Web Date: September 17, 2008
Fullerene Traps Longest Metal-Metal Bond
By trapping two terbium atoms within a C79N fullerene cage, chemists have created the longest metal-metal bond measured to date (J. Am. Chem. Soc., DOI: 10.1021/ja802417d). The terbium atoms share a single-electron bond a tad more than 3.9 Å long.
A research team led by Alan L. Balch of the University of California, Davis, and Harry C. Dorn of Virginia Polytechnic Institute & State University prepared the endohedral fullerene along with an analog that holds a pair of yttrium atoms. To create the compounds, the researchers employed the Krätschmer-Huffman electric-arc process to vaporize graphite rods doped with either Tb4O7 or Y2O3. They then purified enough material for crystallographic and spectroscopic studies.
Computational analyses of the yttrium analog indicate that the compound is a very stable radical in which the metal atoms share an unpaired electron in their bonding orbital.
According to Dorn, these molecules represent a new class of stable heterometallofullerenes. Such compounds could could find practical applications as contrast agents for magnetic resonance imaging or could be used to deliver radioactive atoms in nuclear medicine.
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