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...
A method for the control of absolute stereochemistry in
morphine syntheses has been demonstrated by the resolution
and efficient racemization of the advanced morphine precursor , 9-methoxy-3-methyl-5,6-dihydro-3H-benzofuro[3,2-e]isoquinoline-
7(7aH)-one, I. This was accomplished by the facile coversion of optically resolved I to its ring opened
form, 5,6,7,8-tetrahydro-10-methoxy-3-methyl-7-oxo[1]benzoxonino[
6,7-c]pyridinium tosylate, II, (Equation...
Described herein is the synthesis of an uncharged stereoregular oligonucleotide
analog consisting of cytosine bases linked at specific intervals to a polyamide backbone
derived from (L)-glutamic acid. Preparation of this analog entailed borane reduction of
(L)- pyroglutamic acid to give optically pure lactam alcohol 9. Tosylation and alkylation
with cytosine...
A novel acyl protecting group for cytosine and adenine has been prepared
from 4-( chloromethyl) benzoic acid. Reaction of the acid with morpholine produces
4-( 4-morpholinyl )methyl benzoic acid which is converted to it's acid chloride
with thionyl chloride. This may be used to acylate cytidine and adenosine under
standard...
The first asymmetric synthesis of (-)-7-epicylindrospermopsin via intramolecular nitrone cycloaddition is described. The synthesis utilized a convergent approach to prepare the cycloaddition precursor 176, which was assembled by condensation of hydroxylamine 175 with aldehyde 145. Hydroxylamine 175 was synthesized from ethylene glycol (166) in seven steps. Aldehyde 145 was completed...
A new approach to the discovery of high absorbing semiconductors for solar cells was taken by working under a set of design principles and taking a systemic methodology. Three transition metal chalcogenides at varying states of development were evaluated within this framework. Iron pyrite (FeS₂) is well known to demonstrate...
Oxide materials exhibit a wide variety of structures and properties. In particular, transition metal oxides tend to be highly stable while exhibiting a wide range of properties that can be used for numerous applications. This work focuses on investigating how the structures’ of 4d and 5d transition metal oxides influences...
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...
This dissertation outlines two approaches for improving the efficiency and reducing the cost of photovoltaic energy generation. First, the structures of known binary copper and iron compounds are used to choose the promising compositions Fe₂XS₄ (X = Si, Ge), Cu₃TaQ₄ (Q = Se, Te), and BaCuQ'F (Q' = S, Se,...
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...
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...
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...
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...
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...
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...
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...
Oxo-hydroxo Group 5 metal clusters are an untapped resource to study and advance aqueous solution processing of metal oxide thin films. The tetramethylammonium (TMA) hexatantalate salt (TMA6[H2Ta6O19]) yields dense Ta2O5 films (~95% of the bulk ß-Ta2O5 density) with atomically smooth surfaces (<4 Å root mean square surface roughness). This same...
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...
Novel ternary graphite intercalation compounds (GICs) of alkali metal cations
and a wide variety of amines have been synthesized by one-pot chemical syntheses.
Alkali metals studied includes Li, Na and K. The families of amines employed are nalkylamines,
branched alkylamines, and different structural isomers of diamines and
polyamines. Intragallery structures...
The intriguing size- and shape dependent properties of nanoparticles have garnered recent attention in many science and engineering areas. When the particle size is in the nanometer size range, the material exhibits very different properties such as surface plasmon resonance (of gold nanoparticles) and superparamagnetism (of iron oxide nanoparticles). The...
Pactamycin, first reported in 1962, is a potent antitumor antibiotic produced by the soil bacterium Streptomyces pactum. Structurally, it contains a cyclopentitol core unit, a 3-aminoacetophenone (3AAP), a 6-methylsalicylic acid (6-MSA), and a N,N-dimethyl urea. The aminocyclopentitol ring is derived from glucose, possibly via N-acetyl glucosamine (GlcNAc), the 3-aminoacetophenone (3AAP)...
Novel donor-type graphite intercalation compounds (GICs) containing tetra-n-alkylammonium (TAA) cations have been synthesized by using both ion-exchange and electrochemical methods. Structural and compositional data of the resulting TAA-GICs are investigated by using powder X-ray diffraction (PXRD), one-dimensional electron density calculations, thermogravimetric and elemental analyses, and capillary zone electrophoresis (CZE). A...
Studies toward the total synthesis of a highly potent cytotoxic marine natural product, phorboxazole A, were conducted and resulted in a route to an advanced intermediate, C4-C32, for this purpose. A key feature of our approach is the stereoselective synthesis of two cis-2,6-disubstituted tetrahydropyrans present in the macrolide portion of...
Gold nanostars are a relative newcomer to the nanoparticle scene, and their unique properties make them very desirable for spectroscopic applications. These nanoparticles, with their sharp tips, create electric field enhancements that interact with light in an advantageous way. This Thesis outlines our in-depth study of gold nanostar synthesis, the...
Fluorescence has proven to be a robust and powerful method of analysis in numerous fields: forensics, pharmaceutics, geology, food science, and environmental sciences have all developed a large collection of fluorescence instruments and methods to overcome application-specific challenges. Biological applications saw the same development of a fluorescence toolkit with methods...
PART I. Asymmetric syntheses of both natural (+)- and nonnatural (-)-byssochlamic acid via a [2+2] photoaddition-cycloreversion strategy are described. X-ray crystallographic analysis of the cyclohexylamine salt 99 showed that the structure of the monomethyl ester 100 from esterase hydrolysis of 44 was originally misassigned as 56. The enantiomeric relationship of...
An asymmetric approach to the synthesis of byssochlamic acid (1) is
described. Regioisomeric enzymatic differentiation is described in the selective
hydrolysis of dimethyl ester 30 by porcine liver esterase. Chiral dimethyl ester 42
was prepared by desymmetrization of cyclopentene 34 using porcine liver
esterase. A key intramolecular [2+2]cycloaddition-cycloreversion
photometathesis of...
An examination was made of some reactions involving a transfer
of carbon from boron to carbon. In the case of the reaction of
a C[subscript n] alkylorganoborane with dichlorocarbene the intermediate was
a C[subscript n]₊₁ chloroalkylorganoborane. Oxidation of this intermediate
yielded an homologous acid (33%) and the usual alcohol (66%)....
Fluorescence of adenine, guanine, thymine, cytosine, and uracil
has been detected at room temperature in neutral aqueous solution
using a digital signal accumulation technique and right angle fluorescence
detection from solutions with absorbances between 0. 4 and 0. 7.
The quantum yields are respectively 2.6 x 10⁻⁴, 3.0 x 10⁻⁴,...
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 melt intercalation of poly(ethylene oxide) (PEO) between layers of MoO₃ and MPS3 (M=Mn,Cd) is obtained by heating the ground mixture and LiₓMoO₃, KₓMn₁-ₓ/₂PS₃, or KCd₁-ₓ/₂PS₃. The products are characterized by powder X-ray diffraction (XRD). Below the melting temperature of PEO (66 °C), intercalation rates and yields are low. By...
My work has focused on using density functional theory to elucidate mechanisms of organocatalytic and transition metal catalyzed reactions by considering competing mechanisms. In each of the three presented studies computational investigation complemented experimental work by predicting stereoselectivity or revealing origins of stereo, regio, or chemoselectivity.
A study on the...
The relative rates of hydrogen atom abstraction from a series of
13 homoaryl and heteroarylmethanes by t-butoxy radical were determined at 70°C. The attacking radical was photochemically generated
from di-t-butyl peroxide. A relatively small range of relative rates
(factor of seven) has been found among the compounds studied. The
relative...
Normal adult rats absorbed and metabolized C¹⁴-labeled acetate
rapidly. The greatest percentage of the administered radioactivity
was recovered in the expired CO₂, however small amounts of radioactivity
were also found in the urine and feces. There were two rates
of C¹⁴O₂ elimination in normal adult rats. The small amount of...
Solid state inorganic oxides play an important role in next generation electronics based on their stability, versatility, and enhanced properties over other materials. However, in order to design or tune these materials for a desired functionality it is necessary to fully understand the structure behind the properties exhibited. This dissertation...
In particle induced desorption-ionization mass spectrometry the strength of an
analyte's signal under a given set of bombardment conditions is usually considered to
be representative of the analytes relative surface activity. This rationale is generally
used to explain differences in the technique's sensitivity between and within various
classes of compound....