Photocatalytic hydrogen evolution from rhenium(I) complexes to [FeFe] hydrogenase mimics in aqueous SDS micellar systems: a biomimetic pathway.

Abstract

To offer an intriguing access to photocatalytic H(2) generation in an aqueous solution, the hydrophobic photosensitizer, Re(I)(4,4'-dimethylbpy)(CO)(3)Br (1) or Re(I)(1,10-phenanthroline)(CO)(3)Br (2), and [FeFe] H(2)ases mimics, [Fe(2)(CO)(6)(mu-adt)CH(2)C(6)H(5)] (3) or [Fe(2)(CO)(6)(mu-adt)C(6)H(5)] (4) [mu-adt = N(CH(2)S)(2)], have been successfully incorporated into an aqueous sodium dodecyl sulfate (SDS) micelle solution, in which ascorbic acid (H(2)A) was used as a sacrificial electron donor and proton source. Studies on the reaction efficiency for H(2) generation reveal that both the close contact and the driving force for electron transfer from the excited Re(I) complexes and [FeFe] H(2)ases mimics are crucial for efficient H(2) generation with visible light irradiation. Steady-state and time-resolved investigations demonstrate that the electron transfer takes place from the excited Re(I) complex 1 or 2 to [FeFe] H(2)ases mimic catalyst 3, leading to the formation of the long-lived Fe(I)Fe(0) charge-separated state that can react with a proton to generate Fe(I)Fe(II).H, an intermediate for H(2) production. As a result, a reaction vessel for the photocatalytic H(2) production in an aqueous solution is established.