M₂@C₇₉N (M = Y, Tb): Isolation and Characterization of Stable Endohedral Metallofullerenes Exhibiting M−M Bonding Interactions inside Aza[80]fullerene Cages

Abstract

Y 2 @C 79 N and Tb 2 @C 79 N have been prepared by conducting the Krätschmer-Huffman electric arcprocess under 20 torr of N 2 and 280 torr of He with metal oxide doped graphite rods. These new heterofullerenes were separated from the resulting mixture of empty cage fullerenes and endohedral fullerenes by chemical separation and a two stage chromatographic process. Crystallographic data for Tb 2 @C 79 N • Ni(OEP) • 2C 6 H 6 demonstrate the presence of an 80-atom cage with idealized I h symmetry and two, widely separated Tb atoms inside with a Tb---Tb separation of 3.9020(10) Å for the major terbium sites. The EPR spectrum of the odd-electron Y 2 @C 79 N indicates that the spin density largely resides on the two, equivalent yttrium ions. Computational studies on Y 2 @C 79 N suggest that the nitrogen atom resides at a 665 ring junction in the equator on the fullerene cage and that the unpaired electron is localized in a bonding orbital between the two yttrium ions of this stable radical. Thus, the Tb-Tb bond length of the single-electron bond is the longest metal-metal bond reported so far.

Mononuclear Clusterfullerene Single‐Molecule Magnet Containing Strained Fused‐Pentagons Stabilized by a Nearly Linear Metal Cyanide Cluster

“…For the reported YNC@ C s (6)‐C 82 and TbNC@ C 2 (5)‐C 82 mononuclear cyanide clusterfullerenes, the entrapped MNC clusters both take a triangular geometry, and it is difficult to distinguish N and C atoms crystallographically because of their similarities on the atomic size and scattering power 10, 11d. However, for the present case of MNC@ C 2 v (19138)‐C 76 , N and C atoms within MNC cluster can be distinguished by combining the crystallographic data with DFT computational results.…”

Vibrational spectrum of the endohedralY2C2@CBurke1, Chan2, Williams3 et al. 2011Phys. Rev. BSelf Cite172160View full textAdd to dashboardCite

“…Within these molecules, entirely novel core species are stable and generate completely new behavior. Recently, these materials have shown promise for numerous applications including electronic devices 4 , organic solar cells 5 , components for spin-based quantum computing 6,7 , and for medical purposes as labels and therapeutic agents 3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] . The fullerene cage (less than 1 nm in diameter) acts to protect the interior complex and can provide ways of maintaining selected properties of the clusters, such as magnetism, fluorescence, and radioactivity, while the endofullerene is functionalized.…”

Thermally Activated Delayed Fluorescence in a Y3N@C80 Endohedral Fullerene: Time‐Resolved Luminescence and EPR Studies

“…[20] As trikingly different situation is found for the unpaired electron delocalized between two Yatoms in Y 2 @C 79 Na nd Y 2 @C 80 (CH 2 C 6 H 5 )w ith A iso ( 89 Y) close to 220 MHz (17.6 %s -spin pop.f or each Y). [21] A iso ( 14 N) values reported earlier for nitride clusterfullerenes are 3.7 MHz in the anion radical of Y 3 N@C 80 and 1.4 MHz in its pyrrolidine adduct. [20] TADF has recently been proposed as third generation emitter concept since it allows all triplets to be harvested radiatively and thus the internal quantum efficiency approaches 100 %.…”