In addition to the regular curricular offerings, there are many research opportunities available to students throughout the year; we feel strongly that exposure to scientific research is very important and highly complementary to the training that our students receive in the classroom. We encourage all students to find a way a take part in a research experience during their years at Williams. During the fall and spring semesters, as well as Winter Study, students can undertake projects in faculty labs for academic credit (either as independent study or senior honors projects, or as a 3-week Winter Study course). During the summer months, students can work in faculty labs, typically for 10 weeks at a time; funding for summer research positions is obtained through individual faculty grants, as well as departmental and divisional sources. Students of all years are encouraged to talk to different faculty members about their research interests. Chemistry students have worked on biology, physics, mathematics, environmental science, and geoscience research projects on campus, as well as off-campus projects throughout the world.
To learn more about faculty research opportunities for students, please visit our faculty’s individual profiles.
Anthony Carrasquillo, environmental/physical-organic chemist
Atmospheric particulate matter, or aerosol particles, have important implications for human health, visibility, and the global climate. Our ability to accurately predict ambient concentrations, chemical composition, and relevant properties (e.g., optical properties, toxicity, cloud forming potential, etc.) is limited primarily due to significant gaps in our understanding of how the organic aerosol fraction forms and evolves over time. Organic aerosol is immensely complex, containing hundreds to thousands of individual molecules, each with their own chemical properties and reactivities. Even the most carefully executed laboratory experiments and sophisticated models are unable to produce material with a chemical composition similar to that of the organic aerosol measured in the atmosphere, yielding quite possibly the biggest open question in atmospheric (or environmental) chemistry. In my research group we will address this significant knowledge gap by taking a multi-phase approach, studying the radical oxidation pathways occurring within three fundamentally distinct atmospheric molecular environments: the gas, organic aerosol, and aqueous phases. Student researchers will draw on techniques from across all areas of chemistry, utilizing a combination of organic synthesis, advanced chromatography, mass spectrometry, spectroscopy, and kinetic modeling to identify the major chemical mechanisms responsible for the formation and chemical evolution of organic aerosol particles.
Amy Gehring, biochemist
If you have smelled fresh dirt, you have already been introduced to bacteria of the genus Streptomyces. In addition to producing the characteristic odor of dirt, these common soil bacteria manufacture the majority of known antibiotics. These medicinally important compounds are produced during the course of the bacterium’s unusual and complicated life cycle that culminates in sporulation. Research in my lab involves understanding the regulation of this developmental process and concurrent antibiotic production in the model organism Streptomyces coelicolor. Beginning with mutant strains that are defective in certain aspects of development, we have identified genes and thereby proteins that are necessary to progress through the various stages of the bacterium’s life cycle. Current projects in the lab include (1) using proteomics approaches including 2D gel electrophoresis and MALDI-TOF mass spectrometry to characterize changes in the cell resulting from activity of a stress response sigma factor; (2) characterizing the activity of a potential transcription factor required for sporulation; and (3) assaying the effects of various mutations on antibiotic production.
Christopher Goh, inorganic/polymer chemist
Metal-based catalysis can be found in many crucial biochemical and chemical processes. Taking advantage of these catalytic reactions as starting points, our group aims to discover new catalysts or to improve the efficiency of existing systems. A research problem in my group starts with an exploration of the variable space of a catalytic system. We examine the factors that influence the performance and hypothesize strategies for improving the catalyst, and probe these ideas by modifying catalyst compositions. One current project involves the synthesis and application of copper based atom transfer radical polymerization (ATRP) catalysts. These catalysts provide the power to dictate the composition, molecular weight and molecular weight distribution of macromolecules, and to precisely control their architecture. Thus, such catalysts have a multitude of applications in designing new materials for packaging, automotive, and medical industries for example. A second project centers on the discovery of homogeneous iron catalysts for the oxidation of fatty acids and their derivatives. Fatty acids can be obtained from plant oils and represent a renewable resource for the polymer industry. The metal catalyzed oxidation of this class of compounds is of interest in the formation of resins, an industrially important class of compounds.
Sarah Goh, organic/polymer chemist
Our research investigates non-covalent assemblies based on biological system through: development of self-assembled hydrogels by integrating synthetic polymer and protein-mimetic components, resulting in materials with tunable properties and function; advancement of enzymatic polymerization methodologies for the preparation of functional polymers by exploring active site geometries through genetic engineering; and evaluation of protein- and polysaccharide-based platforms for the targeted placement of active nano-catalyst centers in order to control macroscale function and architecture of these assemblies.
Kerry-Ann Green, organometallic chemist/catalysis
Catalysis has revolutionized and continues to drive modern synthetic chemistry. The production of more than 80% of chemical products for commercial purposes relies on at least one catalytic step. Despite this, low catalytic efficiency of many transition metal catalysts and organocatalysts limits their broader application. Moreover, despite the increasing demand for more environmentally benign and sustainable catalytic processes, significant challenges remain for synthetic chemists. Research in the Green lab is directed towards the design and synthesis of new, efficient and broadly applicable catalysts based on earth-abundant transition metals for application in developing and improving cross-coupling reactions. Of particular interest is the activation of traditionally inert substrates, which provides an opportunity to take advantage of many naturally occurring and synthetically accessible starting materials (e.g., phenols) in cross-coupling transformations. Central to these studies is elucidating and understanding underlying mechanistic principles governing the catalysts and the reactions they mediate. Research in this lab will facilitate the development of student researchers in organic & organometallic synthesis and characterization.
Katie Hart, biochemist
We are engaged in an arms race with pathogens. And we’re losing. Just as quickly as we can develop new antibiotics or antiviral treatments, resistant strains emerge – often within the year. Evolution, it turns out, doesn’t always take eons. In fact, we are watching microbes evolve in real time in clinics, on farms and in the natural environment, which gives us the opportunity to both study how evolution occurs on short timescales and learn how to combat drug resistance. My lab studies how drug resistance evolves at the molecular level with a particular focus on protein stability. Many forms of drug resistance depend upon a small number of mutations that result in changes to a protein’s amino acid sequence. By investigating how these changes affect protein structure, stability and function, we can begin to understand how evolution works at the molecular level and leverage these insights to inform the design and implementation of new drug treatments. Current projects in the lab investigate drug resistant mutations in β-lactamase, an enzyme critical for antibiotic resistance in bacteria, and HIV protease, an enzyme targeted by antiretroviral therapies using biophysical techniques (circular dichroism, UV-vis and fluorescence spectroscopies) and microbiology techniques (cell growth competitions, minimum inhibitory concentration measurements, screen development).
Lee Park, inorganic chemist
I am interested in various aspects of molecular self-assembly. We are currently investigating the use of fluorocarbon-hydrocarbon interactions as a means of driving the self-assembly of gold nanoparticles. We are hoping to make use of the self-segregating properties of combined fluorocarbon and hydrocarbon to break the symmetry of gold nanoparticle systems, resulting in Janus-type gold nanospheres and nanorods. Such Janus or “patchy” particles have the potential to self-organize into more complex aggregate structures. Other areas of work that we’ve explored in the past have included approaches to controlling the morphology in the active layer of bulk heterojunction organic solar cells by means of surface patterning (via microcontact printing), as well as the design of new liquid crystalline materials, in which small discrete molecules self-assemble to form one-dimensionally aligned structures due to various intermolecular interactions, such as hydrogen bonding or donor-acceptor interactions. Students in my lab do a combination of synthetic work, physical characterization of compounds prepared, and evaluation of those new materials in the context of actual working devices such as solar cells.
Enrique Peacock-López, physical chemist
A large number of biochemical systems show regulatory feedback mechanistic steps either at the cellular level, like in the HIV-Rev protein, or at the physiological level, like in the hypothalamous-pituitary-adrenal hormonal system. Our group has been studying the molecular basis of different chemical, biochemical and physiological mechanisms and has proposed several dynamic models to explain observed temporal and chaotic oscillation in the concentrations of relevant metabolites. We have concentrated most of our effort in understanding chemical self-replication, where several chemical systems have been designed experimentally. For example, oligonucleotides have been considered by von Kiedrowski’s, Orgel’s and Nicolau’s groups, and peptides have been studied by Gadhiri’s and Chmielewski’s groups. More recently Joyce’s group designed a self-replicating and a cross-catalytic self-replicating ribozymes, which may be better suited for Darwiniam evolution than the oligonucleotide or peptide systems. In the case of cross-catalytic mechanisms, we have considered the dynamics of competitive systems and mutualistic hypercycles. We also continue studying and modeling the transport of incompletely spliced mRNAs across the nuclear membrane, which is regulated by HIV-Rev protein, and we have studied the behavior of an insect-predator-ant system, and we want to develop mathematical models that we will allow us to improve our understanding of species competition and coexistence.
Bob Rawle, biochemist
Compartmentalization is a hallmark of life, and at the cellular level compartmentalization is often achieved using lipid membranes. My lab is interested in asking fundamental biophysical questions about lipid membranes in two broad areas – viral infection and model membrane systems. In the first area, we are investigating molecular level events during two essential steps in viral infection – binding to the host cell membrane and membrane fusion/penetration. As an initial model system, we are studying Sendai virus, a member of the paramyxovirus family which includes measles and human parainfluenza viruses. To study Sendai virus, we observe individual viruses binding and fusing with host cell membrane mimics called model lipid membranes. These model lipid membranes are lipid bilayers self-assembled inside a microfluidic device, and they enable us to simplify the complex host cell environment to just a few components. This allows us to ask direct questions about key molecular interactions. To perform these biophysical studies, we use a variety of techniques including fluorescence microscopy, microfluidics, surface chemistry, electron microscopy, kinetic modeling and simulations, and single molecule fluorescence. In the second area, we are studying model lipid membranes themselves. Model lipid membranes are used quite widely in fields ranging from basic science (as in our lab) to biotechnology, drug delivery, and drug formulation, but the composition of these membranes has not been well studied. In particular, we are studying the influence of preparation methodology on the resulting lipid composition of various model membranes. To do this, we use analytical chemistry techniques, relying heavily on high-performance liquid chromatography with evaporative light scattering detection. Our results will likely have important implications for drug delivery, biosensors, and membrane biophysics.
Anne Skinner, Emerita
My lab works at the interface between chemistry and two other disciplines, geology and archaeology. One way to determine the age of materials is to look at the damage caused by radioisotopes in the material and its surroundings. The older the object, the more damage should be found. The extent of damage can be measured with electron spin resonance (ESR), a technique that looks at the unpaired electrons created when a stable bond is broken by radiation. Projects in the past few years have included determining Late Stone Age dates at Olduvai Gorge, clarifying the transition from Neanderthals to Homo sapiens in Central Europe, and discovering the use of fire in South Africa 1.5 million years ago. Current projects are taken from sites in India, Brazil, Africa, and Europe.
Thomas E. Smith, organic chemist
My research interests lie within the broad category of organic synthesis that impacts such areas as biology, pharmacology, materials science, and reaction mechanism. My current focus is on the development of new methods for increased efficiency in organic synthesis and their application to molecules of biological significance. Organotransition metal systems, in particular, are utilized extensively in this endeavor due to their versatile selectivity profiles and catalytic possibilities. In one project, we are exploring a general asymmetric synthesis of the kavalactones. These natural products are the biologically active constituents of kava root, which has been used ceremonially in South Pacific cultures for centuries and has attracted recent attention in the Western world as an “alternative” anti-anxiety remedy. We are also investigating the asymmetric total synthesis of the myxobacterial antibiotic, jerangolid D, wherein both the ?-lactone and cis-dihydropyran rings are assembled using an extension of the methods developed for the kavalactone syntheses. In another project we are probing the scope and limitations of a new method for the thermodynamic deprotonation of readily available heterocyclic systems, thus allowing for the assembly of more complex molecular architectures from simple building blocks. This technique was successfully applied to a novel synthesis of the antiviral marine natural product, hennoxazole A. Studies on other complex pyran-based anticancer natural products such as enigmazole A, tedanolide C, and aplyronine are currently underway.
Jay Thoman, physical chemist
Inter- and intramolecular forces help determine the shape and behavior of molecules. Using the gas-phase fire-suppressant molecules known as hydrofluorocarbons (HFCs) as model systems, my colleagues and I use laser spectroscopic techniques to probe the vibrational overtones of CH stretches and to learn about molecular structure and dynamics. We use ab initio computational chemistry to model these vibrations, and their impact on atmospheric chemistry. Working with Dave Richardson, we synthesize deuterated fluorocarbons; these isotopically substituted HFCs are used to test theories of hydrogen bonding and energy transfer. The local environment provides many chemical research opportunities. Using the resources of the Environmental Analysis Laboratory on campus, I have collaborated on projects including studies of: lead in urban soils, perchlorate ions in drinking water, PCBs in the Hoosic River environment, heavy metals in fish taken from local ponds, and PFOA in the Bennington VT region.
Ben Thuronyi, bioorganic chemist / synthetic biologist
All living things contain incredibly sophisticated biotechnology, built from chemical parts that evolved over millions of years to make organisms grow and reproduce more efficiently. Researchers are starting to take advantage of that evolved technology like never before, reprogramming cells and creating new biomolecular functions in an interdisciplinary field called synthetic biology. Synthetic biologists have created cells that produce chemicals, biomaterials, and therapeutics, carry out computation, and even direct evolution toward researcher goals. In the Thuronyi lab, we are building synthetic biology tools for a promising but underdeveloped bacterium, Vibrio natriegens, that is among the fastest growing known organisms. We are establishing new methods for directed evolution of biomolecules in V. natriegens that can effectively harness its entire genomic and metabolic repertoire. Our first directed evolution target is improving production of the bioplastic polyhydroxyalkanoate, which V. natriegens naturally makes in small quantities. Synthetic biology draws on skills across disciplines and relies on the design-build-test-learn cycle of engineering. Many of our experiments involve creating DNA constructs using computer-aided design, assembling and inserting them into bacteria with molecular biology techniques, and investigating the results with analytical chemistry methods (luminescence and fluorescence, HPLC, GC/MS or NMR).
Amanda Turek, organic chemist
Charge and electron transfer are fundamental and essential processes in all areas of chemistry, from biochemistry to materials to synthetic organic chemistry. The impacts of light-promoted electron transfer are profound: visible light-initiated electron transport drives life-sustaining photosynthesis, materials that harness abundant solar energy are in increasing demand, and new reactivity paradigms enabled by photoredox catalysts have sparked a revolution in organic synthesis. Our research involves (1) the design and characterization of molecules that can undergo both intra- and intermolecular electron transfers, and (2) application of these molecules as a new class of photoredox catalysts for organic reactions. Molecules capable of undergoing visible light-promoted intramolecular electron transfer to generate a charge-separated excited state will be synthesized; through electrochemical and spectroscopic techniques, we can systematically investigate how the structure of these molecules affects their ability to participate in electron transfer. These studies will in turn enable strategic design of molecules for use as effective photoredox catalysts for redox-neutral organic transformations.