Pyrolytic trifluoromethylation of [76]-, [78]-, [84]-, and aza[60]fullerenes with silver trifluoroacetate; evidence for coordination of fullerenes to silver

Pyrolytic trifluoromethylation of [76], [78], [84], and aza[60]fullerenes with silver trifluoroacetate at 300 degrees C results in extensive polyaddition of up to 18, 18, 20 and 20 CF3 groups, respectively. In contrast to trifluoromethylation of [60]- and [70]fullerenes that give a full range of derivatives ranging upwards from C-n(CF3)(2) , [76]-, [78]-, and [84]-fullerenes only give C-n(CF3)(6-18) derivatives, largely in the 10-12 CF3 range; reaction with [76]fullerene is accompanied by formation of C-60 (CF3)(6) attributed to cage fragmentation. For aza[60]fullerene the hexa-addition level dominates, in contrast to its other reactions which give predominantly penta-addition products. All the compounds showed peaks at 12562 and 1180-1190 cm(-1) , due to the CF3 group, and peaks in this region are shown also by the soluble extract obtained on trifluoromethylation of nanotubes. As in trifluoromethylation of [60]- and [70]-fullerenes, the products obtained initially are involatile, attributed to formation os silver complexes; these are decomposed on subsequent solution in toluene. Mixed isomeric trifluoromethylated C60F8 derivatives viz . C-60 F7CF3, C60F6 (FG(3))(2), C60F5 (CF3)(3) and C60F4 (CF3)(4) , and C60F4CF3 CF2CF3(a C60F6 derivative) have been isolated from fluorination of [60]fullerene with MnF3/K-2 NilF(6) at 510 degrees C.