Investigations of Small Carbon Cluster Ion Structures by Reactions with HCN

Article abstract of DOI:10.1021/ja00189a004

The results of a detailed study of the primary and secondary reactions of carbon cluster ions, Cn(1+) (3<= n >=20), with HCN are used as a probe of the structures of small carbon cluster ions.The experiments were performed in a Fourier transform ICR mass spectrometer (FTMS), using direct laser vaporization of graphite to form the carbon cluster ions.The only ionic products observed for the HCN reactions were CnX(1+) (primary reaction product) and CnXY(1+) (secondary reaction product) where X and Y = H, CN, or HCN.Radiative association is an important reaction channel.Products resulting from fragmentation of the reactant carbon cluster ion were not observed.Evidence for two structural forms of the n = 7-9 cluster ions is presented.The anomalous behavior of C7(1+) is interpreted by an isomerization mechanism.Low-energy collision-induced dissociation studies of the primary product ions support a mechanism of carbene insertion into the H-CN bond and formation of covalently bonded products.In contrast, the HCN associates weakly with most primary product ions.