Thermal stability of Li@C60

Krawez, N.; Gromov, Andrey; Buttke, K.; Campbell, Eleanor E. B.

doi:10.1007/s100530050453

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…This yields an activation energy for the cage destruction within the oven of 1.27±0.05 eV (errors are the 95% confidence limits from the straight line fit). This value is remarkably close to the activation energy determined previously for Li loss from the dimerised endohedral species in solution (1.1 ± 0.2 eV) [15]. It is much lower that the value of 5.4±0.2 eV obtained for release of Li from the isolated gas phase cationic endohedral molecules that is similar to the threshold energy for Li + implantation in C 60 [16] and the bias voltage at which Li loss from the C 60 cage is observed in STM experiments [9].…”

Section: Methodssupporting

confidence: 90%

Sublimation of Li@C60

2020

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Experiments that probe the fundamental properties of endohedral fullerenes often require the preparation of molecular beams or thin films of the neutral molecules. It is challenging to cleanly sublime this class of molecules without producing some thermal degradation. We report combined gas phase and scanning tunnelling microscopy studies that probe the thermal decay of commercial [Li+C60]PF6- in a quartz ampoule and provide treatment conditions that will allow the sublimation of intact, neutral Li@C60 accompanied by a well-characterised component of neutral C60. The decay of the material at appropriate temperatures can be modelled with the assumption of a second order decay process in the oven yielding Arrhenius parameters that can predict the ratio of Li@C60 to C60 in the sublimed material. Graphical abstract

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Section: Methodssupporting

confidence: 90%

Sublimation of Li@C60

2020

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“…This finding does not contradict the LD TOF MS results, which show for both fractions pronounced peaks at 727 u, corresponding to monomeric LiC 60 . It has been shown that isolated endohedral Li@C 60 species possess limited thermal stability, and they undergo complete dissociation of the interfullerene bonds under the rather extreme LD MS conditions. The same problem occurs for other dimeric species, for example, (C 60 ) 2 42 and (C 70 ) 2 …”

Section: Resultsmentioning

confidence: 99%

“…The production and isolation of Li@C 60 from unreacted C 60 and other byproducts have been described elsewhere. , The fullerene film after low-energy ion bombardment was washed from the substrate by carbon disulfide (CS 2 ) in an ultrasonic bath. The CS 2 -soluble part was examined by HPLC using a Cosmosil 5PBB column (Nacalai Tesque), 10 mm i.d., 25 cm length, and 1,2-dichlorobenzene as eluent at a flow rate of 2.5 mL/min.…”

Section: Methodsmentioning

confidence: 99%

Fourier Transform Infrared and Raman Spectroscopic Study of Chromatographically Isolated Li@C₆₀ and Li@C₇₀

et al. 2003

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IR and Raman investigations have been carried out on purified Li@C60 and Li@C70 produced by low-energy ion implantation. The structural interpretations, based on theoretical considerations and comparison of the obtained vibrational spectra with those of different known fullerene oligomers, have shown that neither of the chromatographically isolated endohedral species (Li@C60(70)) correspond to monomeric nonderivatized molecules. We ascribe the two different fractions of Li@C60 to a double-bonded dimer and a trimer, presumably with the shape of closed triangle. The infrared and Raman spectra of the Li@C70 compound are similar to those of (C70)2, and we therefore propose for this species the structure of a double-bonded dimer (Li@C70)2. The IR spectra of the Li@C60 fractions prepared with 6Li and 7Li isotopes are identical except for the position of broad bands at about 450−600 cm-1, originating from vibrational−rotational movement of the Li+ cation inside the carbon cage.

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“…tended to polymerize within the C 60 matrix so that the product was difficult to be extracted with common organic solvents. 91 Recently, an improved ion implantation method was reported jointly by several Japanese groups. 35 They used Li + plasma to attack the C 60 -films deposited on a metal plate.…”

Section: Ion Implantationmentioning

confidence: 99%

Current status and future developments of endohedral metallofullerenes

et al. 2012

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Endohedral metallofullerenes (EMFs), a new class of hybrid molecules formed by encapsulation of metallic species inside fullerene cages, exhibit unique properties that differ distinctly from those of empty fullerenes because of the presence of metals and their hybridization effects via electron transfer. This critical review provides a balanced but not an exhaustive summary regarding almost all aspects of EMFs, including the history, the classification, current progress in the synthesis, extraction, isolation, and characterization of EMFs, as well as their physiochemical properties and applications in fields such as electronics, photovoltaics, biomedicine, and materials science. Emphasis is assigned to experimentally obtained results, especially the X-ray crystallographic characterizations of EMFs and their derivatives, rather than theoretical calculations, although the latter has indeed enhanced our knowledge of metal-cage interactions. Finally, perspectives related to future developments and challenges in the research of EMFs are proposed. (381 references).

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Thermal stability of Li@C60

Cited by 10 publications

References 11 publications

Sublimation of Li@C60

Sublimation of Li@C60

Fourier Transform Infrared and Raman Spectroscopic Study of Chromatographically Isolated Li@C₆₀ and Li@C₇₀

Current status and future developments of endohedral metallofullerenes

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Thermal stability of Li@C60

Cited by 10 publications

References 11 publications

Sublimation of Li@C60

Sublimation of Li@C60

Fourier Transform Infrared and Raman Spectroscopic Study of Chromatographically Isolated Li@C60 and Li@C70

Current status and future developments of endohedral metallofullerenes

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Fourier Transform Infrared and Raman Spectroscopic Study of Chromatographically Isolated Li@C₆₀ and Li@C₇₀