Aggregation in water solutions of tetrasodium diprotonated meso-tetrakis(4-sulfonatophenyl)porphyrin

Ribó, Josep M.; Crusats, Joaquim; Farrera, Joan‐Anton; Valero, M. Luz

doi:10.1039/c39940000681

Cited by 265 publications

(264 citation statements)

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“…An optical and topographic resolution of about 100 and 160 nm, respectively, with an optical contrast C ) 18% is derived. sulfonatophenyl)porphine (TPPS), [24][25][26][27][28] which under strong acidic conditions form extended J-aggregates. Several investigators have pointed out that coplanarity is a prerequisite for the initial dimerization step, together with the presence of negatively charged groups on the periphery.…”

Section: Discussionmentioning

confidence: 99%

Aggregation Behavior of Protoporphyrin IX in Aqueous Solutions: Clear Evidence of Vesicle Formation

et al. 2002

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The aggregation behavior of protoporphyrin IX in aqueous solution, as a function of pH and ionic strength, has been studied by means of UV/vis, fluorescence emission spectroscopy, and resonant light scattering (RLS) techniques. Our experimental results agree with previous literature assignments: (i) protoporphyrin IX is a monomer in the pH range 0-3, (ii) a dimer is present for pH > 8, and (iii) higher aggregates are present in the pH range 3-7. Addition of sodium chloride up to 0.3 M to a porphyrin solution at pH 12 gives a process resembling a phase transition, whereas it has little effect on acidic or neutral solutions. The apparent split Soret band observed in the intermediate pH range has been explained using a model in which dimers of porphyrins (with a slip angle R ) 38°or 52°, as derived from depolarized RLS measurements) are the basic units and they interact axially through π-π stacking and laterally by edge-to-edge hydrophobic contacts. The half neutralization of the carboxylic acid side chains is responsible for the occurrence of a network of intermolecular hydrogen bonds, which contribute to a better stabilization of the supramolecular assembly. Evaporation on a glass surface of solutions containing protoporphyrin IX aggregates from samples at intermediate pH leads to aggregates stable enough to be investigated for the first time through scanning electron (SEM) and scanning near-field optical microscopy (SNOM). These species evidence a prolate shape with an average size of 200-500 nm and a medium height of 60 nm, which is in agreement with the hydrodynamic radii as measured in solution by dynamic light scattering. On consideration of the amphiphilic character of protoporphyrin IX, these observations suggest the formation of multilamellar or onion-like vesicles. The analysis of the SNOM images points to the presence of regions in which the aggregation process resulted in a thin film covering the vesicles. An analysis of SEM experiments reveals also the contemporary presence of large regions in which the vesicles collapse in a continuum layered structure.

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Section: Discussionmentioning

confidence: 99%

Aggregation Behavior of Protoporphyrin IX in Aqueous Solutions: Clear Evidence of Vesicle Formation

et al. 2002

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“…2−9 Much of this effort has been focused on water-soluble meso-tetra(4-sulfonatophenyl)porphyrin (TPPS). Ribóet al 6 investigated aqueous solutions thereof spectroscopically. In studies performed at various concentrations and pH values, they found evidence for the formation of small J (edge-to-edge) and H (face-to-face) aggregates.…”

Section: ■ Introductionmentioning

confidence: 99%

Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

et al. 2016

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ABSTRACT:We have combined ion mobility mass spectrometry with quantum chemical calculations to investigate the gasphase structures of multiply negatively charged oligomers of mesotetra(4-sulfonatophenyl)metalloporphyrins comprising the divalent metal centers Zn II , Cu II , and Pd II . Sets of candidate structures were obtained by geometry optimizations based on calculations at both the semiempirical PM7 and density functional theory (DFT) levels. The corresponding theoretical cross sections were calculated with the projection approximation and also with the trajectory method. By comparing these collision cross sections with the respective experimental values we were able to assign oligomer structures up to the tetramer. In most cases the cross sections of the lowest energy isomers predicted by theory were found to agree with the measurements to within the experimental uncertainty (2%). Specifically, we find that for a given oligomer size the structures are independent of the metal center but depend strongly on the charge state. Oligomers in low charge states with a correspondingly larger number of sodium counterions tend to form stacked, cofacial structures reminiscent of H-aggregate motifs observed in solution. By contrast, in higher charge states, the stack opens to form coplanar structures. ■ INTRODUCTIONMetalloporphyrins constitute the reactive centers in a large number of biochemical systems such as hemoglobin, myoglobin, and chlorophyll. As a consequence, they are wellstudied in condensed phase. 1 It is also well-known that porphyrins and metalloporphyrins can self-assemble into larger oligomers in solution. This aggregation has attracted considerable interest, especially for porphyrins functionalized with highly polar groups such as sulfonic acids. 2−9 Much of this effort has been focused on water-soluble meso-tetra(4-sulfonatophenyl)porphyrin (TPPS). Ribóet al. 6 investigated aqueous solutions thereof spectroscopically. In studies performed at various concentrations and pH values, they found evidence for the formation of small J (edge-to-edge) and H (face-to-face) aggregates. The light scattering measurements of Micali et al. 10 have in fact suggested that even larger mesoscopicself-similar clusters of TPPS J-aggregates may form in solution. More recently, Hollingsworth et al. 9 have investigated the aggregation of TPPS in aqueous solution using UV−vis and fluorescence spectroscopy, small-angle X-ray scattering, analytical ultracentrifugation, and transmission electron microscopy. They inferred stacks of ring structures containing typically 25 monomeric units.TPPS oligomers as well as aggregates of the corresponding metalloporphyrins, MTPPS, can also be prepared and studied in gas phase, i.e., in the absence of solvent molecules. For example, multiply negatively charged aggregates of MTPPS (also containing sodium counterions) can be generated by electrospray ionization (ESI) and detected with mass spectrometry. To what extent such isolated aggregates can also provide an indirect measure of aggregatio...

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“…The resulting new zwitterionic species (Figure 1b) form J-aggregates, as is evident from the appearance of new absorption bands in the optical spectra. [21][22][23] Specifically, the monomeric absorption peak at around 434 nm (B or, so-called, Soret band) and peaks in the range of 500-650 nm (Q bands) transform into much narrower red-shifted peaks at 490 and 709 nm, respectively, which has been attributed to the appearance of extended excited states [21][22][23] shared by a number of TPPS 4 monomers.…”

Section: Introductionmentioning

confidence: 99%

Exciton Spectra and the Microscopic Structure of Self-Assembled Porphyrin Nanotubes

et al. 2009

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Exciton spectra and the microscopic structure of self-assembled porphyrin nanotubes Vlaming, S. M.; Augulis, R.; Stuart, M. C. A.; Knoester, J.; van Loosdrecht, P. H. M. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands ReceiVed: September 16, 2008; ReVised Manuscript ReceiVed: December 11, 2008 The optical properties of tubular aggregates formed by self-assembly of zwitterionic meso-tetra(4-sulfonatophenyl)porphyrin (TPPS 4 ) molecules are studied through a combination of experimental and theoretical techniques. The interest in these systems, with diameters of 18 nm and lengths extending up to micrometers, derives from their strong interaction with light and their similarity to natural light-harvesting systems for photosynthesis. The absorption and linear dichroism spectra are obtained in the spectral region from 300 to 750 nm, which includes the exciton bands deriving from the molecular B (Soret) as well as the Q transitions. We demonstrate that a Frenkel exciton model which takes into account the four dominant molecular excited states (B x , B y , Q x , and Q y ) provides a good global fit to the experimental spectra. From comparison between theory and experiment, we propose a detailed molecular structure within the nanotube.

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Aggregation in water solutions of tetrasodium diprotonated meso-tetrakis(4-sulfonatophenyl)porphyrin

Abstract: The title porphyrin shows non ideal cmc with formation of J-aggregates, due to the formation of intermolecularly stabilized zwitterions, which at high concentration also results in H-aggregates.

Cited by 265 publications

References 17 publications

Aggregation Behavior of Protoporphyrin IX in Aqueous Solutions: Clear Evidence of Vesicle Formation

Aggregation Behavior of Protoporphyrin IX in Aqueous Solutions: Clear Evidence of Vesicle Formation

Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

Exciton Spectra and the Microscopic Structure of Self-Assembled Porphyrin Nanotubes

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