Is the Isolated Pentagon Rule Merely a Suggestion for Endohedral Fullerenes? The Structure of a Second Egg-Shaped Endohedral Fullerene—Gd₃N@C_s(39663)-C₈₂

Abstract

The structure of Gd3N@Cs(39663)-C82 has been determined through single crystal X-ray diffraction on Gd3N@Cs(39663)-C82.NiII(OEP).2(C6H6) The carbon cage has a distinct egg shape because of the presence of a single pair of fused pentagons at one apex of the molecule. Although 9 IPR structures are available to the C82 cage, one of the 39709 isomeric structures that do not conform to the IPR was found in Gd3N@Cs(39663)-C82. The egg-shaped structure of Gd3N@Cs(39663)-C82 is similar to that observed previously for M3N@Cs(51365)-C84 (M = Gd, Tm, Tb). As noted for other non-IPR endohedral fullerenes, one Gd atom in Gd3N@Cs(39663)-C82 is nestled within the fold of the fused pentagons.

Chemical, Electrochemical, and Structural Properties of Endohedral Metallofullerenes

“…[9, 140c] Gd 3 N@C 86 and the two non-IPR metallic nitride EMFs Gd 3 N@C 82 (C s :39 663) [116] and Gd 3 N@C 84 (C s :51 365) [118] showed three irreversible reduction and one reversible oxidation processes, a behavior qualitatively similar to that of the IPR Gd 3 N@C 80 (I h ). In contrast, both reductions and oxidations are reversible for Gd 3 N@C 88 .…”

“…The first reports of EMFs with carbon cages containing fused pentagon systems were those of Sc 2 @C 66 [115] and Sc 3 N@C 68 (D 3 :6140). [110] Other examples are [75b, 104,[116][117][118][119][120][121] On the other hand, spectroscopy along with DFT calculations strongly suggested that the major isomer of Dy 3 N@C 78 and Tm 3 N@C 78 both have the non-IPR carbon cage of symmetry C 2 :22 010 [122] and that Ce 2 @C 72 possesses a non-IPR carbon cage of D 2 symmetry, as in the case of La 2 @C 72 . [123] It is interesting to note that as the size of the fullerene increases, the number of fused pentagon systems decreases; for example, Sc 3 N@C 68 (D 3 :6140) has three fused pentagon systems while Gd 3 N@C 82 (C s :39 663) and M 3 N@C 84 (C s :51 365) (M = Gd, Tb, Tm) have only one ( Figure 5).…”

Yb@C2n (n = 40, 41, 42): New Fullerene Allotropes with Unexplored Electrochemical Properties

“…11 Surprisingly, a TNT cluster tends to template a non-IPR cage of C s (39663), forming, for example, Gd 3 N@C 82 . 64 These experimental results implied again that the formation of EMFs not only is determined by the electronic configuration of the resulting EMFs but also depends on the number of internal metals. One metal atom generally engenders the formation of three or four cage isomers with lower cage symmetries, whereas two metal atoms would template the isomers with higher symmetries (C 3V and C 2V ).…”

An atlas of endohedral Sc2S cluster fullerenes

“…As shown in Fig. 2 [39,40], this cage is an S-W rotation away from the parent cage of the most favored isomer Sc 2 S@C 82 :39715. C 70 :7892, the parent of the most favored isomer of Sc 2 S@C 70 can transform into C 70 :8111 via a C 2 extrusion (C 68 :6094) and C 2 insertion, and then isomerize into C 70 :8149; C 68 :6094 has been captured as C 68 Cl 8 by in situ chlorination in the gas phase during radio-frequency synthesis [41] and theoretically predicted to be the parent of …”