Laser-Induced Formation, Fragmentation, Coalescence, and Delayed Ionization of the C₅₉N Heterofullerene

Abstract

The formation of the nitrogen heterofullerene, C59N, following the ablation of a variety of fullerene derivatives, all of which possess organic ligands bound to the carbon cage through a nitrogen atom, has been investigated utilizing laser desorption/ionization mass spectrometry. Investigating the formation of cationic and anionic C59N+/-, this approach is found to be a new and very efficient way to implement the initially exohedral nitrogen atom into the carbon cage. The laser-induced heterofullerene formation is discussed in terms of the structure and the charge state dependency of the target material. In further experiments, the coalescence reactivity, leading toward the formation of larger clusters has been examined following laser ablation of thin films of the (C59N)2 dimer. Coalescence leads to two major reaction products, consisting of larger C n - 1N+ clusters which retain the nitrogen atom networked into a larger carbon cage and pure C n + (n = even) carbon clusters. The C n - 1N+ cluster formation is accompanied by abundant metastable transitions caused by the loss of CN and the resulting implications for the coalescence mechanism are discussed. Finally, evidence is presented for the delayed electron emission of C59N·. The observation of delayed ionization of heterofullerenes is unprecedented, revealing a similar resistance toward fragmentation as in the case of their all-carbon fullerene analogues.

Transformation of doped graphite into cluster-encapsulated fullerene cages

“…16 ), in contrast to C 2 -loss with retention of N for the Y 3 N@C 80 endohedral nanocluster. These results are consistent with empty cage N-containing heterofullerenes 44 . Thus, the present gas-phase dissociation studies are shown to be a structural diagnostic for identification of clusterfullerenes and endohedral heterofullerenes.…”

Interstellar fullerene compounds and diffuse interstellar bands

“…One clue is precisely the high value of the energy of maximum efficiency for ion implantation, proving that below this value the probability of cage destruction or opening remains low. Another proof is the evidence that delayed laser photoemission of electrons is similar for endohedral and empty fullerenes, showing that both are capable of storing large amounts of internal energy without dissociation (Beck et al 1996;Clipston et al 2000). Except for very small atoms and their ions (H and He, but also N), opening the cage enough to allow the atom or its ion to escape requires injecting a lot of energy, typically a few tens of eV (see e.g.…”

Ab initio quantum chemical studies of fullerene molecules with substitutes C59X [XSi, Ge, Sn], C59X− [XB, Al, Ga, In], and C59X [XN, P, As, Sb]

“…Synthesis and isolation of heterofullerenes, such as, C 60− x B x ( x 1–2) 3–7, C 59 N 8–13, C 59 O, 14, 15, C 60− x Si x , 16–24, C 59 P, 25 and transition‐metal doped C 59 M (MPt, Fe, Co, Ni, Rh, Ir) 26, 27 have been carried out successfully 3. It is known that crystal lattice defects and impurities significantly influence the properties of traditional materials.…”

“…Also, isomers of the C 60 , C 58 clusters, and C 59 type species, and other carbon clusters have been synthesized, but in insignificant quantities 30–32. Most experimental studies are devoted to neutral systems 3–27, one method to distinguish fullerene clusters when output is minimal is mass spectroscopy which separates various charged cluster sizes based on the mass. Despite the interesting properties and possible applications, the details concerning the formation of such defects, their structures and influence on the physical and chemical properties remain scarcely investigated.…”