Chlorination of C₈₆ to C₈₄Cl₃₂ with Nonclassical Heptagon‐Containing Fullerene Cage Formed by Cage Shrinkage

Abstract

Geschrumpftes Fulleren: Ein ungewöhnlicher C84‐Fullerenkäfig mit siebengliedrigem Ring liegt in C84Cl32 vor, das (neben C86(16)Cl28) bei der Chlorierung von C86(16) mit VCl4 gebildet wird. Ein Vergleich der Strukturen von C84Cl32 (siehe Bild; C grau, Cl grün; rote Bindungen markieren das Heptagon) und C86(16)Cl28 sowie theoretische Studien zeigen, dass der C86(16)‐Käfig schrumpft, wenn eine C2‐Einheit aus dem Corranulen‐Fragment entfernt wird.

Carbon arc production of heptagon-containing fullerene[68]

“…These POAV angles are even smaller than those in the stable buckminsterfullerene I h - C60 (11.64°), rendering heptafullerene[68] a heptagon-related planarity. Such kinds of decreased POAV angle have also been seen in the recently reported C 84 Cl 32 molecule, in which the POAV angles at the carbon atoms of the heptagon are in the range of 3.2–5.8° (average 5.2°) 28 . As the heptagon-related planarity facilitates strain relief in a curved surface of a cage, the existence of a heptagon may be expected to bring extra stabilization for the carbon cage involved.…”

“…Experimental corroboration of such a prevalence of heptagons heavily depends on the in situ capture of heptafullerene in the carbon clustering venue for the growth of the whole family of fullerenes. However, the previously reported heptafullerene derivatives (hepta-C 58 F 18 and hepta-C 84 Cl 32 ) were synthesized by an off-line top-down method through chemical detachment of a C 2 unit from a stable fullerene ( C60 or C 86 ) 27 28 . This top-down approach is similar to the so-called open-cage method in which the hexagons/pentagons of fullerene cages (typically C60 ) are modified to give so-called open-cage fullerenes containing rings with twelve-, sixteen-, or eighteen-membered-rings and beyond 37 38 39 .…”

“… 27 ) and C 84 Cl 32 (ref. 28 ). Such work has provided a breakthrough in the synthesis of heptafullerene derivatives by a top-down chemical method.…”

Geometrical and Electronic Rules in Fullerene‐Based Compounds

“…Meanwhile, some derivatives of nonclassical isomers have been experimentally synthesized. [69][70][71] Consequently, a topic in the field of fullerene that deserves a more in-depth look should be the carbon polyhedra formed by any combination of different kinds of polygons to reveal whether a stable carbon polyhedron obeys a rule similar to, or more general than, the established IPR and PAPR. To address this issue, Gan et al [72] performed systemic calculations on carbon polyhedra that consisted of squares, pentagons, hexagons, and heptagons by using DFT methods.…”

Punching a Carbon Atom of C60 into its Own Cavity to Form an Endohedral Complex CO@C59O6 under Mild Conditions

“…[3] Halogenation at high temperature also leads to the loss of a C 2 unit to form C 58 F 18 from C 60 [4] and C 84 Cl 32 from C 86. [5] Both ozonation [6] of C 60 and thermolysis [7] of C 120 O results in removal of one carbon atom to form C 58 and C 119 , respectively. In the preparation of azafullerenes C 59 NR [8][9][10][11] and C 69 NR, [10] one carbon atom of the fullerene skeleton was removed from the cage and replaced by a nitrogen atom.…”