Structures of Gd₃N@C₈₀ Prato Bis-Adducts: Crystal Structure, Thermal Isomerization, and Computational Study

Abstract

The structures of two bis-ethylpyrrolidinoadducts of Gd3N@I h -C80, obtained by regioselective 1,3-dipolar cycloadditions, were elucidated by single crystal X-ray, visible-near infrared (vis-NIR) spectra, studies on their thermal isomerization, and theoretical calculations. The structure of the minor-bis-adduct reveals a C 2-symmetric carbon cage with [6,6]­[6,6]-addition sites and with an endohedral Gd3N cluster that is completely flattened. This is the first example of a crystal structure of Gd3N@I h -C80 derivatives. The structure of the major-bis-adduct was inferred by the vis-NIR spectrum being corresponded to the structure of a previously reported major-bis-adduct of Y3N@I h -C80 known to have an asymmetric [6,6]­[6,6]-structure. Based on experimental results showing that the minor-bis-adduct of Gd3N@I h -C80 isomerized to the major-adduct, a possible second addition site was elucidated with support from density functional theory calculations.

Unexpected formation of 1,2- and 1,4-bismethoxyl Sc3N@Ih-C80 derivatives via regioselective anion addition: an unambiguous structural identification and mechanism study

“…[1][2][3][4] Exohedral functionalization of EMFs has shown its effectiveness to broaden their applications by generation a variety of useful derivatives. During the last decades, many synthetic methods have been applied to modify EMFs, among which cycloadditions, such as the BingelHirsch reaction, 5,6 [2+2] benzyne addition, 7, 8 1,3dipolar reaction, [9][10][11][12] DielsAlder reaction, 13 carbene addition 14 and so on, 5,15,16 have been widely utilized. Results show that the chemical properties of EMFs are much different from those of empty fullerenes, resulting in a fact that some chemical reactions which are effective to C 60 do not work on EMFs.…”

Unexpected Formation of Metallofulleroids from Multicomponent Reactions, with Crystallographic and Computational Studies of the Cluster Motion

“…[20,46] This is a feature typically seen in the synthetically challenging multiadducts of NCFs which, understandably, has ordered clusters fixed by multiple organic groups. [47,48] The crystal of 4 was further studied at different temperatures. First, at 120 K, the final difference density map reveals ordered sites for all cluster atoms (Figure 3 a, top).…”

Multicomponent Reactions Among Alkyl Isocyanides, sp Reactants, and sp2 Carbon Cages

“…33 In functionalized NCFs, fully ordered clusters were mostly achieved via direct and strong interactions between the functional group and the cage (e.g., multiadditions or formal charge on the ligand and cage, etc.). 16b 21c 24 34 Our work demonstrated that weak intermolecular interactions between the organic ligands and the NCF cage can also restrict the cluster motion in the solid state of synthetically straightforward monoadducts, which provides a new direction of materials design for magnetic and quantum applications.…”