The properties of crystalline materials are controlled by their composition and by their structure, however, the structure of a crystal is only partly controlled by its composition. Development of specifically directed inorganic syntheses will require an understanding of the dynamics of crystal phase forming processes, especially those processes involved in...
The FDA approvals of afatinib and ibrutinib in 2013 led to a heightened interest in cysteine-reactive covalent inhibitors. However, there are few methods to discover new cysteine-reactive inhibitors for enzymes for which reversible binding scaffolds are not known. To this end, we rationally designed a chemical system to attach a...
Metalloporphyrins fulfill incredibly diverse chemical roles in biology and photocatalysis, where they act as photosensitizers, redox sites, substrate binding sites, and facilitators of long range electron transfer. Metalloporphyrin chemistry is uniquely tuneable through conformation and functionalization of the porphyrin ring, choice of metal, and interaction with the environment as these...
Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for characterizing molecular systems. It combines the chemical selectivity of vibrational spectroscopy with plasmonic signal enhancement to achieve the ultimate limit of detection--a single molecule. By overcoming the effects of ensemble averaging, single molecule SERS (SMSERS) probes distributions in molecular interactions and...
Interprotein electron transfer (ET) occupies a central role in both chemistry and biology, as it is important in a variety of functions including cellular respiration, metabolism, and energy transduction during photosynthesis. Consequently, understanding the protein-protein recognition and docking that controls interprotein ET is an important field of scientific research.
One...
Raman spectroscopy is an established and versatile molecular sensing technique, but it is limited by its modest chemical sensitivity. Surface-enhanced Raman spectroscopy (SERS) can amplify otherwise weak normal Raman signals up to nine to ten orders of magnitude, giving rise to its application in many molecular sensing problems, including those...
Organic photovoltaics (OPVs) are an attractive solar energy technology for low-current applications. Herein is described the supramolecular design and methodology to manipulate intermolecular interactions in order to create an active layer in OPVs devices composed of crystalline and amorphous donor-acceptor domains, which has been proposed as the ideal morphology for...
With the dual challenges of meeting global energy demand and mitigating anthropogenic climate change, significant effort is being applied to generating power from renewable sources. The dye-sensitized solar cell (DSC) is a photovoltaic technology capable of generating electricity from sunlight, but suffers losses in efficiency due to deleterious electron transfer...
Halide perovskites, AMX3 (A = monocation, B = Ge, Sn, or Pb, and X = halogen), present a versatile class of solution-processable semiconductors made from earth abundant materials with outstanding electrical and optical properties. Their solar cell efficiencies have dramatically increased from ~9% to ~22% in less than five years...
Ultrafast spectroscopy offers an unprecedented view on the dynamic nature of chemical reactions. From charge transfer in semiconductors to folding and isomerization of proteins, these all important processes can now be monitored and in some instances even controlled on real, physical timescales. One of the biggest challenges of ultrafast science...
Heterogeneous catalysts play a prominent role in our society, used in applications that range from the production of plastics to the catalytic cracking of crude oil. Industrial catalysts are typically made of mixed metal oxides or nanosized metal particles deposited on high surface area supports. Industrially relevant catalytic materials are...
Climate change may be one of the most important puzzles the world has attempted to solve and one of the greatest challenges in this area is to improve our understanding of how atmospheric aerosol particles impact climate processes. We seek to overcome this challenge by focusing on the chemistry and...
This dissertation describes the relationship between the surface chemistry of colloidal semiconductor nanocrystals (quantum dots, QDs) and their optoelectronic properties, such as photoluminescence and degree of quantum confinement. We primarily focus our efforts on one particular subset of ligands known to couple strongly to the inorganic core of the QD...
Understanding the nature of quantum effects in dense biological systems is of great interestto many scientists today. It seems that the question is not does quantum mechanics dictatebiological processes, but rather by how much and to what extent. A big challenge though in thisfield is how to properly test and...
In Chapter 1, a series of "constrained geometry" organoactinide complexes, (CGC)An(NMe)2 (CGC = Me2Si(h5-Me4C5)(tBuN); An = Th, 1; U, 2), prepared via efficient in situ, two-step protodeamination routes in good yields and high purity, is presented. Both 1 and 2 are quantitatively converted to the neutrally charged, solvent-free dihalides (1-Cl2,...
Four series of doped CdO thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates by metal-organic chemical vapor deposition (MOCVD), and their phase structure, microstructure, electrical, and optical properties investigated. Epitaxial films grown on single-crystal MgO(100) exhibit biaxial, highly textured microstructures. These as-deposited doped CdO thin...
Counteranion effects on the rate and stereochemistry of propylene polymerization mediated by ion-pair complexes derived from dimethylzirconocene precatalysts activated with strongly Lewis-acidic perfluoroarylmetalloid cocatalyst/activators are shown to arise from the strength of the cation-anion interaction. This is quantified using CS-symmetric Me2C(Cp)(Flu)ZrMe2 (Cp = C5H4, η5 cyclopentadienyl; Flu = C13H8, η5...
Local structure determination in amorphous and disordered systems, which are crystallographically intractable, is critical for gaining an understanding of their properties. X-ray absorption spectroscopy (XAS) is an excellent tool for local structure determination in amorphous and disordered environmental materials. Amorphous manganese oxides produced by the freshwater bacterium Leptothrix discophora SP6...
Two new strategies have been developed to accomplish direct nucleophilic acylation reactions. In the first approach, acylsilanes are added to various electrophiles using N-heterocyclic carbenes as catalysts. The second method utilizes O-silyl thiazolium carbinols as stoichiometric acyl anion precursors to afford acylated products under mild reaction conditions.
N-heterocyclic carbenes generated...
High relaxivity contrast agents are of great importance in the advancement of magnetic resonance imaging diagnostics for use in biomaterials. Biomaterials that are implanted into the body, with the goal of repairing or regenerating lost or damaged tissue, need to be tracked noninvasively, over time. I have completed work using...