Nitrofullerene CT complexes. A new class of fullerene derivatives

Fullerene C60 is well known as an electron acceptor, but its nitro derivative (hexanitro[60]fullerene, HNF) appears to be even better. We have prepared nitrofullerene complexes with aniline, o, m- and p-phenylenediamine, pyridine, tacrine, triethylamine, 1-aminoanthraquinone, N-N-dimethylaniline, TTF and BEDT-TTF (ET). The products, obtained mostly as dark powders, were examined with the aid of UV-VIS, FTIR, MS and EPR. Very characteristic UV-VIS absorption bands and more or less intense EPR signals registered in all cases prove that we have obtained charge transfer (CT) complexes. We found hexanitro[60]fullerene to be able to form complexes of stoichiometry mainly 1:6 (HNF donor molecule) which are stable as solid samples, but 1:3, 1:7 and 1:12 have also been detected in solutions (THF). The complexes are medium-conducting (10−5–10−7 S cm−1), paramagnetic materials with EPR spectra appearing in most cases as a singlet line (g=2.0030–2.0089, linewidth 0.3–0.8 mT), but more complex signals have also been observed (g=2.0026–2.0089, linewidth 0.4–5.5 mT) (J. J. Langer and T. Gibinsky, paper presented at International Conference Towards Molecular Electronics, TME'99, Śrem, 1999). We have even found the EPR signal in the product described previously as a fullerene derivative with covalently bonded aniline moieties. Copyright © 2000 John Wiley & Sons, Ltd.