Triplet−Triplet Intramolecular Energy Transfer in a Covalently Linked Copper(II) Porphyrin−Free Base Porphyrin Hybrid Dimer:  A Time-Resolved ESR Study

1997 ◽  
Vol 101 (25) ◽  
pp. 4484-4490 ◽  
Author(s):  
Motoko Asano-Someda ◽  
Takatoshi Ichino ◽  
Youkoh Kaizu
Keyword(s):  
Energy Transfer ◽  
Intramolecular Energy Transfer ◽  
Free Base ◽  
Time Resolved ◽  
Covalently Linked

Intramolecular Energy Transfer in a Covalently Linked Copper(II) Porphyrin−Free Base Porphyrin Dimer:  Novel Spin Polarization in the Energy Acceptor

1999 ◽  
Vol 103 (34) ◽  
pp. 6704-6714 ◽  
Author(s):  
Motoko Asano-Someda ◽  
Art van der Est ◽  
Uwe Krüger ◽  
Dietmar Stehlik ◽  
Youkoh Kaizu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Spin Polarization ◽  
Intramolecular Energy Transfer ◽  
Free Base ◽  
Covalently Linked ◽  
Porphyrin Dimer ◽  
Energy Acceptor

Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer

2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Energy Transfer ◽  
Photophysical Properties ◽  
Fluorescence Decay ◽  
High Yield ◽  
Free Base ◽  
Time Resolved ◽  
Zinc Porphyrin ◽  
Relative Contribution ◽  
Synthetic Strategy ◽  
Decay Times

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.

Photoinduced intramolecular energy transfer in covalently linked chromophore-quencher ruthenium(II) complexes

1991 ◽  
Vol 180 (1-2) ◽  
pp. 28-33 ◽  
Author(s):  
Gaetano Giuffrida ◽  
Giovanni Guglielmo ◽  
Vittorio Ricevuto ◽  
Sebastiano Campagna
Keyword(s):  
Energy Transfer ◽  
Intramolecular Energy Transfer ◽  
Covalently Linked

Polypeptides with pendant porphyrins of defined sequence of chromophores: towards artificial photosynthetic systems

2008 ◽  
Vol 12 (12) ◽  
pp. 1232-1241 ◽  
Author(s):  
Farid Aziat ◽  
Régis Rein ◽  
Jorge Peón ◽  
Ernesto Rivera ◽  
Nathalie Solladié
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Amino Acid ◽  
Fluorescence Spectroscopy ◽  
Photophysical Properties ◽  
Free Base ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Absorption And Fluorescence Spectroscopy ◽  
Artificial Photosynthetic

In this paper we now report our ongoing progress in the preparation of artificial photosynthetic systems through the preparation of light harvesting multi-porphyrins. A tetramer, constituted of a central dipeptide functionalized by two free-base porphyrins and surrounded by one amino-acid bearing a pendant Zn ( II ) porphyrin on each side, has been chosen. The optical and photophysical properties of this tetramer have been studied by absorption and fluorescence spectroscopy. In addition, the energy transfer phenomenon has been studied and monitored by femtosecond time-resolved fluorescence. Our results indicate that the excited state dynamics redounding in the excitation being localized in the inner free-base porphyrins takes place in the time scale of approximately 1 ps.

Intramolecular Energy Transfer in Molecular Dyads Comprising Free-base Porphyrin and Ruthenium(II) Bis(2,2‘:6‘,2‘ ‘-terpyridine) Termini

2004 ◽  
Vol 108 (42) ◽  
pp. 9026-9036 ◽  
Author(s):  
Andrew C. Benniston ◽  
Glen M. Chapman ◽  
Anthony Harriman ◽  
Maryam Mehrabi
Keyword(s):  
Energy Transfer ◽  
Intramolecular Energy Transfer ◽  
Free Base ◽  
Molecular Dyads

Energy Transfer in a Supramolecular Complex Assembled via Sapphyrin Dimer-mediated Dicarboxylate Anion Chelation

1998 ◽  
Vol 02 (04) ◽  
pp. 315-325 ◽  
Author(s):  
STACY L. SPRINGS ◽  
ANDREI ANDRIEVSKY ◽  
VLADINÍR KRÁL ◽  
JONATHAN L. SESSLER
Keyword(s):  
Energy Transfer ◽  
Fluoride Anion ◽  
Free Base ◽  
Light Harvesting Complex ◽  
Fluorescence Studies ◽  
H Nmr ◽  
Steady State Fluorescence ◽  
Spectroscopic Analyses ◽  
Affinity Constants ◽  
Covalently Linked

The synthesis of a new terephthalate-strapped porphyrin is described. This porphyrin, prepared in the form of the free base and corresponding zinc(II) complex, was designed to act as the photo-donor portion of a novel, non-covalent artificial light-harvesting complex, the other, acceptor component of which is comprised of a covalently linked sapphyrin dimer. UV-vis and 1 H NMR spectroscopic analyses were used to establish that strong complexes are formed between the porphyrin terephthalate and sapphyrin dimer components (affinity constants on the order of 105 M−1 in dichloromethane). In these complexes the dicarboxylate portion of the strapped porphyrin is sandwiched between two sapphyrins of an individual dimer. Steady state fluorescence studies of the resulting ensembles support the conclusion that, upon photoexcitation of the porphyrin subunit, energy transfer from the porphyrin to the sapphyrin dimer occurs efficiently. This intra-ensemble, anion-chelation-based energy transfer can be inhibited by the addition of fluoride anion.

Decoupling the artificial special pair to slow down the rate of singlet energy transfer

2012 ◽  
Vol 16 (05n06) ◽  
pp. 685-694 ◽  
Author(s):  
Pierre D. Harvey ◽  
Adam Langlois ◽  
Mikhail Filatov ◽  
Daniel Fortin ◽  
Kei Ohkubo ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Transient Absorption ◽  
Geometry Optimization ◽  
Transient Absorption Spectroscopy ◽  
Free Base ◽  
Functional Theory ◽  
Time Resolved ◽  
Slow Rise

Trimer 2, composed of a cofacial heterobismacrocycle, octamethyl-porphyrin zinc(II) and bisarylporphyrin zinc(II) held by an anthracenyl spacer, and a flanking acceptor, bisarylporphyrin free-base ( Ar = -3,5-(t Bu )2 C 6 H 3), has been studied by means of absorption spectroscopy, "steady state and time-resolved fluorescence" and fs transient absorption spectroscopy, and density functional theory (DFT) in order to assess the effect of decoupling the chromophores' low energy MOs on the rate of the singlet, S1, energy transfer, k ET , compared to a recently reported work on a heavily coupled trimeric system, Trimer 1, [biphenylenebis(n-nonyl)porphyrin zinc(II)]-bisarylporphyrin free-base ( Ar = -3,5-(t Bu )2 C 6 H 3). The position of the 0–0 peaks of the absorption and fluorescence spectra of Trimer 2 indicates that these porphyrin units are respectively energy donor 1, donor 2, and acceptor. The DFT computations confirm that the MOs of the cofacial donor 1-donor 2 dyad are decoupled, but significant MO coupling between donor 2 and acceptor 1 is still present despite the strong dihedral angle between their respective average planes (77.5°: geometry optimization by DFT). The fs transient absorption spectra exhibit a clear S1–Sn fingerprint of the bisarylporphyrin zinc(II) chromophore and the kinetic trace exhibits a slow rise time of 87 ps, due to a S1 donor 1 → donor 2 ET. The transient species donor 2 and acceptor decay respectively in the short (~1.5) ns and 6 ns time scale.

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