title: Tuning the singlet oxygen quantum yield of near-IR-absorbing porphyrazines.
abstract: 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.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208-3113, USA.
authors.forename: Sangwan
authors.initials: S
authors.lastname: Lee
authors.forename: Robert
authors.initials: R
authors.lastname: Stackow
authors.forename: Colleen
authors.initials: C
authors.lastname: Trevithick-Sutton
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Foote
authors.forename: Anthony G M
authors.initials: AG
authors.lastname: Barrett
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hoffman
mesh_terms: D007259:Infrared Rays; D049449:Luminescence; D055095:Optics and Photonics; D011166:Porphyrins / Q000737:chemistry* / Q000528:radiation effects*; D026082:Singlet Oxygen / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D011166:Porphyrins; D026082:Singlet Oxygen