4 publications

4 publications

Aqueous Light Driven Hydrogen Production by a Ru–Ferredoxin–Co Biohybrid

Utschig, L.M.

Chem. Commun. 2015, 51, 10628-10631, 10.1039/c5cc03006d

Long-lived charge separation facilitates photocatalytic H2 production in a mini reaction center/catalyst complex.


Metal: Co
Ligand type: Oxime
Host protein: Ferredoxin (Fd)
Anchoring strategy: Dative
Optimization: ---
Reaction: H2 evolution
Max TON: 210
ee: ---
PDB: ---
Notes: Recalculated TON

Nature-Driven Photochemistry for Catalytic Solar Hydrogen Production: A Photosystem I-Transition Metal Catalyst Hybrid

Tiede, D.M.; Utschig, L.M.

J. Am. Chem. Soc. 2011, 133, 16334-16337, 10.1021/ja206012r

Solar energy conversion of water into the environmentally clean fuel hydrogen offers one of the best long-term solutions for meeting future energy demands. Nature provides highly evolved, finely tuned molecular machinery for solar energy conversion that exquisitely manages photon capture and conversion processes to drive oxygenic water-splitting and carbon fixation. Herein, we use one of Nature’s specialized energy-converters, the Photosystem I (PSI) protein, to drive hydrogen production from a synthetic molecular catalyst comprised of inexpensive, earth-abundant materials. PSI and a cobaloxime catalyst self-assemble, and the resultant complex rapidly produces hydrogen in aqueous solution upon exposure to visible light. This work establishes a strategy for enhancing photosynthetic efficiency for solar fuel production by augmenting natural photosynthetic systems with synthetically tunable abiotic catalysts.


Metal: Co
Ligand type: Oxime; Pyridine
Host protein: Photosystem I (PSI)
Anchoring strategy: Undefined
Optimization: ---
Reaction: H2 evolution
Max TON: 2080
ee: ---
PDB: ---
Notes: Recalculated TON

Protein Delivery of a Ni Catalyst to Photosystem I for Light-Driven Hydrogen Production

Tiede, D.M.; Utschig, L.M.

J. Am. Chem. Soc. 2013, 135, 13246-13249, 10.1021/ja405277g

The direct conversion of sunlight into fuel is a promising means for the production of storable renewable energy. Herein, we use Nature’s specialized photosynthetic machinery found in the Photosystem I (PSI) protein to drive solar fuel production from a nickel diphosphine molecular catalyst. Upon exposure to visible light, a self-assembled PSI-[Ni(P2PhN2Ph)2](BF4)2 hybrid generates H2 at a rate 2 orders of magnitude greater than rates reported for photosensitizer/[Ni(P2PhN2Ph)2](BF4)2 systems. The protein environment enables photocatalysis at pH 6.3 in completely aqueous conditions. In addition, we have developed a strategy for incorporating the Ni molecular catalyst with the native acceptor protein of PSI, flavodoxin. Photocatalysis experiments with this modified flavodoxin demonstrate a new mechanism for biohybrid creation that involves protein-directed delivery of a molecular catalyst to the reducing side of Photosystem I for light-driven catalysis. This work further establishes strategies for constructing functional, inexpensive, earth-abundant solar fuel-producing PSI hybrids that use light to rapidly produce hydrogen directly from water.


Metal: Ni
Ligand type: Phosphine
Host protein: Flavodoxin (Fld)
Anchoring strategy: Supramolecular
Optimization: ---
Reaction: H2 evolution
Max TON: 94
ee: ---
PDB: ---
Notes: Recalculated TON

Metal: Ni
Ligand type: Phosphine
Host protein: Photosystem I (PSI)
Anchoring strategy: Undefined
Optimization: ---
Reaction: H2 evolution
Max TON: 1870
ee: ---
PDB: ---
Notes: Recalculated TON

Ru–protein–Co Biohybrids Designed for Solar Hydrogen Production: Understanding Electron Transfer Pathways Related to Photocatalytic Function

Utschig, L.M.

Chem. Sci. 2016, 7, 7068-7078, 10.1039/c6sc03121h

A series of Ru–protein–Co biohybrids have been prepared using the electron transfer proteins ferredoxin (Fd) and flavodoxin (Fld) as scaffolds for photocatalytic hydrogen production. The light-generated charge separation within these hybrids has been monitored by transient optical and electron paramagnetic resonance spectroscopies. Two distinct electron transfer pathways are observed. The Ru–Fd–Co biohybrid produces up to 650 turnovers of H2 utilizing an oxidative quenching mechanism for Ru(II)* and a sequential electron transfer pathway via the native [2Fe–2S] cluster to generate a Ru(III)–Fd–Co(I) charge separated state that lasts for ∼6 ms. In contrast, a direct electron transfer pathway occurs for the Ru–ApoFld–Co biohybrid, which lacks an internal electron relay, generating Ru(I)–ApoFld–Co(I) charge separated state that persists for ∼800 μs and produces 85 turnovers of H2 by a reductive quenching mechanism for Ru(II)*. This work demonstrates the utility of protein architectures for linking donor and catalytic function via direct or sequential electron transfer pathways to enable stabilized charge separation which facilitates photocatalysis for solar fuel production.


Metal: Co
Ligand type: Oxime
Host protein: Ferredoxin (Fd)
Anchoring strategy: Dative
Optimization: Chemical
Reaction: H2 evolution
Max TON: 650
ee: ---
PDB: ---
Notes: Recalculated TON