Spectroelectrochemistry of (bpy)_2Ru(tatpp)Cl_2, a Photocatalyst for Hydrogen Generation

摘要

The mononuclear ruthenium(II) complex [(bpy)2Ru(tatpp)]~(2+) (with bpy = bypyridine, tatpp = 9,11,20,22-tetraaza tetrapyrido[3,2-a:2'3'-c:3",2"-1:2'",3"']-pentacene) is photoactive and capable of proton-coupled electron transfer reactions. Electrochemical characterization in acetonitrile and aqueous media indicates that four electrons are accepted by the tatpp ligand of this complex. A rich array of electroreduced and protonated products was determined by UV-visible transmittance and reflectance spectroelectrochemistry. The multiple-electron uptake capability and appropriate energy levels in this complex is shared by its analog, the dinuclear [(bpy)_2Ru(tatpp)(bpy)_2]~(4+) complex, and therefore both are considered potential photocatalysts for hydrogen generation. Their photocatalytic lifetime was found significantly longer than the standard [Ru(bpy)_3]~(2+) photocatalyst.