Synthesis of starburst hexa(oligoanilinated) C-60 using hexanitro[60]fullerene as a precursor

Efficient syntheses of starburst hexaanilino, hexa(dianilino), hexa(tetraan ilino), and hexa(hexadecaanilino)[60]fullerenes (HHDAF) were demonstrated u sing hexanitro[60]fullerene (HNF) as a reactive precursor molecule. The ter tiary nitro groups of HNF were found to act as excellent leaving groups for replacement by a nucleophilic substituent. Utilizing this reactivity with electron-donor nucleophiles, a synthetic approach was developed for the pro duction of oligoanilinated fullerenes as intramolecular donor-acceptor A-(D )(6) starburst macromolecules with a well-defined arm number and chain leng th. The reactivity of HNF with oligomeric anilines increases with increasin g number of repeating aniline units. Only an equal molar quantity of tetraa niline and hexadecaaniline was necessary for a complete reaction with HNF u nder mild conditions. The quantitative measurement of the material's proton counts over the H-1 NMR spectrum was utilized for determining the number o f addends per C-60 in the composition of oligoanilinated fullerenes. As a r esult, the NMR data fits well with the structure of tetraanilinated and hex adecaanilinated fullerenes, containing 6 tetraanilino and hexadecaanilino a rms per C-60, respectively. This composition of HHDAF was also supported by the DCI--MS spectroscopic data showing an approximate correlation of the t otal relative peak intensities of fragmented oligoanilino mass ion groups. The optical properties of hexa(hexadecaanilino)[60]fullerenes revealed a cl ose similarity with that of high molecular weight polyanilines.