Spectral, photophysical and photochemical properties of tetra- and octaglycosylated zinc phthalocyanines

Abstract

Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100-430 μs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.

Glycosylated Porphyrins, Phthalocyanines, and Other Porphyrinoids for Diagnostics and Therapeutics

“…Zn(II)Pc’s are of great interest to develop Pc-based new generation PS for PDT because of the high triplet quantum yield and long triplet lifetimes. 324,325 The longer lifetimes of the PS are advantageous as they promote the diffusional encounter between the excited triplet state of the PS and endogeneous molecular oxygen.…”

Towards new multivalent supramolecular helical structures based on phthalocyanines for PDT applications

“…The nature of the aggregates has been assessed by different techniques, observing the formation of stable one-dimensional helical columnar aggregates by π-π stacking of the hydrophobic cores, whose helicity is biased by the chirality of glucose substituents. The formation of dynamic helical supramolecular polymers in water decorated with saccharides at the periphery together with the excellent singlet oxygen quantum yields shown by Pc [34] can potencially result in a new, and specific multivalent system for PDI treatment.…”

“…[32][33] Moreover, excellent triplet quantum yield (0.68) and singlet oxygen quantum yield (0.67) were found for this phthalocyanine in DMSO as a first step for its use in PDT. [34] However, the dynamic nature, the size, and the chirality of those aggregates have been never studied before.…”

Synthesis of Glycoconjugated Phthalonitriles for New Phthalocyanine-Based Photosensitizers

“…[29][30][31][32][33][34][35] The achieved glycosylated and glycoconjugated zinc phthalocyanine species with excellent solubility in water, absorption maxima beyond 700 nm, and high triplet quantum yields ranging from 0.68 to 0.88 fulfilled the basic requirements for the successful application in PDT. [36,37] Herein, we present the synthesis and full characterization of 3,6-bisglycosylated and 3,6-bisglycoconjugated phthalonitriles, which are necessary starting materials for the formation of new nonperipheral glycosylated and glycoconjugated phthalocyanines.…”