The First Experimentally Confirmed Isolated Pentagon Rule (IPR) Isomers of Higher Fullerene C₉₈ Captured as Chlorides, C₉₈(248)Cl₂₂ and C₉₈(116)Cl₂₀

Abstract

High-temperature chlorination of pristine C98 fullerene isomers separated by HPLC from the fullerene soot afforded crystals of C98Cl22 and C98Cl20. An X-ray structure elucidation revealed, respectively, the presence of carbon cages of the most stable C2-C98(248) and rather unstable C1-C98(116), which represent the first isolated pentagon rule (IPR) isomers of fullerene C98 confirmed experimentally. The chlorination patterns of the chlorides are discussed in terms of the formation of isolated C=C bonds and aromatic substructures on the fullerene cages.

Probing the structure of giant fullerenes by high resolution trapped ion mobility spectrometry

“…This method has proven to be quite powerful and it has been possible to identify and structurally characterize specific IPR isomers for a large number of fullerene cage sizes ranging up to C 108 . [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] A drawback is however that such giant fullerene isomers can only be identified if they are functionalized in a well-defined way and if the corresponding derivatives can be crystallized. Furthermore, the reaction conditions for fullerene derivatization are often quite harsh and may be associated with isomerization and/or fragmentation.…”

New Isolated-Pentagon-Rule Isomers of Fullerene C98 Captured as Chloro Derivatives

“…Using the chlorination method, the first two IPR isomers of C 98 fullerene nos. 248 and 116 were confirmed very recently as chloro derivatives, C 98 (248)­Cl 22 and C 98 (116)­Cl 20 , respectively (the IPR isomer numbering in parentheses is according to the spiral algorithm) . There are several theoretical studies on IPR isomers of C 98 , which report the highest stability of isomer C 2 -C 98 (248) but differ in the stability orders of other isomers …”

Trifluoromethyl Derivatives of Elusive Fullerene C98

“…A comparison of the addition patterns in C 98 (116)(CF 3 ) 18 and in chloro derivative C 98 (116)Cl 20 showed many similar features, such as 13 common addition sites or the same positions of two isolated C=C bonds and one benzenoid ring. A noticeable difference of the addition pattern of C 98 (116)Cl 20 concerns the absence of an attachment in THJ and the presence of two pairs of Cl atoms attached in adjacent positions.…”

“… Schlegel diagram presentation of C 98 (116)(CF 3 ) 18 and C 98 (120)(CF 3 ) 20 (top) and the corresponding C 98 (116)Cl 20 and C 98 (120)Cl 22 (bottom) given for comparison. Cage pentagons are shown with red.…”

“…It is interesting to compare the addition patterns of CF 3 and Cl addends on the same C 2 ‐C 98 (248) cage. The addition patterns of C 98 (248)(CF 3 ) 20 and C 2 ‐C 98 (248)Cl 22 contain 19 positions of common attachments sites including those in THJs (Figure ). It means that the difference in addend sizes between CF 3 and Cl does not play a decisive role in this case, whereas the stabilizing factors of isolated substructures are of greater importance.…”