Self-aggregation of synthetic zinc 21-hydroxy-121/131-oxo-porphyrins

Tamiaki, Hitoshi; Kimura, Satoshi; Kimura, Tadashi

doi:10.1016/s0040-4020(03)01128-1

Cited by 55 publications

(42 citation statements)

References 32 publications

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“…Two zinc porphyrins possessing an OH and a C=O group at the 3/13-and 3/12-positions, respectively, have been investigated previously. [36] The former possesses a linear order of the chlorosomal moieties and self-aggregates, whereas the latter is bent slightly and forms no self-aggregates. The presence of a 13-C=O moiety in chlorosomal chlorin is therefore significant for such selfaggregation, and the orientation of this C=O moiety is also important for the formation of strong intermolecular interactions.…”

Section: Oligomeric States Of Zinc Chlorins 1-3: the 13-methoxycarbonmentioning

confidence: 99%

“…), [24] and a C=O moiety (vide supra), and their linear situation along the Qy axis in a molecule (see arrow in the left drawing of Figure 1). [35,36] The strongest transition dipole moment in a chlorin chromophore is on the Qy axis, so parallel and slipped overlapping of the Qy axis in chlorins creates their J-aggregates, which give the above-mentioned red-shifts in the Qy absorption bands. We have previously reported that two representatives of the BChl models, zinc 3-(hydroxymethyl)-and 3-(1-hydroxyethyl)chlorins 5 [12] and 6, [22] respectively, easily form chlorosomal self-aggregates in an aqueous medium containing Triton X-100 (TX-100) as a surfactant, and that their stability and availability would be suitable for a composite molecule in an artificial lightharvesting system.…”

Section: Introductionmentioning

confidence: 99%

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Self‐Aggregation of Synthetic Zinc Chlorins Possessing a 13‐Ester‐Carbonyl Group as Chlorosomal Chlorophyll Models

Kunieda

Tamiaki

2006

Eur J Org Chem

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We have synthesized zinc 31‐hydroxychlorins 1–4 possessing a methoxycarbonyl group at the 13‐position by modifying naturally occurring chlorophyll‐a. Synthetic zinc chlorins 1–4 have three specific substituents, namely 31‐OH, central Zn and 13‐C=O moieties, along the Qy axis, and 1–3 self‐aggregate in an aqueous medium containing Triton X‐100, as do natural bacteriochlorophylls in the main light‐harvesting antennas (chlorosome) of green photosynthetic bacteria. The 13‐methoxycarbonyl group in 1–3 is a prerequisite for such self‐aggregation, while the other methoxycarbonyl groups at the 151‐ and/or 172‐positions are not. This indicates that such a linear situation of these substituents is significant for chlorosomal self‐aggregation of chlorophyllous pigments and also that the 13‐methoxycarbonyl group is an alternative to the 13‐keto‐carbonyl group in natural pigments. Furthermore, the resulting oligomers of 1–3 have fluorescence emission peaks at less than 700 nm, which are considerably more blue‐shifted than previously prepared self‐aggregates of chlorins possessing the 13‐keto‐carbonyl group fixed onto an exo five‐membered ring, and are a new class of artificial light‐harvesting systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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Section: Oligomeric States Of Zinc Chlorins 1-3: the 13-methoxycarbonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self‐Aggregation of Synthetic Zinc Chlorins Possessing a 13‐Ester‐Carbonyl Group as Chlorosomal Chlorophyll Models

Kunieda

Tamiaki

2006

Eur J Org Chem

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“…[7] Since our initial report, [5] Tamiaki's group, using an elegant synthesis, have implemented the same design principles to obtain the self-assembling octaethylporphyrin-derived porphyrin 17-Zn. [8] The authors rightly argue that 17-Zn, possessing only alkyl substituents, is more closely related than the meso-aryl-substituted porphyrins 12-ZnϪ16-Zn to the natural BChls. If practical applications are envisaged, [9] however, our compounds require fewer synthetic steps and so are more easily available, although octaethylporphyrin is a commercially available compound.…”

Section: Introductionmentioning

confidence: 99%

“…As judged from the broad, red-shifted absorption spectra, structurally very similar self-assembly patterns were obtained from 12-Zn, 13-Zn, 14-Zn, and 17-Zn. [5,8] These four compounds each have the hydroxy group (originating either from an achiral hydroxymethyl or from a 1-hydroxyethyl group), the zinc atom, and the carbonyl group arranged collinearly. A very intriguing result is that the isomeric zinc porphyrin 18-Zn failed to give red-shifted and broad absorption spectra upon self-assembly, which led the authors to speculate that collinearity of these three groups is an essential condition for the self-assembly to occur.…”

Section: Introductionmentioning

confidence: 99%

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

Balaban¹,

Linke‐Schaetzel²,

Bhise³

et al. 2004

Eur J Org Chem

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Novel porphyrins and chlorins that self-assemble in nonpolar solvents in a manner similar to that of the bacteriochlorophylls c, d, and e have been synthesized by a common protective group approach. The supramolecular assemblies have broad and red-shifted absorption spectra in comparison to those of the monomeric building blocks. The presence of a carbonyl group in conjugation with the tetrapyrrolic macrocycle produces green colors both in the free bases and in their zinc complexes, which, after self-assembly, are thus perfect artificial mimics of the chlorosomal antennas encountered in green photosynthetic bacteria. Enantiopure building blocks produce large helical aggregates with M or P helicity determined by the chirality of the 1-hydroxyethyl substituent. It is demonstrated that the groups essential for self-or- IntroductionThe ubiquitous green color of light-harvesting apparata is encountered in (bacterio)chlorophyll-based photosynthetic organisms. In conjunction with other pigments, such as carotenoids, the light absorption characteristics, which include broad wavelength ranges and high extinction coefficients, have been optimized during evolution in order to ensure conversion of light into biochemical energy by adaptation to different habitats. Thus, bacteria that live under the water surface at depths of over 50 m have evolved antenna systems different to those of bacteria or algae living at the surface, and these differ in turn from terrestrial plants in their light-harvesting systems. While the last, more highly evolved, of these species have developed protein complexes to bind chromophores, in the early green photosynthetic bacteria, due to the pressures of synthetic and genetic economy, self-assembly of bacteriochlorophylls c, d, and e (Figure 1) is used. [1,2] This much simpler architectural construct, which is fully functional, is worth mimicking [a] Forschungszentrum Karlsruhe,

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“…The self-assembly algorithm programmed within chlorosomes could be reproduced with completely artificial pigments (18)(19)(20)(21)(22), that lends hope that it can be used in solid-state devices such as hybrid solar cells (23,24). This would enable efficient light capturing and operation also under lowlight illumination conditions.…”

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confidence: 99%

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

Jochum

Reddy

Eichhöfer

et al. 2008

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

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Bacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding interaction between the 3 1 hydroxyl group and the 13 1 carbonyl group. We have synthesized different self-assemblies of BChl c mimics having the same functional groups as the natural counterparts, that is, a hydroxyethyl substituent, a carbonyl group and a divalent metal atom ligated by a tetrapyrrole. These artificial BChl mimics have been shown by single crystal x-ray diffraction to form extended stacks that are packed by hydrophobic interactions and in the absence of hydrogen bonding. Time-resolved photoluminescence proves the ordered nature of the self-assembled stacks. FT-IR spectra show that on self-assembly the carbonyl frequency is shifted by Ϸ30 cm ؊1 to lower wavenumbers. From the FT-IR data we can infer the proximal interactions between the BChls in the chlorosomes consistent with a single crystal x-ray structure that shows a weak electrostatic interaction between carbonyl groups and the central zinc atom. chlorosome model ͉ crystal structure ͉ FT-IR ͉ light-harvesting ͉ time-resolved fluorescence

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Self-aggregation of synthetic zinc 21-hydroxy-121/131-oxo-porphyrins

Cited by 55 publications

References 32 publications

Self‐Aggregation of Synthetic Zinc Chlorins Possessing a 13‐Ester‐Carbonyl Group as Chlorosomal Chlorophyll Models

Self‐Aggregation of Synthetic Zinc Chlorins Possessing a 13‐Ester‐Carbonyl Group as Chlorosomal Chlorophyll Models

Green Self‐Assembling Porphyrins and Chlorins as Mimics of the Natural Bacteriochlorophylls c, d, and e

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

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