In order to accomplish the selective synthesis of [60]fullerene bisadducts, the reactions of [60]fullerene with compounds in which two α,α‘-dibromo-o-xylene moieties were connected by an oligomethylene chain (n = 2−5) were investigated. By this method, only two isomers (cis-2- and cis-3-isomers) were selectively obtained when n = 2 and 3, while another isomer (e-isomer) was obtained when n = 5. When n = 4, a complex mixture of bisadducts was formed and has not been separated so far. cis-2-Bisadducts have been, for the first time, selectively obtained in the fullerene chemistry. The structures of bisadducts were determined on the basis of 1H, 13C NMR, IR, UV−vis, and mass spectroscopies. According to the NMR experiments, the symmetries of cis-2-, cis-3-, and e-isomers were concluded to be C s , C 2, and C 1, respectively. Chiral cis-3- and e-bisadducts were successfully resolved into the respective enantiomers on a chiral HPLC column, although cis-2-bisadducts only gave a single peak. The UV−vis spectra of cis-2-, cis-3-, and e-bisadducts were remarkably different from one another. Specifically, the e-bisadducts showed a characteristic absorption peak around 420 nm. The cleavage of the oligomethylene chain produced the corresponding [60]fullerene derivatives possessing two phenol moieties. These compounds are applicable to further functionalization.

In the [2.3](2,7)phenanthrenophanes prepared by the intramolecular [2 + 2] photocycloaddition of 1,3-bis(7-vinyl-2-phenanthryl)propane, excimer fluorescence was observed for not only syn- but also anti-isomer, though the maximal position of the latter was slightly blue-shifted relative to the former.

Selective Functionalization on (60)Fullerene Governed by TetherLength.-The synthesis of (60)fullerene bisadducts is carried out by the reaction of the fullerene and compounds, where two α,α'-dibromo-o-xylene moieties are connected by an oligomethylene chain -( CH2)n-, n = 2-5. Depending on the tether length specific bisadducts are obtained. The selectivity, structural analysis and optical resolution are investigated. Removal of the tether affords fullerene derivatives possessing phenolic hydroxy groups which are applicable to further transformations. -(TAKI, M.; SUGITA, S.; NAKAMURA, Y.; KASASHIMA, E.; YASHIMA, E.; OKAMOTO, Y.; NISHIMURA, J.; J. Am. Chem. Soc. 119 (1997) 5, 926-932; Dep. Chem., Gunma Univ., Kiryu 376, Japan; EN)