Singlet oxygen quantum yield determination for a fluorene-based two-photon photosensitizer

Abstract

The quantum yield, Φ Δ, of singlet oxygen generation under two-photon excitation has been determined for a fluorene derivative. A photochemical method was developed using 1,3-diphenylisobenzofuran (DPBF), a chemical quencher of 1O 2, and 2-(9,9-didecyl-7- nitrofluoren-2-yl)benzothiazole (1) as a two-photon photosensitizer (PS). The photochemical kinetics of the quencher was measured by two different fluorescence methods. Fluorene 1 exhibited relatively high singlet oxygen quantum yield, Φ Δ∈≈∈0.4∈±∈0. 1, and had a two-photon absorption cross-section of 28∈±∈5GM. Thus, 1 may have potential for use as a two-photon PS in the near-IR spectral region for biomedical applications. © 2006 Springer Science+Business Media, Inc.