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.

Re-examination of the emission properties of alkoxy- and thioalkyl-substituted phthalocyanines

“…p * in origin this assignment would still be problematic, however. The wavelength of violet emission lies significantly to the blue of a significant portion of the band envelope in the 400-600 nm region, both in the case of Zna(OC 4 H 9 ) 8 Pc [2][3][4][5][6][7][8][9][10][11][12][13][14] and the mixed alkoxy-and thioalkyl-substituted porphyrazines reported by Hoffman and coworkers [15,16]. This pattern can be observed in the emission spectra recorded during the irradiation of a tetrahydrofuran (THF) solution of H 2 a(SC 4 H 9 ) 8 Pc, Fig.…”

“…p * bands in the 400-600 nm region cannot be excluded as a possibility, however. This brings us to the assignment of the violet emission, which has sometimes been assigned to an np * excited state [7,[11][12][13][14] based on the assumption that np * states do not deactivate as efficiently to the S 1 state as the higher energy pp * states do [7,11].…”

“…Sulfonated AlClPcs are currently being used commercially for this purpose in Russia [2]. In the emission spectra of alkoxy-and thioalkyl-substituted phthalocyanines and porphyrazines [3][4][5][6][7][8][9][10][11][12][13][14][15][16], an S 1 emission peak is observed in the 600-900 nm region, while a second higher energy peak has also frequently been reported in the 400-600 nm region. The higher energy emission has been assigned as S 2 emission and np * excited states associated with the lone pairs of the peripheral oxygen and/or sulfur atoms have sometimes been proposed as the origin of this peak [7,[11][12][13][14].…”

The Application of Heptamethine Cyanine Dye DZ-1 and Indocyanine Green for Imaging and Targeting in Xenograft Models of Hepatocellular Carcinoma

“…These clinical observations reinforce the cancer-specific targeting ability of NIRF dye as well as the roles of HIF1α/OATPs in mediating dye uptake in liver cancer. In addition to the well-elucidated hypoxia/HIF1α- and OATPs-mediated mechanisms, other alternative mechanisms might involve in the accumulation of NIRF dyes in liver cancer cells, such as IR-780 and Pz 247 [34,35]. These heptamethine cyanine dyes can achieve organelle-preferential accumulation in cancer cells by the enhanced permeability and retention (EPR) effect, which facilitates the entrance of dyes to the intracellular compartment with higher retention in the mitochondria and lysosomes through ATP-dependent endocytosis [3].…”

Spectroscopy, Binding to Liposomes and Production of Singlet Oxygen by Porphyrazines with Modularly Variable Water Solubility

“…The product Mg[pz( A x B 4− x )] compounds were demetallated with trifluoroacetic acid to yield the free‐base, H 2 [pz( A x B 4− x )] and chromatographed to give H 2 [pz( A 4 )] ( B2 ), H 2 [pz( A 3 B )] ( B9, B10, B175 ), and trans ‐H 2 [pz( A 2 B 2 )] ( B15, B16, B17, B176, B214 ) in moderate yield. The [Zn]pzs B13, B20, B55, B179 and B215 were prepared quantitatively by re‐metallation of B9, B16, B15, B176 and B214, respectively with zinc acetate dihydrate in refluxing MeOH/CH 2 Cl 2 (1:3), for 30 min (23).…”