Sulfonated phthalocyanines: aggregation and singlet oxygen quantum yield in aqueous solutions

Abstract

The influence of sulfonation degree (n) and central atom nature on singlet oxygen quantum yield (ΦΔ) were studied for a series of sulfonated phthalocyanine metal complexes MPcS n mix . It was found that in DMSO, where the studied dyes exist as monomers, ΦΔ values are independent of number and position of the sulfogroups and are equal to 0.11 ± 0.02, 0.19 ± 0.03, 0.37 ± 0.05, 0.38 ± 0.05 and 0.68 ± 0.10 for the metal-free and Mg , Gd , Al and Zn complexes, correspondingly. However, in aqueous solutions, aggregation of the dyes determines their photochemical activity. Substitution in adjacent to macrocycle 3 and 6 benzene positions interferes with aggregation compared to 4 and 5 positions, presumably due to enhanced steric hindrances in the former case. In the ZnPcS n mix series (n varied from 2 to 4), as an example, the linear relationship between degree of aggregation and ΦΔ indicates that only the monomer fraction of the dye is responsible for singlet oxygen production. For less sulfonated samples the order of activity of the dyes in water is as follows: H 2 PcS n mix < M II PcS n mix < M III PcS n mix which is in contrast to their tendencies to form aggregates.

Plasma membrane activatable polymeric nanotheranostics with self-enhanced light-triggered photosensitizer cellular influx for photodynamic cancer therapy

“…Nonetheless, PDT still serves as a fringe cancer treatment option due to many limitations, especially a lack of an ideal clinical PDT formulation [6]. One crucial issue is that most classic PS molecules are hydrophobic and prone to aggregate in aqueous condition, leading to a severe self-quenching effect, and therefore drastically reducing 1 O 2 generation as well as the therapeutic efficacy [7,8]. Besides, problems including difficult intravenous delivery [6] and low selectivity toward tumor areas remain poorly solved [9].…”

Improvement of Heterogeneous Sensitizer Photobactericidal Activity by Elongation of Linker between Phthalocyanine and Silica Gel Support

“…It is well known that monomerization of sensitizer is one of the key factors for high photodynamic activity so far as aggregation decreases the efficiency of 1 O 2 photogeneration. [18] In addition, absence of Q band broadening for immobilized SiPcChol 7 suggests electronic structure of phthalocyanine molecule is not perturbed by interaction with the carrier. On the whole, obtained results show that effect of spacer length upon phthalocyanine electronic levels and spectra was not observed.…”

Synthesis and Some Properties of Phosphonomethyl Substituted Phthalocyanines

“…Φ ∆ values were determined relatively to the sulfonated aluminum phthalocyanine (in water Φ ∆ 0.38 [19] ). Sulfonated aluminum phthalocyanine was irradiated through an interference filter with transmission 680 ± 25 nm.…”