Theoretical Examination of New Forms of Carbon Formed by Intra- or Intermolecular Dehydrogenation of Polycyclic Aromatic Hydrocarbons, Particularly Helicenes

Abstract

Generalized helicenes are defined. A theoretical analysis is presented for the intramolecular dehydrogenation of helicenes, bridging adjacent rungs of the helix with the formation of 4-, 5-, and/or 6-membered rings, yielding helical tubulenes to which Euler's formula for polyhedra no longer applies as such constructions are derived from Möbius strips and correspond to nonplanar graphs (i.e., have crossing lines when drawn in two dimensions). Intermolecular dehydrogenation of two parallel-superimposed polycyclic aromatic hydrocarbons with formation of similar rings leads to convex polyhedral carbon cages. Carbon helical nanotubes and some carbon cages that are different from fullerenes are also discussed.

Keywords:

• Carbon
• Helical Tubulenes
• Helicenes
• Polycyclic Aromatic Hydrocarbons
• Tori