Rosario González

Isolation of the heterofullerene C59N as its dimer (C59N)(2)

The heterofullerene ion C59N+ is formed efficiently in the gas phase during fast atom bombardment mass spectroscopy of a cluster-opened N-MEM (N-methoxyethoxy methyl) ketolactam. This transformation is shown to occur also in solution in the presence of strong acid, affording biazafullerenyl (C59N)2 in good yield. It is proposed that the azafullerene dimer is formed upon in situ reduction of the highly reactive azafulleronium ion. The isolation and characterization of biazafullerenyl opens a viable route for the preparation of other heterofullerenes in solution.

Isolation, structure, and electronic calculations of the heterofullerene salt K6C59N

An intercalation compound of azafullerene, K6C59N, was prepared and structurally characterized. It is isostructural with the fullerene compound K6C60, adopts a body-centered- cubic structure (lattice constant a = 11.31 angstroms), and consists of quasi-spherical monomeric (C59N)6− ions. Density functional calculations of the structural and electronic properties confirm the similarity to K6C60 but also suggest a sizable deformation, principally confined in the vicinity of the nitrogen atom, of both the molecular structure and the electron states. These results show that study of the intercalation chemistry of azafullerene promises to reveal a rich family of both n- and p-doped systems with novel conducting and magnetic properties, like their fullerene antecedents.

Near IR photoluminescence in mixed films of conjugated polymers and fullerenes

The photoinduced electron transfer between conjugated polymers and a series of functionalized fullerenes was studied. A new photoluminescence signal was observed in the near IR (∼1.4 eV). This weak IR photoluminescence does not result from direct excitation of the fullerene, but from radiative electron-hole recombination between the fullerene excited state and the polymer ground state. The intensity of this recombination luminescence depends on the electrochemical nature of the functional group; it is observed only for fullerenes with first reduction potential higher than that of C60.

Heterocyclic and heteroatom derivatives of buckminsterfullerene C-60

The synthesis of hydroazafullerene and the dimer of azafullerenyl are presented. The structures of these heterofullerene molecules were characterized with the use of proton and carbon NMR as well as C-H and C-15N coupling constants.