Self-Assemblies of Novel Magnesium Porphyrins Mimicking Natural Chlorosomal Bacteriochlorophylls

Szmytkowski, Jędrzej; Conradt, Jonas; Kuhn, Hendrik; Reddy, C. Malla; Balaban, Mihaela Carmen; Balaban, Teodor Silviu; Kalt, H.

doi:10.1021/jp112244m

Cited by 16 publications

(7 citation statements)

References 43 publications

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“…Mimicking biological processes, which occur in living systems, is of great current interest. In this regard, synthetic metalloporphyrin assemblies have been widely studied because they are key functional systems for many biochemical processes. − Porphyrins and their metal complexes are important building blocks for self-organization of highly ordered assemblies that have different dimensionality and topology (1D, 2D, and 3D structures) because of their unique structural and coordination properties, thermal and chemical robustness, and rich physicochemical properties. − It is not easy to predict how exactly molecular building blocks will assemble in the solid state, but some tuning can be made by changing the peripheral functional groups, the ligand topology, and the nature of the metal center. The majority of known porphyrin self-assemblies have been formed from zinc porphyrins possessing nitrogen/oxygen-donor functional groups at the meso - or β-pyrrole positions of the macrocycle.…”

Section: Introductionmentioning

confidence: 99%

Unusual Formation of a Stable 2D Copper Porphyrin Network

et al. 2013

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Copper(II) 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin was obtained and characterized by means of cyclic voltammetry, electron paramagnetic resonance, Fourier transform infrared, and UV-visible spectroscopy. Three crystalline forms were grown and studied by means of X-ray diffraction methods (single crystal and powder). The highly electron-withdrawing effect of phosphoryl groups attached directly to the porphyrin macrocycle results in a self-assembling process, with formation of a stable 2D coordination network, which is unusual for copper(II) porphyrins. The resulting 2D structure is a rare example of an assembly based on copper(II) porphyrins where the copper(II) central metal ion is six-coordinated because of a weak interaction with two phosphoryl groups of adjacent porphyrins. The other polymorph of copper(II) 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin contains individual (isolated) porphyrin molecules with four-coordinated copper(II) in a distorted porphyrin core. This polymorph can be obtained only by slow diffusion of a copper acetate/methanol solution into solutions of free base 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin in chloroform. It converts to the 2D structure after dissolution in chloroform followed by consecutive crystallizations, using slow diffusion of hexane. A six-coordinated copper(II) porphyrin containing two axially coordinated dioxane molecules was also obtained and characterized by X-ray diffraction crystallography. The association of copper(II) 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin in solution was also studied.

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Section: Introductionmentioning

confidence: 99%

Unusual Formation of a Stable 2D Copper Porphyrin Network

et al. 2013

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“…In recent years, extensive efforts have been made to prepare photoactive nanomaterials to simulate natural photosynthesis for converting solar energy into clean storable energy. − In nature, a self-assembled structure of chlorophyll (a magnesium-containing porphyrin compound) and protein plays a key role in light harvesting, electron transportation, and energy conversion in the process of photosynthesis. , Recently, many porphyrin supramolecular structures have been synthesized by self-assembly through one or more noncovalent bond interactions (π–π stacking, hydrogen bond, metal coordination, etc. ). − Due to their long-range orderly stacked structures, self-assembled porphyrin nanomaterials usually exhibit strong light absorption capability and enhanced photocatalytic activity.…”

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confidence: 99%

Self-Assembled Porphyrin Nanoleaves with Unique Crossed Transportation of Photogenerated Carriers to Enhance Photocatalytic Hydrogen Production

et al. 2021

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The preparation of self-assembled porphyrins with orderly stacked nanostructures for emulating natural photosynthesis has stimulated extensive efforts to optimize the energy conversion efficiency. However, the elucidation of how orderly stacked structures promote photocatalysis at the molecular level remains a great challenge. Here, unique porphyrin nanoleaves with designed and ordered structure are synthesized and show a hydrogen evolution rate higher than that of commercial powder. Photodeposition of cocatalysts and Kelvin probe force microscopy measurement suggest selective aggregation of photogenerated electrons and holes at different active sites. Combined with theoretical calculations, we find that the orderly packing changes molecular symmetry and induces a molecular dipole, which increases linearly along the π–π stacking direction and forms a strong built-in electric field. The built-in electric field drives photogenerated electrons and holes for the unique crossed transportation along different directions. These findings reveal how orderly stacked structures promote photocatalysis and provide a novel approach for highly efficient water splitting.

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“…Magnesium analogs of 5 and 6 have also been synthesized and their photophysical properties were investigated. 20 One important difference between Mg and Zn metallated tetrapyrroles resides in the fact that the Mg ion is never four-coordinate, usually having one apical ligand. In strongly coordinating solvents it may even become six-coordinate.…”

Section: Single Crystal Diffraction Studiesmentioning

confidence: 99%

Water coordinated zinc dioxo-chlorin and porphyrin self-assemblies as chlorosomal mimics: variability of supramolecular interactions

Jesorka

Holzwarth

Eichhöfer

et al. 2012

Photochem Photobiol Sci

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Semisynthetic zinc chlorins are shown for the first time to self-assemble in the absence of an intrinsic hydroxy group, which is always present in the chlorosomal bacteriochlorophylls (BChl's) c, d and e. Instead, the presently studied compounds have carbonyl groups. These cannot function as hydrogen bond donating groups. However due to interspacing water molecules bound to the zinc ion, double hydrogen bonding can occur to adjacent tetrapyrrolic macrocycles equipped with carbonyl recognition groups. Solution studies comprising UV-Vis absorption, electronic circular dichroism (ECD) and FT-IR show that different aggregates are formed in hydrated solvents in comparison to dry nonpolar solvents. Single crystal X-ray studies show variable supramolecular interactions either with interspacing water molecules coordinating the Zn ion within a porphyrin or with the 17(2) carbonyl group of a chlorin ligating the Zn ion. Our findings have implications for a minimalistic design of self-assembling chromophores, which can act as efficient light-harvesting units.

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Self-Assemblies of Novel Magnesium Porphyrins Mimicking Natural Chlorosomal Bacteriochlorophylls

Cited by 16 publications

References 43 publications

Unusual Formation of a Stable 2D Copper Porphyrin Network

Unusual Formation of a Stable 2D Copper Porphyrin Network

Self-Assembled Porphyrin Nanoleaves with Unique Crossed Transportation of Photogenerated Carriers to Enhance Photocatalytic Hydrogen Production

Water coordinated zinc dioxo-chlorin and porphyrin self-assemblies as chlorosomal mimics: variability of supramolecular interactions

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