In this study, undergraduate student attitudes towards organic chemistry and the influences that shape those attitudes were explored using the Attitudes Towards Organic Chemistry Instrument (ATOC) to collect both qualitative and quantitative data. The findings from the qualitative ATOC items provide evidence that students displayed a wide range of attitudes towards organic chemistry, including positive, negative, neutral, and blended attitudes. Five major influences were shown to have shaped these attitudes including the reputation of the course, students' educators, experiences with organic chemistry, experiences with introductory chemistry, and individual experiences. Students responses longitudinally provide evidence that their influences and attitudes change over time in the course. The findings from the quantitative ATOC items provided evidence that the data generated was valid and reliable, and a relationship was found to exist between what students think and what they had heard about the course. Limitations of this investigation, as well as implications for research and practitioners, are discussed.

The use of enamines continues to be an important tool in organic syntheses as both a catalyst and reactant. The addition of metal catalysts coupled with enamine catalysis has generated many reactions that normally would not occur separately. However, catalysts' incompatibility is an issue that we wish to solve allowing new chemistry to occur without hindrance. The use of enamines has continued to be a well-studied area of organic chemistry, but the field is ripe for different types of enamines to gain the spotlight. Enaminones are enamines with both nucleophilic and electrophilic properties. They allow reactions that are normally not possible with enamines to become obtainable. Chapter 1 is a brief introduction on enamines and the reason they gained so much attention. Then ends with enaminones and what makes them interesting reactants. Chapter 2 described a new synthesis for the tricyclic synthesis of chromanes using a novel bifunctional catalyst system of enamine-metal Lewis acid giving great yields (up to 87 %yield) and excellent stereoselectivity (up to 99 % ee). Chapter 3 covered new reactions for ring-open cyclopropane (up to 94% yield), tetrahydroquinolinones (up to 84% yield) and enantiospecific tetrahydroquinolinones (up to 84% yield and 97% ee) using α-enaminone and donor-acceptor …

As countries pledge their commitment to a net-zero future, much of the previously forgotten climate change research were revitalized by efforts from both governmental and private sectors. In particular, the utilization of lignocellulosic materials saw a special spotlight in research interest for its abundance and its carbon removal capability during photosynthesis. The initial effort in mimicking enzymatic active sites of β-glucosidase will be explored. The crystalline covalent organic frameworks (COFs) allowed for the introduction of a variety of noncovalent interactions, which enhanced the adsorption and the catalytic activity against cellobiose and its glycosidic bonds. The physical processes associated with this reaction, such as the kinetics, equilibrium, and activation energies, will be closely examined and compared with existing standard materials and comparable advanced catalysts. In addition, several variants of COFs were synthesized to explore the effect of various noncovalent interactions with cellobiose. A radical-bearing COF was synthesized and characterized. The stability of this radical was examined by electron paramagnetic resonance spectroscopy (EPR) and its oxidative capability tested with model lignin and alcoholic compounds. The reaction products are monitored and identified using gas chromatography-mass spectroscopy (GC-MS). An oxidative coupling of phenol was explored, and its initial results are presented in chapter 5.

The gas phase reactions of atomic chlorine with hydrogen sulfide, ammonia, benzene, and ethylene are investigated using the laser flash photolysis / resonance fluorescence experimental technique. In addition, the kinetics of the reverse processes for the latter two elementary reactions are also studied experimentally. The absolute rate constants for these processes are measured over a wide range of conditions, and the results offer new accurate information about the reactivity and thermochemistry of these systems. The temperature dependences of these reactions are interpreted via the Arrhenius equation, which yields significantly negative activation energies for the reaction of the chlorine atom and hydrogen sulfide as well as for that between the phenyl radical and hydrogen chloride. Positive activation energies which are smaller than the overall endothermicity are measured for the reactions between atomic chlorine with ammonia and ethylene, which suggests that the reverse processes for these reactions also possess negative activation energies. The enthalpies of formation of the phenyl and β-chlorovinyl are assessed via the third-law method. The stability and reactivity of each reaction system is further rationalized based on potential energy surfaces, computed with high-level ab initio quantum mechanical methods and refined through the inclusion of effects which arise from the …

Machine learning and artificial intelligence are increasingly becoming mainstream in our daily lives, from smart algorithms that recognize us online to cars that can drive themselves. In this defense, the intersection of machine learning and computational chemistry are applied to the generation of new PFAS molecules that are less toxic than those currently used today without sacrificing the unique properties that make them desirable for industrial use. Additionally, machine learning is used to complete the SAMPL6 logP challenge and to correlate molecules to best DFT functionals for enthalpies of formation.

Gas phase kinetics of the reactions involving hydroxyl radical and hydrogen atom were studied using experimental and ab initio theoretical techniques. The rate constant for the H + H2S reaction has been measured from 298 to 598 K by the laser photolysis/resonance fluorescence (LP-RF) technique. The transition state theory (TST) analysis coupled with the measurements support the suggestion that the reaction shows significant curvature in the Arrhenius plot. The LP-RF technique was also used to measure the rate constant of the H + CH3Br reaction over the temperature range 400-813 K. TST and density functional theory (DFT) calculations show that the dominant reaction channel is Br-abstraction. The reaction H + CF2=CF-CF=CF2 was first studied by flash photolysis/resonance fluorescence (FP-RF) method. The experiments of this work revealed distinctly non-Arrhenius behavior, which was interpreted in terms of a change in mechanism. DFT calculations suggest that the adduct is CF2H-CF•-CF=CF2. At lower temperatures a mixture of this molecule and CF2•-CFH-CF=CF2 is likely. The theoretical calculations show that H atom migrates in the fluoroethyl radicals through a bridging intermediate, and the barrier height for this process is lower in the less fluorinated ethyl radical. High level computations were also employed in studies of the …

Many previous studies have demonstrated that gold compounds possess successful results in catalysis and in medicinal chemistry. The central aim of this dissertation is the design and synthesis of novel gold (I) acyclic diamino carbene complexes as a chemotherapeutic agent for triple-negative breast cancer (TNBC) and for catalysis. In this study, a series of chiral neutral and cationic gold (I) acyclic diamino carbene (ADC) complexes and neutral gold (I) bis- ADC complexes have been synthesized. As the chiral neutral gold (I) ADCs, four diastereomers of S binaphthyl L proline tertiary butyl ester gold (I) chloride, S binaphthyl D proline tertiary butyl ester gold (I) chloride, R binaphthyl L proline tertiary butyl ester gold (I) chloride, and R binaphthyl D proline tertiary butyl ester gold (I) chloride have been synthesized and characterized. Different chiral gold (I) ADC complexes with bulky chiral binaphthyl group and with different amine groups of morpholine, chiral proline methyl ester, and benzyl ester have been synthesized and characterized. After that four diastereomers of the nitrile adduct of cationic binaphthyl proline tertiary butyl ester nitrile and four diastereomers of the isonitrile versions of it have been synthesized and characterized. A series of gold (I) cationic bis ADC complexes …

This study addressed five key applications of paper spray mass spectrometry (PS-MS): (i) comparative analysis of the microporous substrate with the cellulose-based substrate in drug detection; (ii) detection of more than 190 fentanyl analogs with their fragmentation pattern can be implemented in the future reference for quicker, accurate and sensitive determination; (iii) exploring sweat in a fingerprint to be considered an alternate method to recognize non-invasive markers of metabolites, lipids, narcotics, and explosive residues that can be used in forensic testing applications; (iv) extending and improving better, cost-effective and quick real-time monitoring of the diseased stage using biofluid samples to obtain vastly different lipid information in viral infection such as COVID-19; and (v) mass spectral detection in chemical warfare agent (CWA) stimulant gas exposure with microporous structure absorbency capabilities in air quality monitoring. This novel synthetic material is known as Teslin® (PPG Industries), consisting of a microporous polyolefin single-layered silica matrix, can be used for precise, sensitive, selective, and rapid sample analysis with PS-MS. The Teslin® substrate provided longer activation time for samples and an active signal with a higher concentration of ion formation and mobility compared to cellulose-based papers. Direct analysis of multiple samples showed that, besides being more …

In this study, thiol and two disulfide compounds have been tested as new corrosion inhibitors for brass and aluminum alloys. Pyridine-2-thiol and 2,2'-dipyridyl disulfide were tested for brass alloys in 0.5 M H2SO4 solution and both inhibitors showed excellent corrosion protection against the aggressive corrosive ion attack. Both inhibitors adsorbed to brass surface forming a protective film via a chemisorption process. XPS studies showed formation of Cu-S bond which allows these molecules to chemisorb on to brass surfaces. Pyridine-2-thiol, 2,2'-dipyridyl disulfide and 4'4-diaminodiphenyl disulfide were tested as corrosion inhibitors for AA6061-T6 alloy in 1 M HCl solution and all inhibitors showed excellent corrosion protection over wide range of temperatures. To evaluate the corrosion inhibition efficiencies many different instruments and electrochemical techniques were used. Overall results from this study showed sulfur-based corrosion inhibitors can be used effectively to mitigate the corrosion process of brass and aluminum alloys in acidic solutions.

Computational chemistry examination of the bond dissociation enthalpies of tungsten and main group elements. Includes quantification and calibration of theoretical methods to address the question of bond strengths including component σ and π molecular bonds.

Gas phase kinetics and thermochemistry of several halogenated species relevant to atmospheric, combustion and plasma chemistry were studied using experimental and ab initio theoretical techniques.

The porous materials discussed in this dissertation are metal-organic frameworks (MOFs) and porous liquids. Due to their high surface areas, tunable structures, and controllable porosities, MOFs have been explored for a wide variety of drug delivery applications. In chapter 2, MOFs have been used as magnetothermal-triggered release carriers through spatially distributed iron oxide nanoparticles within MOF matrix as a magnetic heating mediator and surface-grafted thermal-responsive nanocap as an alternating magnetic field (AMF)-responsive gatekeepers, achieving monitoring of drug release via external AMF by a conformational change of nanocap. In chapter 3, MOF, as a non-toxic loading carrier, encapsulate naringin, a natural product to serve as a multifunctional bio-platform capable of treating Gram-positive bacteria and certain cancers by slowly and progressively releasing the encapsulated naringin as well as improving and modulating immune system functions through the synergies between naringin and MOF. In chapter 4, porous liquid with unique solvent-free fluidity properties as a drug delivery platform for the first time. The interaction between hollow silica nanoparticle and polymerized ionic liquid, followed by ionic grafting brush of poly (ethylene glycol) telomer, makes this designed porous liquid responsible for high drug-loading and pH-responsive drug-releasing abilities along with slow degradation behavior. In addition to their …

Design and development of novel one-step reactions that produce nitrogen-containing scaffolds is an invaluable area of chemistry due to the abundance of these moieties in natural products and biologically active molecules. Discovering novel methods using uncommon substrates and rare earth metals to access these significant scaffolds present a challenge. Over the course of my doctoral studies, I have designed, developed and optimized novel reactions by using rarely known substrates and rare earth metals that have afforded important nitrogen-containing scaffolds. The products obtained allow access to otherwise long-to-synthesize molecules and expeditious construction of biologically active molecules.

This dissertation demonstrates that it is possible to create a donor-acceptor system that can transform sunlight into electrons. By using site-directed synthesis, it was possible to create a novel trans-A2B2 porphyrin. In the pursuit of creating a supramolecular system, both the novel (TPA-BT)2ZnP and C60imidazole combined in solution such that the nitrogenous lone pair of C60 imidazole would coordinate axially to the zinc atom in the porphyrin. The conjugates' characterization utilized spectral, electrochemical, and computational techniques. Computational studies revealed in the optimized structure that the HOMO localized on the porphyrin and LUMO centered over the C60imidazole entity. Rehm-Weller calculations showed feasibility of singlet-electron transfer. Femtosecond transient absorption studies documented an efficient photoinduced charge separation in the conjugate. The subsequent work through steady-state and time-resolved transient absorption techniques that photoinduced electron transfer takes place between the synthesized phenylimidazole functionalized bisstyrylBODIPY (BDP(Im)2) and three selected zinc tetrapyrroles. This dyad consisted of BDP(Im)2 and either zinc tetratolylporphyrin (ZnP), zinc-tetra-t-butyl phthalocyanine (ZnPc), or zinc tetra-t-butyl naphthalocyanine (ZnNc) in a solution solvated by σ-dichlorobenzene (DCB). The three dyads (BDP(Im)2:ZnP, BDP(Im)2:ZnPc, and BDP(Im)2:ZnNc) were investigated by spectroscopic, computational, and electrochemical methods. The 1:1 complex of the dyads in optical absorption studies were approximately ~104 M-1 suggesting …

Opioid abuse and in particular fentanyl, a synthetic opioid, has been of concern in the last decade. Fentanyl is an illicit drug of concern to due to its prevalence and potency. Research to date has focused on supporting law enforcement by developing methods suitable for chemical profiling and identifying fentanyl from various matrices. However, methods geared towards analysis of fentanyl isomeric analogues are rare. Analysis of isomers is challenging due to similar mass spectral fragmentation patterns and exhibiting co-elution using common gas chromatographic columns. Developing methods to use in forensic labs utilizing already available equipment will advance current capabilities in the detection of fentanyl compounds. Thus, investigation into alternative stationary phases and development of special gas-liquid chromatographic (GLC) based methods for isomeric fentanyl analogues has been done. Several studies were done to investigate the use of ionic liquid chromatographic phases in analyzing fentanyl analogues. The first study focused on investigating the thermal stability of ionic liquids to identify those suitable to withstand the high oven temperatures that was needed to elute fentanyl analogues in gas chromatography. Total synchronous fluorescence spectroscopy and differential scanning calorimetry were demonstrated to be sensitive enough to detect the decomposition products of ionic liquids. In the …

Seventeen new dithiophenyl- and napthodithiophenyl- fused porphyrins were synthesized; from these an additional 7 porphyrin oligomers were also synthesized. Additionally freebase 2,7-dimethoxytriphenylene fused porphyrin was also synthesized from a freebase precursor. Aromatic indices NICS and AICD were used to evaluate these new molecules.