Energy transfer and distance independent charge separation in self-organised porphyrin-quinone aggregates

Rempel, U.; Meyer, Stephan; Maltzan, B. von; Borczyskowski, C. von

doi:10.1016/s0022-2313(97)00310-4

Cited by 24 publications

(24 citation statements)

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“…Steady-state absorption spectra of the triads are essentially a linear combination of the dipyridinated dimer (ZnOEP) 2 Ph, extra-ligand and A [8,9]. Thus, the interaction between the corresponding subunits is weak in the ground state, and they retain their individual identities.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the interaction between the corresponding subunits is weak in the ground state, and they retain their individual identities. Fluorescence spectra of A-containing triads consist of the extra-ligand uorescence bands and are characterised by the substantial quenching of the dimer (ZnOEP) 2 Ph emission [9]. It means that the initial uorescence of the A-containing dimers (ZnOEP) 2 Ph-Q or (ZnOEP) 2 Ph-Pim being strongly quenched due to ET process dimer→A [9,10], does show a remarkable additional quenching upon the triad formation (toluene, 293 K).…”

Section: Resultsmentioning

confidence: 99%

“…Fluorescence spectra of A-containing triads consist of the extra-ligand uorescence bands and are characterised by the substantial quenching of the dimer (ZnOEP) 2 Ph emission [9]. It means that the initial uorescence of the A-containing dimers (ZnOEP) 2 Ph-Q or (ZnOEP) 2 Ph-Pim being strongly quenched due to ET process dimer→A [9,10], does show a remarkable additional quenching upon the triad formation (toluene, 293 K). The second feature of the A-containing triads is that the uorescence quantum e ciency of complexed extra-ligands is smaller essentially with respect to that found for the same extra-ligands in the triads without A's.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, (k 5 + k 6 )k 9 , and the direct one-step ET process (i) is low probable with respect to processes (ii) and (iii). In addition, (k 5 + k 6 )k 1 = 1= 0 S = 1=1:15 ns = 8:7 × 10 8 s −1 , thus no detectable uorescence of the dimer (ZnOEP) 2 Ph is observed in the triads.…”

Section: A)mentioning

confidence: 97%

“…Apart from covalent linking the desired subunits the non-covalent self-assembly of various kinds has attracted a lot of interest [7]. In this relation, using the complexation of Zn-porphyrin chemical dimers by pyridyl-substituted tetrapyrrole extra-ligands (via two-point extra-coordination) we have succeeded to form self-organised nanosized multimolecular tetrapyrrole assemblies in solutions and ÿlms [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Zenkevich

Шульга

Borczyskowski

2002

Physica E: Low-dimensional Systems and Nanostructures

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Well-deÿned structurally organised porphyrin triads of a controlled geometry and nanoscale size have been formed in liquid solutions using the combination of a covalent approach and non-covalent self-assembly. The triads contain zinc-octaethylporphyrin chemical dimer, (ZnOEP)2Ph, with covalently linked electron acceptors (p-benzoquinone, Q or pyromellitimide, Pim), and additional dipyridyl-substituted tetrapyrrole extra-ligands. Steady-state, picosecond uorescence ( t 1=2 ≈ 75 ps) and femtosecond pump-probe ( 1=2 ≈ 280 fs) data show that non-radiative deactivation of the dimer S1-states ( S ¡ 1 ps) is due to both the S-S energy transfer (ZnOEP)2Ph→extra-ligand and the sequential photoinduced electron transfer (ZnOEP)2Ph→Q (or Pim) at rDA = 10:8 A. The additional decay shortening of the extra-ligand S1-states by 3-6 times (toluene, 293 K) is attributed to the increased "superexchange" mediated long distant (rDA ≈ 18-21 A) one-step electron transfer extra-ligand→Q (or Pim). ?

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: A)mentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Zenkevich

Шульга

Borczyskowski

2002

Physica E: Low-dimensional Systems and Nanostructures

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Exploring the Supramolecular Coordination Chemistry‐Based Approach for Nanotechnology

Toma

Araki

2009

Progress in Inorganic Chemistry

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Highly Coupled Heterobicycle‐Fused Porphyrin Dimers: Excitonic Coupling and Charge Separation with Coordinated Fullerene, C₆₀

et al. 2023

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Porphyrin dimers have been widely explored and studied owing to their importance in photosynthetic systems. A vast variety of dimers linked by different groups and at different angles have been synthesized and studied; however, the means by which to synthesize rigidly fused porphyrins with direct conjugation of the chromophores remains limited. Such a class of porphyrins may possess interesting properties that unconjugated or stacked dimers may not exhibit. In this study, bisbenzimidazolefused porphyrin dimers and their mono-and bisÀ zinc derivatives are synthesized and characterized. As a consequence of excitonic coupling, these dimers exhibit a split Soret band irrespective of the metal ion in the porphyrin cavity. Steadystate fluorescence and excitation spectra followed by femtosecond transient absorption spectral studies of the heterometallated dimer, (free-base and zinc porphyrin) reveals the occur-rence of efficient singlet-singlet energy transfer (> 95 % efficiency and rate constant > 10 12 s À 1 ) within the dyad. Further, donor-acceptor conjugates were formed by metal-ligand axial coordination of phenyl imidazole functionalized C 60 and were characterized by a variety of physicochemical techniques. Excited state charge separation from both singlet and triplet excited states of ZnP in the conjugates has been established. The lifetime of the final charge-separated state was in the 30-40 μs range revealing charge stabilization. Interestingly, no charge separation in the conjugate derived from the heterometallated dimer was observed wherein excitation transfer dominated the process. The present study brings out the importance of the rigid π-spacer connecting porphyrin dimers in governing the energy and electron transfer events when coupled with an electron acceptor.

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Energy transfer and distance independent charge separation in self-organised porphyrin-quinone aggregates

Cited by 24 publications

References 24 publications

Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Exploring the Supramolecular Coordination Chemistry‐Based Approach for Nanotechnology

Highly Coupled Heterobicycle‐Fused Porphyrin Dimers: Excitonic Coupling and Charge Separation with Coordinated Fullerene, C₆₀

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Energy transfer and distance independent charge separation in self-organised porphyrin-quinone aggregates

Cited by 24 publications

References 24 publications

Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Multistep photoinduced electron transfer in self-organised nanoscale porphyrin triads

Exploring the Supramolecular Coordination Chemistry‐Based Approach for Nanotechnology

Highly Coupled Heterobicycle‐Fused Porphyrin Dimers: Excitonic Coupling and Charge Separation with Coordinated Fullerene, C60

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About

Highly Coupled Heterobicycle‐Fused Porphyrin Dimers: Excitonic Coupling and Charge Separation with Coordinated Fullerene, C₆₀