Photoinduced electron transfer in covalently linked ruthenium tris(bipyridyl)-viologen molecules: observation of back electron transfer in the Marcus inverted region

Yonemoto, Edward H.; Riley, Richard L.; Kim, Yeong Il; Atherton, Stephen J.; Schmehl, Russell H.; Mallouk, Thomas E.

doi:10.1021/ja00047a017

Cited by 176 publications

(142 citation statements)

References 1 publication

Supporting

Mentioning

133

Contrasting

Order By: Relevance

“…In contrast to the very weak emission (lifetime of τ ≈ 20 ps , k ≈ 6 × 10 10 s -1 ) in acetonitrile, 20,23,24 there is a resolvable emission on ZrO 2 ( Figure 1). Kinetic analysis of the emission decay, using the expression in eq 1, yields a lifetime of ∼40 ns (k ≈ 2.5 × 10 7 s -1 ).…”

Section: Resultsmentioning

confidence: 91%

See 1 more Smart Citation

Effect of Surface Immobilization on Intramolecular and Intermolecular Electron Transfer in a Chromophore−Donor−Acceptor Assembly

2005

View full text Add to dashboard Cite

A chromophore-donor-acceptor assembly [Ru(bpyCOOH)(bpyCH(2)MV(2+)) (bpyCH(2)PTZ)](4+)(1) (where bpyCOOH = 4-carboxylic acid-4'-methyl-2,2'-bipyridine, bpyCH(2)MV(2+) = 1-[(4'-methyl-2,2'-bipyridin-4-yl)methyl]-1'-methyl-4,4'-bipyridinediium, and bpyCH(2)PTZ = 10-[(4'-methyl-2,2'-bipyridin-4-yl)methyl]phenothiazine) has been adsorbed on the surface of nanocrystalline ZrO(2) and its excited state properties studied by emission and transient absorption spectroscopy. In deaerated acetonitrile solution, the complex emits weakly with an emission quantum yield of phi(em) approximately equal to 0.01 with an excited-state lifetime of tau approximately equal to 20 ps. Emission from the surface-adsorbed complex is intense, with phi(em) approximately equal to 0.4 and tau approximately equal to 40 ns. The increase in emission on the surface is likely due to a significant inhibition to the electron-transfer quenching of the metal-to-ligand charge transfer (MLCT) excited state caused by surface adsorption-induced changes in the redox potentials. Transient (nanosecond time scale) absorption monitoring, following laser flash photolysis, reveals the presence of a transient or transients that are formed during the flash. Transient spectral changes that occur during and after the flash are consistent with the formation and decay of the intermediate ZrO(2)-[Ru(bpyCOOH)(bpyCH(2)MV(+*))(bpyCH(2)PTZ(+*))](4+). It returns to the ground state by both intramolecular and intermolecular processes. Intramolecular electron transfer occurs with k(BET) = 6.3 x 10(6) s(-1) (tau = 160 ns), which is comparable to the rate constant for back-electron transfer in solution. The back-electron transfer is a second-order process and is much slower, with k(BET) = 390 M(-1) s(-1) (tau = 2.6 ms).

show abstract

Section: Resultsmentioning

confidence: 91%

“…In acetonitrile solution, Ru II f bpy metal-to-ligand charge-transfer (MLCT) excitation is followed by electron transfer to the appended MV 2+ group on the time scale of tens of picoseconds. 23,24 This sequence results in the redox-separated (RS) state, shown in eq 3.…”

Section: Resultsmentioning

confidence: 99%

Effect of Surface Immobilization on Intramolecular and Intermolecular Electron Transfer in a Chromophore−Donor−Acceptor Assembly

2005

View full text Add to dashboard Cite

show abstract

“…This indicates that an intramolecular oxidation of the ligand L is much slower than intermolecular oxidation by strong oxidants present in solution under turnover conditions. The O 2 yield correlates to some extent with the lifetime of their excited states ( (17).…”

Section: Structure-activity Correlationmentioning

confidence: 99%

Bis(4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine)ruthenium(ii) complexes and their N-alkylated derivatives in catalytic light-driven water oxidation

Rudd

Zhuk

et al. 2013

RSC Adv.

View full text Add to dashboard Cite

Hydrogen sulfate salts of [Ru(1) 2 ] 2+ where 1 ¼ 4 0-(4-pyridyl)-2,2 0 :6 0 ,2 00-terpyridine and four N-alkylated derivatives [Ru(L) 2 ] 4+ were used as photosensitizers (l max $510 nm) for water oxidation in light driven reactions with peroxydisulfate as a sacrificial electron acceptor and Na 10 [Co 4 (H 2 O) 2 (a-PW 9 O 34) 2 ] (Co 4 POM) as the catalyst in sodium borate buffers at pH 8.0 and 9.0. The N-substituents investigated were benzyl (L + ¼ 2 +), ethyl (L + ¼ 3 +), allyl (L + ¼ 4 +) and 4-cyanobenzyl (L + ¼ 5 +). The O 2 yield in the presence of [Ru(L) 2 ] 4+ (L + ¼ 2 +-4 +) was comparable to that obtained in the presence [Ru(bpy) 3 ] 2+ (bpy ¼ 2,2 0bipyridine) using light sources with l max z 490 nm. The ruthenium(III) complexes [Ru(1) 2 ] 3+ and [Ru(L) 2 ] 5+ (L + ¼ 2 +-5 +) are rather unstable in acidic conditions and could not be isolated. The most efficient photosensitizers [Ru(L) 2 ] 5+ (L + ¼ 2 + and 4 +) were the least stable under weakly basic conditions (pH 9.0) with a half-life s 1/2 $ 10 ms. The stability of the complexes under photocatalytic turnover conditions is probably controlled by the rate at which ligand L + is oxidized by Co 4 POM in its highest oxidation state.

show abstract

“…The overall reaction is fast because of the close proximity of the reactants; a similar conclusion was reached by Mallouk et al for a related system that, however, was not part of a cyclophane. [10] [*] Dr. A. C. Benniston The triplet energy of the metal complex was determined to be about 1.90 eV from the low-temperature emission spectrum. The thermodynamic driving force [11] for light-induced reduction of the viologen subunits in acetonitrile was estimated as DG 0 %À 0.36 eV, which indicates that the reaction is likely to fall within the ªnormal Marcus regionº.…”

mentioning

confidence: 99%

Artificial Photosynthesis: Mimicking Redox Asymmetry

Benniston

Mackie

Harriman³

1998

Angewandte Chemie International Edition

View full text Add to dashboard Cite

Directional light-induced electron transfer takes place in the catenane shown schematically on the right. This catenane is similar to the photosynthetic reaction center: The two chemically identical electron acceptors (rectangles) bound to a ruthenium complex as donor have different reduction potentials because their environments are of different polarity. The electron transfer proceeds preferentially (85 %) to the external acceptor.

show abstract

Photoinduced electron transfer in covalently linked ruthenium tris(bipyridyl)-viologen molecules: observation of back electron transfer in the Marcus inverted region

Cited by 176 publications

References 1 publication

Effect of Surface Immobilization on Intramolecular and Intermolecular Electron Transfer in a Chromophore−Donor−Acceptor Assembly

Effect of Surface Immobilization on Intramolecular and Intermolecular Electron Transfer in a Chromophore−Donor−Acceptor Assembly

Bis(4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine)ruthenium(ii) complexes and their N-alkylated derivatives in catalytic light-driven water oxidation

Artificial Photosynthesis: Mimicking Redox Asymmetry

Contact Info

Product

Resources

About