Cyano adduct anions of C-70: Electrospray mass spectrometric studies

Negative-ion electrospray mass spectrometry of C-70/CN- solutions was used to study the cyano adduct anions of [70]fullerene, revealing both monoanionic and dianionic species. The most abundant anions are C-70(CN)(n)(-), n = 1, 2, 3, and C-70(CN)(n)(2-), n = 2, 4, 6, with C-70(CN)(-) as the dominant anion at low concentrations. The observation of C-70(CN)(2)(.-), the only odd-electron species identified, is at variance with the behavior of C-60 where only even-electron anions were observed under similar experimental conditions. Semiempirical calculations suggest that CN addition is generally favored in the unique ''equatorial'' region of C-70 and that in the dianion species this region is able to support two negative charges in relative proximity, in contrast to the results obtained for C-60 dianion adducts.