Facile Access to Y₂C_2<i>n</i> (2<i>n</i> = 92–130) and Crystallographic Characterization of Y₂C₂@<i>C</i>₁(1660)‑C₁₀₈: A Giant Nanocapsule with a Linear Carbide Cluster

A series of giant metallofullerenes Y₂C_2<i>n</i> (2<i>n</i> = 92–130) have been successfully obtained through the treatment of the fraction enriched by 1,2-dichlorobenzene with SnCl₄. Subsequent chromatographic separation gives a pure sample with a composition of Y₂C₁₁₀. Crystallographic results reveal that this endohedral takes the carbide form, namely Y₂C₂@<i>C</i>₁(1660)-C₁₀₈, representing as the largest metallofullerene that has been characterized by crystallography to date. Despite the disorder of the metal cluster, the major Y₂C₂ adopts a previously predicted linear configuration, indicating that the compression of the internal cluster by the cage is almost negligible in this giant cage. Electrochemical studies suggest that Y₂C₂@<i>C</i>₁(1660)-C₁₀₈ is a good electron donor instead of an electron acceptor

Regioselective Synthesis and Crystallographic Characterization of Isoxazoline-Ring-Fused Derivatives of Sc₃N@<i>I</i>_<i>h</i>‑C₈₀ and C₆₀

Highly regioselective 1,3-dipolar cycloaddition of 3,5-dichloro-2,4,6-trimethoxybenzonitrile oxide (<b>1</b>) to Sc₃N@<i>I</i>_<i>h</i>-C₈₀ or C₆₀ affords the corresponding isoxazoline-ring-fused derivatives Sc₃N@<i>I</i>_<i>h</i>-C₈₀(C₁₀H₉O₄NCl₂) (<b>2a</b>) and C₆₀(C₁₀H₉O₄NCl₂) (<b>2b</b>). <b>2a</b> represents the first example of an endohedral metallofullerene derivative with an isoxazoline ring. Crystallographic and NMR spectroscopic studies reveal a [5,6]-bond addition pattern in <b>2a</b> but a [6,6]-bond addition manner in <b>2b</b>

Regioselective Synthesis and Crystallographic Characterization of Isoxazoline-Ring-Fused Derivatives of Sc₃N@<i>I</i>_<i>h</i>‑C₈₀ and C₆₀

Highly regioselective 1,3-dipolar cycloaddition of 3,5-dichloro-2,4,6-trimethoxybenzonitrile oxide (<b>1</b>) to Sc₃N@<i>I</i>_<i>h</i>-C₈₀ or C₆₀ affords the corresponding isoxazoline-ring-fused derivatives Sc₃N@<i>I</i>_<i>h</i>-C₈₀(C₁₀H₉O₄NCl₂) (<b>2a</b>) and C₆₀(C₁₀H₉O₄NCl₂) (<b>2b</b>). <b>2a</b> represents the first example of an endohedral metallofullerene derivative with an isoxazoline ring. Crystallographic and NMR spectroscopic studies reveal a [5,6]-bond addition pattern in <b>2a</b> but a [6,6]-bond addition manner in <b>2b</b>

Regioselective Synthesis and Crystallographic Characterization of Isoxazoline-Ring-Fused Derivatives of Sc₃N@<i>I</i>_<i>h</i>‑C₈₀ and C₆₀

Highly regioselective 1,3-dipolar cycloaddition of 3,5-dichloro-2,4,6-trimethoxybenzonitrile oxide (<b>1</b>) to Sc₃N@<i>I</i>_<i>h</i>-C₈₀ or C₆₀ affords the corresponding isoxazoline-ring-fused derivatives Sc₃N@<i>I</i>_<i>h</i>-C₈₀(C₁₀H₉O₄NCl₂) (<b>2a</b>) and C₆₀(C₁₀H₉O₄NCl₂) (<b>2b</b>). <b>2a</b> represents the first example of an endohedral metallofullerene derivative with an isoxazoline ring. Crystallographic and NMR spectroscopic studies reveal a [5,6]-bond addition pattern in <b>2a</b> but a [6,6]-bond addition manner in <b>2b</b>

Lu₂@C_2<i>n</i> (2<i>n</i> = 82, 84, 86): Crystallographic Evidence of Direct Lu–Lu Bonding between Two Divalent Lutetium Ions Inside Fullerene Cages

Although most of the M₂C_2<i>n</i>-type metallofullerenes (EMFs) tend to form carbide cluster EMFs, we report herein that Lu-containing EMFs Lu₂C_2<i>n</i> (2<i>n</i> = 82, 84, 86) are actually dimetallofullerenes (di-EMFs), namely, Lu₂@<i>C</i>_<i>s</i>(6)-C₈₂, Lu₂@<i>C</i>_3<i>v</i>(8)-C₈₂, Lu₂@<i>D</i>_2<i>d</i>(23)-C₈₄, and Lu₂@<i>C</i>_2<i>v</i>(9)-C₈₆. Unambiguous X-ray results demonstrate the formation of a Lu–Lu single bond between two lutetium ions which transfers four electrons in total to the fullerene cages, thus resulting in a formal divalent state for each Lu ion. Population analysis indicates that each Lu atom formally donates a 5d electron and a 6s electron to the cage with the remaining 6s electron shared with the other Lu atom to form a Lu–Lu single bond so that only four electrons are transferred to the fullerene cages with the formal divalent valence for each lutetium ion. Accordingly, we confirmed both experimentally and theoretically that the dominating formation of di-EMFs is thermodynamically very favorable for Lu₂C_2<i>n</i> isomers