Azafullerene dimer

Its application to according derivatives of C70 afforded the achiral azafullerene dimers 97 and 98 for the first time.47,159... 

Method (a). The first example of a reaction according to this method has already been mentioned in the preceding section. Another example is the reaction depicted in Fig. 17. Hence, when a 15-fold excess (relative to 8) of hydroquinone was added to the reaction mixture that otherwise yielded the azafullerene dimer, the intermediate azafulleronium ion 2 was reduced to azafullerenyl radical 1, which was subsequently trapped by the hydroquinone to give the parent mono-... 

Fig. 30. Method 1 for the preparation of mixed azafullerene dimers through generation of a mixture of azafullerene radicals from the corresponding ketolactams. The mixed dimer obtained from a mixture of 8 and 64 is proposed to have the structure 70, the C59N- 1) -C69N isomer with the dimer bond position on the a- a carbon atom of the C69N moiety...

Fig. 32 a. UV-Vis spectrum of mixed C59N-C69N azafullerene dimer 71 and of both corresponding homodimers (C59N)2 (28) and (C69N)2 isomer 66... 

The Dimer Bond in Azafullerene Dimers Generation and Study of Aza[60]fulleren-2-yl and Aza[70]fullerenyl Radicals... 

By substituting single atoms, for example, with N, a heterofullerenyl radical is obtained from >. Usually this will form a dimer, which indeed is the species that has first been detected. The bond connecting two azafullerenes is formed between... 

Up to now, two types of synthetic methods towards monomeric aza[60]fullerene derivatives have been developed Method (a) starting from non-azafullerene precursors and Method (b) starting from the dimer (C59N)2. 

Method (b). Several examples of the preparation of monomeric aza[60]ful-lerene derivatives from the dimer 28 have been reported. First, it was found that treatment of the dimer with excess diphenylmethane in refluxing ODCB for 48 h afforded, after chromatographic purification, 2-diphenylmethyl-azafullerene 37 in 42% yield, as depicted in Fig. 19 [69]. 

Thermal treatment of the dimer with anisole, toluene, and 1-chloronaphtha-lene in the presence of a large excess of pTsOH and air leads to the formation of mono-arylated azafullerenes in 78-90% isolated yields [68]. The reaction with anisole and toluene yield para-substitution products 35 and 39, while 1-chloro-naphthalene is substituted at various positions (Fig. 21). The reaction does not take place in the absence of air or pTsOH. The reaction is presumed to proceed through electrophilic aromatic substitution by C59N, which was proposed as being formed via thermal homolysis of the dimer, followed by oxidation with O2. 

Synthetically, the weakness of the dimer bond was used to prepare azafullerene monomer derivatives from the dimer and mixed dimers from two different dimers, as was discussed in Sects. 2.3 and 3.2, respectively. The dimer can be cleaved both thermally and photo chemically, yielding two C59N radicals 1 [69]. C59N and Cg9N radicals are isoelectronic with Cgg and CJq, respectively. Initial... 

When C118N2, a dimer of azafullerene C59HN, is excited with the nanosecond laser, transient absorption bands appeared at 1280, 1000, 880, and 680 nm which are quite... 

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