The Vinylamine Mode

Under these conditions only one mixed [6,6]-triazoline-[5,6]-iminofullerene isomer 59 was formed which is explained by the fact that 58 behaves as a strained electron-poor vinylamine. The significantly highest Mulliken charge of 0.06 (AMI) is located at C-1 and C-6, and the lowest of -0.07 at C-2 and C-5 (Fig. 33). The most negatively polarized N-atom of the azide (AMI) is that bearing R. A kinetically controlled attack of the azide, therefore, leads predominantly to 59. 

Bis-[5,6]-bridged iminofullerenes with another addition pattern can only be obtained in good yields if a tether directed synthesis is applied. If the tether between two azide groups is rigid enough than the second addition is forced to occur at specific regions of the fullerene cage [128]. 

This characteristic structure type is completely different from those polyadducts of Cgo described in the preceding paragraphs. In many cases the detailed mechanisms of these polyadduct formations remain unclear, although it can be assumed that sequential additions of radicals or nucleophiles Hke the cuprate Ph2Cu are involved. 

The ESR spectra of 63 and 65 do not provide information on whether or not the corresponding radical species carry an even number of benzyl groups attached elsewhere on the surface of the Cgg molecule. Looking at the high reactivity of radicals towards Cgo it is very unlikely that only single radical adducts, such as RgCgo or RgCgg are responsible for the observed ESR spectra. But very important information about the electronic and chemical properties of a coran-nulene substructure are extractable from these experiments. The orbitals with a 

5 kcal/mol lower in energy than 67, where the groups are added in non-adja-cent positions. 

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