Synthesis of a lithium-encapsulated fullerenol and the effect of the internal lithium cation on its aggregation behavior
Endohedral fullerene, fullerenol, lithium cation, cation-encapsulated anion nanoparticle, electrostatic interaction
ABSTRACT A lithium-encapsulated fullerenol Li@C60(OH)18, as an example of a polar solvent-soluble endohedral fullerene derivative, has been synthesized and fully characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, UV spectroscopy, electron spin resonance (ESR) spectroscopy, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), elemental analysis, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the particle size was determined using the induced grating (IG) method, and scanning probe microscopy. The encapsulated Li+ was clearly detected by 7Li NMR at very high field in the range –15 to –19 ppm, an intermediate lithium-encapsulated fullerenol was detected by MALDI-TOF-MS, and the molar ratio of lithium-encapsulated fullerenol to empty fullerenol was quantitatively determined to be 12:88 by ICP-AES. The solid-state ESR and particle size measurements using the IG method showed the characteristic anionic behavior with no external counter cations, in what can be called a “cation-encapsulated anion nanoparticle”, revealing the drastic differences between its properties and those of empty C60(OH)16.
Tsinghua University Press
Hiroshi Ueno,Yuji Nakamura,Naohiko Ikuma,Ken Kokubo,Takumi Oshima, Synthesis of a lithium-encapsulated fullerenol and the effect of the internal lithium cation on its aggregation behavior. NanoRes.2012, 5(8): 558–564