Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc2TiC@Ih-C80, Sc2TiC@D5h-C80 and Sc2TiC2@Ih-C80: Metal Size Tuning of the TiIV/TiIII Redox Potentials

Katrin Junghans, Kamran B. Ghiassi, Nataliya A. Samoylova, Qingming Deng, Marco Rosenkranz, Marilyn M. Olmstead, Alan L. Balch, Alexey A. Popov

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed-metal Sc-Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4C2@C80 (the most abundant EMF from this synthesis), Sc3C2@C80, isomers of Sc2C2@C82, and the family Sc2C2n (2n=74, 76, 82, 86, 90, etc.), as well as Sc3CH@C80. The Sc-Ti/CH4 system produces the mixed-metal Sc2TiC@C2n (2n=68, 78, 80) and Sc2TiC2@C2n (2n=80) clusterfullerene families. The molecular structures of the new, transition-metal-containing endohedral fullerenes, Sc2TiC@Ih-C80, Sc2TiC@D5h-C80, and Sc2TiC2@Ih-C80, were characterized by NMR spectroscopy. The structure of Sc2TiC@Ih-C80 was also determined by single-crystal X-ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2TiC- and Sc2TiC2-containing cluster-fullerenes have Ti-localized LUMOs. Encapsulation of the redox-active Ti ion inside the fullerene cage enables analysis of the cluster-cage strain in the endohedral fullerenes through electrochemical measurements.
Original languageEnglish
JournalChemistry-a European Journal
Volume22
Issue number37
Pages (from-to)13098-13107
Number of pages10
ISSN0947-6539
DOIs
Publication statusPublished - 2016
Externally publishedYes

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Dive into the research topics of 'Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc<sub>2</sub>TiC@<i>I</i><sub>h</sub>-C<sub>80</sub>, Sc<sub>2</sub>TiC@D<sub>5h</sub>-C<sub>80</sub> and Sc<sub>2</sub>TiC<sub>2</sub>@<i>I</i><sub>h</sub>-C<sub>80</sub>: Metal Size Tuning of the Ti<sup>IV</sup>/Ti<sup>III</sup> Redox Potentials'. Together they form a unique fingerprint.

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