A ruthenium water oxidation catalyst containing a bipyridine glycoluril ligand

Abstract

A mononuclear ruthenium complex [Ru(tpy)(bpg)H₂O]²⁺ bearing a bipyridine glycoluril where bpg = 4b,5,7,7a-tetrahydro-4b,7a-nepiminomethanoimino-6H-imidazo[4,5-f][1,10]phenanthro-line-6,13-dione acts as a robust water oxidation catalyst (WOC) at pH = 1 using Ce(IV) as a sacrificial oxidant. The turn over number (TON) for water oxidation is found to be ∼5 times higher than the parent complex [Ru(tpy)(bpy)H₂O]²⁺ where tpy = 2,2′:6′,2′′-terpyridine; bpy = 2,2′-bipyridine. The presence of intermolecular H-bonding groups and the electronic effect of the functionalized bipyridine ligand may play a significant role in water oxidation.