NEWS OF THE WEEK NANOELECTRONICS
SUPRAMOLECULAR EXTENSION CORD
PHOTOINDUCED Electron transfer occurs in supramolecular system
Light excitation induces electron transfer in socket-plug system
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SELF-ASSEMBLING SUPRA-
molecular triad mimics, at a molecular level, the function of a macroscopic electrical extension cord, according to chemists in California and Italy. The triad consists of a wirelike central cationic component that plugs into crown ether sockets at both ends. One of the crown ethers is attached to an electronrich bipyridyl ruthenium complex. When the system is illuminated, electrons flow from the ruthenium complex to the other end of the moiety. The work was carried out by chemistry professor Vincenzo Balzani and associate professor of chemistry Maria Teresa Gandolfi of the University of Bologna; chemistry professor J. Fraser Stoddart of the University of California, Los Angeles; and their coworkers \J. Am. Chem. Soc, published online Oct. 4, http://dx.doi.org/ 10.1021/ja025813x]. "This is an example of a supramolecular system specifically designed to play the role of a molecular-level device," Balzani tells C&EN. "Owing to the properties incorporated into the three components, self-assembly occurs in a specific, well-defined manner, and the two plug-socket connections can be controlled reversibly and independently by two different external inputs: acid/base and redox stimuli." The team monitored the behavior of the system by light absorption and emission spectroscopies and also by electrochemical techniques such as cyclic voltammetry. "This is a nice piece of work," HTTP://PUBS.ACS.ORG/CEN
comments Oxford University chemistry lecturer Harry L. Anderson. "The system illustrates the versatility of these molecular construction modules and shows how they can be used to build sophisticated and potentially functional supramolecular structures." The controlling phenomena brought into play are particularly interesting, according to John A. Gladysz, chemistry professor at the University of ErlangenNuremberg, in Germany. "The system embodies an added level of complexity and function beyond other supramolecular systems designed to function as molecular-level devices," he says. Balzani points to two limita-
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tions of the present system, however. "The middle component contains two plugs instead of a plug and a socket, giving a socket-plug-plug-socket architecture," he explains. 'And the transferred electrons stop on the dicationic bipyridium unit without reaching the final naphthalene-containing crown ether component. We have designed, and recently synthesized, new molecular components that lead to two consecutive plug-socket motifs and place the final electron acceptor as the last component of the chain."-MICHAEL FREEMANTLE
HONORED
Institute Of Medicine Elects New Members 1
our scientists who work in chemically UCLA-U.S. Department of Energy Laboratory related areas are among the 65 newly of Structural Biology & Molecular Medicine. elected members of the Institute of Med William E. Evans, executive vice president icine, one of the four sister institutions that and deputy director, and chair, department of make up the National Academies, pharmaceutical sciences, St. Jude Washington, D.C. IOM no longer diChildren's Research Hospital, vides its membership into active Memphis. and senior members, so it now has Ira Herskowitz, professor of 1,358 members. In addition, five biochemistry and biophysics, and people were elected foreign associcodirector, program in human geates, bringing that total to 66. netics, University of California, San Francisco. Following are the newly elected chemistry-related IOM members: Also elected to membership is a Harvey J. Alter, chief, infectious man who has had a big impact on disease section, and associate dichemical research, though he's not Eisenberg rector of research, department of a chemist: Gerald M. Rubin, vice transfusion medicine, National Institutes of president for biomedical research, Howard Health, Bethesda, Md. Hughes Medical Institute, and professor of genetics and development, department of David Eisenberg, professor of biological molecular and cell biology, University of Calichemistry and molecular biology, University fornia, Berkeley.-JANICE LONG of California, Los Angeles, and director,
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