Coupling of Metal-Based Light-Harvesting Antennas and Electron-Donor Subunits: Trinuclear Ruthenium(II) Complexes Containing Tetrathiafulvalene-Substituted Polypyridine Ligands

Campagna, Sebastiano; Serroni, Scolastica; Puntoriero, Fausto; Loiseau, Frédérique; Cola, Luisa De; Kleverlaan, Cornelis J.; Becher, Jan; Sørensen, Ane Ploug; Hascoat, Philippe; Thorup, Niels

doi:10.1002/1521-3765(20021004)8:19<4461::aid-chem4461>3.0.co;2-b

Cited by 64 publications

(34 citation statements)

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“…The increase of the amount and strength of base lead to complete deprotonation of the ligand and formation of complexes with higher nuclearity. The reactivity of H 4 L with M(OAc) 2 …”

Section: Resultsmentioning

confidence: 99%

“…The molecular structure of 1 was determined by single crystal X-ray diffraction (see below), which also provided crystallographic evidence for the identity of H 4 L. The analogous reaction with Ni(OAc) 2 15 One possible explanation is that this conformation maximized the energy gained through dipolar contacts within the ligand. This is no longer the case in the absence of the OH from the central phenol group, thus, in complex 3, the syn-syn conformation is restored.…”

Section: Resultsmentioning

confidence: 99%

“…This approach has become common practice in such wide contexts as bioinorganic modelling, 1 photochemistry, 2 or that of molecular devices. 3,4 In the area of molecular magnetism, however, this approach has only recently started to take hold.…”

Section: Introductionmentioning

confidence: 99%

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Complexes of a novel multinucleating poly-β-diketonate ligand

et al. 2004

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“…The increase of the amount and strength of base lead to complete deprotonation of the ligand and formation of complexes with higher nuclearity. The reactivity of H 4 L with M(OAc) 2 …”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Complexes of a novel multinucleating poly-β-diketonate ligand

et al. 2004

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“…[11] Usually the incorporation of tetrathiafulvalene derivatives into ruthenium(ii) complexes results in the above-mentioned intramolecular electron transfer quenching of the ruthenium complex based luminescence. [12] However, in the systems investigated to date, the resulting charge-separated states were not very long-lived, because the tetrathiafulvalene was linked flexibly to the …”

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confidence: 99%

Dual Luminescence and Long-Lived Charge-Separated States in Donor-Acceptor Assemblies Based on Tetrathiafulvalene-Fused Ruthenium(II)-Polypyridine Complexes

Leiggener¹,

Dupont²,

Liu³

et al. 2007

Chimia

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: The creation of long-lived charge-separated states in donor − acceptor assemblies has been the goal of many studies aimed at mimicking the primary processes in photosynthesis. Here we present such assemblies based on tetrathiafulvalene (TTF) as electron donor and a dipyridophenazine (dppz) unit as electron acceptor in the form of a fused ligand (TTF-dppz) coordinated to ruthenium(II) via the dipyrido coordination site and with 2,2'-bipyridine (bpy) as auxiliary ligand, namely [Ru(bpy) 3 − x (TTF-dppz) x ] 2+ (x = 1 − 3). For x = 2, irradiation into the metal to dppz charge transfer transition results in electron transfer from TTF to ruthenium, thus creating a charge-separated state best described by [(TTF + -dppz)Ru(dppz − -TTF)(bpy)] 2+ with a lifetime of 2.5 µ s in dichloromethane.Keywords: Charge-separated states ⋅ Intraligand charge transfer ⋅ Metal-ligand-charge-transfer ⋅ Ruthenium(II)-polypyridine complexes ⋅ Tetrathiafulvalene step is always given by the absorption of a photon, which promotes the chromophore to an electronically and often vibrationally excited state. This initially excited state is most often extremely short-lived, and the system decays via vibrational relaxation, internal conversion, intersystem crossing, luminescence, and energy and electron transfer back to the ground state or via some chemical reaction to a given photochemical product.A key issue of photophysics and photochemistry is the creation of long-lived charge-separated states using so-called donor − acceptor (DA) assemblies, in which the excitation of either the donor to D*A or the acceptor to DA* is followed by the transfer of an electron from D to A to form a state best described by D + A − . As an extension of the simple dyad, the donor and the acceptor may be linked by a photophysically active bridge to afford the triad DBA. In this case, the excitation of the bridge to DB*A results in double electron transfer, namely from the HOMO of D to the SOMO-1 of B* and from the SOMO of B* to the LUMO of A, thus forming a species of the form D + BA − , which in general has a longer lifetime of the charge-separated state than that in the corresponding dyad due to the weaker electronic coupling between D and A. Such triads, composed of tetrathiafulvalene, porphyrins and fullerenes have been successfully used in the creation of artificial photosynthetic systems. [6] Tertrathiafulvalene derivatives, on the one hand, constitute a class of versatile electron donors for a number of interesting applications, [7] in fields such as molecular electronics [8] and in organic conductors and superconductors. [9] Of particular interest in the context of this paper is that they are known to quench the luminescence of almost any chromophore in their vicinity through reductive electron transfer quenching. [10] Ruthenium(ii) polypyridine complexes, on the other hand, are known not only for the luminescence from metal-to-ligand-chargetransfer (MLCT) states but also for their use as sensitizers for light-induced electron transfer in solar ene...

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“…These complexes have very high absorption coefficients in the visible region, are chemically robust and are capable of either energy transfer to other sites or direct charge-separation upon photoexcitation. In particular, significant advances have been made in the use of such complexes in antenna assemblies (Treadway et al 1997;Hissler et al 1999;Campagna et al 2002;Armaroli 2003;McClenaghan et al 2003;Baranoff et al 2004;Johansson et al 2004)for efficient energy transfer to a specific site and in dyad or triad assemblies (Scandola et al 1992;Dupray et al 1997;Campagna et al 2002;Morales et al 2002; to maximize either the CS state lifetime or distance of charge separation or both.…”

Section: Introductionmentioning

confidence: 99%

Driving Multi-electron Reactions with Photons: Dinuclear Ruthenium Complexes Capable of Stepwise and Concerted Multi-electron Reduction

et al. 2006

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Using biological precedents, it is expected that concerted, multi-electron reduction processes will play a significant role in the development of efficient artificial photosynthetic systems. We have found that the dinuclear ruthenium complexes [(phen)(2)Ru(tatpp)Ru(phen)(2)](4+) (P) and [(phen)(2)Ru(tatpq) Ru(phen)(2)](4+) (Q) undergo photodriven 2- and 4-electron reductions, respectively, in the presence of a sacrificial reductant. Importantly, these processes are completely reversible upon exposure to air, and consequently, these complexes have the potential to be used catalytically in multi-electron transfer reactions. A localized molecular orbital description of the ligands and complexes is used to explain both the function and spectroscopy of these complexes. In both complexes, the reducing equivalents are stored in the pi* orbitals of the bridging ligands and depending on the solution pH, various protonation states of the reduced species of P and Q are obtained. Under basic conditions, the photochemical pathway favors sequential single-electron reductions, while neutral or slightly acidic conditions give rise to proton-coupled multi-electron transfer. In fact, at sufficiently acidic pH, only a coupled two-electron, 2-proton process is seen. Few molecular photocatalysts are capable of proton-coupled multi-electron transfer, which is believed to be a fundamental component of light-activated energy storage in nature.

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Coupling of Metal-Based Light-Harvesting Antennas and Electron-Donor Subunits: Trinuclear Ruthenium(II) Complexes Containing Tetrathiafulvalene-Substituted Polypyridine Ligands

Cited by 64 publications

References 9 publications

Complexes of a novel multinucleating poly-β-diketonate ligand

Complexes of a novel multinucleating poly-β-diketonate ligand

Dual Luminescence and Long-Lived Charge-Separated States in Donor-Acceptor Assemblies Based on Tetrathiafulvalene-Fused Ruthenium(II)-Polypyridine Complexes

Driving Multi-electron Reactions with Photons: Dinuclear Ruthenium Complexes Capable of Stepwise and Concerted Multi-electron Reduction

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