Member); Vesselin Shanov Ph.D. (Committee Member); Woo Kyun Kim Ph.D. (Committee Member) Subjects: Materials Science

Master of Science, The Ohio State University, 2021, Biomedical Engineering

Monitoring oxygenation in vivo is critical to ensuring proper health, especially within the context of the global pandemic. Utilizing blends of biodegradable polycaprolactone (PCL) and gelatin, and an already established oxygen-sensitive porphyrin, Pd-MABP, implantable, biodegradable, electrospun oxygen sensors were created and developed. Stable and accurate sensors, with linear Stern-Volmer behavior were created and identified via multiple in vitro tests ranging from one to three months in length. Electrospun sensors successfully and accurately measured oxygen concentrations within this in vitro environment. To increase porphyrin retention within the electrospun matrix, functionalization of PCL was utilized. PCL was aminated utilizing sodium hydride activated hexamethylenediamine (HMD). Pd-MABP was then covalently linked to the amine group using the well-established EDC crosslinking, resulting in “C-PCL.” C-PCL sensors displayed similar sensitivity to oxygen in vitro with significantly higher phosphorescent lifetimes compared to the original sensors. Oxygen sensors were electrospun and directly integrated into existing injection equipment (Profusa Inc.), for in vivo use. These sensors proved to be detectable through equine skin. Finally, increases in [Pd-MABP] were shown to increase the signal-to-noise ratio and thus the depth of injection detectability.

Committee: John Lannutti (Advisor); Derek Hansford (Committee Member) Subjects: Biomedical Engineering; Materials Science

Doctor of Philosophy, University of Akron, 2020, Chemistry

The great potential for the myriad applications of porphyrin-based nanostructures with different morphologies originates from the idea that porphyrins have highly tunable photophysical and photochemical properties. Potential applications of these types of materials include catalysis, molecular sensing, and energy conversion and storage, all of which depend on the electronic structures and morphologies of porphyrin nanoassemblies. These properties are in turn governed by peripheral substituents of the porphyrin ring, central metal ion or solvent. However, the self-assembly into various morphologies is challenging, and has attracted significant recent attention. The self-assembly of porphyrins using non-covalent interactions such as π-π stacking, electrostatic interactions and hydrogen bonding into well-defined supramolecular nanostructures represents an attractive alternative from classic synthetic approaches toward generating highly ordered nanostructures. In this dissertation, the synthesis and characterization of the self-assembled structure(s) of a porphyrin bearing guanidinium salts 1 (5,15-bis(4-guanidiniumphenyl)-10,20-diphenylporphyrin) in the presence of pyrophosphate (PPi), adenosine diphosphate (ADP) and adenosine triphosphate (ATP) in MeOH and H2O was studied. The electrostatic attraction of the phosphate anions and the positive guanidinium salts, as well as π-stacking interactions between porphyrin chromophores is suggested to drive the self-assembly into the formation of nanorods, nanofibers, and nanosheets. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) results reveal the formation of nanorods with length from 266 nm and diameters of 11.3 - 22.5 nm and nanosheets that ~0.354 – 0.537 μm wide. Spectroscopically, the absorption spectra of porphyrin 1 in 1:1 MeOH/H2O solution with increasing concentrations of the phosphates resulted in the decrease and broadening in the Soret band centered at 415 nm, as well as the growth of a (open full item for complete abstract)

Committee: David Modarelli (Advisor); Tessier Claire (Committee Member); Chrys Wesdemiotis (Committee Member); Youngs Wiley (Committee Member); Yu Zhu (Committee Member) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2018, Materials Science and Engineering

Incorporation of luminescent oxygen-sensitive molecules into electrospun polymeric nanofibers can create a sensor with linear Stern-Volmer behavior and a rapid response time. This overcomes several issues associated with traditional polymer film-based sensors. Nevertheless, disadvantages remain that could limit use in biological applications: photobleaching, excitation wavelengths that poorly penetrate tissue and difficulties associated with delivery. This work attempts to address each of these issues. Systematic studies on long-term photobleaching have examined the effect of specific parameters (i.e., electrospinning solvent, porphyrin content) on decreases in sensor brightness and oxygen sensitivity. While ultraviolet and visible excitation wavelengths exhibit poor tissue penetration, near-infrared (NIR) light much more easily penetrates tissue due to decreased scattering and absorbance by tissue chromophores. The ability to achieve NIR-activated oxygen sensing in electrospun bilayer and core-shell nanofibers has been demonstrated by using upconverting particles to locally stimulate oxygen-sensitive molecules. Finally, concerns associated with delivery have been addressed by utilizing the same sensing components in the form of polymeric core-shell particles.

Committee: John Lannutti (Advisor); Heather Powell (Committee Member); Jinwoo Hwang (Committee Member) Subjects: Engineering; Materials Science

Master of Science, The Ohio State University, 2017, Chemistry

Biodegradable polymers made from renewable resources are a promising alternative to oil based materials and are increasing in popularity due to the decreasing quantity and increasing costs of fossil fuel sources. Polylactide is a useful polymer that is biodegradable and made from renewable starting materials and can be used in a wide variety of applications ranging from medical sutures to food packaging. Polylactide was produced from racemic lactide via a tetraphenylporphyrin aluminum (III) catalyst along with PPNCl and propylene oxide as solvent. The resulting polymer was highly isotactically enriched and contained the end group -OCHMeCH2Cl. When tetrahydrofuran is used as solvent no polymer is produced, and when no lactide is present polypropylene oxide is formed. Backbiting reactions lead to cyclic PLA and 6 membered lactone side products when heated. Other metal centers such as Co and Ga also gave polylactide, however the reactivity was different than with the use of an aluminum center. The results of this study indicate that Al(III) acts as a Lewis acid in the ring opening of PO by the chloride ion. The resulting ClCH2CHMeO- then proceeds to perform the ring opening of lactide, which continues to open other lactide molecules eventually leading to PLA with the end group -OCHMeCH2Cl. The polymer was isolated by the addition of acidic methanol and analyzed by mass spectrometry and NMR spectroscopy. Self-assembly is an important process responsible for the formation of many structures found throughout natural systems such as cellular structures, proteins, DNA, and crystals. These types of structures often serve as the inspiration for designing synthetic systems capable of self-assembly. Many self-assembled systems have been reported for applications such as drug delivery, electronics, and chemical sensors. The sum of multiple noncovalent interactions such as hydrogen bonding and p-p stacking are responsible for creating stable self-assembled systems. Stimuli (open full item for complete abstract)

Committee: Jonathan Parquette (Advisor); Psaras McGrier (Committee Member) Subjects: Chemistry

Master of Science, University of Akron, 2017, Polymer Science

A series of precisely defined A-Cn -4B type shape amphiphilic giant molecule has been designed and synthesized by connecting one porphyrin as a core with four hydrophobic T8 polyhedral oligomeric silsesquioxane (BPOSS that represent all isobutyl groups functionalized POSS) via alkyl chain(n= 0,1,10). Here, porphyrin can afford powerful pi- pi interaction, meanwhile variation of the length linker such as zero, one, ten carbon atoms offering mobility during self-assembling, and furthermore bulky BPOSS nanoparticles could form the periphery of the giant molecule to introduce steric hinderer and hydrophobic interactions. With synergistic interactions from porphyrin, different linker length and bulky POSS nanoparticles, various supramolecular structures are expected to be formed. Here, shape amphiphilic giant molecules are designed and synthesized, to research on the influence of the linker length on the final supramolecular structures and the corresponding formation mechanism to form Frank-Kasper phases

Committee: Toshikazu Miyoshi (Advisor); Stephen Z.D. Cheng (Committee Member) Subjects: Organic Chemistry; Polymer Chemistry

Master of Science, Miami University, 2016, Chemistry and Biochemistry

This thesis is comprised of four chapters: Chapter zero gives a brief introduction and points to the importance of this work. Chapter one includes an introduction to Signal Transducer and Activator of Transcription 3 proteins and its activation in cancerous cells. Various inhibitors have been synthesized and will be tested in due course for their biological activity. The design and synthesis of these inhibitors derived from readily available and inexpensive starting materials are summarized in hopeful pursuit to attaining possible building blocks for anti-cancer drugs. Chapter two includes an introduction to highly aromatic and intensely absorbing heterocyclic macrocycles known as porphyrins. Synthesis of π-extended tetraphenylporphyrins with styrene derivatives from their β-β' positions using a concise three-step method is summarized. The successful synthesis of free base mono- and dibenzotetraphenylporphyrins is described using a dual catalyst system. These molecules are obtained with the hope that they can be applied in various areas such as molecular electronics and nanotechnology. Chapter three includes a summarization of this work and describes possible future work that will be carried out with results obtained from the two individual projects.

Committee: Dominik Konkolewicz (Committee Chair); Hong Wang (Advisor); Scott Hartley (Committee Member); Rick Page (Committee Member) Subjects: Chemistry; Organic Chemistry

Doctor of Philosophy, The Ohio State University, 2016, Chemistry

Self-Assembly in nature has demonstrated how functionalized supramolecular architecture from mesoscopic to nanoscale dimension can express its functional characteristics found in enzyme, cell membrane and photosynthetic system via non-covalent interactions. This process provides a convenient, albeit often empirical strategy, to fabricate materials in the nanoscale regime where these properties are present. Non-covalent interactions between multiple components within the assembled system affect its chemical and physical properties, which attributes to modulation of size, shape, and internal/external surface of the assembled structures. While it is often difficult to completely mimic the complex and dynamic biological systems, such as microtubules and actin filament, which are constantly dependent on ATP for energy to sustain their structure, building controllable supramolecular nanoassemblies can serve as a preliminary step towards dynamic, stimuli responsive system. This system can reversibly undergoes structural reorganization into different state of thermodynamically stable nanostructures in respond to changes in chemical and physical environment triggered by external stimuli such as light, sound, chemical and electric field. These responsive features in the supramolecular assemblies can be exploited towards development of intelligent materials in optoelectronics , catalysis, drug delivery and tissue-engineering. In this study, our group explores various strategies to build controllable self-assembly system: 1) Functionalized amino acids via chemical modification for molecular building block. In this study, we employed a bottom-up approach previously developed by our group to synthesize peptide based building blocks appended with functionalize chromophore to assemble via non covalent interactions such as p-p interaction, electrostatic, hydrophobic and intermolecular hydrogen-bonding interactions. While these interactions are relatively weak (Table 1), cumulativ (open full item for complete abstract)

Committee: Jonathon Parquette (Advisor); Jovica Badjic (Committee Member); Psaras Mcgrier (Committee Member); Linda Parsons (Committee Member) Subjects: Chemistry

Master of Science (M.S.), University of Dayton, 2014, Bioengineering

A novel di-runthenated porphyrin has been synthesized that is capable of photocleaving plasmid DNA within the photodynamic therapy window of 600-800nm. The desired porphyrin was synthesized through reaction of 4-pyridine carboxaldehyde, 4-trifuorlomethyl benzaldehyde and pyrrole under reflux in propionic acid and isolated through column chromatography using methylene chloride/methanol as the eluent. Coordination of cis-Ru(bipy)2Cl2 moieties was achieved through reflux under nitrogen in glacial acetic acid to give the bis-Ru(bipy)2Cl]2[5,15-(4-pyridyl)-10,20-(p-trifluoromethylphenyl)-porphyrin. UV-Vis spectra of the porphyrin and its ruthenated analog revealed an intense Soret band at 410 nm and Q-bands at 500 and 650nm. Cyclic voltammetry was used to determine the oxidative and reductive characteristics of the porphyrin and its ruthenated analog. DNA titrations using buffered solutions of the ruthenated porphyrin and calf thymus DNA were performed spectrophotometrically. The binding constant of the ruthenated porphyrin was determined to be 1.30 x 106 M-1. The ability of the ruthenated porphyrin to photocleave DNA was evaluated by irradiating aqueous samples of plasmid DNA and the complex at a ratio of 5 base pairs to 1 complex using a mercury arc lamp with a 500nm filter. Use of the 500nm filter allowed for observation of the photodynamic therapy window of 600-800nm. Samples were taken at 5 minute intervals and compared using gel electrophoresis to confirm the formation of the photocleaved nicked form of the plasmid DNA.

Committee: Shawn Swavey (Advisor); Doug Dudis (Committee Member); Robert Wilkens (Committee Member); Donald Comfort (Committee Member) Subjects: Chemistry; Inorganic Chemistry

Master of Science (M.S.), University of Dayton, 2013, Chemistry

The aggregation of three charged water soluble porphyrins, meso-Tetra(4-sulfonatophenyl)porphine (TPPS), meso-trans-di(N-methyl-4-pyridyl)diphenyl porphine (trans DmPyDPP) and meso-cis-di(N-methyl-4-pyridyl)diphenyl porphine (cis DmPyDPP) on Poly-L-Glutamate (poly-L-Glu) and Poly-D-Glutamate (poly-D-Glu) was studied. Then, the self-assembling supramolecular structures of two pairs of oppositely charged porphyrins were investigated in the presence of the chiral templates. These pairs include TPPS and trans DmPyDPP as well as TPPS and cis DmPyDPP. The structures were characterized using UV-Vis and circular dichroism spectroscopies. The presence of a chiral template during the aggregation of TPPS and trans DmPyDPP or TPPS and cis DmPyDPP should induce chirality on the hetero-aggregate, making it detectable by circular dichroism spectroscopy. The induced chirality of these supramolecular structures was found to depend upon the order of addition, the pH of the solution, the ionic strength and the chirality of the chiral template. The TPPS was able to aggregate with the templates in two different forms- the "wrapping type" and the "pending type". The trans DmPyDPP was found to aggregate with both the random coil structures of poly-L-Glu and poly-D-Glu at pH 7 and the a-helix structure of the templates at lower pHs. The cis DmPyDPP was also able to aggregate with the random coil poly-L-Glu at pH 7.0; however, the porphryin did not aggregate with the a-helix structure of the poly-L-Glu or with either structure of the poly-D-Glu. In a system with both TPPS and trans DmPyDPP, the positively charged porphyrin is able to bridge two adjacent finger-like TPPS J-aggregates due to the position of the positive charges on opposite sides of the molecule when TPPS was added first. This geometry allows the trans DmPyDPP to reorganize dynamically as the polymer changes conformation due to a change in pH. This makes trans DmPyDPP a promising candidate for a biosensor for random coil (open full item for complete abstract)

Committee: Angela Mammana Ph.D. (Advisor); Matthew Lopper Ph.D. (Committee Member); Shawn Swavey Ph.D. (Committee Member) Subjects: Chemistry

Master of Science, University of Toledo, 2008, Chemistry

This work presents the results of UV-Visible absorption and Resonance Raman spectroscopic studies of three different heme complexes. (DMSO)2Fe(II)TPP (1) and (TMSO)2Fe(II)TPP (2) were studied in neat DMSO (dimethylsulfoxide) and neat TMSO (tetramethylene sulfoxide), respectively. A third heme complex, (PSO)2Fe(II)TPP (3), required a binary solvent of benzene and PSO (phenyl sulfoxide) in order to be created and studied. Both (1) and (2) were studied in the same binary solvent as well. The investigation determined that all three complexes behave similarly in relation to their UV-VIS and resonance Raman spectra. Resonance Raman experiments at low incident laser power have shown that (1), (2), and (3) exhibit the properties of a 6-coordinate, low-spin complex in the binary solvent. (1) and (2) exhibit the same properties in neat solvent. The UV-visible absorption data also provides evidence for the presence of a 6-coordinate low-spin complex for all three species in the ground state. The UV-VIS data for (2) and (3) shows a 4 and 5 nm red-shift, respectively, in their Soret bands as compared to (1) in the binary solvent. (2) displays a 3 nm red-shift in its Soret band as compared to (1) in neat solvent. These shifts are attributed to the different sulfoxide ligands bound to the iron center. For all three complexes, at high laser power, photolysis of an axial ligand occurs and a transient 5-coordinate, high-spin photoproduct is created. This transient photoproduct has a core-size of 2.05 Angstroms and 2.04 Angstroms for (1) and (2) in neat solvent. In binary solvent, the transient photoproducts for (1), (2), and (3) all possessed a calculated core-size of 2.05 Angstroms. The resonance Raman data provides evidence that the sulfoxides studied are moderate sigma-donors and pi-acceptors when compared to nitrogenous ligands such as imidazole and pyridine. However, there is no evidence in the resonance Raman data to distinguish among the three sulfoxides the strongest pi-a (open full item for complete abstract)

Committee: Eric Findsen PhD (Advisor); Mark Mason PhD (Committee Member); Xiche Hu PhD (Committee Member) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2012, Chemistry

In the modern era the production of chemicals from sustainable natural resources as an alternative to petrochemicals is an absolute necessity. Among the major commodity polymers, potential candidates for synthesis from renewable natural resources are polyesters and polycarbonates. A series of porphyrin metal (III) compounds of general formula LMX (L = tetraphenylporphyrin (TPP), octaethylporphyrin (OEP), tetrakispentafluorophenylporphyrin (TFPP), M = aluminum, chromium, cobalt, X = Cl, OEt (for Al); Cl, OAc, OH (for Cr); Cl, OAc (for Co)) has been synthesized and used as catalysts to produce polypropylene carbonate and propylene carbonate. These catalysts are further investigated for the copolymerization of propylene oxide with succinic anhydride (SA) or phthalic anhydride (PA) to produce polypropylene succinate and polypropylene phthalate. The metal catalyzed copolymerization process provides an alternative “greener” synthetic route to the preparation of these polymers using renewable feedstocks e.g. CO2 and succinic acid. The electronic nature of the porphyrin ligand, the choice of metal center and the addition of Lewis basic cocatalysts e.g. DMAP or PPN+Cl- showed dramatic influence on the catalytic TOF, product selectivity and polymer quality. Detailed kinetic and mechanistic investigations were carried out to elucidate the nature of various reactive intermediates i.e. M-alkoxide, M-carbonate and M-carboxylates, involved in the polymerization processes. These comparative analyses show how the electronic environment around the metal center and the binding of added Lewis base cocatalysts influence the reactivity of the various metal-oxygenate intermediates, and thereby control the individual reaction steps and equilibria involved in the polymerization processes.

Committee: Malcolm Chisholm Dr. (Advisor); Jon Parquette Dr. (Committee Member); Jovica Badjic Dr. (Committee Chair) Subjects: Chemistry

Master of Science, The Ohio State University, 2011, Chemistry

A dynamic host for studying molecular recognition and encapsulation has been developed by our research group and named molecular basket. The focus of my thesis work was the synthesis and characterization of precursors for molecular baskets capable of promoting chemical reactions. This supramolecular host/catalyst has sizable cavity (570 A) and catalytic center (Mn(III)) embedded inside for promoting the oxidation of alkenes. The basket is, in particular, made of a flat porphyrin base, with four phthalimide-like arms which can be functionalized by condensation with an amine to give dynamic host. The hypothesis of this research program is based on the notion that the gating of the substrates entering and exiting the catalyst will have an effect in the reaction's outcome. The head-to-tail tetramerization of enantiopure carbinols gave cup-shaped compound with all four “walls” in the same direction. The initial synthesis of the intermediates had several drawbacks for the large scale preparation. It required some expensive reagents, the resolution of enantiopure compounds was elaborate, and some of the late steps in the synthetic route were low yielding. This thesis describes the optimization of synthetic steps and characterization of new compounds by NMR spectroscopy and high resolution mass spectrometry.

Committee: Jovica Badjic Dr (Advisor); Johnatan Parquette Dr (Committee Member) Subjects: Chemistry