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Do Carbon Nano‐onions Behave as Nanoscopic Faraday Cages? A Comparison of the Reactivity of C 60 , C 240 , C 60 @C 240 , Li + @C 60 , Li + @C 240 , and Li + @C 60 @C 240
Author(s) -
LuqueUrrutia Jesús Antonio,
Poater Albert,
Solà Miquel
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904650
Subject(s) - enthalpy , chemistry , polarizability , homo/lumo , cage , reactivity (psychology) , electronegativity , crystallography , physics , organic chemistry , thermodynamics , molecule , medicine , alternative medicine , mathematics , pathology , combinatorics
From the analysis of the polarizability of carbon nano‐onions (CNOs), it was concluded that CNOs behave as near perfect nanoscopic Faraday cages. If CNOs behave as ideal Faraday cages, the reactivity of the C 240 cage should be the same in Li + @C 240 and Li + @C 60 @C 240 . In this work, the Diels–Alder reaction of cyclopentadiene to the free C 240 cage and the C 60 @C 240 CNO together with their Li + ‐doped counterparts were analyzed using DFT. It was found that in all cases the preferred cycloaddition is on bond [6,6] of type B of C 240 . Encapsulation of Li + results in lower enthalpy barriers due to the decrease of the energy of the LUMO orbital of the C 240 cage. When the Li + is placed inside the CNO C 60 @C 240 , the decrease in enthalpy barrier is similar to that of Li + @C 240 . However, the location of Li + in Li + @C 240 (off‐centered) and Li + @C 60 @C 240 (centered) is quite different. When Li + was placed in the center of the C 240 cage in Li + @C 240 , the barriers increased significantly. Taking into account this effect, the barriers in Li + @C 240 and Li + @C 60 @C 240 differ by about 4 kcal mol −1 . This result can be attributed to the shielding effect of C 60 in Li + @C 60 @C 240 . As a result, we conclude that this CNO does not act as a perfect Faraday cage.