Light-Driven Electron Transfer between a Photosensitizer and a Proton-Reducing Catalyst Co-adsorbed to NiO

Gardner, James M.; Beyler, Maryline; Karnahl, Michael; Tschierlei, Stefanie; Ott, Sascha; Hammarström, Leif

doi:10.1021/ja3082268

Cited by 95 publications

(95 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…62 An excited coumarin-343 dye was injected into a hole in NiO upon visible-light excitation. The reduced coumarin transferred electrons to neighboring dye molecules until it encountered a coadsorbed catalyst where reduction was favored by ∼500 meV.…”

Section: Direct Evidence For Self-exchange Energymentioning

confidence: 99%

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Meyer

2015

Langmuir

View full text Add to dashboard Cite

Intermolecular self-exchange energy and electron-transfer reactions occur without a loss of free energy. This behavior can be exploited for energy-transport applications when molecules that undergo self-exchange transfer reactions are immobilized on a solid support. This Article focuses upon lateral self-exchange reactions and the relevant interfacial chemistry that occurs on the mesoporous nanocrystalline (anatase) TiO2 thin films that are commonly used in dye-sensitized solar cells. It has been known for some time that all of the dye molecules (termed sensitizers) within such thin films can be reversibly oxidized and reduced by lateral self-exchange electron transfer provided that the sensitizer surface coverage exceeds a percolation threshold. Under conditions where excited-state electron injection into TiO2 is unfavored, lateral intermolecular energy-transfer reactions are also known to occur. The self-exchange rate constants have been quantified by electrochemical, absorption, and/or time-resolved anisotropy techniques and understood within the framework of Marcus theory. Such analysis reveals that the reorganization energy and the electronic coupling are sensitive to the identity of the molecular compound. Time-resolved anisotropy measurements have shown that lateral charge and energy-transfer reactions across the TiO2 surface occur in kinetic competition with charge recombination and excited-state relaxation, respectively. The extent to which lateral self-exchange reactions might be exploited for solar energy conversion applications is discussed, as are critical fundamental issues that remain unresolved.

show abstract

Section: Direct Evidence For Self-exchange Energymentioning

confidence: 99%

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Meyer

2015

Langmuir

View full text Add to dashboard Cite

show abstract

“…26 Only recently did Ott and coworkers report complexes of bdt together with a chelating phosphine to create coordinatively unsaturated monocarbonyl models of the distal iron site of [FeFe]-hydrogenases and to show that these compounds are active in electrocatalytic proton reduction. [27][28][29] In this paper, we present a new coordinatively unsaturated, five-coordinate Fe(II)-carbonyl in a P 2 S 2 coordination environment. The phosphines are provided by 1,1'-{bis(diphenyl)phosphino}ferrocene (dppf), and the steric constraints of the ferrocene moiety in this ligand cause it to have one of the largest bite angles observed for a chelating phosphine.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Hydrogen Evolution by Fe(II) Carbonyls Featuring a Dithiolate and a Chelating Phosphine

et al. 2014

View full text Add to dashboard Cite

Abstract:Two pentacoordinate mononuclear iron carbonyls of the form (bdt)Fe(CO)P 2 [bdt = benzene-1,2-dithiolate; P 2 = 1,1'-diphenylphosphinoferrocene (1) or methyl-2-{bis(diphenylphosphinomethyl)amino}acetate (2)] were prepared as functional, biomimetic models for the distal iron (Fe d ) of the active site of [FeFe]-hydrogenase. Xray crystal structures of the complexes reveal that, despite similar ν(CO) stretching band frequencies, the two complexes have different coordination geometries. In X-ray crystal structures, the iron center of 1 is in a distorted trigonal bipyramidal arrangement, and that of 2 is in a distorted square pyramidal geometry. Electrochemical investigation shows that both complexes catalyze electrochemical proton reduction from acetic acid at mild overpotential, 0.17 and 0.38 V for 1 and 2, respectively. Although coordinatively unsaturated, the complexes display only weak, reversible binding affinity towards CO(1 bar). However, ligand centered protonation by the strong acid, HBF 4 .OEt 2 , triggers quantitative CO uptake by 1 to form a dicarbonyl analogue [1(H)-CO] + that can be reversibly converted back to 1 by deprotonation using NEt 3 . Both crystallographically determined distances within the bdt ligand and DFT calculations suggest that the iron centers in both 1 and 2 are partially reduced at the expense of partial oxidation of the bdt ligand. Ligand protonation interrupts this extensive electronic delocalization between the Fe and bdt making 1(H) + susceptible to external CO binding.3

show abstract

“…24−31 However, most dynamics studies have been limited to single photon-induced electron/hole transfer events. [17][18][19]32,33 Only a few reports are available describing the buildup and use of multiple redox equivalents in model systems. 8,9,34,35 We have reported intramolecular electron transfer dynamics following excitation and electron injection in two bimetallic Ru II assemblies.…”

Section: ■ Introductionmentioning

confidence: 99%

Accumulation of Multiple Oxidative Equivalents at a Single Site by Cross-Surface Electron Transfer on TiO₂

et al. 2013

View full text Add to dashboard Cite

The photodriven accumulation of two oxidative equivalents at a single site was investigated on TiO2 coloaded with a ruthenium polypyridyl chromophore [Ru(bpy)2((4,4'-(OH)2PO)2bpy)](2+) (Ru(II)P(2+), bpy = 2,2'-bipyridine, ((OH)2PO)2-bpy = 2,2'-bipyridine-4,4'-diyldiphosphonic acid) and a water oxidation catalyst [Ru(Mebimpy) ((4,4'-(OH)2PO-CH2)2bpy)(OH2)](2+) (Ru(II)OH2(2+), Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine, (4,4'-(OH)2PO-CH2)2bpy) = 4,4'-bis-methlylenephosphonato-2,2'-bipyridine). Electron injection from the metal-to-ligand charge transfer (MLCT) excited state of -Ru(II)P(2+) (-Ru(II)P(2+)*) to give -Ru(III)P(3+) and TiO2(e(-)) was followed by rapid (<20 ns) nearest-neighbor -Ru(II)OH2(2+) to -Ru(III)P(3+) electron transfer. On surfaces containing both -Ru(II)P(2+) and -Ru(III)OH2(3+) (or -Ru(III)OH(2+)), -Ru(II)OH2(2+) was formed by random migration of the injected electron inside the TiO2 nanoparticle and recombination with the preoxidized catalyst, followed by relatively slow (μs-ms) non-nearest neighbor cross-surface electron transfer from -Ru(II)OH2(2+) to -Ru(III)P(3+). Steady state illumination of coloaded TiO2 photoanodes in a dye sensitized photoelectrosynthesis cell (DSPEC) configuration resulted in the buildup of -Ru(III)P(3+), -Ru(III)OH(2+), and -Ru(IV)═O(2+), with -Ru(IV)═O(2+) formation favored at high chromophore to catalyst ratios.

show abstract

Light-Driven Electron Transfer between a Photosensitizer and a Proton-Reducing Catalyst Co-adsorbed to NiO

Cited by 95 publications

References 19 publications

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Catalytic Hydrogen Evolution by Fe(II) Carbonyls Featuring a Dithiolate and a Chelating Phosphine

Accumulation of Multiple Oxidative Equivalents at a Single Site by Cross-Surface Electron Transfer on TiO₂

Contact Info

Product

Resources

About

Light-Driven Electron Transfer between a Photosensitizer and a Proton-Reducing Catalyst Co-adsorbed to NiO

Cited by 95 publications

References 19 publications

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Lateral Intermolecular Self-Exchange Reactions for Hole and Energy Transport on Mesoporous Metal Oxide Thin Films

Catalytic Hydrogen Evolution by Fe(II) Carbonyls Featuring a Dithiolate and a Chelating Phosphine

Accumulation of Multiple Oxidative Equivalents at a Single Site by Cross-Surface Electron Transfer on TiO2

Contact Info

Product

Resources

About

Accumulation of Multiple Oxidative Equivalents at a Single Site by Cross-Surface Electron Transfer on TiO₂