Carbon nanotubes from short hydrocarbon templates. Energy analysis of the Diels–Alder cycloaddition/rearomatization growth strategy

Abstract

Molecular orbital calculations at the AM1 and B3LYP/6–31G* levels of theory have been used to analyze the Diels–Alder cycloaddition/rearomatization strategy for growing uniform diameter, single-chirality carbon nanotubes from short hydrocarbon templates (aromatic belts and hemispherical end-caps) by metal-free chemical methods. Bay regions on the rim of a [10,10]nanotube end-cap (15) are predicted to exhibit Diels–Alder reactivity comparable to that of bay regions in planar polyarenes that have previously been transformed into new benzene rings by reactions with “masked acetylene” dienophiles. The Diels–Alder reactivity of nanotube template rims was found to be relatively unaffected by the presence or absence of a cap on the other end.