ABSTRACT
A self-assembled M6L8 type cage-connected 1D-coordination network of formula {[Ni6(MeSi(3py)3)8Cl9(H2O)2]Cl3·16H2O}∞ (1) was obtained from a 3-pyridyl substituted silane ligand MeSi(3py)3. This complex shows significantly high performance for the electrocatalytic and photocatalytic hydrogen evolution reaction (HER) in water. A maximum turnover number (TON) of 2824 has been observed for photocatalytic HER after 69 h.
ABSTRACT
The octahedral cage assembly [CoII6L18Cl6(H2O)6]Cl6 has been synthesized in a single-step reaction by using a polypyridyl-functionalized tripodal silane ligand. The electrochemical behavior of the cage in water exhibits the pH dependence of potential as well as catalytic current indicating the possible involvement of proton-coupled electron transfer in H2 evolution. Electrocatalytic hydrogen evolution from an aqueous buffered solution gave a turnover frequency of 16 h-1. Further, this cage assembly has been explored as a photocatalyst (blue light irradiation λ 469 nm) for the evolution of H2 from water in the presence of Ru(bpy)32+ as a photosensitizer and ascorbic acid as a sacrificial electron donor. This catalytic reaction is found to be pseudo first order with a turnover frequency of 20.50 h-1.
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 â¼5 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.
