Effect of Water and Solvent Selection on the SAFA Purification Times for Metallic Nitride Fullerenes

Stevenson, Steven; Rose, Coralie B.; Robson, Alyssa A.; Heaps, David T.

doi:10.1080/1536383x.2013.798725

Cited by 10 publications

(14 citation statements)

References 16 publications

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“…Stage two for isolating Sc 2 @C 82 was the “catch and release” of Sc 2 @C 82 from aminosilica. The 8 mg of the Sc 2 @C 82 -containing sample obtained after MgCl 2 treatment was dissolved in 100 mL of freshly opened xylenes since a wet solvent and/or wet aminosilica affects the SAFA process 37. To this stirring solution was added 5 g of diaminosilica gel, which was freshly vacuum-oven dried overnight at 60 °C.…”

Section: Resultsmentioning

confidence: 99%

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

et al. 2017

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Lanthanide–lanthanide bonds are exceptionally rare, and dimetallofullerenes provide a unique possibility to stabilize and study these unusual bonding patterns. The presence of metal–metal bonds and consequences thereof for the electronic properties of M2@C82 (M = Sc, Er, Lu) are addressed by electrochemistry, electron paramagnetic resonance, SQUID magnetometry and other spectroscopic techniques. A simplified non-chromatographic separation procedure is developed for the isolation of Er2@C82 (Cs(6) and C3v(8) cage isomers) and Sc2@C82 (C3v(8) isomer) from fullerene mixtures. Sulfide clusterfullerenes Er2S@C82 with Cs(6) and C3v(8) fullerene cages are synthesized for the first time. The metal–metal bonding orbital of the spd hybrid character in M2@C82 is shown to be the highest occupied molecular orbital, which undergoes reversible single-electron oxidation with a metal-dependent oxidation potential. Sulfide clusterfullerenes with a fullerene-based HOMO have more positive oxidation potentials. The metal-based oxidation of Sc2@C82-C3v is confirmed by the EPR spectrum of the cation radical [Sc2@C82-C3v]+ generated by chemical oxidation in solution. The spectrum exhibits an exceptionally large a(45Sc) hyperfine coupling constant of 199.2 G, indicating a substantial 4s contribution to the metal–metal bonding orbital. The cationic salt [Er2@C82-C3v]+SbCl6− is prepared, and its magnetization behavior is compared to that of pristine Er2@C82-C3v and Er2S@C82-C3v. The formation of the single-electron Er–Er bond in the cation dramatically changes the coupling between magnetic moments of Er ions.

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Section: Resultsmentioning

confidence: 99%

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

et al. 2017

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“…While stirring, freshly dried monoaminosilica gel (MASG, 14.4 g), which had just been vacuum‐oven dried overnight at 60 °C and cooled to room temperature, was added to this vigorously stirring solution of round 2 precipitate. The importance of using freshly dried aminosilica and anhydrous solvents for SAFA experiments was recently reported 72. After 48 h of fullerene uptake time, the reaction mixture was filtered.…”

Section: Methodsmentioning

confidence: 99%

Isolation of CeLu₂N@I_h‐C₈₀ through a Non‐Chromatographic, Two‐Step Chemical Process and Crystallographic Characterization of the Pyramidalized CeLu₂N within the Icosahedral Cage

Stevenson

Thompson

Arvola

et al. 2015

Chemistry A European J

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By combining two chemical methods of purification, 4mgo fp urified CeLu 2 N@C 80 was readily isolated from 500 mg of carbon soot extract without the use of recycling HPLC, am ethod whichh as previously been necessary to obtain pure samples of endohedral fullerenes. In stage 1, CeLu 2 N@C 80 was selectively precipitated by virtue of its low first oxidation potential (+ 0.01 V) and the judicious choice of MgCl 2 as the Lewisa cidp recipitant. For stage 2, we used as tir and filter approach( SAFA), which employed the electron-rich NH 2 groups immobilized on silica gel to selectively bind residual endohedrals and higher cage fullerenes that were contaminants from stage 1. Crystallographic analysiso fC eLu 2 N@C 80 in the co-crystal CeLu 2 N@I h -C 80 ·Ni(octaethylporphyrin)·2(toluene) reveals that the I h -C 80 cage is presentwith apyramidalized CeLu 2 Nu nit inside.

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“…The bound empty fullerenes and metallofullerenes can be recovered upon heating in the presence of maleic anhydride. Stevenson and coworkers reported an alternative way to separate metal nitride clusterfullerenes through selective reaction with cyclopentadienyl- or amino-functionalized silica, which they call the “Stir and Filter Approach” (SAFA) ( Figure 8 b) [ 68 , 69 , 70 , 71 , 72 ]. This approach can be used to remove Sc 3 N@ D 5 h -C 80 rapidly from its structural isomer, Sc 3 N@ I h -C 80 [ 70 ].…”

Section: Separation/purification Of Metallofullerenes Through Exohmentioning

confidence: 99%

“…This approach can be used to remove Sc 3 N@ D 5 h -C 80 rapidly from its structural isomer, Sc 3 N@ I h -C 80 [ 70 ]. Further studies demonstrate that the content of water and the substituents on the aromatic solvent molecules have significant effects on the separation efficiency of metal nitride clusterfullerenes when using amino-functionalized silica [ 72 ].…”

Section: Separation/purification Of Metallofullerenes Through Exohmentioning

confidence: 99%

Non-Chromatographic Purification of Endohedral Metallofullerenes

2017

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The purification of endohedral metallofullerenes by high performance liquid chromatography is very time-consuming and expensive. A number of rapid and inexpensive non-chromatographic methods have thus been developed for large-scale purification of metallofullerenes. In this review, we summarize recent advances in non-chromatographic purification methods of metallofullerenes. Lewis acid-based complexation is one of the most efficient and powerful methods for separation of metallofullerenes from empty fullerenes. The first oxidation potential of metallofullerenes is a critical factor that affects the separation efficiency of the Lewis acid-based method. Supramolecular methods are effective for separation of fullerenes and metallofullerenes that are different in size and shape. Chemical/electrochemical reduction and exohedral functionalization are also utilized to separate and purify metallofullerenes on a large scale.

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Effect of Water and Solvent Selection on the SAFA Purification Times for Metallic Nitride Fullerenes

Cited by 10 publications

References 16 publications

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

Isolation of CeLu₂N@I_h‐C₈₀ through a Non‐Chromatographic, Two‐Step Chemical Process and Crystallographic Characterization of the Pyramidalized CeLu₂N within the Icosahedral Cage

Non-Chromatographic Purification of Endohedral Metallofullerenes

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Effect of Water and Solvent Selection on the SAFA Purification Times for Metallic Nitride Fullerenes

Cited by 10 publications

References 16 publications

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

Confining the spin between two metal atoms within the carbon cage: redox-active metal–metal bonds in dimetallofullerenes and their stable cation radicals

Isolation of CeLu2N@Ih‐C80 through a Non‐Chromatographic, Two‐Step Chemical Process and Crystallographic Characterization of the Pyramidalized CeLu2N within the Icosahedral Cage

Non-Chromatographic Purification of Endohedral Metallofullerenes

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Isolation of CeLu₂N@I_h‐C₈₀ through a Non‐Chromatographic, Two‐Step Chemical Process and Crystallographic Characterization of the Pyramidalized CeLu₂N within the Icosahedral Cage