Influence of the Medium on the Photochemical and Photophysical Properties of [Ru(phen)(2)(pPDIp)](2+)

This study reports the influence of the medium on the aggregation processes of the complex [Ru(phen)(2)(pPDIp)](2+)(phen=1,10-phenanthroline; pPDIp=a bis-phenanthroline-substituted perylene diimide)and its consequences for the photochemical and photophysical properties of the system. Photolysis leads, initially, to emission of both chromophores: Triplet metal-to-ligand charge transfer ((MLCT)-M-3*; Ru, dphen, *) and singlet intraligand charge transfer ((ILCT)-I-1*; pPDIp, *). However, the medium induces increased - intermolecular interactions that lead to the generation of a pPDIp(.-)moietyin DMSO, pPDIp(.-) (518nm) and pPDIp(.-) and pPDIp(2-)(420nm) in the cell culture medium RPMI, and (3*)pPDIp in buffer (pH7.4) and starch films. The complex activates singlet oxygen in buffer solution without oxygen bubbling and under green light irradiation (dose=0.41J/cm(2); [O-1(2)]=0.03-0.47molL(-1) for [Ru(phen)(2)(pPDIp)](2+)=10-150molL(-1)). No cytotoxic effects on B16F10-Nex2 murine melanoma cell viability were observed up to a concentration of 10molL(-1) of complex. However, under green LED illumination (dose=0.41J/cm(2)) the complex exhibits a strong photocytotoxic effect, displaying IC50=1.2molL(-1).