| Posted: February 27, 2008 |
IIT hosts pioneers in nanotechnology |
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(Nanowerk News) While most IIT (Illinois Institute of Technology) students prepared for weekend social rituals, possibly involving vaguely scientific studies of ethanol, members of the Chicago Section of the American Chemical Society met jointly with IIT students and faculty for a more enlightening experience in the world of chemistry. The featured speaker was Dr. Fraser Stoddart, who has earned great prestige for his contributions to nanotechnology. This joint meeting was the first of three to be hosted at IIT and part of our chemistry department’s Kilpatrick Lecture series. The Kilpatrick Lecture series is named for Martin and Mary Kilpatrick, recognized for their contributions to developing the chemistry department upon arrival in 1947.
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The evening began with a lecture by Dr. William Dichtel, a research associate of Stoddart’s at Caltech and UCLA. He focused on the mechanisms by which a ring structure can be linked around a rod. Imagine clipping a ring around the handle of a dumbbell. The bulky ends of the dumbbell prevent the ring from slipping off either end. This is no trivial feat. The entity that will form the ring must have an attractive force to the rod (through pi-electron donating and accepting interactions) such that the ring will form around the rod instead of bouncing off upon collision. The name of this compound is [2] rotoxane for its two components and the Latin roots “rota” and “axis,” meaning ”wheel” and “axle.” Cu (I)-catalyzed azide-alkyne cycloaddition has shown moderate success, giving 30-60% yields. Also introduced was [2] catenane; two rings linked like a chain.
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Dr. Dichtel’s lecture was followed by a truly impressive display of IIT chefs’ talents. Dinner guests had choices of burgundy beef tenderloin tips, coconut curry salmon or vegetable lasagna. This author, being a graduate student on a tighter budget, chose fried catfish at Commons before the lecture.
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The sound of bagpipes welcomed attendees back into the lecture auditorium. Dr. Fraser Stoddart is a native of Scotland. He received his degrees from Edinburgh University and has since held many research and academic positions in Canada, US and UK. In 2003 he was named Director of the California NanoSystems Institute at UCLA. Stoddart is also a member of the Royal Society and has received many awards for his work including knighthood. On January 1, 2008 Stoddart joined the Chicago community as a Trustees Professor at Northwestern University.
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IIT’s Dr. Lykos, who introduced both speakers, remarked that 80% of scientific publications are read only by their authors. The quality of research is measured by the number of times the research is cited. Over the last ten years Stoddart is the third most cited researcher. “We have a person of consequence in our midst,” said Lykos.
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Stoddart presented Borromean rings (three interlocked rings) and Solomon knots (two rings interlocked twice). Electron-rich moieties in the rings chelated around Zn(II) or Cu(II), thusly directing shape. As if these designs displayed beautifully with computer imagery were not impressive enough, Stoddart introduced how these constructions can be used to make nanoscale machinery. One ring in [2] catenane can be designed with two regions that attract the other ring, one slightly more than the other. If the region with more attraction can be made to repel the other ring when reduced, addition of one electron causes one ring to rotate through the other. Removing the electron restores the original position. The same principle was used in [2] rotoxane to slide the ring position back and forth on the axle.
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The potential for this technology is vast. In computer science, the mechanics of [2] rotoxane could allow for 1 trillion bits on a chip the size of a postage stamp. As a pharmaceutical agent, a 200-400 nm nanomachine could be inserted into a cell and break lysosomes (acid-filled organelles used for digestion) causing cell death. Improving cancer treatment is an important issue for Stoddart because he lost his wife to breast cancer in 2004.
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When speaking briefly with Dichtel and Stoddart after the lectures, Dichtel stressed the importance of basic research and the scope of nanotechnology. Whether used in cells or computer chips, fundamental chemistry will shape the future of science on the nanometer scale. Stoddart offered words of inspiration: “When people came to Chicago 100 years ago for world art and culture, Paris was the still the center of the universe. At this stage the Midwest is becoming the place people are flocking to advance technology.
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