RECENT DEVELOPMENT ON FULLERENE CHEMISTRY .1. CYCLOADDITION OF O-QUINODIMETHANE AND ITS ANALOGS TO [60]FULLERENE, AND PROPERTIES OF CYCLOADDUCTS

Several C-60-o-quinodimethane adducts having various aromatic rings ha ve been synthesized by the simple thermal reaction of C-60 with benzoc yclobutene homologues. The electronic and photophysical properties of the adducts were found to be virtually independent of the attached aro matic rings, according to the absorption, fluorescence, and transient absorption spectra. In the adduct possessing an N,N-dimethylaniline (D MA) moiety, however, intramolecular electron transfer from S-0(DMA) to S-1(C-60) was observed in benzonitrile, while not in cyclohexane. The regio- and stereoselective synthesis of C-60-bisadducts has been succ essful by the reaction between C-60 and the compounds in which two o-q uinodimethane precursors were connected by an oligomethylene unit of t he suitable length (n=2-5). A new nomenclature of C-60 derivatives is also proposed in order to designate such bisadducts.