Nondestructive Formation of Supramolecular Nanohybrids of Single-Walled Carbon Nanotubes with Flexible Porphyrinic Polypeptides

Strategies for single-walled carbon nanotube (SWNT) separation are critical to developing nanotubes as useful nanoscale building blocks. Herein, diameter-selective dispersion of HiPco single-walled carbon nanotubes has been accomplished through noncovalent complexation of the nondestructive nanotubes with a flexible porphyrinic polypeptide bearing 16 porphyrin units [P(H2P)16] in DMF at 298 K. Supramolecular formation occurs through wrapping of peptidic backbone in P(H2P)16 and π−π interaction between porphyrins and nanotubes to extract the large-diameter nanotubes (ca. 1.3 nm) as revealed by ultraviolet−visible-near-infrared and Raman spectroscopy as well as high-resolution transmission electron micropscopy. The photoexcitation of the supramolecular complex affords the long-lived charge-separated state.