Magnetic properties of [70]fulleride compounds

New ionic DA-type charge transfer solids of C70− were prepared with bis(benzene)chromium (Bz2Cr) and decamethylmetallocenes (Cp2∗M) (M=Ni, Cr). In the solid-state EPR spectra, no signals confirming C70− spins were detected below room temperature (RT), probably due to either an electronic or chemical dimerization. Above RT, a signal characteristic of a strong exchange coupling between donor cation and C70− spins gradually emerged for Bz2Cr complex, owing to the decoupling of the dimers. In dimethyl sulfoxide at RT, a signal characteristic of C70− spins was observed at g=2.0012–2.0014 with a narrow linewidth.