Nitroaromatic compounds have important chemical applications and can be found in nature as pollution sources. Synthetic nitroaromatic compounds have been used in a variety of materials including explosives, pharmaceuticals, dyes, plastics, and pesticides. These compounds can find their way into the environment through normal or improper disposal methods.
Poly-aromatic compounds...
Fluorinated alkyl substances, which can be persistent, toxic, and
bioaccumulative, have been quantitated in many densely populated and
remote regions, including in air, surface waters, groundwater, and biota;
however, little is known about their transport or behavior in the environment.
Wastewater effluent is one of the principal routes for introducing...
In this work sample, a student teacher implemented ESOL standards and
strategies on a unit covering chemical compositions in a high school chemistry
classroom. The ELD program at this high school has two types of ELD classes. ELD 1/2
classes have a grammar-based curriculum focused on the English Language, while...
The total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, is described. Both a palladium(II)-mediated and a palladium(II)-catalyzed intramolecular alkoxycarbonylation were used as key steps for the preparation of the two cis-2,6-disubstituted tetrahydropyran rings (C22-C26 and C11-C15) of phorboxazole A.
The synthesis used a convergent approach involving...
The photolysis of the aqueous thymine system has been investigated
at 214 nm, 229 nm and 254 nm at room temperature. Products
of photolysis have been identified as hydrogen peroxide, 6-hydroxy-5-
hydroperoxy thymine and tentatively 5-hydroxy-6-hydroperoxy thymine.
These together with thymine loss, were determined quantitatively
under a variety of conditions....
A procedure is described for the optimization of a previously
described continuous analysis adaptation of the Pearl-Benson or
nitroso method for estimation of spent sulfite liquor (SSL) or ligno-sulfonates.
The optimized procedure has a response time of 6.5 minutes. In order to monitor samples whose SSL concentration is
between 0...
Photolysis of pentachlorobenzene was carried out in the absence
of an electron donor species at 254 nm in cetyltrimethylammonium
bromide surfactant solution. The results are consistent with the
excited triplet undergoing homolytic cleavage of a C-Cl bond in
competition with formation of the excimer, in which the radical anion
undergoes...
Plasma sources with multiple electrodes have been developed and
characterized in this research for atomic emission spectroscopy.
Multi-electrode plasma sources use electrodes to shape the plasma in
order to continuously entrain a sample stream in the center of hot
plasma, in a manner similar to an inductively coupled plasma (ICP)...
¹³⁰ Sn and ¹²⁸Sn were separated from mixed fission products.
The decay of these isotopes were studied with Ge(Li),
LEPS, and plastic scintillator detector systems in single
and two parameter coincidence modes. The decay scheme constructed
for ¹²⁸Sn decay has levels at 0.0 (5+), 45.7 (4+),
77.8 (3+), 152.9 (2+),...
The reaction of cyclodeca-1,215triene with mercuric salts
gave only rearranged hydrocarbon, tricyclo[4.4.0.0²'⁴]deca-5ene
in acetic acid. Other catalysts [Rh(CO)₂C1]₂ and AgC10₄ gave
the same rearranged hydrocarbon. The isomerization is proposed
to proceed through a "metalcomplexed" carbenoid intermediate.
The reaction of bicyclo[7.1.0 ]deca-213diene gave
oxymercurated products.
A method of calculating the normal vibrations of polymer molecules
is presented in detail. The method is based on that used by
Schachtschneider and Snyder in their analysis of polypropylene but
has not heretofore been published. The factoring of the infinite matrix
and reduction to the coordinates of the unit...
Since many 1, 4, 5, 6-tetrahydropyrimidines have become available
and commercially useful in recent years, a study of the chemistry
of certain of these compounds has been undertaken.
2-Hydroxy- and 2-mercapto-1, 4, 5, 6-tetrahydropyrimidine
have been synthesized by the condensation of urea and thiourea, respectively,
with 1, 3-propanediamine, with yields...
An approach to the generation of polyketides was investigated,
which involved ozonolysis of 6, 7 cyclopenteno -1> 4, 5, 8 -tetrahydromethoxy-
3-methylnaphthalene (26), to produce what is believed to be
polyketide 27. Compound 26 was formed by the following sequence:
Die ls -Alder addition of 1, 2 -dim.ethylenecyclopentane and 2...
Both oxy-Cope and siloxy-Cope rearrangements involve
(1, 3) and (3, 3) sigrnatropic shifts. Both the concerted mechanism,
and the stepwise mechanism via a diradical intermediate are possible.
In a cyclic system such as cis-l-vinylcyclooct-3-en-l-ol, the thermal
rearrangement takes place preferably through a diradical intermediate.
At high temperature, the reaction also...
Over the last decade, the use of highly branched macromolecules, called dendrimers, is emerging. Polyamidoamine (PAMAM) dendrimers, in particular, have attracted high interest due to their unique properties, such as well-defined size, shape, and solubility in water. Our group, as part of an interdisciplinary team, is currently working on developing...
Benzylsuccinate (BSA), methylbenzylsuccinate (methylBSA), and ethylbenzylsuccinate (ethylBSA) are unambiguous anaerobic biotransformation products from toluene, xylenes, and ethylbenzene decay, respectively, and may be used to indicate intrinsic bioremediation is occurring at hydrocarbon-contaminated sites. In order to improve upon current methods that detect and quantify anaerobic hydrocarbon metabolites in field samples, solid-phase-extraction...
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...
The rate of removal of benzene, toluene, ethylbenzene and the xylene isomers (BTEX) from contaminated groundwater is needed to design remediation processes. Benzylsuccinic acid (BSA) and methyl-benzylsuccinic acid (methyl BSA) are unambiguous metabolites of anaerobic BTEX biodegradation. An analytical method for quantitative determination of BSA in groundwater samples was developed....
To determine the impact of emerging environmental contaminants on human and environmental health, quantitative analytical methods are required. Analysis of emerging contaminants is hampered by their widely varying physical-chemical properties. Therefore quantitative analytical methods must be developed to determine the behavior of emerging contaminants in environmental systems.
A quantitative analytical...
In this report, three studies are presented that aid in the development of drug discovery and their synthesis. In each, the importance of the marriage between computations and experiments is highlighted. Continued efforts in this vein are essential for future efforts towards improving human health.
The first case study investigated...
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...
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants and are mostly products of the incomplete combustion of organic material. PAHs are often found in environmental samples as a complex mixture of isomers. In addition, the same sources that produce complex PAH mixtures also produce other poorly characterized mixtures of organic compounds,...
Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental contaminants consisting of fused benzene rings. Parent-PAHs, methylated-PAHs (MPAHs), and PAHs with molecular weight of 302 a.m.u (MW302-PAHs) are considered as unsubstituted-PAHs. These unsubstituted-PAHs undergo transformation reactions resulting in the formation of PAH-transformation products (PAH-TPs), or substituted-PAHs, including nitrated-, oxygenated-, and...
Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast vibrational technique which allows rapid collection of Raman spectra with simultaneously high temporal and spectral resolution. With the recent development of FSRS methodology, three FSRS techniques (conventional, tunable, and anti-Stokes) have been implemented in our laboratory to dissect the excited state structural...
In the past decades, femtosecond stimulated Raman spectroscopy (FSRS) has been gaining tremendous popularity in fundamental sciences stemming from chemistry to biology. It is capable of capturing both equilibrium and non-equilibrium structural information across a broad range of timescales with simultaneously high temporal and spectral resolutions. Femtosecond transient absorption spectroscopy...
In this thesis, I present a new method we developed to study low frequency (< 700 cm⁻¹) vibrational dynamics: Time-resolved third-harmonic generation (TRTHG) spectroscopy. Among a variety of vibrational spectroscopy techniques, TRTHG differentiates itself with robustness, versatility, and simplicity. In TRTHG experiment, that involves only two ultrashort laser pulses, the...
One post-transcriptional mechanism that regulates the progression of cancer and other diseases involves small 22-23 nucleotide sequences called microRNA (miR). Early detection of small changes in concentration of these biomarkers holds potential to diagnose diseases at their earliest stages. Use of current nucleic-acid based biosensors, like molecular beacons, for in...
The aqueous chemistries of two transition metal cations, Zr⁴⁺ and Nb⁵⁺, are examined and then used to develop inorganic precursor solutions. The oxides of these cations (ZrO₂ and Nb₂O₅) are deposited and characterized, and their morphological and optical properties discussed. Due to the obstacles created by niobium's aqueous chemistry, an...
The variegated aqueous chemistries of metal cations are applied to the design and synthesis of non-toxic solution precursors suitable for additive printing of large-area oxide electronics. Polycondensation behaviors of aqueous Al+3 and PO4 +3 are manipulated in the deposition of atomically smooth amorphous aluminum oxide phosphate (AlPO) dielectric films. AlPO...
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...
The primary focus of this work is on examining structure-property relationships of interest for high-power nonlinear optical and laser crystals. An intuitive and simply illustrated method for assessing the nonlinear optical potential of structurally characterized noncentrosymmetric materials is introduced. This method is applied to materials including common quartz and tourmaline...
The materials Fe₂(Si,Ge)(S,Se)₄, Cu₃PS[subscript 4-x]Se[subscript x] (0 ≤ x ≤ 4), and Cu₃PxAs[subscript 1-x]S₄ (0 ≤ x ≤ 1) have been synthesized and studied as new earth-abundant absorbers for single and multijunction photovoltaic cells as well as solar fuel generation. The synthesis, single-crystal growth, and optical and electrical properties of...
It is the responsibility of humans, as environmental stewards, to monitor our impact on the environment so that efforts can be made to remediate the effects of our actions and change behaviors. To better understand our environmental footprint, sensitive and simple analytical methods are needed to quantify the contaminants that...
Understanding structural evolution in solids as composition changes is essential to materials properties prediction. Such structure-properties relationships are the theme of solid state chemistry. Materials scientists and chemists have utilized an abundance of simple crystal structures to enhance understanding of chemical and structural origins of properties in materials for decades....
Public attention and concern about per- and polyfluoroalkyl substances (PFASs) are increasing due to detection of PFASs in drinking water supplies, the environment, including remote locations, and wildlife and to the lowering of the federal health advisory levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in drinking water. Aqueous film-forming...
Instrumental and radiochemical neutron activation analyses supported by electron microprobe mineral analyses (Paul Warren, University of New Mexico) and petrographic observations are presented for approximately forty individual clasts separated from the Kapoeta howardite. These clasts are classified into eucritic, cumulate-like, mafic (plagioclase ± olivine-bearing pyroxenites), pyroxenite, polymict and/or metal-rich and...
Trichloroethene (TCE) is the most frequently detected organic contaminant in groundwater, is classified as a probable human carcinogen, and exhibits toxicological effects on the human endocrine, immune, developmental, and reproductive systems. While significant research efforts have been devoted to the development of strategies for remediating TCE-contaminated groundwater, their advancement is...
Investigating the structure-property relationships of solid state materials can help improve many of the materials we use each day in life. It can also lead to the discovery of materials with interesting and unforeseen properties. In this work the structure property relationships of newly discovered layered oxypnictide phases are presented...
Nine Ca-Al-rich inclusions and one olivine inclusion
from Allende meteorite were studied for Ti, Al, Fe, Mg, Ca,
Na, Cl, K, Sc, V, Cr, Mn, Co, Ni, Zn,Hf, W, Ir, Au, Ta,
and Re -via INAA (instrumental neutron activation analysis)
and REE, Ba, Sr via RNAA (radiochemical NAA). The inclusions...
Amorphous metal thin films lack the grain boundaries and dislocations present in
crystalline metal films. As a result, amorphous metal films can be more mechanically robust, atomically smooth, and more resistant to chemical attack than crystalline metals. However, amorphous metals are meta-stable and subject to crystallization upon heating, thus limiting...
The chemistry of hafnium oxide based and materials are described in the context of ion exchange and lithography. HafSOx, represented by the composition HfO₂₋[subscript x](SO₄)x, is described to possess a significant capacity towards ion exchange in acidic and basic solutions, enabling films of HafSOx to be cleanly and readily be...
Phosphate and peroxide stabilize new oxo-hydroxo niobium clusters in water at low pH. The clusters open a new chapter in aqueous niobium chemistry under acidic conditions. The clusters also produce atomically smooth, amorphous niobium oxide phosphate (NbPOx) thin films. Reaction pathways from cluster solutions to amorphous niobium oxide phosphate solids...
The use of an adjacency matrix to determine distant (not maximal or
minimal) subgroup and supergroup relationships between crystallographic spacegroup
types is described. Full lists of space-group types that are supergroups and
subgroups for every space-group type were compiled. A list of the space-group
types connected to each space-group type...
Solid state luminescent sulfides are prepared as powders in order to elucidate the relationship between structure and light emission. While the sulfides studied in this dissertation are known phosphors, materials are investigated in a variety of new ways. Elementary properties and structures of MgS are reviewed, and preparation of MgS...
This dissertation presents a study of structure-property relationships within 3d/4d metal oxides containing precious metals through detailed structure refinements using high-resolution neutron and X-ray diffraction data along with exploration of the resultant properties.
Oxides of 4d or 5d transition metals tend to show new topological phases due to significant spin-orbit...
Synthesis and discovery lies at the core of every field in chemistry. The investigation of the structure-property relationships in compounds known or new is the fundamental purpose of solid state chemistry. Mixing related solid state compounds to form solid solutions can lead to exciting new and/or unexpected properties. Layered compounds...
While properties are extremely important from an application point of view, it is crucial to have a detailed understanding of the underlying structural influence. Once a concrete correlation between the structure and the observed property is established, rational design of novel materials with optimized properties can be realized. These optimized...
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...
Crystals of an incongruent-melting compound, Ba₃MgSi₂O₈, were grown by the flux method and its structure was determined by single crystal X-ray diffraction methods. Ba₃MgSi₂O₈ crystallizes in trigonal space group P-3[bar]m1 with a = 5.6123(3) Å, c = 7.2667(9) Å and Z = 1. Eu²⁺ ions prefer one crystallographic Ba site...
The presence of per- and polyfluoroalkyl substances (PFAS), organic contaminants first synthesized in the 1940s, has been reported worldwide in a variety of environmental matrices and ultimately in biological systems including humans. Ongoing research into PFAS has included identifying novel PFAS, assessing their fate and transport in the environment, and...
The subject of this PhD thesis is part of a research domain of great present interest in new semiconductor materials for photovoltaic and thermoelectric applications. This domain contains the elaboration and the study of both Cu-based chalcogenides bulk and thin-film samples, driven by materials design principles.
One of the most...
Chlorinated aliphatic hydrocarbons (CAHs) such as vinyl chloride (VC) and 1,-2 dichioroethane (DCA), are wide-spread groundwater pollutants found at many contaminated field sites around the world. Quantitative tools are needed to determine the in situ rates of VC and DCA transformation to ethene in contaminated groundwater. The objective of this...
New transparent p- and n-type semiconductors and luminescent materials have been prepared and characterized. Synthesis, structures, optical and electrical properties of new chalcogenide fluoride p-type transparent semiconductors MCuQF (M=Ba, Sr; Q=S, Se, Te) are described. Band-gap tuning and improvement in conductivity through p-type doping are demonstrated in the family. The...
Due to the high cost of precursor materials, complex oxides of 4d and 5d transition metals are under-studied compared to their 3d counterparts. Recent studies have shown that oxides containing heavier transition metals can exhibit exotic electronic states due to presence of strong spin-orbit coupling. The goal of this dissertation...
Enzymes play an important role in the environment, they breakdown natural-occurring and anthropogenic molecules so that they can be transported into cells and utilized. Enzyme assays are routinely used in soil science and oceanography to measure the activities of specific processes and to serve as general indicators of microbial activity....
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...
Thermoelectric materials are playing a larger role in the global effort to
develop diverse, efficient, and sustainable energy technologies: primarily through
power-generating thermoelectric modules. The principal components of
thermoelectric modules are solid-state thermoelectric materials – typically heavily
doped semiconductors – that convert heat directly into electricity. However, this
conversion efficiency...
The Gd3+ ion has been used to induce quantum splitting in luminescent
materials by using cross-relaxation energy transfer (CRET). In Nd:LiGdF4, quantum
splitting results from a two-step CRET between Gd3+ and Nd3+, first involving a
transition 6G→6I on Gd3+ and an excitation within the 4f3 configuration of Nd3+
followed by...
Oxides of post-transition metals often show unique structures and properties due to the presence of lone pair electrons and the diffused s orbitals. The present work focuses on synthesis and characterizations of oxides containing Te, a heavy post transition metal.
New series of pyrochlore oxides of the formula Cs(M,Te)₂O₆ (M...
Several types of solid-state inorganic materials are prepared and characterized. By using the SILAR (Successive Ionic Layer Adsorption and Reaction) deposition method in conjunction with hydrothermal dehydration both low-temperature deposition and crystallization of oxide thin films are achieved. Various aspects of new transparent p-type materials are studied by examining both...
While fluorochemicals have been detected all over the world and in wastewater
treatment plants, the effect of wastewater effluent on the receiving waters has not been
evaluated. In the first study, the mass flow of fluorochemicals emanating from
wastewater treatment plants along the Glatt River in Switzerland was evaluated. The...
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...
Since their discovery in the 1990s, the great potential of carbon nanotubes (CNTs) has made them a focus of many research endeavors, including their application as components of biosensors. The inherent chemical "inertness" of CNTs makes their application to biosensing a challenge. It is necessary to "decorate" their surfaces to...
Heavy alcohol consumption reduces peak bone mass in growing rodents and can lead to bone loss in both adult rats and humans. In contrast, moderate alcohol consumption appears to have a bone sparing effect in post-menopausal women. Alcohol has been reported to increase aromatase activity and influence estrogen receptor (ER)...
The results of the research presented in this work are related to synthesis and investigations of novel color inorganic pigments having various structures and shades. Inorganic pigments play a major role in contemporary life. They are used in paints, rubber, plastic, cosmetics etc. Searching for new, stable, environmentally benign and...
Per- and polyfluoroalkyl substances (PFAS) are a group of contaminants of great concern due to their toxicity and ubiquity in the environment. Remediation efforts historically have focused on granular activated carbon (GAC) because of its low maintenance and relatively low cost. However, GAC is not PFAS selective and is especially...
Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
In this dissertation, the spectroscopic properties and thermodynamic stability of a class of materials known as metal oxo and hydroxo clusters are studied. In aqueous solutions, many metals can aggregate into discrete clusters of metals bridged by oxo or hydroxo ligands. These clusters are of particular interest to us for...
Ultrafast spectroscopy can exploit the structure-function relationship of chemical- and biological-based systems. More specifically, femtosecond stimulated Raman spectroscopy (FSRS) provides ground- and excited-state vibrational information with simultaneously high spectral (spatial) and temporal resolutions. The electronic counterpart, femtosecond transient absorption (fs-TA), complements FSRS data analysis as part of a comprehensive approach...
The overall concept of reducing laboratory operations to a scale that fits on a single microfluidic chip has been an attractive area of research over the last several decades. Despite a surge in research, few commercial success stories have been written. Lab-on-a-chip technologies have the capability to be cost effective...
Contaminant transport in ground water is an important environmental process that
affects a host of natural systems. Transport of contaminants is affected by many
processes, including aqueous complexation, adsorption, and redox reactions. One of the
most important components of an aquifer that controls transport is iron-oxide. In this
study, the...