Energy landscape inside the cage of neutral and charged N@C60

Reactivity and regioselectivity in Diels-Alder reactions of anion encapsulated fullerenes

Encapsulation and surface chemical modification are methodologies to enhance the properties of fullerenes for various applications. Herein, density functional theory calculations are performed to study the Diels-Alder (DA) reactivity of anion encapsulated C₆₀, including [X@C₆₀]^- (X = F, Cl, Br, or I), [S@C₆₀]^2-, and [N@C₆₀]^3-. Computational results reveal that encapsulated Cl^-, Br^-, I^-, or S^2- anions are located close to the center of the C₆₀ molecule; however, encapsulated F^- is displaced from the center. Encapsulated N^3- bonds to the inner surface of the carbon cage, which leads to a negative charge transfer to the C₆₀. In [N@C₆₀]^3-, C-C bonds near to the encapsulated N atom are more reactive. Our calculations reveal that encapsulated halogen or S anions decrease the DA reactivity because of the stronger closed-shell repulsion of the encapsulated anion. However, encapsulated N^3- increases the DA reactivity. The higher distortion energy of the halogen- or S^2--anion encapsulated C₆₀ leads to lower reactivity of the 6-5 bond. Opposite regioselectivity of the DA reaction with [N@C₆₀]^3- is attributed to distortion energy of the cyclopentadiene (CPD) moiety. The asymmetrical transition state geometry leads to a lower distortion energy of the CPD moiety.

Theoretical identification of seven C80 fullerene isomers by XPS and NEXAFS spectroscopy

The molecular geometries and C1s NEXAFS spectra of seven IPR-satisfying isomers of fullerene C₈₀.

Catalytic and non-catalytic roles of pendant groups in the decomposition of N@C60: a DFT investigation

The decomposition mechanism of N@C(60) derivatives has been elucidated by DFT calculations, revealing different roles of the pendant groups in the escape course of the incarcerated nitrogen. Whereas the pyrrolidine group facilitates the inversion of the incarcerated nitrogen, the cyclopropane group prohibits this process.