Mechanical pressure offers unique control over the energy landscape of chemical reactions, opening up pathways that are inaccessible through conventional thermochemistry. We hypothesize that the reduced dimensionality defines the conformational space of the high-pressure reaction, giving rise to new selectivity that is unavailable in 3D systems. Here, we demonstrate this concept through the pressure-controlled topochemical polymerization of the diacetylene molecule deca‐3,5‐diyn‐1‐amine (DDA) incorporated in the two-dimensional (2D) perovskite [DDA]2PbBr4. Compression at 3 GPa drives the first topochemical polymerization through 1,2 addition, forming a polyene product at room temperature. The reaction is initiated by the mechanical bending of the linear DDA molecule, a mechanism fundamentally different from the 1,4-addition in 3D solids. Importantly, pressure hinders the second 1,2-addition by disfavoring the gauche conformation between the remaining acetylene groups, allowing for the selective formation of polyene versus polyacene products. We characterize the reaction mechanisms and products using spectroscopies (Raman, X-ray photoelectron, ultraviolet-visible), X-ray diffraction and density-functional theory simulations. These results highlight the important role of dimensionality in high-pressure chemistry, and offers a new paradigm for creating low-dimensional functional materials.

Transition metal oxynitrides are of growing interest for their use as electrocatalyst for nitrogen reduction reaction. The metals in the oxynitride used for catalytic process are stabilized in intermediate state for effective activation of nitrogen. Therefore, studying the interaction of metal oxynitrides films to ambient exposure is necessary. Here, sputter deposited vanadium oxynitride is compared to cobalt oxynitride using insitu Auger electron spectroscopy (AES), ex situ X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). After deposition in Ar/N2 environment, in situ AES spectra indicate that film is vanadium oxynitride despite oxygen is not the reactive gas. In contrast, in situ AES indicate film is pure cobalt nitride at the same base pressure and deposition condition (as vanadium). For ambient exposure, in situ AES indicate the incorporation of oxygen in the cobalt nitride film to form cobalt oxynitride. Ex situ XPS indicate both films get more oxidized but uniformly distributed as there is only slight difference in grazing and normal emission XPS. XRD and SEM also indicate how homogeneously distributed both films are. These finding confirms how important it is that transition metal centers are kept in intermediate oxidation state for the activation of nitrogen bond.

Previous work was successful at delineating reaction pathways for the photoactivated synthesis of an amine, [CztBu(PyriPr)(NH2−PyriPr)], by double intramolecular C−H activation and functionalization via irradiating a metal(II) azido complex, [CztBu(PyriPr)2NiN3. The present work seeks to expand upon earlier research, and to substitute the metal with iron or cobalt, and to expand the study to photocatalyzed intermolecular C−H activation and functionalization of organic substrates. Density functional theory (DFT) – B3LYP/6-31+G(d') and APFD/Def2TZVP – and time-dependent density functional theory (TDDFT) were used to propose a detailed pathway comprised of intermediates of low, intermediate, or high spin multiplicity and photo-generated excited states for the reaction of the azido complex, [CztBu(PyriPr)2MN3] to form the amine complex [CztBu(PyriPr)M(NH2−PyriPr)], M = Co, Ni or Fe, and the intermediates along the reaction pathway. For applications on quantum computing, the photophysical properties of photoactive d8 nickel(II) complexes are modeled. Such systems take advantage of a two-level system pathway between ground to excited state electronic transitions and could be useful for the discovery of successful candidates for a room temperature qubit, the analogue of a classical computational bit. A modified organometallic model, inspired by a nitrogen vacancy selective intersystem crossing model in diamond, was developed to take advantage of …

Recognizing the dual ability of the nitride ligand to react as a nucleophile or an electrophile – depending on the metal and other supporting ligands – is a key to their broad-range reactivity; thus, three DFT studies were initiated to investigate these two factors effects (the metal and supporting ligands) for tuning nitride ligand reactivity for C-H and N-H bond activation/functionalization. We focused on studying these factors effects from both a kinetic and thermodynamic perspective in order to delineate new principles that explain the outcomes of TMN reactions. Chapter 2 reports a kinetic study of C–H amination of toluene to produce a new Csp3–N (benzylamine) or Csp2–N (para-toluidine) bond activated by diruthenium nitride intermediate. Studying three different mechanisms highlighted the excellent ability of diruthenium nitride to transform a C-H bond to a new C-N bond. These results also revealed that nitride basicity played an important role in determining C–H bond activating ability. Chapter 3 thus reports a thermodynamic study to map basicity trends of more than a one hundred TMN complexes of the 3d and 4d metals. TMN pKb(N) values were calculated in acetonitrile. Basicity trends decreased from left to right across the 3d and 4d rows and increases from …

Donor-acceptor systems exhibit distinctive attributes rendering them highly promising for the emulation of natural photosynthesis and the efficient capture of solar energy. This dissertation is primarily devoted to the investigation of these unique features within diverse donor-acceptor system typologies, encompassing categories such as closely covalently linked, push-pull, supramolecular, and multi-modular donor- acceptor conjugates. The research encompasses an examination of photosynthetic analogs involving compounds such as chelated azadipyromethene (AzaBODIPY), N,N-dimethylaminophenyl (NND), phenothiazine (PTZ), triphenylamine (TPA), phenothiazine sulfone (PTZSO2), tetracyanobutadiene (TCBD), and expanded tetracyanobutadiene (exTCBD). The strategic configuration of the donor (D), acceptor (A), and spacer elements within these constructs serves to promote intramolecular charge transfer (ICT), which are crucial for efficient charge and electron transfer. The employment of cutting-edge analytical techniques, such as ultrafast transient absorption spectroscopy, is integral to the study. Furthermore, a comprehensive suite of analytical methodologies including steady-state UV-visible absorption spectroscopy, fluorescence and phosphorescence spectroscopies, electrochemical techniques (including cyclic voltammetry and differential pulse voltammetry), spectroelectrochemistry, and density functional theory calculation (DFT), collectively contribute to the comprehensive characterization of push-pull donor-acceptor systems, with a particular emphasis on their potential as highly effective solar energy harvesting application.

A rapidly growing topic of great interest is the adaptation of benchtop analytical instrumentation for use in outdoor harsh environments. Some of the areas that stand to benefit from field instrumentation development include government agencies involved with the preservation of the environment and institutions responsible for the safety of the general public. Detection systems are at the forefront of the miniaturization movement as the interest in analyte identification and quantitation appears to only be accessible through the use of analytical instrumentation. Mass spectrometry is a distinguished analytical technique known for its ability to detect the mass-to-charge (m/z) ratios of gas-phase ions of interest. Although these systems have been routinely limited to research lab-based analysis, there has been considerable development of miniaturized and portable mass spectrometry systems. Membrane Inlet Mass Spectrometry (MIMS) is becoming a common method of sample introduction that is subject to significant development. MIMS allows for minimal sample preparation, continuous sampling, and excludes complicated analyte introduction techniques. Sampling is accomplished using a semipermeable membrane that allows selective analyte passage into the vacuum of the mass spectrometer. MIMS is becoming the preeminent choice of homeland security and environmental monitoring applications with increasing opportunities for the future development of specialized …

All oxide heterostructure Cr2O3/TiO2-x was deposited on Al2O3(0001) single crystal via MBE. The analysis of interfacial interactions involving two metal oxides resulting in magnetic properties gave insights for using such heterostructures as potential spintronic device materials. The corundum phase epitaxial growth of TiO2-x on Al2O3 was characterized using XPS, AES, EELS, and LEED. The data obtained gives evidence of presence of two-dimensional electron gas at titania surface due to oxygen vacancies formation after deposition. On titania, the deposition of chrome in UHV results in the formation of oxidized chromia overlayer by abstraction of oxygen from the TiO2-x underlayer further increasing the number of vacancies present. In industrial R&D project, dry etching of multiple optical device components was performed using a novel angled etch prototype tool. The first set of experiments involved plasma etching of SiC thin films optimized for target application. The best-known method (BKM) worked from 300mm full wafer to 200mm product. In second experimentation, a variety of gray-tone photoresist received from customers were etched using BKM. Customer received etch rate on each gray-tone material. The third experiments compared recipe R1 to test recipe R2 on the test vehicle VDC. R2 showed faster etch rate but lower process repeatability …

A series of acene-fused porphyrins and 1,10-phenanthroline-fused porphyrins were synthesized and characterized via NMR spectroscopy and mass spectrometry. The acene-fused porphyrins exhibit unique optoelectronic properties, most notably they exhibit highly red-shifted absorption bands. The 1,10-phenanthroline-fused porphyrins are of interest for their ability to bond to as variety of metals to form chelation complexes.

In the first part of this dissertation work, Al bond pad corrosion behavior was investigated in the presence of common industrial contaminants such as chloride (Cl-) and fluoride (F-). Al corrosion while in direct contact with Cu displayed rapid hydrogen (H2) gas evolution and dendrite propagation. In contrast, Al without bimetallic contact showed only minor surface roughening. This observed difference in the corrosion mechanism between Cl- and F- is attributed to the solubility of the corrosion products (AlCl3 vs. AlF3) formed on the Al surface. Our subsequent work explored corrosion prevention inhibition of wire-bonded devices (WBD) in the Cl- environment. Our research shows that the Al bond pad was protected against corrosion by chemically modifying the surface of the Cu wires, thereby preventing the H2 evolution. The inhibitor was observed to be highly selective, thermally stable, hydrophobic, and cost-effective, making it viable for industrial application of this coating for Al bond pad corrosion prevention. In the second part of the dissertation work, we utilized a novel approach of using ultraviolet-visible spectroscopy (UV-Vis) as a chemical-sensitive monitoring tool of the chemical environment in Cu etch bath. The UV-Vis technique illuminates the roles of H+, Cl-, Cu+, and Cu2+ to the etch …

With the reliability requirements of automobile microelectronics pushing towards near 0 ppb levels of failure control, halide induced corrosion issues in wire bonded devices have to be tightly controlled to achieve such a high reliability goal. With real-time corrosion monitoring, for the first time we demonstrated that the explosive H2 evolution coupled with the oxygen reduction reaction, occurring at the critical Al/Cu interfaces, is the key driving force for the observed aggressive corrosion. Several types of passivation coating on Cu wire surfaces to effectively block the cathodic H2 evolution were explored with an aim to disrupt this explosive corrosion cycle. The properties of the protective coating were evaluated using various analytical techniques. The surface coating exhibited high thermal stability up to 260 °C (evaluated using TGA analysis). A uniform, highly hydrophobic coating (surface contact angle of >130° with water), was achieved by carefully controlling CVD parameters such as time of deposition, surface control of Cu metal, amount of inhibitor compound loading, temperature of coating process etc. FTIR spectroscopy combined with corrosion screening was used to optimize the CVD passivated coating with strong chemisorption. SEM and EDX, XPS were carried out on various coated surfaces to understand the composition and selectivity …

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 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 …

Synthesis of d10 complexes of monovalent coinage metals, copper(I) and gold(I), with dithiophosphinate/diphosphine ligands -- along with their targeted characterization and screening for inorganic or organic light emitting diodes (LEDs or OLEDs, respectively) -- represents the main scope of this dissertation's scientific contribution in inorganic and materials chemistry. Photophysical studies were undertaken to quantify the phosphorescence properties of the materials in the functional forms required for LEDs or OLEDs. Computational studies were done to gain insights into the assignment of the phosphorescent emission peaks observed. The gold(I) dinuclear complexes studied would be candidates of OLED/LED devices due to room temperature phosphorescence, visible absorption/excitation bands, and low single-digit lifetimes -- which would promote higher quantum yield at higher voltages in devices with concomitant lower roll-off efficiency. The copper(I) complexes were not suited to the OLED/LED applications but can be used for thermosensing materials. Crystallographic studies were carried to elucidate coefficients of thermal expansion of the crystal unit cell for additional usage in materials applications besides optoelectronic devices. This has uncovered yet another unplanned potential application for both copper(I) and gold(I) complexes herein, as both types have been found to surpass the literature's threshold for "colossal" thermal expansion coefficients. Two other investigations …

Printed circuit board manufacturing involves subtractive copper (Cu) etching where fine features are developed with a specific spatial resolution and etch profile of the Cu interconnects. A UV-Vis ATR metrology, to characterize the chemical transitions, has been developed to monitor the state of the bath by an in-situ measurement. This method provides a direct correlation of the Cu etch bath and was able to predict a 35% lower etch rate that was not predicted by the three current monitoring methods (ORP, specific gravity, and conductivity). Application of this UV-Vis ATR probe confirmed that two industrial etch baths, in identical working conditions, confirmed a difference in Cu2+ concentration by the difference of the near IR 860nm peak. The scope of this probe allowed chemically specific monitoring of the Cu etch bath to achieve a successful regeneration for repeated use. Interlayer dielectrics (ILDs) provide mechanical and electrical stability to the 3D electrical interconnects found in IC devices. It is particularly important that the structural support is created properly in the multilayered architecture to prevent the electrical cross signaling in short range distances. A combined multiple internal reflection and transmission FTIR has been employed for the characterization of silicon oxycarbonitride (SiOCN) films. These …

This dissertation delves into the catalytic activity of multiple metal-containing complexes with an emphasis on the activation of C–H bonds in small molecules and olefin oligomerization. The research contained in these works employs computational methodologies to better understand the thermodynamics and kinetics of the reactions. Computations can be used to quickly identify novel models and find ideal substitutions for improved catalyst design. Within this dissertation, multiple molecules of divalent and trivalent main group element-containing complexes as well as Group 13 dimetallene complexes were investigated with density functional theory (DFT) to identify their ability to activate C–H of hydrocarbons, including methane, by quantifying their thermodynamics and kinetics of reaction. With several substitutions to the base complex, improved catalysts were designed to decrease the energy barriers of the activations. Multiconfiguration self-consistent field methods were also employed to characterize the biradical character of these Group 13 compounds. Olefin oligomerization by zirconium boratabenzenes with various ancillary pendant groups was also investigated via DFT to identify the most ideal variations as well as the most likely reaction pathway.

The electrocatalytic nitrogen reduction reaction (NRR) is of considerable interest due to its potential for less energy intensive and environmentally friendly ammonia production which is critical for agricultural and clean energy applications. However, the selectivity of NRR compared to the hydrogen evolution reaction (HER) often poses challenges for various catalysts, including Earth-abundant transition metal oxynitrides like Ti, V, and Co. In this work, a comparative analysis of the selectivity of these three metal oxynitrides was conducted, each having different metal oxophilicities. A combination of electrochemical, surface characterizations and density functional theory (DFT) calculations were employed to directly assess NRR and HER activities under the same reaction conditions. Results show that cobalt oxynitrides exhibit NRR activity at pH 10, involving the electrochemical reduction of both lattice-bound nitrogen and dissolved N2, although more HER activity was observed. In contrast, vanadium oxynitride films displayed HER inactivity at pH 7 and 10 but demonstrated NRR activity at pH 7, while titanium oxynitrides were active at pH 3.2 but inactive under neutral and basic pH conditions. These comprehensive studies highlight substantial variations in HER and NRR selectivity based on transition metal oxophilicity/azaphilicity, indicating distinct mechanisms governing NRR and HER mechanisms.

The Abraham solvation model (ABSM) is an experimentally derived predictive model used to help predict various solute properties. This work covers various uses for the ABSM including predicting molar enthalpies of vaporization, predicting solvent coefficients for two new solvents (2,2,5,5-tetramethyloxolane and diethyl carbonate), predicting values for multiple new ionic liquids (ILs). This work also introduces a novel method for updating IL ABSM parameters by updating cation- and anion-specific values using linear algebra and binary matrices.

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.

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.

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.

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 …

In this thesis, micro-mechanical properties and corrosion resistance of laser powder bed fusion (L-PBF) processed additive manufactured (AM) 316L stainless steel parts were investigated for different combinations of processing parameters. Various laser powers were employed for the fabrication of all AM 316L stainless steel parts. Nanoindentation, areal roughness, and electron backscattered diffraction (EBSD) characterization were used to characterize the surface of the AM samples prior to corrosion testing. Open circuit potential (OCP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization tests were done to compare AM L-PBF 316L stainless steels with different processing parameters. Overall, it was observed that the AM part having a 56.67 J/mm3 volumetric energy density (VED) exhibits the best micro-mechanical characteristics. This sample also had the lowest areal surface roughness and smallest grain size. Consequently, this parameter combination had better corrosion resistance compared to the other AM processed 316L parts. The results are useful in process calibration when fabricating for corrosion resistance applications and provide insights into the relationship among nano-mechanical, crystallography, and long-term corrosion performance.

This dissertation focuses on the design, synthesis, characterization of platinum (II) pyridylazolate complexes and develop high performance organic light emitting diodes (OLEDs) and design and execute high-sensitivity humidity sensors based on the luminescent metal-organic complexes of platinum. A majority of existing platinum compounds do not dissolve in organic solvents, making it difficult to analyze the photophysical characteristics of complexes in solution, a key part of understanding chemical photophysical properties. Furthermore, due to the poor quantum yield, it is inefficient for use in devices such as OLEDs. Chapter 2 reports the synthesis and characterization of a novel heteroleptic platinum(II) pyridylazolate complex with high solubility and quantum yield. The photochemistry of the complex is studied, including efficiency, emission profiles, and lifetimes at different temperatures. Chapter 3 reports the power efficiency (lm/W), current efficiency (cd/A), external quantum efficiency (EQE), luminance and operating voltage (V) of OLED devices made with the heteroleptic platinum(II) pyridylazolate complex. The relation between thickness of hole transport layer and electron transport layer on performance of devices has been studied through building a variety of devices. Chapter 4 includes application of a homoleptic platinum(II) pyridylazolate complex in humidity sensor. In many environments, the relationship between moisture content and emissive wavelength …

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 …