Synthesis of a macrocyclic porphyrin hexamer with a nanometer-sized cavity as a model for the light-harvesting arrays of purple bacteria

Mongin, Olivier; Schuwey, Anne; Vallot, Marie-Alix; Gossauer, Albert

doi:10.1016/s0040-4039(99)01787-6

Cited by 82 publications

(42 citation statements)

References 19 publications

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“…Since the transfer of singlet excited-state energy in 4b takes place, to some extent, by intramolecular throughbond interactions (Dexter mechanism), which is not operative in the natural light-harvesting arrays, comparison of the electronic energy-transfer dynamics in the niphaphyrins described here with that in circular porphyrin hexamers, the synthesis of which has recently been achieved in our laboratory, [24] provides a sound basis for further studies of energy transfer within chromophores, the spatial arrangement of which mimics the light-harvesting arrangement in purple bacteria and other photosynthetic organisms.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Light-Harvesting Properties of Niphaphyrins

Mongin

Hoyler

Gossauer³

2000

Eur. J. Org. Chem.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Light-Harvesting Properties of Niphaphyrins

Mongin

Hoyler

Gossauer³

2000

Eur. J. Org. Chem.

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“…The wheel-like and spherical structures of multiporphyrin and dendrimer arrays provide a scaffold for attaining directional energy transfer, allowing excitation energy to cascade efficiently from the periphery to the core. Furthermore, the highly branched nature of dendrimers and multiporphyrin wheels allows coupling of more than one donor moiety per acceptor moiety that can be used to increase the molar absorptivity (52,(75)(76)(77)(78). Building blocks for these structures have included transition metal complexes (ML n ), metal-free and metalchelated porphyrin groups, and various other conjugated photoactive units (20,42,52,76,77,79).…”

Section: Opportunities For Nanotechnology: Synthetic and Biomimetic Amentioning

confidence: 99%

Approaches for biological and biomimetic energy conversion

LaVan

Jennifer²

2006

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

116

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This article highlights areas of research at the interface of nanotechnology, the physical sciences, and biology that are related to energy conversion: specifically, those related to photovoltaic applications. Although much ongoing work is seeking to understand basic processes of photosynthesis and chemical conversion, such as light harvesting, electron transfer, and ion transport, application of this knowledge to the development of fully synthetic and͞or hybrid devices is still in its infancy. To develop systems that produce energy in an efficient manner, it is important both to understand the biological mechanisms of energy flow for optimization of primary structure and to appreciate the roles of architecture and assembly. Whether devices are completely synthetic and mimic biological processes or devices use natural biomolecules, much of the research for future power systems will happen at the intersection of disciplines.biotechnology ͉ nanotechnology ͉ photosynthesis ͉ photovoltaic R ecently, the National Academies and the Keck Foundation held a meeting to discuss the development of new applications for nanotechnology ¶ with the goal of identifying challenges where the convergence of nanoscience and physical and biosciences could provide a revolutionary outcome. One area clearly in need of new technologies is biological and biomimetic methods of energy conversion. Within this broad area, focus was given to two specific applications: the conversion of solar energy into useful electrical or chemical energy and the production of power for in vivo medical devices. The following sections will provide both an economic perspective on current photovoltaic (PV) technology and an overview of the various research efforts toward using or mimicking biological systems to improve current and future energy-conversion systems.

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“…Both the Zn II porphyrin 41´Zn and the free-base porphyrin 41´2 H were cross-coupled to 3-iodobenzamide [34] or PhBr in good yields. With the Zn II derivative, no transmetallation [35] was observed during formation of 42´Zn and 43´Zn under regular Sonogashira coupling conditions (Pd 0 , CuI, base) [36]. The coupling of the freebase porphyrin 41´2 H to give 42´2 H was successfully accomplished according to the CuI-free [33] (4,5,6); numbering as for 44) and, notably, at 4.14 ppm (HÀC(2)).…”

Section: Hand 13mentioning

confidence: 99%

Synthesis of Dendritic Metalloporphyrins with Distal H‐Bond Donors as Model Systems for Hemoglobin

Felber

Diederich

2005

Helvetica Chimica Acta

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We report the synthesis of the first-(G1) and second-generation (G2) dendritic Fe II porphyrins 1´Fe ± 4´Fe (G1) and 6´Fe (G2) bearing distal H-bond donors ideally positioned for stabilization of Fe II ÀO 2 adducts by Hbonding (Fig. 1). A first approach towards the construction of these novel biomimetic systems failed unexpectedly: the Suzuki cross-coupling between appropriately functionalized Zn II porphyrins and orthoethynylated aryl derivatives, serving as anchors for the distal H-bond donor moieties, was unsuccessful (Schemes 1, 3, and 5), presumably due to steric hindrance resulting from unfavorable coordination of the ethynyl residue to the Pd species in the catalytic cycle (Scheme 6). The target molecules were finally prepared by a route in which the ortho-ethynylated meso-aryl ring is introduced during porphyrin construction in a mixed condensation involving the two dipyrrylmethanes 33 and 34, and aldehyde 36 (Schemes 7 and 8). Following attachment of the dendrons (Scheme 11), the distal H-bond donors were introduced by Sonogashira crosscoupling (Scheme 12), and subsequent metallation afforded the dendritic Fe II porphyrins 1´Fe ± 6´Fe. 1 H-NMR Spectroscopy proved the location of the H-bond donor moiety atop the porphyrin surface, and X-ray crystalstructure analysis of model system 45 (Fig. 2) revealed that this moiety would not sterically interfere with gas binding. With 1,2-dimethyl-1H-imidazole (DiMeIm) as ligand, the dendritic Fe II porphyrins formed fivecoordinate high-spin complexes (Figs. 3 and 4) and addition of CO led reversibly to the corresponding stable sixcoordinate gas complexes (Fig. 6). Oxygenation, however, did not result in defined Fe II ÀO 2 complexes as rapid decomposition to Fe III species took place immediately, even in the case of the G2 dendrimer 6´Fe(DiMeIm) (Fig. 7). In contrast, stable gas adducts are formed between dendritic Co II porphyrins and O 2 in the presence of DiMeIm as axial ligand, as revealed by electron paramagnetic resonance (EPR). The possible stabilization of these complexes through H-bonding involving the distal ligand is currently under investigation in multidimensional and multifrequency pulse EPR experiments.

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Synthesis of a macrocyclic porphyrin hexamer with a nanometer-sized cavity as a model for the light-harvesting arrays of purple bacteria

Cited by 82 publications

References 19 publications

Synthesis and Light-Harvesting Properties of Niphaphyrins

Synthesis and Light-Harvesting Properties of Niphaphyrins

Approaches for biological and biomimetic energy conversion

Synthesis of Dendritic Metalloporphyrins with Distal H‐Bond Donors as Model Systems for Hemoglobin

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