N@C60–Porphyrin: A Dyad of Two Radical Centers

Guoquan Liu†, Andrei N. Khlobystov‡, Georgios Charalambidis§, Athanassios G. Coutsolelos§, G. Andrew D. Briggs†, and Kyriakos Porfyrakis*†

email*:kyriakos.porfyrakis@materials.ox.ac.uk.

† Department of Materials, Oxford University, Oxford OX1 3PH, United Kingdom.

‡ School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom.

§ Department of Chemistry, University of Crete, Heraklion 71003, Greece.

J. Am. Chem. Soc., Article ASAP, DOI: 10.1021/ja209763u.

Abstract

Dyads of endohedral nitrogen fullerene and porphyrin have been synthesized. In the two-radical-center dyad, the copper(II) tetraphenylporphyrin suppressed the electron spin resonance (ESR) signal of N@C60 through intramolecular dipolar coupling with a strength of 27.0 MHz. Demetalation of the metalloporphyrin moiety of the dyad, which effectively turned the two-radical-center dyad into a single-radical-center dyad, recovered 82% of the ESR signal of N@C60. Such mechanism of switching a spin state on and off could find use in molecular spintronics applications.