The overarching theme of this thesis is the development of non-natural oligomers for use in biological applications. Chapter I details the synthesis and studies of modified peptide nucleic acid (PNA) oligomers. PNA is a synthetic oligonucleotide mimic that binds to natural nucleic acids with extremely high affinity and specificity, making...
Preventing the build-up of indoor pollutants represents an emerging goal in environmental chemistry. Heterogeneous catalysis provides an attractive method of remediating indoor air pollution, but optimization through rational catalyst design requires a detailed understanding of the catalytic surface and surface-pollutant interactions. In this work, a chemical ionization mass spectrometry (CIMS)...
Interfaces and surfaces are ubiquitous in the environment. Heterogeneous binding events and reactions control the transport and speciation of dissolved pollutants in groundwater. Many heterogeneous processes occur at mineral oxide/water interfaces, and can be controlled either by the mineral oxide, or organic molecules bound to the surface. The prevalent natural...
The first section of this thesis focuses on applications of DNA-modified gold nanoparticles (AuNPs) while the second part addresses the fundamental properties that arise from conjugating DNA to inorganic AuNPs. Two types of applications are discussed. The first application utilizes the colorimetric properties of AuNPs to screen duplex and triplex...
This dissertation focuses on the utilization of two coordination chemistry-based synthetic approaches, which provide the ability to rapidly and quantitatively assemble sophisticated supramolecular cofacial porphyrin complexes. Significantly, by adopting a coordination chemistry-based approach, the porphyrin-porphyrin interactions can be regulated in situ via the addition or removal of chemical effector molecules....
Two new methods have been developed employing silicon-containing molecules in novel organic transformations. The first strategy utilizes Lewis base-activation of triethoxysilylalkynes to deliver mild acetylide nucleophile equivalents. The second approach involves the use of enolate additions to acylsilanes to generate β-silyloxy homoenolate intermediates.
Lewis base-catalyzed activation of triethoxysilylalkynes promotes the...
The work presented in this thesis describes investigations into linear and nonlinear optical properties of two-dimensional silver nanoparticle arrays. The linear optical measurements - extinction measurements were performed on two-dimensional square arrays of L-shaped silver nanoparticles fabricated by electron beam lithography in order to study the effect of dipole coupling...
This dissertation describes the use of alkanethiols and polymers for the development of lithographic affinity and resist array templates that can be utilized for directing the assembly of biological molecules, for building up multilayered polyelectrolyte thin films, and for fabricating metal solid-state nanostructures. The first two chapters of the work...
Theoretical analysis of DNA bridge-mediated electron transfer (ET) led to the proposal that photoinduced ET might occur via either superexchange or hopping mechanisms. Electron transfer has been proposed to occur via a superexchange mechanism at short distances and via a hopping mechanism at longer distances. However, a crossover in mechanism...
The contents of this dissertation are divided into two sections: (1) the preparation and characterization of quaternary rare-earth chalcogenides and oxychalcogenides and (2) the localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles fabricated by nanosphere lithography (NSL).
Single crystals of CsTmCoS3, CsYbCoS3, CsHoCoSe3, CsYbCoSe3, and CsYbZnSe3 have been prepared...
The work described in this dissertation focuses on the optical characterization of micron-sized structures with mesoscale (100-1000 nm) features to investigate of the optical analog to the quantum corral. Lithographically patterned arrays of metallic rings and ellipses were used to study how light can be manipulated and confined within these...
This thesis attempts a combined theoretical/experimental investigation of two fundamental scaling laws in charge transfer reactions: how the rate of those reactions varies as a function of distance between an electron donor and an electron acceptor and how the rate varies as a function of the number of distinct pathways...
This thesis investigates singlet exciton fission, a physical process that converts one singlet exciton to a pair of triplet excitons. Singlet fission was discovered nearly forty years ago, but the mechanism for this process is still not well understood. Recent work has suggested that singlet fission may be capable of...
Metallic nanostructures are able to confine and manipulate electromagnetic fields because light can couple to free electron oscillations called surface plasmons (SPs). These plasmons exist on metal surfaces as localized (short-range) or as propagating (long-range) modes depending upon the size and geometry of the nanostructure. This dichotomy is primarily an...
This thesis summarizes our research efforts on the application of the nano-structured anodic aluminum oxide (AAO) membrane in heterogeneous catalysis. Procedures for growing the AAO membrane in the center of an aluminum disc have been developed by appropriately masking the disk's perimeter during the anodization and etching steps. The remaining...
Chemical vapor deposition (CVD) is a well-developed technique for growing thin films of a wide variety of materials, which relies on the development of new and better performing metal-organic precursors. To this end, three studies have been conducted into the compatibility of sulfur and phosphine containing ligands with low- and...
Conjugated organic molecules and polymers hold significant promise for use as active materials in electronic devices. Employing such "soft" materials can decrease cost of device fabrication, while enabling unique properties such as mechanical flexibility, large-area coverage, and highly tunable materials properties. A primary roadblock to the realization of this dream...
Metal nanoprisms are a novel class of anisotropic nanomaterials with unique optical properties dependent on their size, shape, and composition. Silver nanoprisms are of particular interest because their surface plasmon resonance bands are readily tunable in the visible and near-IR region. The objectives of this thesis research focus on photochemical...
Chapter 1 describes the homopolymerization of styrene and the copolymerization of ethylene and styrenic comonomers mediated by the single-site bimetallic "constrained geometry catalysts" (CGCs), (µ-CH2CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [EBICGC(TiMe2)2; Ti2], (µ-CH2CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [EBICGC(ZrMe2)2; Zr2], (µ-CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](TiMe2)}2 [MBICGC(TiMe2)2; C1-Ti2], and (µ-CH2-3,3'){(η5-indenyl)[1-Me2Si(tBuN)](ZrMe2)}2 [MBICGC(ZrMe2)2; C1-Zr2], in combination with the borate activator/cocatalyst Ph3C+B(C6F5)4- (B1). Under identical styrene homopolymerization conditions,...
N-Heterocyclic carbene catalysis has recently emerged as an important field in organic chemistry. Two new strategies have been developed to advance the use of N-heterocyclic carbenes (NHCs) as Lewis-base organic catalysts. The first approach utilizes NHCs to catalyze the generation of homoenolates and the conjugated Breslow intermediate is added to...