Endohedral Homoconjugation in Cyclopentadiene Embedded in C₆₀. Theoretical and Electrochemical Evidence

Chemistry of η5-fullerene metal complexes

“…The bond alternation inherent to [60]fullerene has disappeared, and all bonds associated with the indenide skeleton are almost equal, and the molecular orbital (e.g., HOMO) characteristic of indenyl anion was readily identified. This calculated structural feature received full support from the crystal structure of a related tri-adduct obtained from [70]fullerene [7].…”

“…Experimentally, however, these two parts show a strong sign of mutual electronic interaction [12]. In such a sense, one can draw an analogy between the η 5 -fullerene metal complexes 12 and metal porphyrin 13: Porphyrin acts as an electronrich donor ligand to the center metal, while fullerene may act as an electron-deficient acceptor ligand.…”

Bucky ferrocene. Hybrid of ferrocene and fullerene

“…5. The structural features of the ferrocene moiety in 11 are similar to those of Fe(η 5 -indenyl) 2 (12). The distances between the pentagon carbon atoms and the iron (average 2.054 Å for Cp-Fe, and 2.083 Å for fullerene Cp-Fe) as well as the C-C bond lengths in the Cp ligand, 1.41-1.43 Å, are comparable to those of ferrocene and 12.…”

“…The pentaaryl-and pentamethyl fullerene anions K + RFCp -(7, a:R = Ar, b:R = Me) show remarkable stability and solubility in water. The stability of the anions is due to the intrinsically high stability of the Cp anion through delocalization of the negative charge toward the 50 π-electron system at the bottom of the C 60 cage through "endohedral homoconjugation" [12]. Being composed solely of carbon atoms and hydro-E. NAKAMURA gen atoms, these compounds represent a rare example of hydrocarbon anions with well-defined water solubility.…”

[60]Fullerene–Metal Cluster Complexes: Understanding Novel η1 and η2[6:5] Bonding Modes of Metallofullerenes

“…Because of the large proportion of π-character in η 2 [6:6] coordination, the stability of η 2 [6:6] coordination decreases steeply as electron reductions continue. On the basis of the EPA results, we could explain why the reaction of [Os 3 (CO) 8 (CNR)(µ 3 -η 2 [6:6] ,η 2[6:6] ,η 2[6:6] -C 60 )] (R = CH 2 Ph) with CNR (4e donor) produces [Os 3 (CO) 8 synthesis of various metallofullerene complexes with η 1 -, [15] η 2 -, [10,[16][17][18][19][20][21][22] η 5 -, [23][24][25] and η 6 -bonding modes [26] , but peculiar chemistry is dominated by π-type M-C 60 interactions, as a metal atom is attached in an η 2 fashion to a [6:6] bond in C 60 . There have been various metallofullerene complexes M-C 60 bond across the periodic table. [10, [16][17][18][19][20][21][22] The chemistry of metal-C 60 cluster σ complexes has remained relatively unexplored, although such complexes are very important in the selective functionalization of C 60 .…”