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Seven of the Department of Chemistry's top doctorate students have received 2014-15 Doctoral Dissertation Fellowship program awards. Recipients include Christopher "Chris" Huber who is advised by Professor Aaron Massari; Katherine "Katie" Hurley who is advised by Professor Christy Haynes; William "Will" Isley III who is advised by Professor Christopher Cramer; Maral Mousavi who is advised by Professor Philippe Buhlmann; Mayank Puri who is advised by Professor Lawrence Que Jr.; Pragya Verma who is advised by Professor Donald Truhlar; and Tao Wang who is advised by Professor Thomas Hoye.
The Doctoral Dissertation Fellowship program gives the university's most accomplished doctorate candidates an opportunity to devote full-time efforts to outstanding research projects by providing time to finalize and write a dissertation during the fellowship year. Awardees receive an academic year stipend of $22,500 and tuition. They participate in a monthly seminar series, present their research at an annual poster session, and receive travel grants to present their work at national or international conferences.
Christopher "Chris" Huber is entering his fifth year of graduate study. He is advised by Professor Aaron Massari. Chris is interested in using two-dimensional infrared spectroscopy (2DIR) to study silica sol-gel materials. Specifically, he is interested in measuring the solvent dynamics within the confined volumes within the pores of silica sol-gel materials. Confined volumes typically exhibit dynamics that are slower than in bulk solutions. This is due to the solvent-surface interactions which slow the solvent dynamics within these pores. So, by varying the solvent within the pore, interactions can be studied. He is also studying porous silica particles with varying pore sizes, which will speak to the depth of the solvent-surface interactions. In order to study these confined dynamics, Chris developed a synthesis that includes an intrinsic probe into those materials. Those studies will be the first to use this specific probe in 2DIR spectroscopy. 2DIR spectroscopy is primarily used to measure dynamics of systems in equilibria; however, Chris is interested in applying it to non-equilibrium systems. He has started another project using 2DIR to measure the structural dynamics of a solution as it approaches gel formation.
Katherine "Katie" Hurley is entering her fifth year of graduate study. She is advised by Professor Christy Haynes. Katie works at the interface of materials and analytical chemistry, the bridge between making a material and studying its behavior in relevant environments. Currently, she synthesizes and characterizes iron oxide and mesoporous silica nanoparticles for biomedical applications. Iron oxide can provide magnetic resonance imaging (MRI) contrast and can be heated upon exposure to an alternating magnetic field. This means that the platform could be used to both detect and treat diseases like cancer. Adding a shell of mesoporous silica imbues colloidal stability, protection against degradation, and the additional opportunity for drug loading due to its large surface areas and pore volumes. Katie studies these core/shell particles in vitro and, very recently, in vivo, looking for relationships between biological structure (i.e., aggregates) and function.
William "Will" Isley III is entering his fifth year of graduate school studying under the supervision of Professor Christopher Cramer. Will’s research focuses on physical and computational investigations of macromolecular systems, including host-guest complexes and metal organic frameworks (MOF). This work is divided into two categories: modeling molecular recognition through prediction of intermolecular interactions with highly accurate methods and the modeling of chemical reactivity in macromolecular porous frameworks. Some of Will’s most recent work has been to investigate spin-crossover in host-guest complexes. Using the predicted nuclear magnetic resonance (NMR) spectra of a paramagnetic, iron host-guest system, the spin-crossover behavior of the host complex was able to be accurately modeled. Will has also studied gas adsorption on M-MOF-74, contributing to a prediction of a yet-unsynthesized material capable of separating N2 and CH4.
Maral Mousavi is advised by Professor Philippe Bühlmann and is entering her 5th year of graduate study in the spring of 2015. Her research is focused on expanding the application of fluorous-phase ion-selective electrodes (ISE) for analyses in biological and environmental media. The large sample volume required for measurement with ion-selective electrodes limits their application in real-life samples. To enable widespread application of fluorous-phase ISEs in biological analyses, Maral is working on reducing the sample volume needed for detection with these sensors by developing fluorous-phase ion-selective microelectrodes. Her work involves synthesis of the components of the fluorous-phase ion-selective microelectrode and optimizing the fabrication procedure. Since reference electrodes are an inevitable part of almost any electrochemical measurement, they need to be miniaturized as well to allow detection in small sample volumes. To achieve this goal, Maral is investigating different materials (e.g., porous glass and polymer) that can contain salt bridges in the miniaturized reference electrodes and provide a sample independent reference potential. To investigate the reliability of fluorous-phase ion-selective electrodes in environmental and biological samples, she uses the silver selective fluorous-phase ISEs in studying the toxicity and environmental hazards of silver nanoparticle. She is particularly interested in the effect of media on the extent and kinetics of Ag+ release from silver nanoparticles.
Mayank Puri is beginning his fifth year of graduate studies under the guidance of Professor Lawrence Que Jr. Research in the Que lab is focused on understanding the chemistry of iron-containing enzymes, many of which have been shown to efficiently catalyze reactions of great practical importance, such as the conversion of methane to methanol and the reduction of dioxygen to water-two reactions thought to be central in establishing clean, alternative energies for the future. Mayank’s thesis work has focused on synthesizing and examining model compounds that are proposed to be similar to intermediates involved in the catalytic cycles of these iron-containing enzymes. In this context, Mayank is particularly interested in understanding the factors that affect the reactivity of these model compounds with organic substrates. Two factors currently being investigated include the sterics of the ligands that support the iron center and the electron distribution at the iron center itself. In addition, Mayank has been studying the rate of oxygen-atom exchange between a number of synthetic iron-oxo compounds and H218O. Establishing the kinetics and elucidating the mechanism of this exchange reaction will be key in determining if iron-oxo intermediates are involved in important catalytic processes.
Pragya Verma is entering her fourth year of graduate studies. Her adviser is Professor Donald Truhlar. A research focus is on the quantum mechanical investigation of the structure and properties of metal-organic frameworks (MOFs). MOFs are novel and versatile materials that have gained considerable attention in the last decade due to the variety of applications they can have in industry. Researchers are interested in theoretically studying the ability of MOFs to act as molecular sieves, to do catalysis, and to behave as magnetic materials. The extended and periodic structure of these MOFs is currently being studied using cluster models carved from the experimental structures. The clusters are designed to have size large enough to capture the main interactions occurring at the active site and are also suitable for performing high-level quantum mechanical calculations. The in-house developed Minnesota suite of density functionals and charge models are currently being tested and applied to determine the ground spin states, binding strengths, and anisotropic and isotropic properties of the cluster models of MOFs both in the absence and presence of an adsorbate. The ultimate goal of this project is to develop good theoretical methods that would work well for MOFs.
Tao Wang is entering his fourth year of graduate study under the guidance of Professor Thomas Hoye. His research is focused on the (i) biomimetic synthesis of natural products as well as (ii) developing new strategies in the synthesis of arene derivatives. (i) He has demonstrated a case for a spontaneous, Diels–Alderase-free dimerization as the key step in the biosynthesis of paracaseolide A. This discovery is important at the fundamental level of understanding. Th concise synthesis provides a pathway for producing analogs and material required to support further studies of the biological activity and potential pharmaceutical application of paracaseolide A. (ii) New hexadehydro-Diels-Alder (HDDA) reaction-based strategies hold the potential to greatly streamline arene synthesis, as exemplified by Tao's recent success in developing a four-step total synthesis of murrayacine. His mechanistic studies of new aspects of new HDDA reactions are also providing better understanding of fundamental features of aryne reactions.