Linden (Tilia spp.), a profusely flowering temperate tree that provides bees with vital pollen and nectar, has been associated with bumble bee (Bombus spp.) mortality in Europe and North America. Bee deaths have been attributed, with inadequate evidence, to toxicity from mannose in nectar or starvation due to low nectar...
Metal-oxo clusters can be described as soluble pieces of metal-oxide frameworks. Currently, metal-oxo clusters are being considered as solution-based precursors for extreme ultraviolet (EUV, 13.5 nm) photoresist materials, which are a crucial component in the fabrication of microelectronic devices. Two different photoresist precursor systems have been investigated – alkyltin clusters...
Atmospheric fine particulate matter (PM2.5) has been linked to the death of 7 million people per year around the planet. The organic portion of PM2.5 is responsible for increases in oxidative stress, inflammation, mutation and carcinogenesis. Anthropogenic activity releases more organic material into the atmosphere, and has increased the amount...
Exploring bioactive natural products has contributed largely to clinically approved drugs we have been using over the last 100 years. Especially among the anti-infective drugs, around 70% of currently used antibiotics were discovered or derived from microbial secondary metabolites, among them compounds like vancomycin, chloramphenicol, and erythromycin. Facing the unavoidable...
Metal-oxo clusters are discrete molecular metal-oxides. Most metals form numerous cluster compounds that can be ligated, unligated, charged or neutral, controlling their solubility in water and/or organic solvents. They are important species to study reaction pathways from the monomeric building units to the bulk metal oxides, and have many application...
Dental plaque is one of the well-characterized biofilms in the human body. Oral bacterial species play vital roles in maintaining healthy bacterial homeostasis as well as causing oral infections. Many of the oral diseases are caused by opportunistic pathogens, and therefore, the bacterial metabolic activities become important in dictating their...
Part I of this dissertation includes the chronological synthetic background of mandelalide A as well as the synthesis of the C1-C14 glycosylated southern subunit of mandelalide. A key aspect of the synthesis includes a novel silver-catalyzed cyclization (AgCC) of a propargylic benzoate to construct the substituted cis-pyran ring system present...
Small molecule drugs have been instrumental in our fight against diseases, beginning when some of the earliest ancient cultures used plant remedies to treat illnesses. More recently, the skill of isolating and characterizing the active ingredients within bioactive plants and microbial extracts has led to the isolation and design of...
Fungi have long been used for discovery of new chemical scaffolds. In the clinical setting, the fungal natural products penicillin, statins, and cyclosporine have revolutionized medicine to treat diseases and infections. In the environment, fungal natural products have been used as herbicides, fungicides, and insecticides to protect crops, livestock, and...
Dearomatization reactions exist broadly in biosynthesis and chemical synthesis. The highly functionalized atoms of arenes can be masked by it aromaticity, and upon dearomatization, those reactive atoms can be readily applied to bond formation and further manipulation. The total synthesis of (–)-cephalotaxine and (–)- homoharringtonine is described via an oxidative...
Mandelalide A has attracted considerable interest from the synthetic community due to its intriguing structure and important cytotoxic activity. Madeirolide A, a structurally related macrolide, shows promising antifungal activity but no appreciable anticancer activity. This dissertation describes synthetic studies toward mandelalide A, madeirolide A and their hybrid structures.
Part I...
Nanostars have many potential applications, particularly in biomedicine, such as drug delivery, detection assays, and even cancer treatment. Seeing how their plasmon changes in response to changes to the environment of the nanostars can give us an insight to the stability of the nanostars. Our current studies involve the effect...
Tethering fluorophores on metal nanoparticles for metal enhanced fluorescence (MEF) has attracted a lot of attention from scientists interested in fluorescence based approaches. MEF has many benefits in fluorescence related techniques, because the analytical signal increases and enables potentially lower detection limits or better sensitivity. Many types of nanoparticles have...
Analytical techniques are utilized in a wide variety of applications. Traditionally, analytical measurements are achieved by trained personnel in a laboratory setting using expensive scientific instruments, which limits their applicability in resource-limited areas and point-of-care applications. Therefore, the concept of enabling these laboratory-based qualitative and quantitative assays in microfluidic device...
My work has focused on streamlining the study of organic compound structure, properties, and reactions by 1) understanding and using available computational software, 2) developing software packages to facilitate data manipulation as well as augment public programs, and 3) applying public and in-house developed software to further the understanding of...
In this dissertation, the process of computational modeling of amorphous oxide materials is studied. Amorphous oxides have random atomic arrangements with no long-range structural order which makes it difficult to study structure-property relationships. Despite the difficulties, amorphous oxides have great uses as semiconductors and dielectrics in thin-film transistors. The ability...
In this dissertation, I describe the experimental investigation of large superfluid helium droplets. The goal and direction of this thesis is to facilitate the use of these droplets as part of our project ss-EDI. The overall scheme of ss-EDI is to dope proteins inside helium droplets and collect a diffraction...
Aqueous film forming foams (AFFFs) are proprietary mixtures containing hydrocarbon surfactants and per-and polyfluoroalkyl substances (PFASs) that are used to extinguish hydrocarbon-based fuel fires. There is limited information on hydrocarbon surfactants in AFFFs and AFFF-contaminated groundwater even though they are more abundant (5-10% w/w) than PFASs (0.9-1.5% w /w) in...
Mensacarcin is a stereogenic complex polyketide with potent anti-tumor activity produced by a soil-dwelling Streptomyces bottropensis. The US National Cancer Institute (NCI) 60 human tumor cell line anticancer drug screen (NCI-60) reveals mensacarcin’s cytostatic properties in almost all tested cell lines and distinct cytotoxic properties specifically in eight melanoma cell...
This dissertation is separated into two parts according to the two major distinct research projects. In Part I, the full account of synthetic studies toward C10-functionalized lycopodium alkaloids is described. In Part II, the detailed discussion on the exploration of the Pummerer cyclization methodology and its application to the total...
In this dissertation, the structure and electronic properties of multiple metal oxide thin films are characterized and presented. Prompt inorganic condensation (PIC) of metal-oxo and –hydroxo clusters was evaluated as a technique for making metal oxide clusters in two separate studies. The first focuses on the synthesis of lithium niobate...
This work investigates the effect of cation substitution on the properties of the lead-free, solid solution (Na₀.₅Bi₀.₅)TiO₃-BaTiO₃ (NBT-BT). Substitution into NBT-BT increases disorder and increases the relaxor ferroelectric properties. These relaxor ferroelectric materials show large piezoelectric strains that can be utilized in actuator applications. Ceramic samples were prepared using standard...
Water is an absolute necessity for life as we know it. It provides a useful medium in which chemical reactions take place that allowed for the development of single cellular organisms. When combined with the evolutionary accident that was pho- tosynthesis, water became not only a useful medium chemical reactions,...
Structure-property relationships have always underpinned the field of solid state chemistry; dependable structural descriptions are integral to understanding and controlling the physical properties of inorganic compounds old and new. While a handful of crystal structures are celebrated for their versatility, flexibility, and functionality, the existence of more exotic structures is...
Mass Spectrometry has emerged as an analytical core technique in omics sciences, in particularly mass spectrometry has advanced the fields of proteomics, metabolomics and lipidomics in recent years. Mass spectrometric techniques have enabled the characterization and determination of abundance levels of a wide range of biomolecules at molecular and system-wide...
Recently researchers have discovered that groups of small non-coding RNAs (ncRNAs) play regulatory roles in gene expression and participate in various biological processes. For example, pathogenesis of many diseases, cell cycle regulation, and signaling pathways. Intracellular and live cell imaging of small ncRNA groups will reveal their relative expression levels...
The furanyl diterpenoid family of natural products has drawn the attention of both synthetic organic chemists and pharmacologists due to their complex structural architectures and diverse biological activity. Among them, wortmannin has been most extensively studied for biological activities. All these furanyl diterpenoids consist of a highly strained naptha[1,8-bc]furan core,...
Pharmaceuticals, molecular catalysts, and secondary metabolites often contain nitrogen. The problems faced synthesizing compounds which contain nitrogen was because of the Lewis base reactivity of nitrogen lone pairs, and the acidic protons of some nitrogenous functional groups. We developed two methods for the synthesis of nitrogeous compounds. Additionally, we successfully...
Grid-scale energy storage systems are urgently needed to increase the flexibility and rigidity of the grid for modern society and take full advantage of the renewable green energy resources such as solar energy and wind energy. Na-ion batteries (NIBs) and K-ion batteries (KIBs) have been emerged as one of the...
Widespread installation of renewable energy sources, such as wind and solar, has been delayed by the lack of suitable stationary energy storage solutions. Current large-scale technologies, such as pumped hydro and compressed air, are geographically restricted. This is where electrochemical energy storage - batteries or hybrid capacitors can play a...
Frontier research of non-aqueous actinide clusters is discussed. Since the inception of the uranyl peroxide clusters over the last decade, they have only been synthesized and characterized as solid crystals and in aqueous solution. This thesis provides thorough characterization of aqueous uranyl clusters and the first demonstration of uranyl cluster...
My work has focused on investigating synthetic organic reactions using applied computational methods. Non-covalent interactions are critical to catalysis, mechanism, and stereoselectivity, with the most prominent interaction for isothioureas being the S···O contact between the catalyst sulfur atom and the oxygen of the acyl group. A comprehensive joint experimental and...
Fungi have long been a prolific source of clinically approved drugs. The antibiotic penicillin, the cholesterol lowering statins, and the immunosuppressant cyclosporine have changed the treatment of human diseases in the last century. Recently, genome analysis of filamentous fungi has revealed that the biosynthetic potential for natural product expression is...
The synthesis of superheavy element evaporation residues is described by the product of the capture cross section, fusion probability, and survival probability. Capture cross sections are moderately well known. The fusion probability is the least known with many uncertainties. The formalism for the survival probability is known, but the parameters...
The physical properties of hydrochloric acid and deuterium chloride were derived through the use of the harmonic oscillator and rigid rotor quantum mechanical models. By first obtaining angular momentum quantum values for HCl and DCl through Fourier Transform Infrared Spectroscopy, these two systems could be summed and processed with additional...
Two perovskite materials (Bi0.5(A)0.5)(Sc0.5Nb0.5)O3, where A = K+ and Na+ were synthesized phase pure for the first time. Their structures were determined by indexing synchrotron X-ray diffraction data and subsequent combined Rietveld refinement on neutron and synchrotron X-ray diffraction data revealing significant disorder on the A-sites of these materials. A...
The general theme of this dissertation is the application of novel carbon based micro sensors with the scanning electrochemical microscopy (SECM). SECM allows positioning of the probe without touching the substrate while mapping the chemical parameters in 3D space above the substrate. The main focus of the dissertation is the...
Iron oxide materials including ferrihydrite and magnetite play essential roles in contaminant transport, pH control of surface and groundwater, and microbial activity. They have various applications ranging from data storage to cancer therapy. Recent studies showed that the NPs growth does not involve atom by atom nucleation but starts by...
The post-emission total kinetic energy release (TKE) in the neutron induced fission of ²³²Th was measured (using white spectrum neutrons from LANSCE) for neutron energies from En = 3 to 91 MeV. In this energy range the average post-neutron total kinetic energy release decreases from 162.3 ± 0.3 at En...
Inorganic structures play an important role in materials due to their versatility and diversity. A complete understanding of the structure of a material is vital to enhance the creation of new materials that fill voids in research. The rational design of these compounds is driven by the exploitation of structure-property...
Polyoxometalates are discrete anionic oxo clusters of the Group V and VI transition metals that can be conceptualized as molecular metal oxides. Because they are pairable with any alkali cation, a great deal of fundamental chemistry can be gleaned from their study, including solubility trends and insight into cation binding...
Femtosecond stimulated Raman spectroscopy (FSRS) is a powerful ultrafast technique which can track photoinduced excited state structural events on femtosecond (fs) to picosecond (ps) timescales. In addition to high temporal and spectral resolutions, FSRS provides a broad spectral window from ca. 100—2000 cm-1 for detection, enabling the direct mapping of...
State-of-the-art, high-resolution mass spectrometry techniques for acquisition of metabolomic and lipidomic data coupled with advanced computational methods provide new opportunities for interpreting large and complex datasets and comprehending the underlying biological processes of diseases. Both metabolomics and lipidomics strive to obtain comprehensive analyses of small molecules, i.e., metabolites and lipids,...
The solution chemistry and kinetic behavior of hafnium peroxy sulfate solutions ("HafSOx") is described in terms of peroxide content and solution speciation. Additionally, thin film behavior, including thermal behavior and solubility, is characterized, and a mechanism of patterning is presented, as well as parameters that should be considered when looking...
Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants produced mainly from the incomplete combustion and pyrolysis of organic matter. PAHs are among the major contaminants at over 800 Superfund sites, nationwide. Thermal remediation is used as a method to remediate soils contaminated with PAHs through the use of heat to mobilize...
In this dissertation, excited state proton transfer (ESPT) and its inhibition in solution and protein environments are revealed using both femtosecond transient absorption (fs-TA) spectroscopy and femtosecond stimulated Raman spectroscopy (FSRS). Using a tunable Raman pump to enhance transient vibrational features of the photoacidic chromophore HPTS in methanol and methanol...
Air particulate matter (PM) samples were collected from June 2006 to May 2007 for determination chemical elements. PM samples were taken in two size fractions (PM₂.₅ and PM₁₀) with MiniVolume air samplers on rooftops of various buildings (15-25 m above ground) in the city of Riyadh. The samples were subjected...
Novel donor-typed ternary graphite intercalation compounds (GICs) are synthesized and characterized containing (1) pyrrolidinium cations with DMSO co-intercalates; (2) alkali metal cations with crown ether co-intercalates; and (3) alkali metal cations with polyethylene glycol co-intercalates. Structural and compositional data are obtained for the stable products. A new ether-amine co-intercalate exchange...
The first part of this manuscript is about the total synthesis of the Arundo donax bis(indole) natural products. The A. donax alkaloids were prepared using the first example of an ynindole Diels–Alder reaction. Each were then separated, isolated, and determined to have stable enantiomeric conformations at room temperature (Chen, J.;...