Spin density and cluster dynamics in Sc3N@C80 - upon [5,6] exohedral functionalization: An ESR and DFT study

A radical-anion of [5,6]-pyrrolidine-Sc3N@C80 is generated both chemically and electrochemically and studied by ESR spectroscopy. The rotation of the Sc3N cluster is shown to be frozen on the ESR time scale resulting in nonequivalent Sc atoms with hyperfine coupling constants noticeably smaller than in the radical anion of the pristine Sc3N@C80 but larger than in any other derivatives of Sc3N@C80. Experimental ESR studies are supported by extended DFT calculations of the cluster rotational pathways, spin density distribution, and hyperfine coupling constants.