Stabilization of a kinetically favored nanostructure:: Surface ROMP of self-assembled conductive nanocoils from a norbornene-appended hexa-peri-hexabenzocoronene

Newly designed norbornene-appended hexabenzocoronene 1 self-assembles, upon diffusion of an Et2O vapor into its CH2Cl2 solution, to form either graphitic nanocoils or nanotubes, depending on the self-assembling conditions. The coiled assembly, selectively formed at 15 degrees C, is a kinetic intermediate for the tubular assembly and transforms into nanotubes on standing at 25 degrees C. However, post-ring-opening metathesis polymerization of the norbornene pendants of 1 enhances the thermal stability of the coiled assembly as well as the tubular one and disables a thermodynamic coil-to-tube transition. The polymerized nanocoils show an electroconductivity of 1 x 10(-4) S cm(-1) upon doping with I-2, while the nonpolymerized nanocoils are disrupted upon being doped.