Tetrathiafulvalene fullerene dyads

Some novel C60-based assemblies were recently synthesized by [4+2] Diels-Alder cycloaddition reactions. Thus, fused tetrathiafulvalene-C60 dyads and C60-tetra-thiafulvalene-C60 dumbbell triads, in which the fullerene acceptor is doubly tethered to the donor tetrathiafulvalene through a rigidified cyclohexene ring [108], were prepared. With this novel approach, control of the relative orientation as well as the distance between the donor and acceptor units was achieved. Thereby, through-space interactions were expected to dominate because of the special topology of the constructed molecules. More examples of such donor-acceptor hybrid systems are discussed in the appropriate following sections, with their potential use in innovative technological applications. 

Novel triads that contained tetrathiafulvalenes as electron donors and porphyrin chromophores (refer to previous section for porphyrin-fullerene dyads) as donor units have been recently reported [246] (Scheme 12). Improved analogs of the latter triads were soon considered by connecting the tetrathiafulvalene unit to a 7r-extended conjugated network [247]. 

The synthesis of the triazolino[4, 5 l,2][60]fullerene 204, a novel donor-acceptor dyad exhibiting efficient electron-transfer dynamics, was reported by Guldi et al. (44) (Scheme 9.44). The azido tetrathiafulvalene 203, on heating with [60]fullerene in o-dichlorobenzene at 60 °C, gave the triazoline 204 in 24%... 

Recently, in another synthetic approach for the construction of efficient fullerene-tetrathiafulvalene dyads, a fullerotriazoline dyad (fullerotriazolines are thermally labile intermediates that are formed upon reaction of fullerenes with azides [243]) possessing a substituted tetrathiafulvalene functionality was reported [244]. 

For further information on synthesis, properties, and applications of pyrro-lidinofullerenes, the chiral representatives of which were generally prepared and used as racemates, we refer to a recent review by Prato and Maggini.214 Fields in which many fullerene-fused pyrrolidines have been studied are biological and medicinal chemistry351 and, above all, advanced materials science.352,353 In the latter context, dyads and triads used for photoinduced charge separation between a fullerene acceptor moiety and electron donors like porphyrins, tetrathiafulvalenes, ferrocenes, or polyenes, are worth particular mentioning.354-356... 

D-A triads 2.134 (Chart 1.26) based on tetrathiafulvalene and oUgothiophenes as combined donor and fullerene as acceptor were synthesized by a Stille-type coupling reaction of bromooligothiophenes and stannylated tetrathiafulvalene. The attachment of the fullerene was achieved by successive reaction with the system fullerene-/V-methylglycine [234]. An increased photo-current generation was observed for triads 2.134 in comparison with oUgothiophene-fuUerene dyads 2.112. 

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