We report herein the synthesis of six precursor molecules for the rational synthesis of isomerically pure armchair, zigzag, or chiral single-walled carbon nanotubes (SWCNTs). The polycyclic aromatic hydrocarbons possess the required carbon connectivity for the generation of extended hemispherical buckybowls with predefined geometry through intramolecular cyclodehydrogenation. The precursors for the short carbon nanotubes and the large-diameter hemispherical buckybowls have potential for the rational initiation of single-chirality SWCNT growth on metal surfaces. The options for the construction of precursors for various SWCNT chiralities based on the suggested synthesis strategy are presented.

Various functional groups have been tested as alternative promoters of the intramolecular condensation of benzo[c]phenanthrene under flash vacuum pyrolysis conditions. Methyl and fluorine functionalization were found to be promising approaches. Unexpectedly high selectivity was observed in the cyclization of fluorinated benzo[c]phenanthrenes. The mechanism for the condensation reaction and the advantages of fluorine as a promoter for the rational synthesis of fullerenes are discussed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)