Tuning the singlet oxygen quantum yield of near-IR-absorbing porphyrazines.
We report the quantum yields for singlet oxygen production by a series of porphyrazines (pz) of the form M[pz(An;B4-n)] (Scheme 1), where the peripheral substituent A is [S-R]2 with R = (CH2CH2O)3H, B is a fused alpha,alpha'-dialkoxybenzo group and M = 2H, Mg or Zn. These compounds show intense near-IR absorbance/emission (longest wavelength emission, approximately 830 nm). Their solubilities vary with R, whereas their optical properties do not. We show that singlet oxygen sensitization by these luminescent compounds can be "tuned" from essentially off to on by varying n and selection among M = 2H, Mg or Zn. The quantum yields vary ca 60-fold within the set of compounds studied, from phidelta = 0.007 for compound 3 to phidelta = approximately 0.4 for compound 11.
Lee
Sangwan
S
Department of Chemistry, Northwestern University, Evanston, IL 60208-3113, USA.
Stackow
Robert
R
Trevithick-Sutton
Colleen
C
Foote
Christopher S
CS
Barrett
Anthony G M
AG
Hoffman
Brian M
BM
D007259:Infrared Rays; D049449:Luminescence; D055095:Optics and Photonics; D011166:Porphyrins / Q000737:chemistry* / Q000528:radiation effects*; D026082:Singlet Oxygen / Q000737:chemistry*; D013057:Spectrum Analysis
D011166:Porphyrins; D026082:Singlet Oxygen