The structure of small carbon cluster anions, Cn(-) (4 = n = 20), was investigated with the use of ion chromatography. With this technique, both the existence and the relative amounts of possible structural isomers can be determined. More than 99% of the ions C(5)(-) to C(9)(-) were found to be linear under these experimental conditions. Starting with C(10)(-), a monocyclic isomer was observed, and linear and moncyclic structures coexisted from C(10)(-) through at least C(20)(-). This result is in contrast to previous work on positive ions, which showed the existence of linear isomers from C(5)(+) to C(10)(+), with linear and cyclic isomers coexisting only from C(7)(+) to C(10)(+). Above C(10)(+), no linear clusters were observed.
Ion chromatography studies were performed to assess various models proposed for the structure of M(8)C(12) species, the met-cars. A laser desorption source was used to make a sequence of titanium-carbon clusters centered around Ti(8)C(12)(+). The Ti(8)C(12)(+) 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 Ti(8)C(12)(+) yielded only Ti(7)C(12)(+) under the experimental conditions described herein, and modeling indicated that the cage structure was retained. Both Ti(8)C(11)(+) and Ti(8)C(13)(+) were made by the cluster source, and again, dodecahedral-type cage structures were consistent with experiment. The extra carbon atom in Ti(8)C(13)(+) was attached exohedrally to a single titanium atom. No evidence for an endohedral species was found.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.