Carbon Nanotube-Acridine Nanohybrids: Spectroscopic Characterization of Photoinduced Electron Transfer

Change happens: Acridine–carbon nanotube nanohybrids were built (see figure) and their photoinduced electron‐transfer properties investigated, showing variable behaviour depending on the acridine partner. Single‐walled carbon nanotubes (NT) were covalently functionalized with either 9‐phenyl acridine (PhA) or 10‐methyl‐9‐phenyl acridinium (PhMeA+). Absorption and fluorescence properties of acridine derivatives tethered to the nanotubes were studied in homogeneous dispersions. Exciplex emission was observed for NT functionalized with 9‐phenylacridine. This phenomenon was attributed to an “intramolecular” interaction between excited phenyl acridine and carbon nanotubes. Interestingly, reverse photoinduced electron transfer from the nanotube to 10‐methyl‐9‐phenylacridinium was detected for the NT‐PhMeA+ nanohybrid. This electron transfer led to a strong quenching of the acridinium fluorescence and to the formation of a metastable acridine radical. Evidence for the formation of this radical was obtained by ESR studies. Change happens: Acridine–carbon nanotube nanohybrids were built (see figure) and their photoinduced electron‐transfer properties investigated, showing variable behaviour depending on the acridine partner.