P. Burbank

Isolation and Monitoring of the Endohedral Metallofullerenes Y@C82 and Sc3@C82 : On-Line Chromatographic Separation with EPR Detection

The direct coupling of high-performance liquid chromatography (HPLC) with on-line electron paramagnetic resonance (EPR) detection is demonstrated for monitoring separations of endohedral metallofullerenes (MC{sub 2a}). The HPLC-EPR approach readily permits detection of the paramagnetic species, such as YC{sub 82} and Sc{sub 3}C{sub 82}, in the presence of the dominant empty-cage fullerenes (C{sub 60}, C{sub 70}) and diamagnetic metallofullerenes (e.g., M{sub 2}C{sub 2n}). The results indicate that on-line EPR provides a noninvasive, selective detector for HPLC metallofullerene separations that is readily adaptable to air-sensitive and/or labile compounds. Specifically, the `EPR-active` metallofullerenes, YC{sub 82} and Sc{sub 3}C{sub 82}, are selectively monitored on-line for an initial separation of the metallofullerene fraction from the dominant empty-cage fullerenes utilizing a combination of polystyrene columns. This preparative `cleanup` procedure is followed by HPLC-EPR separation and monitoring of YC{sub 82} and Sc{sub 3}C{sub 82} species using a selective tripodal {pi}-acidic-phase column (Trident-Tri-DNP) for the final stages of isolation. 30 refs., 8 figs.

Far infrared transmittance of Sc2@C84 and Er2@C82

Abstract We have measured the far infrared transmittance of Sc 2 @C 84 and Er 2 @C 82 at 1.5 K between 30 and 200 cm −1 . Both materials are observed to have a large primary absorption feature centered at 95 cm −1 with a width of approximately 50 cm −1 , as well as a number of secondary absorption features which are different in the two materials. This is the first study of the far infrared properties of metallofullerenes and may help in the determination of the structural and electronic properties of these materials.

Isolation and monitoring of the endohedral metallofullerenes YC{sub 82} and Sc{sub 3}C{sub 82}. On-line chromatographic separation with EPR detection

The direct coupling of high-performance liquid chromatography (HPLC) with on-line electron paramagnetic resonance (EPR) detection is demonstrated for monitoring separations of endohedral metallofullerenes (MC{sub 2a}). The HPLC-EPR approach readily permits detection of the paramagnetic species, such as YC{sub 82} and Sc{sub 3}C{sub 82}, in the presence of the dominant empty-cage fullerenes (C{sub 60}, C{sub 70}) and diamagnetic metallofullerenes (e.g., M{sub 2}C{sub 2n}). The results indicate that on-line EPR provides a noninvasive, selective detector for HPLC metallofullerene separations that is readily adaptable to air-sensitive and/or labile compounds. Specifically, the `EPR-active` metallofullerenes, YC{sub 82} and Sc{sub 3}C{sub 82}, are selectively monitored on-line for an initial separation of the metallofullerene fraction from the dominant empty-cage fullerenes utilizing a combination of polystyrene columns. This preparative `cleanup` procedure is followed by HPLC-EPR separation and monitoring of YC{sub 82} and Sc{sub 3}C{sub 82} species using a selective tripodal {pi}-acidic-phase column (Trident-Tri-DNP) for the final stages of isolation. 30 refs., 8 figs.

Isolation and Monitoring of the Endohedral Metallofullerenes Y@C82 and Sc3@C82

The direct coupling of high-performance liquid chromatography (HPLC) with on-line electron paramagnetic resonance (EPR) detection is demonstrated for monitoring separations of endohedral metallofullerenes (MC{sub 2a}). The HPLC-EPR approach readily permits detection of the paramagnetic species, such as YC{sub 82} and Sc{sub 3}C{sub 82}, in the presence of the dominant empty-cage fullerenes (C{sub 60}, C{sub 70}) and diamagnetic metallofullerenes (e.g., M{sub 2}C{sub 2n}). The results indicate that on-line EPR provides a noninvasive, selective detector for HPLC metallofullerene separations that is readily adaptable to air-sensitive and/or labile compounds. Specifically, the `EPR-active` metallofullerenes, YC{sub 82} and Sc{sub 3}C{sub 82}, are selectively monitored on-line for an initial separation of the metallofullerene fraction from the dominant empty-cage fullerenes utilizing a combination of polystyrene columns. This preparative `cleanup` procedure is followed by HPLC-EPR separation and monitoring of YC{sub 82} and Sc{sub 3}C{sub 82} species using a selective tripodal {pi}-acidic-phase column (Trident-Tri-DNP) for the final stages of isolation. 30 refs., 8 figs.