Fullerodendrimers

Nierengarten J-F (2003) Fullerodendrimers Fullerene-Containing Macromolecules with Intriguing Properties. 228 87-110... 

Fullerodendrimers Fullerene-Containing Macromolecules with Intriguing Properties... 

Langa and co-workers have prepared fullerodendrimers 18 and 19 in which the phenylenevinylene dendritic wedge is connected to a pyrazoHno [60] fullerene core rather than to a fulleropyrrolidine one as for 12-17 (Fig. 9) [44]. Preliminary photophysical investigations suggest that the efficient energy transfer from the excited antenna moiety to the pyrazolino [60] fullerene core is followed by an electron transfer involving the fullerene moiety and the pyrazoHne N atom. 

Methanofullerene 20 with phenylacetylene dendrimer addends has also been reported [45] (Fig. 10). The UV absorption of fullerodendrimer 20 is particularly strong and is mainly attributed to transitions located on the two dendritic branches of the molecule. The photophysical investigations revealed that the large poly(aryl)acetylene branches act as photon antennae [46]. 

In a recent study, poly(aryl ether) dendritic branches terminated with triethyleneglycol chains were attached to Cgg [66] dendrimer 32 represents the fourth generation. The photophysical properties of these fullerodendrimers have been systematically investigated in three solvents, namely toluene, dichloromethane, and acetonitrile. On increasing dendrimer generation, it has been found that in each solvent (i) the maximum of the fullerene fluorescence band is red-shifted... 

This route has been used to prepare fullerodendrimers in 31-34% yield [113]. 

Nierengarten et al. have reported many examples of fullerene-rich dendrimers, obtained by either covalent linking or self-assembly of proper units.72,73 A very interesting example is represented by a family of fullerodendrimers from the first to the third generation, containing a hexaphenylbenzene core and 6, 12, and 24 C60 units (compound 26 in Fig. 6.19) at the periphery, respectively.74... 

Let us note that two homologues of the malonate addends and of the corresponding methanofullerene derivatives described above (Fig. 66) were also prepared with chiral pendant mesogenic groups, laterally attached (Fig. 69). Both the G1 [304] and G2 [57] fullerodendrimers were found to show a chiral nematic phase (Fig. 69, Gl G 26 N 69 1 G2 G 24.3 N 80.61), and are the first Ceo derivatives that possess a chiral mesophase the Gl Geo-free malonate was also mesomorphic (G 20 N 113 I). 

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