Porphyrin–Phthalocyanine/Pyridylfullerene Supramolecular Assemblies

Pereira, Ana; Hausmann, Anita; Tomé, João P. C.; Trukhina, Olga; Urbani, Maxence; Neves, Maria G. P. M. S.; Cavaleiro, José A. S.; Guldi, Dirk M.; Torres, Tomás

doi:10.1002/chem.201103776

Cited by 45 publications

(15 citation statements)

References 83 publications

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“…The 1 ZnPc* formed decayed with a lifetime of 0.94 ns in DCB. The time constants recorded for excitation energy transfer for the present triad were similar to that reported earlier by Pereira et al [23] and us [24] on porphyrin-phthalocyanine dyads using up conversion and femtosecond-transient measurements.…”

Section: Electrochemistry and Energy-level Diagramsupporting

confidence: 89%

Supramolecular Tetrad Featuring Covalently Linked Bis(porphyrin)–Phthalocyanine Coordinated to Fullerene: Construction and Photochemical Studies

Lim

Karr

et al. 2014

Chemistry A European J

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A multimodular donor-acceptor tetrad featuring a bis(zinc porphyrin)-(zinc phthalocyanine) ((ZnP-ZnP)-ZnPc) triad and bis-pyridine-functionalized fullerene was assembled by a "two-point" binding strategy, and investigated as a charge-separating photosynthetic antenna-reaction center mimic. The spectral and computational studies suggested that the mode of binding of the bis-pyridine-functionalized fullerene involves either one of the zinc porphyrin and zinc phthalocyanine (Pc) entities of the triad or both zinc porphyrin entities leaving ZnPc unbound. The binding constant evaluated by constructing a Benesi-Hildebrand plot by using the optical data was found to be 1.17×10(5) M(-1), whereas a plot of "mole-ratio" method revealed a 1:1 stoichiometry for the supramolecular tetrad. The mode of binding was further supported by differential pulse voltammetry studies, in which redox modulation of both zinc porphyrin and zinc phthalocyanine entities was observed. The geometry of the tetrad was deduced by B3LYP/6-31G* optimization, whereas the energy levels for different photochemical events was established by using data from the optical absorption and emission, and electrochemical studies. Excitation of the zinc porphyrin entity of the triad and tetrad revealed ultrafast singlet-singlet energy transfer to the appended zinc phthalocyanine. The estimated rate of energy transfer (k(ENT)) in the case of the triad was found to be 7.5×10(11) s(-1) in toluene and 6.3×10(11) s(-1) in o-dichlorobenzene, respectively. As was predicted from the energy levels, photoinduced electron transfer from the energy-transfer product, that is, singlet-excited zinc phthalocyanine to fullerene was verified from the femtosecond-transient spectral studies, both in o-dichlorobenzene and toluene. Transient bands corresponding to ZnPc(⋅+) in the 850 nm range and C60(⋅-) in the 1020 nm range were clearly observed. The rate of charge separation, k(CS), and rate of charge recombination, k(CR), for the (ZnP-ZnP)-ZnPc(⋅+):Py2C60(⋅-) radical ion pair (from the time profile of 849 nm peak) were found to be 2.20×10(11) and 6.10×10(8) s(-1) in toluene, and 6.82×10(11) and 1.20×10(9) s(-1) in o-dichlorobenzene, respectively. These results revealed efficient energy transfer followed by charge separation in the newly assembled supramolecular tetrad.

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Section: Electrochemistry and Energy-level Diagramsupporting

confidence: 89%

Supramolecular Tetrad Featuring Covalently Linked Bis(porphyrin)–Phthalocyanine Coordinated to Fullerene: Construction and Photochemical Studies

Lim

Karr

et al. 2014

Chemistry A European J

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“…To tune the supramolecular interactions between electron donors and acceptors we opted for ar ecognition motif that relies on the well-known complexation of pyridyl functionalities by ZnPc. [25,26] From titration assays with several electron acceptors-namely,p erylenebisimides (PDI) and fullerenes (C 60 ), to which pyridyl groups are covalently appended-the association constantsw ere determined. Transient-absorptions pectroscopy was employed to corroborate formation of the corresponding charge-separated states.…”

Section: Introductionmentioning

confidence: 99%

“…Considering that the former is prone to coordinate alkali ions, potassium ions lead to the formation of ZnPc TeCr monomers, whereas the presence of rubidium ions leads to ZnPc TeCr dimers. To tune the supramolecular interactions between electron donors and acceptors we opted for a recognition motif that relies on the well‐known complexation of pyridyl functionalities by ZnPc 25. 26 From titration assays with several electron acceptors—namely, perylenebisimides (PDI) and fullerenes (C 60 ), to which pyridyl groups are covalently appended—the association constants were determined.…”

Section: Introductionmentioning

confidence: 99%

Tuning Electron Donor–Acceptor Hybrids by Alkali Metal Complexation

Lederer

Hahn

Fernández-Ariza

et al. 2015

Chemistry A European J

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A zinc phthalocyanine endowed with four [18]-crown-6 moieties, ZnPcTeCr, has been prepared and self-assembled with either pyridyl-functionalized perylenebisimides (PDI-Py) or fullerenes (C60-Py) to afford a set of novel electron donor-acceptor hybrids. In the case of ZnPcTeCr, aggregation has been circumvented by the addition of potassium or rubidium ions to lead to the formation of monomers and cofacial dimers, respectively. From fluorescence titration experiments, which gave rise to mutual interactions between the electron donors and the acceptors in the excited state, the association constants of the respective ZnPcTeCr monomers and/or dimers with the corresponding electron acceptors were derived. Complementary transient-absorption experiments not only corroborated photoinduced electron transfer from ZnPcTeCr to either PDI-Py or C60-Py within the electron donor-acceptor hybrids, but also the unexpected photoinduced electron transfer within ZnPcTeCr dimers. In the electron donor-acceptor hybrids, the charge-separated-state lifetimes were elucidated to be close to 337 ps and 3.4 ns for the two PDI-Pys, whereas the longest lifetime for the photoactive system that contains C60-Py was calculated to be approximately 5.1 ns.

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“…If Pcs are modified with suitable special ligands, such as 8-hydroxy quinoline-5-sulfonic acid in a or b positions, it could be induced to disaggregate by their bulky structure and, therefore, major changes carry out in their optical properties. Controlling the aggregation is thought to be crucially important [30,31].…”

Section: Introductionmentioning

confidence: 99%