Encapsulation of Mg2 inside a C60 cage forms an electride

• Published in: Journal of computational chemistry 2020-06, Vol.41 (17), p.1645-1653
• Main Authors: Das, Prasenjit, Saha, Ranajit, Chattaraj, Pratim K.
• Format: Article
• Language: English
• Subjects: Buckminsterfullerene; Cages; Chemical bonds; Density functional theory; Dimers; electride; Electron density; electron localization function (ELF) basin; Encapsulation; endohedrally encapsulated fullerene; energy decomposition analysis (EDA); Fullerenes; Magnesium; non‐nuclear attractor (NNA)
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.26207

Density functional theory (DFT) based calculations have been carried out for the endohedral encapsulation of magnesium dimer inside fullerene, that is, Mg2@C60. It is observed that the minimum energy structure of the Mg2@C60 system is C2h symmetry. The MgMg bond distance in the Mg2@C60 system is much shorter than that in the free Mg2 and Mg22+ ion. The formation of the endohedral Mg2@C60 system is thermochemically spontaneous in nature. The natural bond orbital (NBO) analysis showed the presence of an Mg22+ fragment with an MgMg bond inside the C60 cage. The electron density descriptors have identified the covalency in the MgMg bond. A non‐nuclear attractor (NNA) is present in the middle of the two Mg‐atoms. The bonding interaction between the Mg2 and C60 fragments is ionic in nature and the [Mg22+] and [C602−] represent the bonding pattern in the Mg2@C60 system. The designed endohedrally encapsulated system behaves as an electride. Density functional theory based computations predict the spontaneous formation of an endohedral encapsulation complex, Mg2@C60. The Mg‐atoms are in the +1 oxidation state and an MgMg bond is present. The presence of a non‐nuclear attractor, a negative region in the Laplacian of electron density and an electron localization basin within the bonding region as well as high nonlinear optical properties highlight the electride nature of this system.