C₁‐(C₈₄‐C₂(11))(CF₃)₁₂: Trifluoromethylation Yields Structural Proof of a Minor C₈₄ Cage and Reveals a Principle of Higher Fullerene Reactivity

Abstract

Ribbon pattern: An isomer of C84(CF3)12 fullerene with the C84‐C2(11) cage (see molecular structure determined by X‐ray crystallography) demonstrates a new principle of hollow higher fullerene reactivity: For 1,4‐additions of bulky groups that produce ribbons or loops of edge‐sharing p‐C6X2 hexagons, the “most reactive” double bonds remain intact.

C80Cl12: A Chlorine Derivative of the Chiral D2‐C80 Isomer—Empirical Rationale of Halogen‐Atom Addition Pattern

“…Indeed, in most of the reported halogenated higher fullerenes, [9] the halogen atoms bind to carbon atoms at 1,4-positions in the hexagons (i.e., to PHJ carbon atoms) in such a way that contiguous ribbons of halogen atoms form. The tendency of generating ribbons of 1,4-addition exclusively was first reported by Strauss et al, [10] proposing by this a principle of higher fullerene reactivity. However, the violation of this principle in the case of C 76 Cl 18 in which ten out of eighteen chlorine atoms bind to ICCB carbon atoms, thus at 1,2-positions in hexagons, [5] needs to be discussed.…”

Isolation and Structural X‐ray Investigation of Perfluoroalkyl Derivatives of Six Cage Isomers of C84

“…Single-crystal Xray crystallography with the use of synchrotron radiation allowed structure elucidation of eight C 84 (R F ) n compounds containing six different C 84 cages (the number of the C 84 isomer is given in parentheses): C 84 (23) 12 (VI with toluene and VII with hexane as solvate molecules), and C 84 (18)A C H T U N G T R E N N U N G (C 2 F 5 ) 12 (VIII). Whereas some connectivity patterns of C 84 isomers (22,23,11) had previously been unambiguously confirmed by different methods, derivatives of C 84 isomers numbers 4, 16, and 18 have been investigated crystallographically for the first time, thus providing direct proof of the connectivity patterns of rare C 84 isomers. General aspects of the addition of R F groups to C 84 cages are discussed in terms of the preferred positions in the pentagons under the formation of chains, pairs, and isolated R F groups.…”

“…[8] The choice between several candidates is usually supported by theoretical calculations of relative stability for all 24 C 84 isomers. [9] The carbon cage connectivity has been confirmed by single-crystal X-ray diffraction for only three C 84 isomers: an iridium derivate of C 84 (23), [C 84 Ir(CO)Cl-A C H T U N G T R E N N U N G (PPh 3 ) 2 ]·4 C 6 H 6 , [10] trifluoromethylated fullerene C 84 (11), C 84 -A C H T U N G T R E N N U N G (CF 3 ) 12 , [11] and a non-functionalized C 84 (14) in co-crystals with Ag tetraphenylporphyrin. [12] The powder diffraction Xray synchrotron study of a pristine C 84 fullerene mixture reveals the existence of an face-centered cubic (fcc) crystal packing of disordered C 84 cages, which does not allow characterization of cage connectivities.…”

“…In the present work, we report the functionalization (trifluoromethylation or pentafluoroethylation, respectively) of a higher fullerene mixture, HPLC separation and isolation of perfluoroalkyl derivatives of six C 84 isomers (no. 4,11,16,18,22, and 23), [14] and their structural characterization by means of single-crystal X-ray diffraction. The results obtained are discussed in terms of connectivity patterns of the known and new C 84 isomers, and the structural motifs of addition in the perfluoroalkylated compounds.…”

Dichlorophenyl Derivatives of La@C3v(7)‐C82: Endohedral Metal Induced Localization of Pyramidalization and Spin on a Triple‐Hexagon Junction

“…[17] As a result, no fullerene derivative having fewer than 38 substituents has substituents singly bonded to THJs. [18] Only upon severe derivatization are some THJs substituted to stabilize the resulting molecule by, for example, formation of local aromaticity. Such cases are only found for C 2n F 38 (2n = 70, 74).…”