Intramolecular Energy Hopping and Energy Trapping in Polyphenylene Dendrimers with Multiple Peryleneimide Donor Chromophores and a Terryleneimide Acceptor Trap Chromophore

Maus, Michael; De, R.; Lor, Marc; Weil, Tania; Mitra, Sivaprasad; Wiesler, Uwe-M.; Herrmann, Andreas; Hofkens, Johan; Vosch, Tom; Müllen, Kläus; Schryver, F. C. De

doi:10.1021/ja010570e

Cited by 135 publications

(130 citation statements)

References 24 publications

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“…25,26 The nano-space around the core unit is utilized as a molecular-capsule for capturing metal ions, [27][28][29][30][31][32][33] clusters, [34][35][36][37][38][39][40][41][42] or other guest molecules. 43,44 The dendrimers can manage electron [45][46][47] or energy [48][49][50][51][52][53][54][55][56][57][58] transfer between the core and the periphery due to their unique density-gradated architecture.…”

Section: Metallo-dendrimer Complexesmentioning

confidence: 99%

Dendrimer Complexes Based on Fine-Controlled Metal Assembling

Yamamoto¹,

Imaoka²

2006

Bulletin of the Chemical Society of Japan

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A series of novel dendrimers composed of dendritic phenylazomethines (DPAs) were synthesized with several types of functional cores. The metal assembling to the DPAs is stepwise by the layers, therefore, they can be used as a scaffold for the precise hybridization between metal ions and organic macromolecules. Because of uniform structure of the dendrimer, there is no structural dispersion in the macromolecule-metal hybrid of the DPAs. Also, the number of metal ions loaded in one dendrimer should have no statistical distribution in principle due to the precise metal assembling. A rigid -conjugating backbone structure contributes not only to the stepwise metal assembly, but also to the solid-state stability under high temperature. Development of this property without any reduction in solubility in organic media enabled the easy preparation of homogeneous amorphous films in which the metal and macromolecule are precisely hybridized. As a result, the thin solid of the metal-assembling dendrimer acts as an excellent organic semiconductor in the hole-transport layer of a light-emitting diode. Metal-assembling DPAs also enhance the electron-transfer reaction as a protein-like catalyst. The DPA having a cobalt porphyrin core-could catalyze the CO 2 reduction at an applied overpotential 1.1 V lower than that needed for the catalysis by a model compound of the porphyrin core (CoTPP). Reversible encapsulation/release of multiple irons is also demonstrated as a mimic of the iron storage protein (Ferritin). The switching between these two coordinating states can be completely controlled by the redox states of the iron (Fe II / Fe III ). The finding of these unique dendritic ligands will afford new insight into molecular design for finely controlled macromolecule-metal hybrid materials. Metallo-Dendrimer ComplexesMacromolecule-metal complexes 1 are defined as molecularlevel hybrids built up with metal complexes and organic polymers. They have been noted in evolution of novel functions based on synergetic effect between the functionality of each part (metal and polymer). For example, applications of these materials for fixation of catalysts, 2 functional modified electrodes based on electron [3][4][5] /ion 6 conductivity, electron-spin control, 7 and amplification of photoelectron conjugating properties 8 demonstrate outstanding enhancement. Most of them are induced by (1) supporter effect, (2) concentration/dilution effect, (3) environmental effect, (4) conformational effect, and (5) cooperative/concerted effect by micro domains in the polymers. For maximum use of these domains, a general methodology that can handle the higher-order structure of the hybrids is strongly required. All the molecular, hybrid, and higher-order structures of the conventional macromolecule-metal complexes are however dispersed with statistical distribution, and impossible to fix themselves into one limited form. Now many research interest moved to the next stage focusing on the control of higher-order structures using self-assembling approach based...

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Section: Metallo-dendrimer Complexesmentioning

confidence: 99%

Dendrimer Complexes Based on Fine-Controlled Metal Assembling

Yamamoto¹,

Imaoka²

2006

Bulletin of the Chemical Society of Japan

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“…The discrepancy may be partly attributed to the fact that we implicitly assumed the relation ÿ1 f k rad to hold. The fluorescence yield f of the PM monomer, however, was reported [19] to be smaller than 1 ( f 0:95) and may be slightly different for the dimer and the monomer. Quenching of the monomer by the final bleaching product [11] seems to be highly unlikely because for PM in solution we find f 4:4 ns which is similar to the value found after the first chromophore bleached (Fig.…”

mentioning

confidence: 94%

“…2, however, the type II spectrum is due to emission from a localized state within an intact dimer where coherent coupling has been lifted by static disorder. The two proximate PM chromophores will now communicate by incoherent Förster-type energy hopping [19] (weak coupling) eventually giving rise to emission from a single chromophoric site.…”

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confidence: 99%

Coherent Electronic Coupling versus Localization in Individual Molecular Dimers

et al. 2004

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“…for the T 1 3 T n transition (11,12,14,20,21). Using an orientation factor ( 2 ) of 4 for perfectly parallel dipoles of the chromophores gives R 0 values of 5.4, 5.9, and 8.7 nm for energy hopping, S-S annihilation, and S-T ET, respec- tively.…”

mentioning

confidence: 99%

Revealing competitive Förster-type resonance energy-transfer pathways in single bichromophoric molecules

Hofkens

Cotlet

Vosch

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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T he current renaissance of the use of the fluorescence resonance energy-transfer (FRET) (1) process between two weakly coupled dipoles, one acting as donor and the other acting as acceptor, results from various elegant and successful studies of distance changes in individual biomolecules by using singlemolecule spectroscopy (SMS). This type of study is often referred to as single-pair Förster resonance ET (2-4). Recent advances in fluctuation microscopy allow the observation of changes in the ET efficiency in single-pair Förster resonance ET systems at the millisecond-to-nanosecond time scale (5, 6). It has been suggested that, in the latter time scale, thermally excited conformational dynamics of (bio)macromolecules will become accessible (5). Thus far, FRET measurements at these time scales have overlooked competitive Förster-type ET pathways, which might complicate data analysis and interpretation of the FRET data. The FRET process involves nonradiative transfer from a donor to an acceptor. For molecules within the weak coupling limit, Förster derived an expression for the rate constant of dipole-dipole-induced ET (7). This relation shows that the ET efficiency scales with the sixth power of the distance between the chromophores:Here, R 0 is the distance at which the efficiency equals 50%, i.e., the distance at which an equal probability exists for the excited chromophore to relax to the ground state via emission of a photon or to undergo ET. It includes the spectral properties and the relative orientation (in terms of the orientation factor 2 ) of donor and acceptor transition dipoles. If the distances and orientations of the chromophores are kept constant, the ET efficiency is determined by the spectral overlap of the corresponding transitions, i.e., the overlap of the emission spectrum of the donor and the absorption spectrum of the acceptor. Therefore, FRET can also occur between identical molecules if the Stokes shift is small enough to allow for a sufficient overlap of the emission and absorption spectrum of the chromophores. This so-called homo-transfer or energy hopping represents a key mechanism for energy transport in some light-harvesting complexes (8).However, Förster-type resonance ET is not restricted to the nonradiative transfer of energy from a donor in the excited state to a ground-state acceptor. Transfer processes that are allowed within the Förster formalism are those for which there are no changes in electron spin in the acceptor transition. Therefore, even ET processes between donor and acceptor molecules with different spin multiplicity likewise are possible. Hence, the transfer of excitation energy from a chromophore residing in the first excited singlet (S) state to another chromophore residing either in the triplet (T) or in an excited singlet state are possible and competitive ET pathways.In the present contribution, we demonstrate that, because of the specific excitation conditions that are applied in SMS, indeed several Förster-type ET pathways are prevalent in single bichromopho...

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Intramolecular Energy Hopping and Energy Trapping in Polyphenylene Dendrimers with Multiple Peryleneimide Donor Chromophores and a Terryleneimide Acceptor Trap Chromophore

Cited by 135 publications

References 24 publications

Dendrimer Complexes Based on Fine-Controlled Metal Assembling

Dendrimer Complexes Based on Fine-Controlled Metal Assembling

Coherent Electronic Coupling versus Localization in Individual Molecular Dimers

Revealing competitive Förster-type resonance energy-transfer pathways in single bichromophoric molecules

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