New fluorene-based two-photon singlet oxygen photosensitizers

ORGN 98

Stephen J. Andrasik, sandrasi@mail.ucf.edu1, Kevin D. Belfield, belfield@mail.ucf.edu2, Mykhailo V. Bondar, mike_bondar@hotmail.com3, Alma R. Morales, amorales@mail.ucf.edu1, Olga V. Przhonska3, and Sheng Yao, syao@mail.ucf.edu1. (1) Department of Chemistry, University of Central Florida, P.O. Box 162366, Orlando, FL 32816-2366, (2) Department of Chemistry and CREOL, College of Optics and Photonics, University of Central Florida, 4000 Central Florida Blvd., P.O. Box 162366, Orlando, FL 32816-2366, (3) Department of Photoactivity, Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev, Ukraine
The spectral properties of new fluorene-based photosensitizers for efficient singlet oxygen production were investigated at room temperature and 77 K. Two-photon absorption (2PA) cross-sections of the fluorene derivatives were measured by the open aperture Z-scan method. The quantum yields of singlet oxygen generation under one- and two-photon excitation were determined by the direct measurement of singlet oxygen luminescence at ca. 1270 nm. The values of singlet oxygen quantum yield were independent of excitation wavelength, ranging from 0.6 - 0.9. The singlet oxygen quantum yields under two-photon excitation were about half of the corresponding single-photon quantum yield, indicating that the two processes exhibited the same mechanism of singlet oxygen production, independent of the mechanism of photon absorption.
 

Process R&D, Physical Organic Chemistry, Heterocycles, Aromatics, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, March 25, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Organic Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007