Novel proficient method for isolation of endometallofullerenes from fullerene-containing soots by two-stepo-xylene–N, N-dimethylformamide extraction

Laukhina, Elena; Бубнов, В. П.; Estrin, Yakov I.; Golod, Yurii A.; Khodorkovskii, M. A.; Koltover, Vitali K.; Yagubskii, Eduard B.

doi:10.1039/a708385e

Cited by 20 publications

(10 citation statements)

References 10 publications

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“…12 In practice, two-step extraction was usually employed to enrich EMFs. [15][16][17] A large amount of C 60 , C 70 , and other empty fullerenes are first extracted with toluene, xylene, or carbon disulfide, and the residues are further extracted with carbon disulfide, DMF, or pyridine, and then a concentrated extract is available for further HPLC isolation.…”

Section: Introductionmentioning

confidence: 99%

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

et al. 2004

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On the basis of high-yield preparation, arc-produced soot containing endohedral Y, La, Nd, Sm, Gd, Tb, Yb, Ca, and Ba fullerenes are successively extracted with carbon disulfide, N,N-dimethylformamide, pyridine, and aniline. The continuous four-step extraction procedure generates endohedral metallofullerenes (EMFs) with high content and abundant species, and novel EMFs such as Tb@C66, Yb@C60, and Tb3@C80 were extracted. This makes it possible for us to systemically study the varying extraction behaviors of divalent and trivalent metallofullerenes. Trivalent EMFs are characterized by higher content and multimetallofullerenes, whereas divalent species are characterized by lower content and solely monometallofullerenes. A positive relationship between the content and the species abundance of EMFs is proposed. The differences in extracting ability of the above solvents toward certain EMFs are summarized and explained on the basis of the number of transferred electrons from the encaged metal atom(s), the back-donation from carbon cages, and the solvent reduction of EMFs.

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Section: Introductionmentioning

confidence: 99%

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

et al. 2004

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“…Whatever type of ionization, the mass spectra of DMF, DMA, and DMSO extracts have no peaks corresponding to molecular masses of empty fullerenes (C 60 , C 70 , and the higher ones); the most intense peak always corresponds to M@C 82 (see Table ). The absence of empty fullerenes in the second stage extracts was earlier confirmed by HPLC and optical spectra 5 Mass spectra of the DMF extract from the La@C 2 n containing soot: ionization by 252 Cf decay products (a); laser desorption ionization (b). …”

Section: Resultsmentioning

confidence: 73%

“…By applying the selective extraction sequence (see Introduction), we were able to estimate the M@C 2 n formation realistically. As shown earlier, this two-step extraction procedure with o -xylene as the first solvent and dimethylformamide (DMF) as the second solvent makes it possible to isolate a mixture of EMFs avoiding the use of a laborious HPLC technique. We have successfully developed this extraction method to provide the complete EMF isolation (see below).…”

Section: Resultsmentioning

confidence: 99%

“…Difficulties associated with the EMF isolation 9-11 hinder an estimation of the efficiency of their formation, hence making impractical an optimization of electric arc parameters for the EMF-rich soot production. To solve this problem, we have suggested to use a simple selective extraction sequence that has been recently developed. Applying this technique for the estimation of the EMF yields requires an in-depth study of this method to make sure that it permits a total removal of EMFs from the soot.…”

Section: Introductionmentioning

confidence: 99%

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Endohedral Metallofullerenes: A Convenient Gram-Scale Preparation

et al. 2002

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We have examined various parameters of the electric arc synthesis of endohedral metallofullerenes (EMFs or M@C2 n ). The influence of some experimental parameters (M/C ratio, helium vapor pressure, and values of the direct current arc) on yields of EMFs has been studied. The optimization of these parameters allows us to bring the EMF yield to a record level of 6−8% of the primary soot mass. Furthermore, a selective extraction sequence [o-xylene (five cycles) − dimethylformamide (seven cycles)] has been studied in detail in order to apply this technique to the estimation of the EMF yield. It has also been shown that polar organic solvents, among them dimethylformamide (DMF), dimethylacetamide (DMA), and dimethylsulfoxide (DMSO), are the most favorable ones for a selective extraction of EMF.

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“…Organic solvents such as toluene, 1,2,4-trichlobenzene, xylene, carbon disulfide, pyridine, N , N -dimethylformamide (DMF), and aniline have been tested. Although carbon disulfide is a good solvent for both metallofullerenes and empty fullerenes, it is possible to selectively extract M@C 82 , M@C 80 , and M 2 @C 80 with pyridine or DMF − and M@C 60 and M@C 70 with aniline. , For the step of isolation and purification of metallofullerenes, HPLC has been almost the only preferred technique.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Preparation of La@C₈₂ (I and II) and La₂@C₈₀: Efficient Production of the “Minor” Isomer La@C₈₂ (II)

Lian

Yang

2002

J. Phys. Chem. B

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An Arc-discharge anode made of a LaNi2 alloy and graphite is used to prepare lanthanum metallofullerenes under different conditions such as helium pressure. Nickel exhibits a catalytic effect on the production of the metallofullerenes, particularly the “minor” isomer of La@C82 (II). DMF is demonstrated to be a better extraction solvent than carbon disulfide for La@C82 (II). Under appropriate conditions, La2@C80 and La@C82 (II) are efficiently produced from the arc-discharge of the Ni-containing and oxygen-free composite anodes, DMF extraction, and single-stage HPLC separation. In particular, the yield of La@C82 (II) that used to be a “minor” isomer can even be higher than that of La@C82 (I) previously known as a “major” isomer in some cases. This work opens new avenues to preferentially synthesize specific metallofullerene isomers.

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Novel proficient method for isolation of endometallofullerenes from fullerene-containing soots by two-stepo-xylene–N, N-dimethylformamide extraction

Cited by 20 publications

References 10 publications

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

Endohedral Metallofullerenes: A Convenient Gram-Scale Preparation

Revisiting the Preparation of La@C₈₂ (I and II) and La₂@C₈₀: Efficient Production of the “Minor” Isomer La@C₈₂ (II)

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Novel proficient method for isolation of endometallofullerenes from fullerene-containing soots by two-stepo-xylene–N, N-dimethylformamide extraction

Cited by 20 publications

References 10 publications

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

Different Extraction Behaviors between Divalent and Trivalent Endohedral Metallofullerenes

Endohedral Metallofullerenes: A Convenient Gram-Scale Preparation

Revisiting the Preparation of La@C82 (I and II) and La2@C80: Efficient Production of the “Minor” Isomer La@C82 (II)

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Revisiting the Preparation of La@C₈₂ (I and II) and La₂@C₈₀: Efficient Production of the “Minor” Isomer La@C₈₂ (II)