Inclusion Polymerization of Pyrrole and Ethylenedioxythiophene in Assembled Triphenylamine Bis-Urea Macrocycles

Herein, two different monomers, pyrrole (Py) and ethylenedioxythiophene (EDOT), are loaded into a self-assembled bis-urea host 1 and oxidatively polymerized within its nanochannels, dramatically changing the properties of the crystalline complexes. Molecular dynamics (MD) simulation of both monomers within the channel demonstrates that they diffuse through the confinement upon applying thermal energy, which may facilitate the polymerization reaction. The structures of these host-guest complexes are characterized before and after polymerization using solid-state and photophysical measurements. The host maintains its columnar morphology during polymerization at 90 °C using iodine as an oxidizing agent. Intriguingly, upon dissolution of the host and recovery by filtration, the polymers exhibit memory of their nanoreactor environment, displaying unusual order by scanning electron microscopy, powder X-ray diffraction, and small- and wide-angle X-ray analysis. Solid-state ¹³C cross-polarized magic angle spinning NMR suggests that polypyrrole (PPy) exhibits primarily α,α′ linkages with some contributions from the quinoid form. Similarly, poly(ethylenedioxythiophene) (PEDOT) also exhibits formation of primarily α,α′ linkages with minor quinoid contributions. Both the 1·PPy and 1·PEDOT crystals show a 10³-fold increase in conductivity to ∼10^-6S/cm versus host 1 crystals, which are nonconductive ∼10^-9S/cm. Overall, supramolecular polymerization strategies have the potential to readily modulate the properties of nanostructured materials.