Photoinduced Electron Transfer of Porphyrin Isomers: Impact of Molecular Structures on Electron‐Transfer Dynamics

Fujitsuka, Mamoru; Majima, Tetsuro

doi:10.1002/asia.201500649

Cited by 4 publications

(3 citation statements)

References 54 publications

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“…[2] Porphyrins have been commonlyu sed as photosensitizers for the construction of artificial photosynthetic systemsb ecause of their resemblance to the naturally occurring chlorophyll pigments. [3] However, other sensitizers, including phthalocyanines, [4] corroles, [5] subphthalocyanines, [6] bodipy, [7] and structural isomers of porphyrins [8] have also been exploited for this purpose. Furthermore, in recent work, molecular engineering has been applied in the preparation of elegant multi-modular donor-acceptor systems that are capable of wide-band capturea nd of generating the long sought after long-lived charge-separated states upon photoexcitation.…”

Section: Introductionmentioning

confidence: 99%

Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates

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Zieba

Webre

et al. 2015

Chemistry A European J

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An electron-deficient copper(III) corrole was utilized for the construction of donor-acceptor conjugates with zinc(II) porphyrin (ZnP) as a singlet excited state electron donor, and the occurrence of photoinduced charge separation was demonstrated by using transient pump-probe spectroscopic techniques. In these conjugates, the number of copper corrole units was varied from 1 to 2 or 4 units while maintaining a single ZnP entity to observe the effect of corrole multiplicity in facilitating the charge-separation process. The conjugates and control compounds were electrochemically and spectroelectrochemically characterized. Computational studies revealed ground state geometries of the compounds and the electron-deficient nature of the copper(III) corrole. An energy level diagram was established to predict the photochemical events by using optical, emission, electrochemical, and computational data. The occurrence of charge separation from singlet excited zinc porphyrin and charge recombination to yield directly the ground state species were evident from the diagram. Femtosecond transient absorption spectroscopy studies provided spectral evidence of charge separation in the form of the zinc porphyrin radical cation and copper(II) corrole species as products. Rates of charge separation in the conjugates were found to be of the order of 10(10) s(-1) and increased with increasing multiplicity of copper(III) corrole entities. The present study demonstrates the importance of copper(III) corrole as an electron acceptor in building model photosynthetic systems.

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Section: Introductionmentioning

confidence: 99%

Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates

Ngo

Zieba

Webre

et al. 2015

Chemistry A European J

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“…The relaxation process of photoexcited molecules when interacting with biomolecules is closely related to the phototoxicity, photocarcinogenesis, and effect of the photosensitizer for phototherapy. − In the case of photodynamic therapy (PDT), which is a less invasive treatment for cancer and other nonmalignant conditions, administered photosensitizers necessarily interact with biomacromolecules. ,− In general, a mechanism of PDT is the oxidation of biomacromolecules by singlet oxygen ( 1 O 2 ), which is generated through energy transfer from the excited photosensitizer to molecular oxygen. − Singlet oxygen is the lowest excited state of molecular oxygen and induces oxidation of various biomolecules, including DNA. − DNA is a potentially important target biomacromolecule for PDT, and DNA-targeting drugs have been studied. − Furthermore, DNA modification might be a fundamental process for manipulating genes by a photochemical reaction. The relaxation process of a photoexcited photosensitizer interacting with DNA can be utilized to control the activity of a photosensitizer.…”

Section: Introductionmentioning

confidence: 99%

Relaxation Process of Photoexcited meso-Naphthylporphyrins while Interacting with DNA and Singlet Oxygen Generation

2015

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Electron donor-connecting cationic porphyrins meso-(1-naphthyl)-tris(N-methyl-p-pyridinio)porphyrin (1-NapTMPyP) and meso-(2-naphthyl)-tris(N-methyl-p-pyridinio)porphyrin (2-NapTMPyP) were designed and synthesized. DFT calculations speculate that the photoexcited states of 1- and 2-NapTMPyPs can be deactivated via intramolecular electron transfer from the naphthyl moiety to the porphyrin moiety. However, the quenching effect through the intramolecular electron transfer is insufficient, possibly due to the orthogonal position of the electron donor and the porphyrin ring and the relatively small driving force: Gibbs energies are 0.11 and 0.07 eV for 1- and 2-NapTMPyPs, respectively. It was speculated that more than 0.3 eV of the driving force is required to realize effective electron transfer in similar electron-donor connecting porphyrin systems. These porphyrins aggregated around the DNA strand, accelerating the deactivation of their excited singlet state and decreasing their photosensitized singlet oxygen-generating activities. In the presence of a sufficiently large concentration of DNA, these porphyrins can bind to a DNA strand stably, leading to an increased fluorescence quantum yield and lifetime. Singlet oxygen generation was also suppressed by the aggregation of porphyrins around DNA. Although the quantum yield of singlet oxygen generation was recovered in the presence of sufficient DNA, the singlet oxygen generated by DNA-binding porphyrins was significantly smaller than that without DNA. These results suggest that DNA-binding drugs limit the generation of photosensitized singlet oxygen by quenching the DNA strand.

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“…Porphyrin constitutional isomers such as porphycene, hemiporphycene, and isoporphycene exhibit different properties from [18]porphyrin(1.1.1.1), so-called regular porphyrin (Figure ). These isomers have been employed as functional materials because of their unique features. For example, these materials have been used extensively in photodynamic therapy , and device materials .…”

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confidence: 99%

Synthesis and Properties of meso-Arylated Corrphycenes

Nozawa

Shinokubo

2017

Org. Lett.

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A novel synthetic procedure for meso-aryl-substituted corrphycenes has been developed. Suzuki-Miyaura coupling of α,α'-dibromodipyrrin with vic-diborylalkene and o-diborylbenzene afforded ethenylene- and phenylene-bridged bisdipyrrins, respectively, which were transformed to the corresponding corrphycenes upon treatment with palladium acetate. The bridging units significantly affect the macrocyclic π-conjugation circuits, thus changing the aromatic characters and absorption features of corrphycenes.

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Photoinduced Electron Transfer of Porphyrin Isomers: Impact of Molecular Structures on Electron‐Transfer Dynamics

Cited by 4 publications

References 54 publications

Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates

Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates

Relaxation Process of Photoexcited meso-Naphthylporphyrins while Interacting with DNA and Singlet Oxygen Generation

Synthesis and Properties of meso-Arylated Corrphycenes

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