Evidence from Ion Chromatography Experiments That Met-Cars Are Hollow Cage Clusters
Seonghoon Lee 1,
Nigel G. Gotts 1,
Gert von Helden 1, and
Michael T. Bowers 1
1 Department of Chemistry, University of California, Santa Barbara, CA 93106, USA.
Ion chromatography studies were performed to assess various models proposed for the structure of M8C12 species, the met-cars. A laser desorption source was used to make a sequence of titanium-carbon clusters centered around Ti8C12+. The Ti8C12+ was determined to be a hollow cage cluster, with the dodechadron structure originally propposed termined to be a hollow cage cluster, with the dodecahedron structure originally proposed giving the best fit to experiment; cubic structures could be excluded. Collisional breakup of Ti8C12+ yielded only Ti7C12+ under the experimental conditions described herein, and modeling indicated that the cage structure was retained. Both Ti8C11+ and Ti8C13+ were made by the cluster source, and again, dodecahedral-type cage structures were consistent with experiment. The extra carbon atom in Ti8C13+ was attached exohedrally to a single titanium atom. No evidence for an endohedral species was found.
Submitted on September 27, 1994
Accepted on November 21, 1994
