A soft supramolecular carrier with enhanced singlet oxygen photosensitizing properties

Voskuhl, J.; Kauscher, U.; Gruener, M.; Frisch, H.; Wibbeling, B.; Strassert, C. A.; Ravoo, B. J.

Abstract

Herein we report the self-assembly of a supramolecular singlet oxygen photosensitizing system from an adamantane-functionalized{,} hexaanionic water-soluble zinc(ii) phthalocyanine (PC) and β-cyclodextrin vesicles (CDV). Characterisation of the designed PC{,} which was synthesized by an asymmetric statistical condensation{,} was carried out by several analytical techniques such as MALDI-HRMS{,} NMR{,} IR{,} UV/vis as well as steady state and time resolved fluorescence spectroscopy. The influence of the docking of the PC to the CDVs on the PC photoluminescence as well as on the singlet oxygen photoproduction quantum yields was investigated. The results indicate that the host–guest interaction of the photosensitizer and the CDVs significantly prevents the formation of inactive aggregates{,} and enhances the photosensitizing ability of the PC. The supramolecular assembly constitutes a biocompatible photoactive platform for the design of phototherapeutic agents.