Chemistry Newsblog

Published July 20, 2015

Xu Xiang
PhD Defense
Doctoral Candidate, Department of Chemistry
Advisor: Dr. Patrica Heiden

Friday July 24, 2015
Memorial Union Ballroom A-1
9:00 a.m.

Novel Drug Delivery Systems: Thermo-responsive drug delivery designs and Multi-drug delivery scaffold designs

Abstract:
This research has three parts: two deal with novel medical devices for drug delivery, and one looks at properties of fish scales as an abundant waste resource that can be modified to have value in medical and other areas. This presentation discusses two novel drug delivery designs, including their synthesis and characterization. These nanoparticle devices address two current challenges in drug delivery. The first is designing a drug-carrier to more efficiently deliver toxic (e.g. chemotherapy) drugs, which harm all cells. So non-specific delivery of the drug is wasteful and harmful to the patient. Knowledge gained from a fundamental study of the effects of polymer architecture (linear amphiphilic diblock and triblock copolymers and star copolymers) and end group polarity, on thermally triggered drug delivery led to selecting two diblock copolymers to assemble into novel gold-core hybrid nanoparticles. These nanoparticles were tested for their ability to reduce low temperature release and efficiently release the drug at a triggered temperature. The second drug delivery system extended the capabilities of a new type of tissue support device (a scaffold) by showing that the system can independently control the simultaneous release of different drugs, and that the spatial distribution of these drugs within the device, called a “nanoparticle fiber”, can be controlled. Three different model drugs were assembled and their release proven, within the nanoparticle fiber. This work succeeded in yielding a novel, flexible, and robust system of assembled fibers of nanoparticles that could independently control the release of multiple drugs.

Total Synthesis of Belizentrin

Published July 1, 2015

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Total Synthesis of Belizentrin

Shahien Shahsavari
Original Research Proposal
Michigan Technological University
Department of Chemistry
Advisor- Dr. Shiyue Fang
Monday July 6, 2015
10:00 am
Chem-Sci 101

Abstract

Marine organisms are known to produce some of the most bioactive secondary metabolites found in nature. Currently, many of these marine-derived molecules are used as “first-in-class” drugs in the market. This proposal describes the total synthesis of belizentrin, a novel polyketide-derived macrocycle isolated from the marine dinoflagellate Prorocentrum belizeanum. Belizentrin has already demonstrated effective changes in neuronal survival assays in vitro at nanomolar concentrations. Additionally, its highly bioactive properties and structural similarities with other known immunosuppressant compounds make it a valuable target for medical research. However, since the extraction yield is minimal, it is essential to produce this compound in larger quantities from readily available starting materials for a complete investigation of its biological activities. The overall synthetic strategy involves a convergent late-stage coupling of three major fragments. The key features of the synthesis include iterative asymmetric allylic substitutions, titanium-catalyzed asymmetric epoxidation of terminal olefins, and the Yamaguchi macrolactonization to form the macrocyclic core of the molecule.

Valenzano on Research Funding Tour

Published June 8, 2015

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News

Group Faculty Visit to Washington, DC

For the past five years, Michigan Tech deans and the vice president for research have sponsored a group visit to Washington, D.C. for early-career research faculty. To date, 70 Michigan Tech faculty and administrators have participated.

Trip participant, Loredana Valenzano shared these comments about the trip:

“What I enjoyed most was having the feeling that, indeed, PDs [program directors] and POs [program officers] are there to help, and to provide valuable guidance especially to those of us who are trying to build a career in the STEM in times where funding is decreasing and the competition is high. The availability to talk and somehow the capability to alleviate frustrations and anxieties which the people we had the chance to interact with provided, was a pleasant and encouraging revelation. I believe that having the occasion to see with our own eyes how the big machine on the East Coast works is absolutely a key aspect to shoot for success.”

Sarah Green Quoted by ThinkProgress

Published May 4, 2015

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News

Professor of Chemistry Sarah Green was quoted by ThinkProgress about her contributions to the edX on-line course “Making Sense of Climate Science Denial.”

The edX course, offered by the University of Queensland, Australia, concerns theories of climate science denial, including myths, psychological and social drivers, and the influence of climate denial on public perceptions of climate change.

Green was quoted in the ThinkProgress Climate Progress article “The Massive New Online Course That Every Climate Science Denier Should Be Very Afraid Of,” stating that “educating people about facts is not sufficient.” Green, who contributed four lectures to the course, said this is especially the case when political or industry groups can “bamboozle them” with easily digestible “pseudo-facts.”

edX courses are MOOCs, or massive open online courses. “Making Sense of Climate Science Denial” is a free 7-week course taught by 13 instructors.

T Synthesis of Isobractatin and Neobractatin

Published April 20, 2015

By

Shanshan Hou
Original Research Proposal
Michigan Technological University
Department of Chemistry
Advisor- Dr. Lanrong Bi
Tuesday April 21, 2015
9:00 am
Chem-Sci 106

T Synthesis of Isobractatin and Neobractatin

Abstract
The new Garcinia derivatives, neobractatin and isobractatin, will be synthesized. These compounds are caged-prenylxanthones which are isolated from Chinese native Garcinia bracteata. They displayed strong inhibition of cancer cells, which could significantly induce cell apoptosis and inhibit autophagy. However, the compounds which are extracted from the Chinese native Garcinia species have very low yield. Total synthesis of these derivatives will provide adequate quantities for biological studies. In addition, the new synthetic methodologies could not only produce the target compounds but also give rise to their isomers which could be potential anti-tumor candidates and used for future research.

Interfaced Heterogeneous Nanodimers

Published April 9, 2015

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Chemistry Seminar
Dr. Yugang Sun
Center for Nanoscale Materials, Argonne National Laboratory
Friday, April 17, 2015 3:00pm Chem-Sci 101

Interfaced Heterogeneous Nanodimers
Abstract:
Synthesis of interfaced nanoparticle dimers made of asymmetric compositions (i.e., interfaced heterodimers) is challenging because it is difficult to manipulate the nanoparticles’ surface properties to control the assembly and/or growth of different nanoparticles. In this presentation, the general principle will be first introduced for the formation of interfaced heterogeneous dimers made of different inorganic nanodomains that exhibit either crystalline or amorphous structures. Although many different combinations are possible, the heterodimers containing plasmonic components (e.g., gold and silver nanodomains) will be focused in this presentation to highlight a number of synthetic methods and unique properties observed in heterodimers. For example, a seed-mediated, surface-confined epitaxial overgrowth strategy is capable of synthesizing high-quality interfaced Au-Ag heterodimers with varying sizes. Au and Ag share a common face-centered cubic lattice and have nearly identical lattice constants, which facilitates epitaxial overgrowth and allows direct contact between the Au and Ag domains. The interfaced Ag nanodomains can be chemical transformed to hollow nanoshells of other materials through a galvanic replacement reaction, resulting in the formation of interfaced dimers made of solid Au nanoparticles and hollow nanoshells. Due to the direct contact between the two components in each interfaced dimer, strong coupling between them are expected to induce new properties that cannot be observed from any individual components.

Biography:

Dr. Yugang Sun is a Scientist at the Center for Nanoscale Materials, Argonne National laboratory. He received his B.S. and PhD degrees from University of Science and Technology of China in 1996 and 2011, respectively. He worked as a Postdoc at University of Washington at Seattle (with Prof. Younan Xia) from 2001 to 2003. During 2004-2004, he had been working with Prof. John Rogers at University of Illinois at Urbana-Champaign as a postdoctoral fellow. In August 2008, he was appointed as an Assistant Scientist at Argonne National laboratory. He was promoted to Scientist in January 2010.

Dr. Sun’s research interests focus on developing novel approaches for the synthesis of a wide range of nanostructures including metal nanoparticles with well-controlled morphologies, single-crystal semiconductor nanostructures with mechanical flexibility, and metal/semiconductor nanocomposites with multiple functionalities. As of now, he has published more than 130 research papers, with an h-index = 47 and citation times > 23,400. He was honored as one of the “Top 100 Materials Scientists with highest impact score (2000-2010), Rank #5” by Thomson Reuters.

Zintl and Polar Intermetallic Compounds

Published March 31, 2015

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Chemistry Department Seminar Faculty Candidate
Dr. Fei Wang
Polymer and Material Chemistry, Lund University Sweden
Monday April 6, 2015
4:00 PM, MUB~ Alumni Lounge A

Abstract:
Zintl and polar intermetallic compounds are compounds between electropositive metals (e.g. alkali, alkaline earth, and rare earth) and electronegative metals/metalloids (e.g. late transition and post transition elements). Just like their constituent elements, these compounds are also metals/metalloids. Meanwhile, partial charge transfer is expected from the electropositive metals to the electronegative metals/metalloids, the latter of which are formal “anions” and covalent interactions can occur among them. Therefore, Zintl and polar intermetallic compounds possess simultaneously metallic, ionic, and covalent characteristics. I will demonstrate what will happen when metallicity, covalency, and ionicity coincide and interplay with each other.
Besides, the bonding between the “anionic” electronegative metals/metalloids is also intriguing. The well-know electron counting rules, such as the octet rule and the Wade-Mingo’s rules, fail frequently in rationalizing the bonding in Zintl and polar intermetallic compounds. I will present a few examples to illustrate the cause, with emphasis on the involvement of d-orbitals and the relativistic effects in bonding.

Biography:
I obtained my master’s degree from Zhejiang University in China in 2005. There I worked on morphology controlled syntheses of inorganic compounds under the direction of Prof. Linhai Yue. After that, I joined Prof. Gordon J. Miller’s research group in Iowa State University, where I developed the majority of my expertise in solid state chemistry, including high temperature synthesis, X-ray crystallography, and first-principle computations. In 2011, I received my PhD degree in inorganic chemistry and moved to Stuttgart, Germany, working as a postdoc in Prof. Martin Jansen’s department in Max Planck Institute for Solid State Research. My project is on the syntheses, structures, and rationalization of thallium cluster compounds featuring significant relativistic spin-orbit coupling. Currently, I am in Prof. Sven Lidin’s group at Lund University in Sweden, working on my second postdoc position which started in 2013 and is supported by the Wenner-Gren Scholarship. Here, my expertise has been further broadened with incommensurate crystallography and thermoelectric materials.

Sustainable Clean Energy Based on Solid State Ionic Materials and Devices

Published March 11, 2015

By

Chemistry Department Seminar Faculty Candidate
Dr. Jianhua Tong
Colorado Center for Advanced Ceramics,
Metallurgical & Materials Engineering, Colorado School of Mines
Thursday March 19, 2015
MUB ~ Alumni Lounge A
1:00 pm

Abstract
It is estimated that global energy consumption will be doubled by 2035 due to growth in global population and continued industrialization of developing countries. Solar energy is a renewable clean energy source and can satisfy the rising energy demand eventually from long-term point of view. However, fossil energy, a non-renewable carbon-based energy source, still dominates the energy supplies in near future. Therefore, the efficient conversions of fossil energy and the efficient storage of solar energy are also very important from both scientific and industrial point of view. Among the energy materials, the leading actors for energy conversion and storage, solid state ionic materials have found a great number of applications such as catalytic membrane reactors, fuel cells, electrolysis cells, heterogeneous catalysts, photovoltaics, thermal electronic devices, materials for solar thermal chemical fuels production, and catalysts for oxygen reduction reaction and oxygen evolution reaction etc.
In the first part of the talk, I would like to briefly highlight my significant research contributions to sustainable clean energy based on solid state ionic materials and devices. In the second part of the talk, I would like to intensively focus on my recent discovery of perovskite-type oxides as promising materials for solar thermochemical (STC) fuels production through two-step redox cycles.

Bio:
Dr. Jianhua Tong is working as an Associate Research Professor in Colorado Center for Advanced Ceramics at the Colorado School of Mines (US). He received his PhD degree in Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Subsequently, he worked as NEDO project researcher in Research Institute of Innovative Technology for the Earth (Japan), JSPS fellow in National Institute of Advanced Industrial Science and Technology (Japan), and postdoctoral scholar in California Institute of Technology (US) for several years. He has made some important contributions to the materials and devices for sustainable clean energy by focusing on fuel cells, catalytic membrane reactors, pure hydrogen production, pure oxygen production, natural gas conversion, mixed conducting oxides, proton conducting ceramics, and solar thermochemical fuels etc. He published >60 peer-reviewed papers, filed >15 patents, and got citations >2500 and H-index >24.

Exploring environmentally relevant aqueous interfaces and reactions on solid surfaces

Published March 9, 2015

By

Chemistry Department Seminar Faculty Candidate
Dr. Kathryn A. Perrine
Department of Chemistry, University of California Irvine
Monday March 16, 2015
Chem-Sci 101
4:00 pm

Abstract:

Ions and solutes impact chemistry at the aqueous liquid/vapor interface, particularly in environmental chemistry where aerosols can carry pollutants into the atmosphere and react to form harmful byproducts. Liquid Jet X-ray Photoelectron Spectroscopy technique probes the surface and bulk of aqueous solutions. Low photoelectron kinetic energies are used to probe the surface layers of solutions and higher photoelectron kinetic energies probe deeper into the bulk of aqueous solutions. Binary acetonitrile-water mixtures are shown to be inhomogeneous and that the surface forms a saturated dipole layer near 0.2 mole fraction. These studies are contrasted to ternary solutions that have added ions from salts that affect the interface of organic solutes. Potassium iodide was added to aqueous acetonitrile and propionitrile solutions to observe the effects of ions on the surface nitrile distributions. Results from other salt solutions suggest specific cation effects are unexpected and apparent at the aqueous interface. These studies help elucidate the role ions play at the interface of aqueous organic solutions.

Solid interfaces can also have an impact on reactions in catalysis and in the environment. Supported metal oxide structures that are commonly found in urban and rural environments can produce various byproducts with pollutants through core-hole activation in the presence of UV and visible light. In order to understand how the interface is impacted on heterogeneous surfaces, thermal desorption studies of water on different heterogeneous structured TiO2 materials were investigated. Results suggest as the size of the metal oxide decreases, its physical properties change its chemistry and reactivity. Monolayer and second layer activation energies of water were determined on different graphite supported TiO2 structures, ranging from supported nanoparticles to thin films. These studies compare the reactivity of small molecules, representative of those in the air/water environment, and will help explain gas/solid reactions on heterogeneous supported metal oxide materials for catalysis and environmental applications.

Biosketch:
Dr. Kathryn A. Perrine found a passion for surface science as an undergraduate student at the University of South Carolina, where she worked on characterizing the decomposition of metal encapsulated dendrimers for supported metal catalysis applications. She then attended graduate school and earned her PhD at the University of Delaware, where she studied semiconductor surface science. Her work there focused on understanding how Cu nanostructures grow on different functionalized silicon surfaces from chemical vapor deposition of copper metal-organic precursors. She also collaborated with researchers at the Materials Science Department to examine how organic molecules react on silicon for future use in organic electronics. There she won the competitive University of Delaware Professional Development Award for her research accomplishments. She also completed a full year in teaching in higher education by completing the Higher Education Teaching Certification.

She later went on to do postdoctoral work at the University of California, Irvine mainly focused on Liquid-Jet X-ray Photoelectron Spectroscopy (LJ-XPS). She collaborated with researchers at the BESSY II light source at the Helmholtz Center for Materials and Energy on aqueous and acidic systems. She helped build a separate LJ-XPS system at Beam line 11.0.2 end station at the Advanced Light Source at Lawrence Berkeley National Laboratory to continue aqueous liquid jet studies in a higher pressure environment. She collaborated with others in the Hemminger group to investigate other projects, including hydrocarbon decomposition on supported Pt nanoparticles and understanding the reactivity of supported TiO2 materials for heterogeneous catalysis applications. There she was a member of the Postdoctoral association and received the UCI postdoctoral service award for developing a seminar series for postdoctoral teaching. She currently works as a visiting postdoctoral scholar at the Joint Center for Photosynthesis at the California Institute of Technology on heterogeneous catalysts for electrochemical solar energy conversion.

Synthesis of Lipodiscamide A

Published March 4, 2015

By

Ashok Khanal
Original Research Proposal
Michigan Technological University
Department of Chemistry
Advisor: Dr. Shiyue Fang
Thursday, March 5, 2015
10:00 am Chem Sci ~ Room 211

Synthesis of Lipodiscamide A

Abstract:
Lipodiscamide A is a cytotoxic lipopeptide extracted from the marine sponge Discodermia kiiensis. Research on lipodiscamide A has been fueled by its properties such as cytotoxicity, and antimicrobial and immunosuppressive activities. In this proposal, the total synthesis of lipodiscamide A will be described. Structurally, lipodiscamide A contains an unsaturated fatty acid moiety and a hexapeptide moiety. The two moieties are linked together with two ester bonds to form a macrocycle. The yield of this compound from natural sources is very low. Therefore, its synthesis from readily available starting materials resulting in large amounts of lipodiscamide A is important for full investigation of its biological activities.