Jump to main content
Jump to site search


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

Abstract

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) is 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 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. 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. Formation of the single-electron Er–Er bond in the cation dramatically changes the coupling between magnetic moments of Er ions.

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 31 Mar 2017, accepted on 04 May 2017 and first published on 05 May 2017


Article type: Paper
DOI: 10.1039/C7NR02288C
Citation: Nanoscale, 2017, Accepted Manuscript
  •   Request permissions

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

    N. Samoylova, S. Avdoshenko, D. Krylov, H. R. Thompson, A. Kirkhorn, M. Rosenkranz, S. Schiemenz, F. Ziegs, A. Wolter, S. Yang, S. Stevenson and A. A. Popov, Nanoscale, 2017, Accepted Manuscript , DOI: 10.1039/C7NR02288C

Search articles by author