A Luminescent and Biocompatible PhotoCORM

The water-soluble rhenium­(I) complex fac-[Re­(bpy)­(CO)3(thp)]+ (1) [CF3SO3 salt; bpy = 2,2′-bipyridine, thp = tris­(hydroxymethyl)­phosphine] is both strongly luminescent and photoactive toward carbon monoxide release. It is stable in aerated aqueous media, is incorporated into cells from the human prostatic carcinoma cell line PPC-1, and shows no apparent cytotoxicity. Furthermore, the solvated Re­(I) photoproduct of CO release (2) is also luminescent, a feature that allows one to track the transformation of 1 to 2 inside such cells using confocal fluorescence microscopy. In this context, 1 is a very promising candidate as a photoactivated CO releasing moiety (photoCORM) with potential therapeutic applications.