Atomic nitrogen in C 60 :N@C 60

Abstract

The nitrogen-atom endohedral fullerene (N@C 60) with relatively higher purity [molar concentration ratio of N@C 60 to pristine fullerene (C 60)] has been synthesized by controlling plasma ion irradiation energy (E i) and C 60 behavior. We have examined the relationship between the synthesis purity of N@C 60 and E i which is controlled by changing the substrate bias voltages (V sub) and gas pressure (P N2) during the plasma irradiation process. It has been clarified that there is an optimum condition of the nitrogen plasma for the high-purity synthesis of N@C 60 , which consists of the high-density nitrogen-molecular ions (N 2 +) with suitable E i from 40 to 80 eV. In addition, control of C 60 behavior contributes to an increase in the reaction between C 60 and N 2 + to form N@C 60 , resulting in the synthesis of N@C 60 with the highest purity of 0.56 % in the world.

Electron Paramagnetic Resonance Investigation of Endohedral Fullerenes N@C60 and N@C70 in a Liquid Crystal

“…The as-prepared material is highly diluted (concentration ca. 10 −4 ) but can be enriched by HPLC chromatography (12). In the present experiment, as-prepared or slightly enriched (up to a factor of ten) material was used.…”

Cerium-Doped Endohedral Fullerene: A Density-Functional Theory Study

“…Unlike the encapsulated N and noble gas atoms [44][45][46][47] and metallic atoms like Be, Ca, Li, Y, La, and Sc [23,[48][49][50][51], which all occupy the center or slightly positioned off-center of the fullerene, the absolute minimum corresponding to the lowest total energy has been found for Ce interacting directly with the six-folded ring of the fullerene, as indicated in panel (b) of Figure 6. It is also noted that during the optimization process, the Ce atom that was initially placed elsewhere inside the cage migrates to the six-membered ring.…”

Control of C₆₀ Behavior for High Yield Synthesis of N@C₆₀ in RF-Plasma

“…Specially, the nitrogen atom endohedral fullerene (N@C 60 ) attracts much interest due to its novel properties and potential application in making an electron spin quantum computer [1][2][3]. Although N@C 60 has been studied over the last decade, the yield is still extremely low at present (10 -3 -10 -2 %) [4,5] due to the difficulty in controlling physical and chemical processes at the preparation stage of N@C 60 . In order to improve the purity, many groups apply high performance liquid chromatography (HPLC) [6][7][8].…”