Ruthenium Pyrazole Complexes: A Family of Highly Active Metallodrugs for Photoactivated Chemotherapy.

Ruthenium complexes bearing bis pyrazole (pzH) ligands, -[Ru(bpy)(R-pzH)] (bpy = 2,2'-bipyridine, R = -H, -Cl), were examined as photoactivated anticancer prodrugs. A dicationic pyrazole complex deprotonated to give monocationic pyrazole-pyrazolate complexes, [Ru(bpy)(R-pz)(R-pzH)], in an aqueous solution with p values of 9.5 and 7.