Chapter 10
Metallo-Carbohedrenes and Their
Reactivity
10.1 The Discovery of Metallo-Carbohedrenes
Since the discovery of C 60 called buckminsterfullerene whose shape resembles that
of geodesic domes, the so-called buckyballs have attracted extensive research interest
and touted for many important applications [1–31]. Furthermore, extensive studies
have been conducted upon the incorporation of metals such as lanthanum into the
interior of C 60 giving rise to promising applications such as in superconductive
materials [32–35]. In addition, researchers have also found that a few carbon atoms
in C 60 cage can be replaced by other atoms without substantially destabilizing the
entire fullerene cage [36–56].
Similar to fullerenes, Castleman and his coworkers discovered a new cluster
species in 1992, named metallo-carbohedrenes or “Met-Cars” for short [57, 58].
It was more or less just a serendipity when they used the laser to probe various
titanium reactions and noticed a very strong peak at 528 mass unit, as shown in
Fig. 10.1 [59–61]. Repeated experiments were tried for the same reaction with a
number of other hydrocarbon gases; also they substituted a different transition metal
for titanium, and substituted a hydrocarbon composed of deuterium (the one-neutron
isotope of hydrogen) as the raw material, as well as
13 C to use in the hydrocarbon
raw material; finally they ascertained the discovery of this mystery material Ti 8 C 12
[57–60, 62, 63].
Following the discovery of the existence of stable Met-Cars clusters, the stoichiometry M 8 C 12 (M = Ti, V, Zr, Nb, and Hf) and their pentagonal dodecahedral
structure of T h symmetry attracted reasonable interest [57–60]. The eight equivalently bonded metal atoms were found to account for the unusual stability of this
class of clusters. Subsequent investigations were also conducted by experimentalists and theoreticians with a reemphasis on the unusual stability of these Met-Cars,
leading knowledge on the range of metals which form this interesting cage cluster
species [64].
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_10
163
Metallo-Carbohedrenes and Their
Reactivity
10.1 The Discovery of Metallo-Carbohedrenes
Since the discovery of C 60 called buckminsterfullerene whose shape resembles that
of geodesic domes, the so-called buckyballs have attracted extensive research interest
and touted for many important applications [1–31]. Furthermore, extensive studies
have been conducted upon the incorporation of metals such as lanthanum into the
interior of C 60 giving rise to promising applications such as in superconductive
materials [32–35]. In addition, researchers have also found that a few carbon atoms
in C 60 cage can be replaced by other atoms without substantially destabilizing the
entire fullerene cage [36–56].
Similar to fullerenes, Castleman and his coworkers discovered a new cluster
species in 1992, named metallo-carbohedrenes or “Met-Cars” for short [57, 58].
It was more or less just a serendipity when they used the laser to probe various
titanium reactions and noticed a very strong peak at 528 mass unit, as shown in
Fig. 10.1 [59–61]. Repeated experiments were tried for the same reaction with a
number of other hydrocarbon gases; also they substituted a different transition metal
for titanium, and substituted a hydrocarbon composed of deuterium (the one-neutron
isotope of hydrogen) as the raw material, as well as
13 C to use in the hydrocarbon
raw material; finally they ascertained the discovery of this mystery material Ti 8 C 12
[57–60, 62, 63].
Following the discovery of the existence of stable Met-Cars clusters, the stoichiometry M 8 C 12 (M = Ti, V, Zr, Nb, and Hf) and their pentagonal dodecahedral
structure of T h symmetry attracted reasonable interest [57–60]. The eight equivalently bonded metal atoms were found to account for the unusual stability of this
class of clusters. Subsequent investigations were also conducted by experimentalists and theoreticians with a reemphasis on the unusual stability of these Met-Cars,
leading knowledge on the range of metals which form this interesting cage cluster
species [64].
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_10
163