Phosphorus (V) 15-crown-5-phthalocyanine as a promising non-toxic near-IR photoinitiator in aqueous medium

The search for novel water soluble red and near-IR photoinitiators for biomedical applications is a very important task. Here we describe the synthesis and photophysical properties of a water soluble complex of P(V) with tetra-15-crown-5-phthalocyanine bearing diethylene glycol monoethyl ether as axial ligand (15C5PcP-gly). In addition to intense near-IR absorption, compound 15C5PcP-gly is characterized by a high quantum yield of singlet oxygen generation with moderate photostability. The combination of these properties with the discovered low dark and light induced cytotoxicity and negligible intracellular accumulation makes the complex 15C5PcP-gly promising for biophotopolymerization. Taking advantage of all the benefits of the 15C5PcP-gly complex, we demonstrate for the first time its successful application in the bulk photocuring of a water-soluble polyethylene glycol diacrylate-based system with simultaneous preservation of mammalian cells viability.