Cyano Adduct Anions of C₇₀:  Electrospray Mass Spectrometric Studies

Negative-ion electrospray mass spectrometry of C70/CN- solutions was used to study the cyano adduct anions of [70]fullerene, revealing both monoanionic and dianionic species. The most abundant anions are C70(CN)n-, n = 1, 2, 3, and C70(CN)n2-, n = 2, 4, 6, with C70(CN)- as the dominant anion at low concentrations. The observation of C70(CN)2•-, the only odd-electron species identified, is at variance with the behavior of C60 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 C70 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 C60 dianion adducts.