Crystal Structures of Saturn‐Like C₅₀Cl₁₀ and Pineapple‐Shaped C₆₄Cl₄: Geometric Implications of Double‐ and Triple‐Pentagon‐Fused Chlorofullerenes

Abstract

Planet pineapple: The structures of two isolated pentagon rule (IPR)‐violating chlorofullerenes (C50Cl10 and C64Cl4; see picture) are determined by X‐ray crystallography and their stabilities rationalized by relief of strain at the active pentagon‐fusion carbon atoms whilst maintaining the aromaticity of their carbon skeletons.

The evolutions of the structure stability, vibrational frequency, frontier orbital, and electronegativity of the unconventional exohedral fullerenes C64X4 (X=H, F, Cl, Br, and I): A density functional study

“…On the other hand, C 64 Br 4 and C 64 Cl 4 two molecules have almost the same Egs compared to those of C 64 H 4 and C 60 , although the BDEs of them are smaller than that of C 64 H 4 , therefore, these two molecules could be isolated successfully because of their positive BDEs and comparatively large Egs. Recently, the C 64 Cl 4 molecule with the smaller BDE and Eg than those of C 64 H 4 has been successfully isolated by Han et al [40]. Therefore, we infer C 64 F 4 and C 64 Br 4 could be isolated and synthesized.…”

“…The VEA is evaluated by adding one electron to the neutral cluster in its equilibrium geometry and taking the difference between their total energies. The MEN was identified by Parr as the negative of the partial derivative of the energy E of an atomic or molecular system with respect to the number of electrons N for a constant external (i.e., due to the nuclei) potential v, written as v ¼ Àð oE oN Þ v [40]. Parr and Pearson, on the basis of the Hard-Soft Acid-Base (HSAB) principle, identified the CH as the second derivative of the energy E with respect to the number of electrons N at fixed external potential, i.e., g ¼ 1…”

“…Commonly, hydrogen atom or halogen atoms can be all used to stabilize the fullerene cage, such as C 28 [9][10][11][12] and C 40 [13] and so on. In addition, the fluorination, chlorination, bromination, and iodination of fullerenes, under controlled conditions, can lead to the isolation of different stable compounds, such as C 20 F 20 [15], C 36 X n (X = F, Cl, and Br, n = 2, 4, 6, and 12) [16], C 50 X 10 (X = F, Cl, and Br) [8], C 60 F 24 [17], C 50 Cl 12 [18,19], C 60 X 24 (X = Br and I) [20], and C 70 I n (n = 2 and 17) [20].…”

Thermochemical stabilities, electronic structures, and optical properties of C56X10 (X = H, F, and Cl) fullerene compounds

“…By the halogenation on the smaller fullerenes, three kinds of exohedral derivatives are synthesized and characterized unambiguously. Examples comprise the C 20 Br n H 202n , 27,28 C 50 Cl 10 , 29,30 C 58 F 18 , and C 58 F 17 CF 3 . 31 Inspired by the successful synthesis of C 50 Cl 10 , Yang et al 32 investigated the electronic properties, static polarizability, and hyperpolarizability using finite-field (FF) approach.…”

Electronic structures, stabilities, and spectroscopies of the fullerene derivatives C68X4 (X=H, F, Cl)

“…Owning to the high strain of the unavoidable adjacent pentagons, these fullerenes are predicted to be highly unstable and difficult to isolate, but they can be stabilized by forming endohedral or exohedral derivatives with other groups. A series of exohedral fullerene derivatives, such as C 50 Cl 10 [2], C 64 H 4 [3], C 64 Cl 4 [4], and C 56 Cl 10 [5], have been successfully synthesized and characterized using the modified graphite arc-discharge method. Many theoretical investigations [6][7][8][9] have also been made to understand why and how these extremely unstable fullerenes are stabilized through exohedral chemical deriving.…”