About the Department
Abstracts for Seminars — Spring 2016
B. Reeja Jayan, Carnegie Mellon University, Department of Mechanical Engineering
Molecular Scale Engineering of Hybrid Thin Film Materials for Energy Storage
Abstract
Ceramic and polymeric thin film materials and the organic-inorganic (hybrid) interfaces they form are critical components in energy storage devices like batteries. This talk will introduce two novel approaches to engineer such materials.
I will demonstrate how initiated chemical vapor deposition (iCVD) polymerization can be used to synthesize nanoscale (~ 20 nm), conformal polysiloxane thin films which serve as hybrid electrolytes for the emerging field of three-dimensional (3D) batteries. An important consideration for miniaturizing on-board electrochemical energy storage for many applications including sensing, actuation, communications, and medical implants is the footprint area of the power source. 3D battery designs use electrodes with non-planar geometries, effectively enabling power sources to possess high energy density and high power density within a small footprint area (1 mm2 – 1 cm2). Electrolyte films in 3D batteries must cover these complex electrode geometries while retaining the underlying morphology of the electrodes, i.e. conformal coverage. Such uniform and thin polymer films are difficult to achieve by solution processing due to de-wetting and surface tension effects. In contrast, the conformal nature of the iCVD polymerization process realizes complete coverage of nanostructured electrodes like nanowires by a uniform, continuous, and pinhole free thin film. This is the first time nanoscale hybrid films with siloxane ring moieties, which are excellent electrical insulators, have been demonstrated as room temperature ionic conductors. These nanoscale films also exhibit good mechanical and chemical stability, and are easily scalable over large areas.
Next, I will introduce a solution-based process that crystallizes ceramic (TiO2) thin films at low temperatures (~ 150 oC) using microwave radiation assisted selective heating. These materials require temperatures over 400 oC to crystallize using conventional synthesis techniques. High temperature processing creates incompatibility with microfabrication processes and limits the choice of substrate materials on which these films can be grown, as flexible plastic or polymeric substrates typically decompose at temperatures > 200 oC. The low temperature microwave process thus enables the integration of ceramic thin films directly onto temperature-sensitive substrates like plastic for use as electrodes and electrolyte layers in flexible thin film batteries.
Biography
B. Reeja Jayan is an Assistant Professor in Mechanical Engineering at Carnegie Mellon University (CMU). She also holds a courtesy appointment in the Materials Science and Engineering department at CMU. Prof. Jayan received her M.S. in Electrical Engineering and Ph.D. in Materials Science and Engineering from The University of Texas at Austin (UT-Austin), working with Professor Arumugam Manthiram. She was subsequently a Postdoctoral Associate in Chemical Engineering at the Massachusetts Institute of Technology (MIT), working under the supervision of Professor Karen Gleason. Her multidisciplinary research group at CMU explores novel design strategies for organic (polymers, small molecules), inorganic (metals, semiconductors, insulators), and organic-inorganic hybrid materials for applications in energy and sustainability. Her work has resulted in 18 peer-reviewed journal publications and filing of 4 patent applications. She is a recipient of the Cockrell School of Engineering Student Leadership Award from UT-Austin, a doctoral fellowship from the American Association of University Women (AAUW), and the H.H. The Maharaja of Cochin Endowment Prize from the University of Kerala, India.
Wenyu Huang, Iowa State University
Control Heterogeneous Catalysts for Superior Catalytic Properties
Abstract
Catalysis—the essential technology for accelerating and directing chemical transformation—is the key to realizing environmentally friendly and economical processes for the conversion of fossil energy feedstocks. Catalysis is also the key to developing new technologies for converting alternative feedstocks, such as biomass, carbon dioxide, and water to chemicals and fuels.1 The two grand challenges of heterogeneous catalysis, understanding mechanisms and dynamics of catalyzed reactions as well as the design and controlled synthesis of catalyst structures, require an atomic and electronic-level understanding of catalysts and catalytic processes. However, due to the structure complexity, especially under reaction conditions (high temperature and pressure), the exact catalytic active site and the molecule-catalyst interaction are extremely difficult to describe. In this presentation, I will discuss the synthesis, characterization, reaction study, and modeling of heterogeneous catalysts precisely synthesized at atomic level using intermetallic compounds2 and metal-organic frameworks3-5, which provide the means for meeting the two grand challenges of heterogeneous catalysis. The synthesis of these heterogeneous catalysts is based on nanoscience and nanotechnology.
Biography
Dr. Wenyu Huang received a B.S. in Chemistry from Nanjing University, China in 2000. After receiving an M.S. in 2002 also from Nanjing University, he started his Ph.D. research with Professor Mostafa A. El-Sayed at Georgia Institute of Technology and received his Ph.D. in 2007. Dr. Huang then began postdoctoral research with Professor Gabor A. Somorjai at University of California, Berkeley and Lawrence Berkeley National Laboratory in August 2007. He joined the faculty at Iowa State in August 2011 as an Assistant Professor.
Christina M. Thiele, Technical Institute of Darmstadt
Using NMR-spectroscopy to Investigate Structure and Dynamics of Organic and Organometallic Compounds
Abstract
The knowledge about the structure and dynamics of organic compounds is essential to find out about their function and/or reactivity. NMR spectroscopy in solution can provide very useful insights into the solution structures of organic and organometallic compounds.
The determination of the three dimensional structure of organic or organometallic compounds by high-resolution solution state NMR spectroscopy usually involves the measurement of 3J couplings and NOEs. Additionally residual dipolar couplings (RDCs), which belong to the class of anisotropic NMR-parameters, can yield information complementary to 3J couplings and NOE parameters and allow the assignment of diastereotopic protons and the determination of relative configurations even in the presence of (a limited degree of) motion. In contrast to conventional NMR-parameters RDCs contain global information.[1] The prerequisites and limits for using RDCs on organic compounds (alignment media, simultaneous determination of configuration and conformation, flexibility, etc.) will be discussed.
The usefulness of NMR-spectroscopy to elucidate structures will be exemplified on two selected applications: one photoswitchable organic compound[2] and one intermediate in Pd-catalyzed allylic substitution [3].
E. W. (Bert) Meijer, Technische Universiteit Eindhoven (Netherlands)
Non-covalent Synthesis of Functional Superamolecular Systems
Abstract
The intriguing prospects of molecular electronics, nanotechnology, biomaterials, and the aim to close the gap between synthetic and biological molecular systems are important ingredients to study the cooperative action of molecules in the self-assembly towards functional supramolecular systems. The design and synthesis of well-defined supramolecular architectures requires a balanced choice between covalent synthesis and the self-assembly of the fragments prepared. The current self-assembly processes are primarily controlled by solvent, temperature or concentration. For synthetic chemists, the non-covalent synthesis of these supramolecular architectures is regarded as one of the most challenging objectives in science: How far can we push chemical self-assembly and can we get control over the kinetic instabilities of the non-covalent architectures made? How can we go from self-assembly to self-organization? Where the number of different components is increasing the complexity of the system is increasing as well. Mastering this complexity is a prerequisite to achieve the challenges in creating functional systems. In the lecture we illustrate our approach using a number of examples out of our own laboratories, with the aim to come to new strategies for multi-step non-covalent synthesis of functional supramolecular systems.
Biography
E.W. “Bert” Meijer is Distinguished University Professor in the Molecular Sciences, Professor of Organic Chemistry at the Eindhoven University of Technology and scientific director of the Institute for Complex Molecular Systems. After receiving his PhD degree at the University of Groningen, he worked for 10 years in industry (Philips and DSM). In 1991 he was appointed in Eindhoven, while in the meantime he has held part-time positions in Nijmegen and Santa Barbara, CA. Bert Meijer is a member of many editorial advisory boards, including Advanced Materials, Angewandte Chemie, and the Journal of the American Chemical Society. Bert Meijer has received a number of awards, including the Spinoza Award in 2001, the ACS Award for Polymer Chemistry in 2006, the AkzoNobel Science Award 2010, the International Award of the Society of Polymer Science Japan in 2011, the Cope Scholar Award of the ACS in 2012, and the Prelog medal in 2014. He is a member of a number of academies and societies, including the Royal Netherlands Academy of Science, where he is appointed to Academy Professor in 2014.
Chris Meier, Universität Hamburg (Germany)
Developing Prodrugs of Antivirally Active Nucleoside Triphosphates — Against All Odds, It Works!
Abstract
Over the last decades a variety of nucleoside analogues were applied clinically in antiviral chemotherapy. However, quite often the antiviral potency of the nucleoside analogues is limited due to the lack of intracellular phosphorylation into the triphosphorylated forms by cellular kinases. This problem cannot be solved by using the phosphorylated nucleosides due to their high polarity which prevent an efficient cell membrane passage. An option to overcome this hurdle is the use of lipophilic precursors of nucleotides, which are able to pass the cell membrane and deliver the corresponding nucleotides intracellularly (pronucleotides).
In the past we developed nucleoside mono- (cycloSal-system) and nucleoside diphosphate prodrug approaches (DiPPro-approach).
Of course, the final aim should be to develop nucleoside triphosphate prodrugs because the delivered triphosphate is the direct acting inhibitor of the viral polymerases. In contrast, mono- or diphosphate delivery systems are still dependent on the forward phosphorylation into the triphosphate. So far, no example of such a prodrug system has been reported.
In our work, d4TTP prodrugs with different aliphatic masking units have been synthesized via two different routes based on phosphoramidite or H-phosphonate chemistry. Our triphosphate delivery system is comprised of enzymatically cleavable masking groups (acyloxybenzy-moieties) which are covalently attached to the γ-phosphate group of the nucleoside triphosphate. In addition, a variety of nucleotide analogues have been investigated. The target prodrug compounds were obtained in yields up to 66%.
Chemical hydrolysis studies, pig liver esterase studies, enzymatic cleavage in CEM/0 cell extract, primer extension assays, PCR assays, CEM whole-cell incubations and antiviral HIV tests will be discussed and proved the successful delivery of nucleoside triphosphates. This new TriPPPro-concept will open up unknown possibilities in Medicinal Chemistry and Chemical Biology.
Wenbin Lin, University of Chicago
Molecular Materials for Sustainability and Human Health
Abstract
Metal-organic frameworks (MOFs) represent an interesting class of crystalline molecular materials that are synthesized by combining metal-connecting points and bridging ligands. The modular nature of and mild conditions for MOF synthesis have permitted the rational structural design of numerous MOFs and the incorporation of various functionalities via constituent building blocks. The structure-property relationships of MOFs can also be readily established by taking advantage of the knowledge of their detailed atomic structures, which enables fine-tuning of their functionalities for desired applications. In this talk, I will discuss our recent works on designing MOFs for sustainable catalysis and cancer therapy. MOFs have enabled the rational synthesis of single-site solid catalysts by not only facilitating the immobilization of known homogeneous catalysts but also allowing the discovery of new molecular catalysts that do not have homogeneous counterparts. Furthermore, we have demonstrated the ability to combine multiple treatment modalities into a single MOF nanoparticle for effective cancer therapy in mouse models.
Biography
Dr. Wenbin Lin is the James Franck Professor of Chemistry and Comprehensive Cancer Center at the University of Chicago. Prior his current position, Dr. Lin was the Kenan Distinguished Professor of Chemistry at the University of North Carolina at Chapel Hill (UNC-CH). He was also a joint professor at Division of Molecular Pharmaceutics (School of Pharmacy) and Lineberger Comprehensive Cancer Center at UNC-CH. Dr. Lin obtained a BS degree from the University of Science and Technology (Hefei, China) in 1988 and received a PhD degree in chemistry from the University of Illinois at Urbana-Champaign in 1994. He was a NSF postdoctoral fellow at Northwestern University in 1994-1997. Dr. Lin’s research efforts focus on designing molecular materials for sustainability and human health. His group has worked on a variety of research areas, including nonlinear optical materials, porous materials for catalysis and separation, solar fuels, and nanomedicine. Dr. Lin’s group has published about 270 peer-reviewed papers, and his work has been well received by the community as evidenced by his selection to be among the top 10 chemists in the 1999-2009 decade based on per article citations. Dr. Lin has won numerous professional honors for his contributions to the rational design of functional molecular materials.
Jonathan Owen, Columbia University
The Synthesis and Coordination Chemistry of Metal Chalcogenide Nanocrystals
Abstract
I will describe our studies of nanocrystal nucleation and growth and surface coordination chemistry. First, I will present a library of derivatized thiourea and selenourea precursors whose wide range of reactivity adjusts the metal chalcogenide formation kinetics. Using this library we observe a well-defined relationship between solute supply and the concentration of nanocrystals allowing a desired nanocrystal size to be obtained in quantitative yield. Second, I will describe the important relationship between nanocrystal coordination chemistry and electronic structure. Using liquid NMR spectroscopy we have discovered a novel ligand exchange mechanism where the surface layer of excess metal cations on metal chalcogenide nanocrystals is displaced in the presence of neutral donor ligands. The importance of this behavior to luminescence quantum yield and nanocrystal synthesis will be discussed.
Jonathan Owen grew up in Midland, MI experimenting in the garage with the help of his father who was a chemist at the Dow Chemical Company. Jon obtained a BS from the University of Wisconsin-Madison in 2000 and a PhD from Caltech in 2005, Following his PhD, Jon joined the lab of Professor Paul Alivisatos as a Petroleum Research Fund - Alternative Energy Fellow at UC Berkeley. In 2009 he joined the faculty at Columbia University where he is currently Associate Professor of Chemistry. His group studies the chemistry of colloidal semiconductor nanocrystals, especially the important influence of coordination chemistry on their electronic structure, as well as the mechanism of nanocrystal nucleation and growth. Jon has received several awards for his work including: The 3M Nontenured Faculty Award (2010); The Early Career Award from the Department of Energy (2011); The DuPont Young Faculty Award (2011); A Career Award from the National Science Foundation (2012); The Award in Pure Chemistry from the American Chemical Society (2016).
Lixin Zhang, Chinese Academy of Sciences Institute of Microbiology (China)
Overcome Drug Resistance from Natural Products
Abstract
One of the major limiting factors in Natural products drug discovery industry is that pharmaceutical companies have been traditionally designed to target individual factors in a disease system, but diseases are complex in nature and vulnerable at multiple attacks. Therefore, a systematic novel synergistic drug screening approach based on a multifactorial principle is urgently needed, especially from our microbial natural product library1-2. Avermectin is identified as a new antifungal agent for drug-resistant pathogens by a high-throughput synergy screening strategy3-7. The production of drugable secondary metabolites from microbial producers could be further increased by synthetic biology approaches. We focused on the design and synthesis of biological chassis, parts, device and modules from the microbial diversity to reconstruct and optimize their dynamical process, as well as predict favorable effective overproduction of Avermectin B1a. We did a computational study on the de novo biosynthesis of Avermectin B1a and followed by a 4M strategy8-9.
Biography
Prof. Lixin Zhang is a Director of Drug Discovery Center for Tuberculosis and Deputy Director of CAS Key Laboratory of Pathogenic Microbiology & Immunology at Institute of Microbiology, Chinese Academy of Sciences (CAS). Before joining IMCAS, Dr. Zhang served as president, section head of drug discovery and senior scientist, respectively, in 3 pharmaceutical biotech companies in USA: SynerZ,Cetek and Microbia, Inc. He once worked as a postdoc at Emory Univ. on structure and functional analysis of 14-3-3 proteins in cell proliferation and differentiation signal pathway and dissect the role of 14-3-3 in ASK1-mediated apoptosis for potential therapeutic intervention. His Avermectin project won China award for "Excellence to improve science and technologies” and the paper was published in PNAS. He was invited as plenary speakers for the 12th International Symposium on the Genetics of Industrial Microorganisms in 2013 and United Nations science forum “Sustainable development, science and technology” at the United Nations headquarters in New York in 2003. He served on the Executive Board of International Symposium on the Biology of Actinomycetes (ISBA) and Genetics of Industrial Microbiology(GIM). He is the president of elect of the International Chemical Biology Society (ICBS) headquarted in US. He is the president of SLAS Asian Council (2015-6). He successfully organized international symposia such as the inaugural conference of BISMiS, and “China-U.S. NIH-IOM TB Drug Discovery Forum: Exploring Opportunities for Research Collaboration” in Beijing. He was recognized as the Excellent Supervisor of CAS in 2011 and as an Awardee for National Distinguished Young Scholar Program, China. He was awarded the Chief Scientist of a “973 Program” in 2012 (the largest basic science consortium grant in China) and “2014 Roche Young Investigator Award”. He co-edited a book with Prof. Arnold Demain on natural products by Humana Press. The long-term goal of his research is to discover and develop synergistic medicines from marine microbial natural products. He has published 8 books, more than 160 papers and holds 40 patents. He is appointed as the founding Editor-in-Chief for “Synthetic and Systems Biotechnology” by Elsevier and Science publisher; and an associate Editor-in-Chief for “Applied Microbiology and Biotechnology” by Springer publisher, and “Frontiers in Antimicrobials, Resistance and Chemotherapy”. He is awarded as a visiting Professor in Cornell University (2012-4) and Harvard University (2013-5) and an advisor (2014-5) in Manchester Institute of Biotechnology. He is on the editorial board of 7 other peer-reviewed journals. He has trained more than 50 postdocs, Ph.D. and master students from more than 10 different countries. URL http://zhanglab.caspmi.cn/