Association Behavior of Protoporphyrin IX in Water and Aqueous Poly(<i>N</i>-vinylpyrrolidone) Solutions. Interaction between Protoporphyrin IX and Poly(<i>N</i>-vinylpyrrolidone)

Inamura, Isamu; Uchida, Kazutomo

doi:10.1246/bcsj.64.2005

Cited by 42 publications

(26 citation statements)

References 3 publications

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“…A value ranging between 4.8 and 5.7 has been reported for the propionate groups in hemin, 31 while the pK a for 3-phenylpropanoic acid is 4.37. 32 In agreement with previous investigations, 10 at pH above 8, the spectroscopic data suggest the presence of a face-to-face dimer. In particular, the emission features are similar to those reported for dimers of other protoporphyrin IX derivatives.…”

Section: Discussionsupporting

confidence: 87%

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: Discussionsupporting

confidence: 87%

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

et al. 2002

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“…This indicates the presence of different intermolecular interactions and conformation of porphyrins, probably due to the formation of aggregates. These results are according to those reported by Inamura et al [37] and Scolaro et al [38], which have studied the stability of the protoporphyrin-IX and 500 nm, as it was also observed in our studies for the anionic micelles. This behavior was explained by the formation of dimers of porphyrin, which are bonded by axial interactions of stacking p-p and by strong lateral hydrophobic "edge-to-edge."…”

Section: Spectroscopic Studies Of Porphyrins Derivatives In Micro-hetsupporting

confidence: 94%

“…This suggests that probably the hydrophobic interaction between the nonpolar chain of the ionic surfactant and the porphyrin is the main type of supramolecular contact. This monomeric form observed in more acidic media is associated to the efficient protonation of pyrrolic nitrogens, which are inside the porphyrin ring [37]. In our study, it was also observed a better solubility of the monomeric form of protoporphyrin-IX derivatives by anionic micelles with higher acidity.…”

Section: Spectroscopic Studies Of Porphyrins Derivatives In Micro-hetsupporting

confidence: 78%

Photophysical properties of porphyrin derivatives: Influence of the alkyl chains in homogeneous and micro-heterogeneous systems

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et al. 2015

J. Porphyrins Phthalocyanines

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This work is focused on the evaluation of the photophysical properties of protoporphyrin-IX derivatives with different alkyl chains. The goal of this work is to understand the physicochemical properties and select prototypes of photosensitizers for photodynamic therapy. Solvents with different dielectric constants were used to obtain relevant data on different physical and chemical processes, such as fluorescence quantum yield and emission level of aggregation in nonpolar media. In addition, studies were conducted in micro-heterogeneous systems through the interaction of porphyrin derivatives with different surfactants, such as cetyltrimethylammonium bromide, sodium dodecyl sulfate and octyl phenol ethoxylate. The compounds were characterized by electronic absorption spectroscopy in the ultraviolet-visible region and fluorescence emission spectroscopy. The comparative study between the different chemical environments evaluated in the present study represents a relevant contribution to the comprehension of the properties acquired by the porphyrins in different micro-heterogeneous systems, which allows us to understand various interactions that these compounds are subject in biological medium, such as the influence of the polarity of the medium in the reactivity of porphyrins with nonpolar substituents. These results show the decisive physicochemical influence of the alkyl chains on the properties of the tetraazomacrocycle porphyrin. +55 11-4996-0155 J. Porphyrins Phthalocyanines Downloaded from www.worldscientific.com by EMORY UNIVERSITY on 07/30/15. For personal use only. J. Porphyrins Phthalocyanines Downloaded from www.worldscientific.com by EMORY UNIVERSITY on 07/30/15. For personal use only.

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“…As PVP has no absorption band higher than 300 nm, reabsorption of emission by PVP cannot be responsible for this effect. However, it could be explained in terms of the occurrence of a physical quenching event, the formation of PVP-hemin and PVP-H 2 O 2 complexes, or less effective contact of the reactants in the heterogeneous condition (21)(22)(23). On the other hand, irradiation has no effect on the emission profile (Fig.…”

Section: Discussionmentioning

confidence: 98%

Studies on PVP hydrogel‐supported luminol chemiluminescence: 1. Kinetic and mechanistic aspects using multivariate factorial analysis

et al. 2006

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Association Behavior of Protoporphyrin IX in Water and Aqueous Poly(N-vinylpyrrolidone) Solutions. Interaction between Protoporphyrin IX and Poly(N-vinylpyrrolidone)

Cited by 42 publications

References 3 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

Photophysical properties of porphyrin derivatives: Influence of the alkyl chains in homogeneous and micro-heterogeneous systems

Studies on PVP hydrogel‐supported luminol chemiluminescence: 1. Kinetic and mechanistic aspects using multivariate factorial analysis

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