Comparative Study of the Aggregation of Sulfosubstituted Ir Photosensitilizers Based on the Inverted Porphyrinoid and Dye in-Docyanine Green New in Aqueous Solutions

The search for new water-soluble low-toxic IR photosensitizers and their application in biomedicine is an actual task of the modern medicinal chemistry. In this work we compare the aggrega-tion of two sulfo-containing compounds of the carbocyanine and inverted porphyrinoid series in aqueous solutions using electron absorption and fluorescence spectroscopy, as well as the dynamic light scattering (DLS) method. Depending on the polarity, acid-base and donor-acceptor properties of the solvent both IR-dyes absorb the light in the long-wave region at 700-850 nm and are characterized by relatively high values of logarithms of the extinction coefficients of the absorption bands varying from 3.8-3.9 for the porphyrinoid to 4.4-5.0 in the case of the cyanine dye. It is concluded that sulfo-containing dyes, regardless of the structural features of the chromophore, are prone to the hydrophobic interactions in aqueous solutions and, depending on the solute concentration, form different sized J- and H-type aggregates in the case of compounds of macroheterocyclic and linear structure, respectively. Decline of the dyes concentration in the range of 10-3-10-6 mol/kg is accompanied by the reduction of the diameter and narrowing of nanoparticles distribution of aggregates by size. Thus, for the dye Indocyanine green new, the size of aggregates (nm) decreases in the following series (mPS, mol/kg): 615 (10-3) > 255 (10-4) > 105 (10-5) > 79 (10-6). The tendency of the carbocyanine dye to aggregate is much higher, as it is controlled by the hydrophobic contribution of the organic π-chromophore. Nanoaggregates of the studied compounds are unstable in an aqueous solutions of the nonionic surfactant Tween 80, while subnano particles of sulfo-containing dyes are preserved under these conditions even at high excess of solubilizer. For citation: Berezin D.B., Bondareva T.V., Shukhto O.V., Batov D.V., Morshnev Ph.K. Comparative study of the aggregation of sulfosubstituted IR-photosensitilizers based on the inverted porphyrinoid and dye in-docyanine green new in aqueous solutions. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 10. P. 26-34. DOI: 10.6060/ivkkt.20256810.7250.