Science/Technology to promote economic development in northeastern Ohio. One major program is the EPIC Macromolecular Modeling Center, codirected by Akron's Mattice and Case Western's Blackwell. Other ef forts include the EPIC Applied Re search Laboratory and the EPIC Mini Pilot Polymerization Plant, both housed in the Olson Research Center, and the Center for Applied Polymer Research at Case Western. Member companies' fees may go to support research programs at or pur chases of services from these and other EPIC facilities. D
"Ferric wheel" molecule characterized at ΜΓΓ Sometimes chemistry is fun just be cause molecules are beautiful. At Massachusetts Institute of Technology, chemistry professor Stephen J. Lippard and graduate stu dent Kingsley L. Taft have discov ered such a molecule. It has no known utility, but it sure is pretty. They call it a molecular "ferric wheel." The molecule, [Fe(OCH3)2(02CCH2Cl)] 10 , is a decairon molecule that forms a nearly perfect circle [}· ^mChem. Soc, 112, 9629 (1990)]. It as sembles spontaneously in methanolic solutions of diiron(III) oxo com plexes that Lippard and Taft are studying. The studies are part of a research program to elucidate the chemistry of polyiron oxo protein cores such as those that occur in the proteins hemerythrin, ribonucle otide reductase, methane monooxygenase, and ferritin. "We were not trying to make this particular compound," Lippard says. "It was a completely serendipitous discovery." The compound was prepared by allowing the monochloroacetate an alog of basic iron acetate, [Fe 3 0(0 2 CCH 2 C1) 6 (H 2 0) 3 ](N0 3 ), to react with ferric nitrate in methanol. Dif fusion of ether into the resulting green-brown solution produced a yellow solution from which goldbrown crystals of the ferric wheel as well as a yellow precipitate deposit ed after several days. Because the crystals were there, 22
December 24, 1990 C&EN
Molecular "ferric wheel Taft and Lippard decided to charac terize them. "X-ray crystallography is so powerful and so rapid now that it was easier for us to characterize the compound by doing the com plete x-ray structure than by using other techniques," Lippard says. "It is hard to ignore a nice crystalline compound because, usually within a day or two, you can do the x-ray structure." The structure of the ferric wheel consists of 10 ferric ions in a circular array. The 10 iron atoms are essen tially coplanar. Each has a distorted octahedral geometry and is joined to its neighbors by methoxide and car-
boxylate bridges, forming a wheel that is about 12 Â in diameter. Lippard points out that "these molecules represent a class of intriguing compounds somewhere between mononuclear iron complexes and rust." He adds that a few other laboratories are engaged in similar research on clusters containing many iron atoms, including that of Richard H. Holm at Harvard University, who is studying iron-sulfur complexes. Lippard's research was supported by the National Science Foundation and the National Institutes of Health. Rudy Baum
IUPAC book updates rules for naming inorganics "Nomenclature of Inorganic Chem istry," published this year by Blackwell Scientific Publications for the International Union of Pure & Ap plied Chemistry, isn't so much a re vision of previous books on the sub ject. Rather, it is an entirely new work in its own right, says G. Jeffery Leigh, its editor. More usually referred to in IUPAC circles as the Red Book because
of the distinctive color of its cover, the 300-page work, with more than 230 illustrations, sets out internationally agreed upon rules for naming various types of inorganic compounds. It is the culmination of 15 years of effort by experts in the field working within the Commission on Nomenclature of Inorganic Chemistry (CNIC), an arm of IUPAC's inorganic chemistry division.
